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JP2012002797A - Radar apparatus - Google Patents
Radar apparatus Download PDF
carrier frequencies
Osamu Sato
Hiroki Sugawara
Yukinobu Tokieda
治 佐藤
幸伸 時枝
博樹 菅原
Japan Radio Co Ltd
日本無線株式会社
2010-05-17 Priority to JP2010113023 priority
2011-02-22 Application filed by Japan Radio Co Ltd, 日本無線株式会社 filed Critical Japan Radio Co Ltd
2011-02-22 Priority to JP2011035929A priority patent/JP2012002797A/en
239000000969 carrier Substances 0 abstract 4
230000000875 corresponding Effects 0 abstract 1
Even when the frequency band allocated to the radar apparatus corresponds to the image frequency in a receiving apparatus used in another communication system, the interference given is reduced.
[Solution]
The radar device receives a pulse signal of each of a plurality of carrier frequencies in order at a predetermined cycle, and a reflected signal reflected by a target to be detected by the pulse signal transmitted from the transmitter. A time-series signal comprising: a receiving unit that receives the reflected signal received by the receiving unit; a frequency dividing unit that divides the reflected signal into a signal corresponding to each of the plurality of carrier frequencies; and a reflected signal that is divided by the frequency dividing unit And a signal synthesizer for synthesizing the signals of the plurality of carrier frequencies that have been phase-synthesized.
The present invention relates to a radar apparatus.
In recent years, depletion of frequency resources has become a problem due to the spread of various wireless communication systems. Therefore, it is required to reduce unnecessary waves (spurious) emitted outside the frequency band assigned to each communication system as much as possible so that communication failure does not occur due to interference or interference between different communication systems. Yes. Internationally, various wireless communication systems are required to achieve a strict attenuation level (such as ITU-R recommendation SM.1541). Similar to the radio communication system, the radar apparatus is required to achieve a more severe attenuation level in order to prevent interference or interference caused by unnecessary waves.
A technique for preventing interference between adjacent radar devices has already been studied (for example, Patent Document 1). However, it has not been a technique for achieving a severe attenuation level as described above. In order to meet these requirements, the development and popularization of radar devices that use solid state (solid elements), which can easily suppress spurious, from magnetrons, which are easy to obtain high-power oscillation signals but are difficult to suppress spurious. Progressing.
However, for example, when using a magnetron in a ship radar, a transmission power of several tens of kilometers [W] is obtained, whereas when using a solid state, only a few hundred [W] can be obtained. In general, the radar apparatus has a short search distance when the peak value of the transmission power is low. Therefore, the radar apparatus using the solid state has a short search distance.
Therefore, the decrease in search performance caused by the decrease in transmission power that occurs when the magnetron is changed to the solid state is compensated by combining the signal transmission time and the pulse compression processing. This achieves a strict attenuation level against spurious and maintains search performance.
However, in other communication systems that use a frequency band adjacent to a frequency band allocated for use of a radar device (hereinafter referred to as a radar band), even though the attenuation level against spurious is satisfied, A signal transmitted from the device may cause interference due to interference or interference.
In general, a receiving apparatus used in a communication system performs demodulation and decoding by down-converting a received signal in a frequency band assigned to the communication system to an intermediate frequency or a baseband frequency. At this time, when the relationship between the radar band, the frequency band of the communication system, and the local oscillation frequency used for down-conversion by the receiving apparatus of the communication system is as follows, the above-described communication failure may occur.
FIG. 10 is a diagram illustrating an example of frequency band allocation and local oscillation frequency in the reception device when a communication failure occurs. As shown in FIG. 10 (a), the frequency band from frequencies F 1 to the frequency F 2 is assigned to radar band, the frequency band from the frequency F 3 until the frequency F 4 are assigned to other communication systems, communication A case where the local oscillation frequency F Lo in the receiving apparatus of the system is set between the frequency F 2 and the frequency F 3 will be described.
FIG. 10B is a diagram illustrating a frequency band of a signal obtained by down-conversion by the receiving apparatus when the frequency allocation as illustrated in FIG. 10A is performed. A desired signal in a frequency band from frequency F 3 to frequency F 4 allocated to the communication system is down-converted and a signal in a frequency band from frequency (F 3 -F Lo ) to frequency (F 4 -F Lo ). Is converted to In addition, signals in the radar band from the frequency F 1 to the frequency F 2 including the image frequency that are lower than the local oscillation frequency F Lo are also frequencies from the frequency (F Lo −F 1 ) to the frequency (F Lo −F 2 ). It is converted into a band signal.
Thus, the pulse signal transmitted from the radar device appears as an image signal to any one of the frequency (F Lo -F 1) up to a frequency (F Lo -F 2), from the frequency (F 3 -F Lo) It overlaps with the frequency band up to the frequency (F 4 -F Lo ). At this time, the pulse signal transmitted from the radar apparatus may cause interference due to interference or interference in communication in the communication system.
That is, depending on the setting of the local oscillation frequency used in the receiving device of another communication system, the signal in the radar band becomes an image signal that overlaps the signal in the communication system. Will be caused. On the other hand, a receiving apparatus used in a communication system usually has a function of suppressing an image frequency signal so as to suppress interference caused by an image frequency signal.
However, when the reception device and the radar device are close to each other, the reception device cannot sufficiently suppress the image frequency signal when the reception power of the signal transmitted from the radar device is significantly higher than the reception power of the desired signal. The desired signal may not be demodulated and decoded.
In addition, when switching from magnetron to solid state in a radar device, the transmission time is extended to compensate for the decrease in search capability due to a decrease in transmission power, so that interference generated in the receiver of the communication system may appear more prominently. There is.
The present invention has been made in view of the above situation, and an object thereof is a case where a frequency band allocated to a radar apparatus corresponds to an image frequency in a receiving apparatus used in another communication system. Another object of the present invention is to provide a radar device that can reduce interference or interference.
In order to solve the above problem, the present invention provides a transmission unit that sequentially transmits pulse signals of a plurality of carrier frequencies at a predetermined period, and a target that is a detection target of the pulse signal transmitted from the transmission unit. A receiving unit that receives the reflected signal reflected by the receiving unit, a frequency dividing unit that divides the reflected signal received by the receiving unit into a signal corresponding to each of the plurality of carrier frequencies, and the frequency dividing unit. A radar comprising: a signal synthesizing unit that synthesizes a time-series signal composed of reflected signals for each of the plurality of carrier frequencies, and further synthesizes the phase-synthesized signals of the plurality of carrier frequencies. Device.
Further, in the present invention according to the above invention, the signal synthesis unit may determine a predetermined number of signals obtained by performing orthogonal detection on the reflected signal divided by the frequency division unit for each of the plurality of carrier frequencies. Phase-synthesizing unit that adds and outputs phases over the transmission period of the signal, and phase-shifts the signals for each of the plurality of carrier frequencies output from the phase-synthesizing unit for each combination of a plurality of predetermined phase-shift amounts. And an inter-frequency signal synthesizer that selects and outputs the largest addition result among the addition results for each of the combinations of the plurality of phase shift amounts.
Further, the present invention is the above invention, wherein the signal synthesizer has the most power among the frequency spectrum obtained by Fourier transform with respect to the reflected signal divided by the frequency divider for each of the plurality of carrier frequencies. A phase synthesis unit that selects and outputs a signal corresponding to a large frequency spectrum, and for each combination of a plurality of predetermined phase shift amounts, the signals for each of the plurality of carrier frequencies output from the phase synthesis unit. And an inter-frequency signal synthesizer that selects and outputs the largest addition result among the addition results for each of the combinations of the plurality of phase shift amounts.
Furthermore, the present invention provides a transmitter that sequentially transmits pulse signals of each of a plurality of carrier frequencies at a predetermined period, and a reflected signal that is reflected by a target that is a pulse signal transmitted from the transmitter. A time division unit that divides the reflected signal received by the reception unit for each predetermined period, and a time-series signal that includes the reflected signal divided by the time division unit. And a signal synthesizing unit that synthesizes the signals of the plurality of carrier frequencies and further synthesizes the synthesized signals over a plurality of the predetermined periods.
Also, in the present invention according to the above invention, the signal synthesis unit shifts the phase of each of the signals for each of the plurality of carrier frequencies output from the time division unit for each combination of a plurality of predetermined phase shift amounts. And the inter-frequency signal synthesizer that selects and outputs the largest addition result among the addition results for each of the combinations of the plurality of phase shift amounts, and is output from the inter-frequency signal synthesizer. And a combining unit that adds and outputs the signals.
Further, the present invention is the above invention, wherein the signal synthesizer has the most power among the frequency spectrum obtained by Fourier transform with respect to the reflected signal divided by the time division unit for each of the plurality of carrier frequencies. A signal combining unit that selects and outputs a signal corresponding to a large frequency spectrum, and a combining unit that adds and outputs a signal output from the signal combining unit between different frequencies To do.
Further, according to the present invention, in the above invention, the frequency interval between the plurality of carrier frequencies is set according to a frequency interval of channel assignment in a communication system in which a frequency band assigned to the own device appears as an image frequency. It is characterized by.
Also, in the present invention according to the above invention, the transmission time of the pulse signal at each of the plurality of carrier frequencies is a burst error duration that can be corrected in a communication system in which the frequency band assigned to the device is displayed as an image frequency. It is characterized by being set accordingly.
According to this invention, even if the pulse signal transmitted from the radar apparatus corresponds to the image frequency in the receiving apparatus used in another communication system, it is possible to reduce interference or interference.
It is a schematic block diagram which shows the structure of the radar apparatus 1 in 1st Embodiment. 3 is a diagram illustrating an example of a sequence of pulse signals transmitted by a transmission unit 11. FIG. It is a figure which shows the image of the frequency characteristic of a pulse signal transmitted by the transmission part 11, and an amplitude characteristic. It is a schematic block diagram which shows the structure of the signal synthetic | combination part 171a between PRI in 1st Embodiment. It is a schematic block diagram which shows the structure of the different frequency signal synthetic | combination part 175 in 1st Embodiment. It is a schematic diagram which shows the process of the different frequency signal synthetic | combination part 175 in 1st Embodiment. It is a schematic diagram which shows the outline | summary of the process in the radar apparatus 1 of 1st Embodiment. It is a schematic block diagram which shows the structure of the signal synthetic | combination part 271a between PRI comprised with the radar apparatus in 2nd Embodiment. It is a figure which shows an example of the setting of the carrier wave frequency f1, f2, and f3 in 1st and 2nd embodiment. It is a figure which shows an example of allocation of the frequency band in case a communication failure generate | occur | produces, and the local oscillation frequency in a receiver. It is a schematic block diagram which shows one structure of the radar apparatus 3 in 3rd Embodiment. It is a schematic block diagram which shows the structure of the different frequency signal synthetic | combination part 371a in 3rd Embodiment. It is a schematic diagram which shows the process of the different frequency signal synthetic | combination part 371a in 3rd Embodiment. It is a schematic block diagram which shows the structure of the signal synthetic | combination part 376 between PRI in 3rd Embodiment. It is a schematic diagram which shows the outline | summary of the process in the radar apparatus 3 of 3rd Embodiment. It is a schematic block diagram which shows the structure of the different frequency signal synthetic | combination part 471a with which the radar apparatus in 4th Embodiment is equipped.
Hereinafter, a radar apparatus according to an embodiment of the present invention will be described based on four embodiments with reference to the drawings.
All of the radar devices according to the four embodiments described below have a transmission unit that transmits pulse signals in order of different carrier frequencies f1, f2, and f3 in a predetermined cycle, and a pulse signal transmitted from the transmission unit is a detection target. And a receiving unit that receives a reflected signal reflected by the target. In each embodiment, the way of dividing and synthesizing the reflected signal received by the receiving unit is different.
FIG. 1 is a schematic block diagram illustrating a configuration of a radar apparatus 1 according to the first embodiment. As shown in the figure, the radar apparatus 1 includes a transmission unit 11, an antenna 12, a reception unit 13, an A / D (Analog / Digital) conversion unit 14, a frequency division unit 15, a signal storage unit 16, and a signal. A synthesis unit 17 and an output processing unit 18 are provided.
The transmission unit 11 transmits pulse signals via the antenna 12 in the order of different carrier frequencies f1, f2, and f3 determined in advance. That is, the transmission unit 11 transmits a pulse signal by performing frequency hopping to change the carrier frequency. Here, the carrier wave frequencies f1, f2, and f3 are set using the fact that the amount of frequency phase shift due to reflection from the object to be detected (target target) is proportional to the frequency interval. Specifically, it is set so that f2 = f1 + Δf and f3 = f1 + 2 × Δf. Further, the pulse signal transmitted from the transmitter 11 may be a chirp pulse in which the frequency is linearly drawn.
The pulse signal transmitted by the transmission unit 11 will be described with reference to FIGS. FIG. 2 is a diagram illustrating an example of a series of pulse signals transmitted by the transmission unit 11. In the figure, the horizontal axis indicates time, and the vertical axis indicates transmission power. As shown in FIG. 2, the transmission unit 11 according to the present embodiment transmits a pulse signal that is predetermined by three different carrier frequencies f1, f2, and f3 in each pulse signal transmission period (PUL). Transmit continuously for time Trx. The transmission time of each of the carrier frequencies f1, f2, and f3 is, for example, time (Trx / 3). Here, the transmission time Trx is a transmission time of a pulse signal required to satisfy search performance required for detecting an object.
FIG. 3 is a diagram illustrating an image of frequency characteristics and amplitude characteristics of a pulse signal transmitted by the transmission unit 11. FIG. 3A shows the frequency characteristics of the pulse signal. The horizontal axis indicates time, and the vertical axis indicates frequency. As shown in FIG. 3A, in each PRI, pulse signals are transmitted by switching carrier frequencies in the order of carrier frequencies f1, f2, and f3. FIG. 3B shows the amplitude characteristics of the pulse signal. The horizontal axis indicates time, and the vertical axis indicates the maximum value of the amplitude (peak value, peak value). As shown in FIG. 3B, transmission is performed so that the maximum value of the amplitude of the pulse signal transmitted at each carrier frequency is the same.
Returning to FIG. 1, the receiving unit 13 receives, via the antenna 12, a reflected signal in which the pulse signal transmitted from the antenna 12 is reflected by the target to be detected. The A / D converter 14 performs analog-digital conversion on the reflected signal received by the receiver 13 and outputs the reflected signal to the frequency divider 15. The frequency dividing unit 15 divides the reflected signal digitized by the bandpass filter having the carrier frequencies f1, f2, and f3 as center frequencies into signals of three frequency bands.
The signal storage unit 16 stores the signal divided into three by the frequency dividing unit 15 for each corresponding carrier frequency. Specifically, the signal storage unit 16 includes a first signal storage unit 161a, a second signal storage unit 161b, and a third signal storage unit 161c. The first signal storage unit 161a stores a signal in a frequency band corresponding to the carrier frequency f1. Similarly to the first signal storage unit 161a, the second signal storage unit 161b and the third signal storage unit 161c store signals in frequency bands corresponding to the carrier frequency f2 and the carrier frequency f3. The first signal storage unit 161a, the second signal storage unit 161b, and the third signal storage unit 161c are arranged in chronological order so that reflected signals in the PRI are processed in parallel by the signal synthesis unit 17. Store the signal.
The signal synthesizing unit 17 synthesizes a time-series signal composed of signals stored in the signal storage unit 16 over a predetermined number of PRIs and outputs the synthesized signal to the output processing unit 18. The signal synthesizer 17 further synthesizes a phase synthesizer 171 that performs phase synthesis for each of the carrier frequencies f1, f2, and f3, and a signal that is further synthesized by the phase synthesizer 171 for each of the carrier frequencies f1, f2, and f3. And an inter-frequency signal synthesizing unit 175 that outputs the signals as one signal.
The phase synthesizer 171 includes inter-PRI signal synthesizers 171a, 171b, and 171c corresponding to the carrier frequencies f1, f2, and f3, respectively. The inter-PRI signal synthesizer 171a outputs a signal corresponding to the carrier frequency f1 by coherent synthesis (phase addition) over 4 PRI. Similarly to the inter-PRI signal synthesizer 171a, the inter-PRI signal synthesizers 171b and 171c add and output signals corresponding to the carrier frequencies f2 and f3 over 4 PRIs. In other words, the phase synthesizer 171 performs Doppler filter bank processing on the signal corresponding to each carrier frequency for each carrier frequency f1, f2, and f3.
The inter-frequency signal synthesizer 175 synthesizes the signals calculated by phase addition over 4 PRI for each of the carrier frequencies f1, f2, and f3 by the inter-PRI signal synthesizers 171a to 171c. The output processing unit 18 performs further processing on the signal synthesized by the inter-frequency signal synthesizing unit 175 and outputs the processed signal. For example, processing such as conversion into a video signal for display on an externally connected display device is performed.
An example of a specific configuration of the inter-PRI signal synthesis units 171a to 171c will be described. FIG. 4 is a schematic block diagram showing the configuration of the inter-PRI signal synthesis unit 171a in the present embodiment. Since the inter-PRI signal synthesizers 171b and 171c have the same configuration as the inter-PRI signal synthesizer 171a, description thereof is omitted.
The inter-PRI signal synthesis unit 171a includes a quadrature detector 172 and accumulators 173a and 173b. The quadrature detector 172 sequentially reads out signals corresponding to the carrier frequencies f1 for four consecutive PRIs stored in the first signal storage unit 161a, sequentially performs quadrature detection on the read signals, and converts them into I and Q signals. To separate. The amplitudes of the I signal and the Q signal are the same, and the phases are different from each other by 90 degrees. In the subsequent processing, the I signal is treated as the real part of the complex number, and the Q signal is treated as the imaginary part of the complex number. The quadrature detection can be realized by, for example, a method of mixing signals of the same frequency whose phases are different from each other by 90 degrees with a signal to be detected, a method using a Hilbert filter, or the like.
The accumulator 173a adds the I signal output from the quadrature detector 172 by 4PRI and outputs the result. The accumulator 173b adds the Q signal output from the quadrature detector 172 by 4PRI and outputs the result. The inter-PRI signal synthesis unit 171a reads the signals stored in the first signal storage unit 161a over 4 PRIs as described above, in the order of PRI1 to PRI4, PRI2 to PRI5,. Phase addition is performed in which the I signal and the Q signal based on the read signal are added independently, and the signals are sequentially output.
Next, an example of a specific configuration of the inter-frequency signal synthesizing unit 175 will be described. FIG. 5 is a schematic block diagram showing the configuration of the inter-frequency signal synthesizing unit 175 in the present embodiment. As shown in the figure, the inter-frequency signal synthesizer 175 has phase shifters 176 and 177, adders 178a and 178b, and a maximum value determiner 179.
The phase shifters 176 and 177 shift the phase of the signals output from the inter-PRI signal synthesis units 171b and 171c according to a combination of a plurality of predetermined phase shift amounts, and output the signals. The adder 178a adds the I signal output from the inter-PRI signal synthesis unit 171a, the I signal output from the phase shifter 176, and the I signal output from the phase shifter 177. The adder 178b adds the Q signal output from the inter-PRI signal synthesis unit 171a, the Q signal output from the phase shifter 176, and the Q signal output from the phase shifter 177.
That is, the adders 178a and 178b add the phases of the carrier frequency f1 output from the inter-PRI signal synthesis unit 171a and the carrier frequencies f2 and f3 phase-shifted by the phase shifters 176 and 177. Maximum value determiner 179 calculates the square sum square root of the phase-added signal for each phase shift amount combination, and selects and outputs the signal having the largest square sum square root among the plurality of phase shift amount combinations.
Here, a case will be described in which a predetermined combination of a plurality of phase shift amounts is set as follows with reference to a signal corresponding to the carrier frequency f1. Set to 4 combinations of (0, 0, 0), (0, π / 2, 2π / 2), (0, 2π / 2, 4π / 2), (0, 3π / 2, 6π / 2) It is assumed that Here, (a, b, c) represents a combination of phase shift amounts, where a is the phase shift amount for the signal corresponding to the carrier frequency f1, and b is the phase shift amount for the signal corresponding to the carrier frequency f2. C is the amount of phase shift for the signal corresponding to the carrier frequency f3.
The phase shifter 176 performs phase shift amounts of 0, π / 2, 2π / 2, and 3π / 2 with respect to the I signal and the Q signal corresponding to the carrier frequency f2 synthesized by the inter-PRI signal synthesizer 171b. The phase-shifted signals are output in order. The phase shifter 177 performs phase shift amounts of 0, 2π / 2, 4π / 2, and 6π / 2 with respect to the I signal and the Q signal corresponding to the carrier frequency f3 synthesized by the inter-PRI signal synthesis unit 171c. The phase-shifted signals are output in order.
For each combination of the above phase shift amounts, the adder 178a outputs the I signal output from the inter-PRI signal synthesizer 171a, the I signal output from the phase shifter 176, and the I signal output from the phase shifter 177. Add the signal. For each combination of the above phase shift amounts, the adder 178a outputs a Q signal output from the inter-PRI signal synthesis unit 171a, a Q signal output from the phase shifter 176, and a Q signal output from the phase shifter 177. Add the signal. That is, the adders 178a and 178b perform phase addition for independently adding the phase-shifted I signal and Q signal for each combination of the above-described phase shift amounts.
The maximum value determiner 179 calculates the square sum square (amplitude) of the I signal and the Q signal added by the adders 178a and 178b for each combination of the four phase shift amounts, and calculates the four phase shift amounts. The I signal and Q signal having the largest sum of squares in the combination are selected and output.
FIG. 6 is a schematic diagram showing processing of the inter-frequency signal synthesizing unit 175 in the present embodiment. As shown in the figure, the signals corresponding to the carrier frequencies f1, f2, and f3 and output from the inter-PRI signal synthesizers 171a to 171c are subjected to phase addition in four ways. Then, the result having the largest square sum square (amplitude) is selected and output from the four phase addition results. Thereby, SNR (Signal-Noise Ratio; signal-to-noise ratio) can be improved by 2.6 times. In this embodiment, there are four combinations of phase shift amounts. However, if the number of phase shift amount combinations (phase pattern) is increased infinitely, the SNR can be improved to three times. Thus, the inter-frequency signal synthesizer 175 rotates the phase of the signals corresponding to the carrier frequencies f1, f2, and f3 to be synthesized in proportion to the difference in the carrier frequencies by combining the phase shift amounts. Then, phase addition (coherent synthesis) is performed so that the amplitude is maximized.
FIG. 7 is a schematic diagram showing an outline of processing in the radar apparatus 1 of the present embodiment. In the radar apparatus 1, as shown in the figure, the transmission unit 11 periodically transmits pulse signals in the order of the carrier frequencies f1, f2, and f3 in each PRI, and receives the reflected signal reflected by the object. To do. The received reflected signal is divided into signals corresponding to the carrier frequencies f1, f2, and f3 by the frequency dividing unit 15, and the first signal storage unit 161a and the second signal storage unit 161b provided in the signal storage unit 16 are provided. And stored in the third signal storage unit 161c.
The signals corresponding to the carrier frequencies f1 to f3 stored in the first signal storage unit 161a, the second signal storage unit 161b, and the third signal storage unit 161c are subjected to 4 PRIs by the inter-PRI signal synthesis units 171a to 171c. The phases are added, and further, the signals are combined into one signal by the inter-frequency signal combining unit 175 and output. In this way, the pulse signals transmitted at the carrier frequencies f1, f2, and f3 can be combined to improve the SNR, and the transmission time at each of the three carrier frequencies is a pulse required to satisfy the search performance. Even if the transmission time is shorter than the signal transmission time Trx, the search performance can be maintained.
Since the radar apparatus according to the second embodiment is different from the radar apparatus 1 according to the first embodiment and the inter-PRI signal synthesis units 171a to 171c included in the radar apparatus 1, different configurations will be described, and other configurations will be described. Is omitted.
FIG. 8 is a schematic block diagram illustrating a configuration of the inter-PRI signal synthesis unit 271a provided in the radar apparatus according to the present embodiment. The inter-PRI signal synthesizer 271a is provided in place of the inter-PRI signal synthesizer 171a in the first embodiment. Also, the inter-PRI signal synthesis units 271b and 271c are provided in place of the inter-PRI signal synthesis units 171b and 171c in the first embodiment, similarly to the inter-PRI signal synthesis unit 271a. Further, since the inter-PRI signal synthesis units 271b and 271c have the same configuration as the inter-PRI signal synthesis unit 271a, description thereof is omitted.
As shown in FIG. 8, the inter-PRI signal synthesizer 271a includes an FFT calculator 272 and a maximum value selector 273. The FFT computing unit 272 reads a signal corresponding to the carrier frequency f1 for four consecutive PRIs stored in the first signal storage unit 161a, and converts it into a frequency domain signal by fast Fourier transform on the read four PRI signals. . The maximum value selector 273 selects a signal having the highest power frequency among the signals in the frequency domain converted by the FFT calculator 272, and the I signal (real part) and Q signal (imaginary part) of the selected signal. Is output to the inter-frequency signal synthesizer 175.
As described above, the inter-PRI signal synthesizers 271a to 271c of the present embodiment convert the frequency domain signals by the FFT calculator 272 and synthesize them, so that the distance between the antenna 12 and the object changes. In this case, since the synthesis is performed for each frequency shifted according to the speed, the SNR can be improved over the phase addition. Further, the moving speed of the object may be detected based on the frequency shift of each of the carrier frequencies f1, f2, and f3.
Although the configuration in which the FFT calculator 272 performs the fast Fourier transform on the signal for 4 PRI has been described, a signal having an amplitude of zero is added to the signal for 4 PRI and the number of FFT points is increased to more than 4 to perform fast Fourier transform. You may make it do. Thereby, the precision of the synthesis between PRI signals can be improved.
The radar apparatus in each of the above embodiments coherently synthesizes a time-series reflected signal stored in the signal storage unit 16 for each carrier frequency over a predetermined period (PRI). Then, coherent synthesis is performed between carrier frequencies to improve the SNR of the reflected signal. Thereby, even if each of the transmission times at a plurality of carrier frequencies is shorter than the transmission time Trx of the pulse signal required to satisfy the search performance, the search performance can be maintained.
Further, in each of the above-described embodiments, the configuration in which phase addition is performed by the adders 178a and 178b for each combination of phase shift amounts in the inter-frequency signal synthesizer 175 has been described, but the phase shift is performed without performing phase addition. The sum of the amplitudes (square sum of squares) of each signal may be calculated (amplitude synthesis). In this case, the maximum value determiner 179 may select and output the sum total of the largest amplitudes among the combinations of phase shift amounts.
Further, in the inter-frequency signal synthesizing unit 175 of each of the above-described embodiments, four combinations of a plurality of predetermined phase shift amounts are used. For example, the following may be used. When there are N combinations of phase shift amounts (N is an integer of 4 or more), the phase shift amounts are (0, j × (2π / N), 2 × j × (2π / N)), (j May be set to an integer satisfying 0 ≦ j <N).
For example, when the number of phase shift amount combinations is 8 (N = 8), the phase shift amount combinations are {(0, 0, 0), (0, π / 4, 2π / 4), (0, 2π / 4, 4π / 4), (0, 3π / 4, 6π / 4), (0, 4π / 4, 8π / 4), (0, 5π / 4, 10π / 4), (0, 6π / 4,12π / 4), (0,7π / 4,14π / 4)}. At this time, the maximum value determiner 179 selects and outputs the result having the largest square root sum of squares among the eight phase addition results. Thereby, the SNR of the signal obtained by the synthesis can be further improved.
Further, in the signal synthesizer 17 of each of the embodiments described above, the case where the signal input to the signal synthesizer 17 is input to the inter-frequency signal synthesizer via the phase synthesizer 171 has been described. However, the present invention is limited to this configuration. Not. This is because the configuration of the signal synthesizer 17 is determined by how the received signal is divided after being output from the A / D converter 14.
For example, when the received signal is time-divided for each PRI without providing the frequency divider 15, the signal storage unit 16 stores the signal separately for each PRI over a predetermined number of PRIs. Since each PRI includes a different carrier frequency, it is preferable that each PRI is input to the signal synthesizing unit 17 through the inter-frequency signal synthesizing unit for each PRI, and then the signal is synthesized for each PRI and then input to the inter-PRI signal synthesizing unit. .
Thus, the signal division method for the received signal received is not limited to frequency division. Therefore, since the specific configuration of the signal synthesizer 17 should be determined in accordance with the method of dividing the received signal, the configuration of various embodiments can be made. Hereinafter, a specific implementation method when the received signal is time-divided for each PRI without providing the frequency division unit 15 will be described.
(Embodiment 3)
The radar apparatus 3 in the third embodiment is configured as shown in the schematic block diagram of FIG. The radar apparatus 3 includes a transmission unit 31, an antenna 32, a reception unit 33, an A / D conversion unit 34, a time division unit 35, a signal storage unit 36, a signal synthesis unit 37, and an output processing unit 38.
The operations of the transmission unit 31, the antenna 32, the reception unit 33, and the A / D conversion unit 34 are the same as those of the transmission unit 11, the antenna 12, the reception unit 13, and the A / D conversion of the radar apparatus 1 according to the first and second embodiments. Since it is the same as each operation | movement of the part 14, description is abbreviate | omitted here. The A / D conversion unit 34 outputs the digitized reflected signal to the time division unit 35.
The time division unit 35 divides the received signal between a predetermined number of PRIs. In the present embodiment, a case in which a received signal is divided between four PRIs (PRI1, PRI2, PRI3, PRI4) will be described. The time division unit 35 to which the received signal is input time-divides the received signal for each PRI and outputs the signal to the signal storage unit 36. The received signals divided for each PRI include different carrier frequencies f1, f2, and f3.
The signal storage unit 36 stores the data separately for each PRI. The signal storage unit 36 includes a first signal storage unit 361a, a second signal storage unit 361b, a third signal storage unit 361c, and a fourth signal storage unit 361d. The first signal storage unit 361a stores a signal corresponding to PRI1. Similar to the first signal storage unit 361a, the second signal storage unit 361b, the third signal storage unit 361c, and the fourth signal storage unit 361d send signals corresponding to PRI2, PRI3, and PRI4 to the first signal storage unit 361a. Memorize by the same configuration.
The signal combining unit 37 combines the signals stored in the signal storage unit 36 over a predetermined number of PRIs and outputs the combined signal to the output processing unit 38. The signal synthesis unit 37 includes inter-frequency signal synthesis units 371a, 371b, 371c, and 371d that synthesize signals having a plurality of carrier frequencies for each transmission period PRI1, PRI2, PRI3, and PRI4, and transmission periods PRI1, PRI2, PRI3, and PRI4. An inter-PRI signal synthesizer 376 that further adds the amplitudes of the synthesized signals and synthesizes them into one signal and outputs the resultant signal is provided.
Inter-frequency signal synthesizers 371a, 371b, 371c, and 371d synthesize signals corresponding to the transmission periods PRI1, PRI2, PRI3, and PRI4, respectively. The inter-different-frequency signal synthesizer 371a performs phase addition (coherent synthesis) between three carrier frequencies by combining a plurality of phase shift amounts of signals corresponding to PRI1 over three frequencies. To select and output the maximum value. Similarly to the inter-frequency signal synthesizer 371a, the inter-frequency signal synthesizers 371b, 371c, and 371d perform PRI2, PRI3, and PRI4 over three carrier frequencies by combining a plurality of predetermined phase shift amounts. The phase corresponding to the signal corresponding to is added and the maximum value is selected and output
The inter-PRI signal synthesizer 376 includes a combination of a plurality of phase shift amounts determined in advance between the carrier frequencies f1, f2, and f3 for each of the PRI1, PRI2, PRI3, and PRI4 by the inter-frequency signal synthesizers 371a to 371d. The signal added over the three carrier frequencies is output to the output processing unit 38.
Similar to the output processing unit 18 of the radar apparatus 1 in the first and second embodiments, the output processing unit 38 performs further processing on the signal synthesized by the inter-PRI signal synthesis unit 376 and outputs the signal. For example, processing such as conversion into a video signal for display on an externally connected display device is performed.
An example of a specific configuration of the inter-frequency signal synthesizing units 371a to 371d will be described. FIG. 13 is a schematic diagram illustrating processing of the inter-frequency signal synthesizing unit 371a in the present embodiment. FIG. 12 is a schematic block diagram showing the configuration of the inter-frequency signal synthesizer 371a in the present embodiment. Since the inter-frequency signal synthesizers 371b, 371c, 371d have the same configuration as the inter-frequency signal synthesizer 371a, description thereof is omitted.
The inter-frequency signal synthesizer 371a includes a quadrature detector 372, a phase shifter 373a, a phase shifter 373b, an adder 374a, an adder 374b, and a maximum value determiner 375. The quadrature detector 372 sequentially reads signals corresponding to the carrier frequencies f1, f2, and f3 for 1PRI stored in the first signal frequency storage unit 361a, sequentially performs quadrature detection on the read signals, and outputs the I signal and Separated into Q signals. The amplitudes of the I signal and the Q signal are the same, and the phases are different from each other by 90 degrees. In the subsequent processing, the I signal is treated as the real part of the complex number, and the Q signal is treated as the imaginary part of the complex number. The quadrature detection can be realized by, for example, a method of mixing signals of the same frequency whose phases are different from each other by 90 degrees with a signal to be detected, a method using a Hilbert filter, or the like.
The phase shifters 373a and 373b shift the phase of the signal output from the first signal storage unit 361a according to a predetermined combination of a plurality of phase shift amounts and output the phase shift signal. The adder 374a adds the f1 I signal output from the first signal storage unit 361a, the f2 I signal output from the phase shifter 373a, and the f3 I signal output from the phase shifter 373b. To do. The adder 374b adds the f1 Q signal output from the first signal storage unit 361a, the f2 Q signal output from the phase shifter 373a, and the f3 Q signal output from the phase shifter 373b. To do. The inter-frequency signal synthesizer 371a reads the signal stored in the first signal storage unit 361a over three frequencies as described above, and independently generates the I signal and the Q signal based on the read signal. The phase is added and output by a combination of a plurality of predetermined phase shift amounts.
That is, the adders 374a and 374b add the phases of f1 output from the first signal storage unit 361a and f2 and f3 phase-shifted by the phase shifters 373a and 373b. Maximum value determiner 375 calculates the square sum square root of the phase-added signal for each phase shift amount combination, and selects and outputs the signal having the largest square sum square root among the plurality of phase shift amount combinations.
Here, a case will be described in which a predetermined combination of a plurality of phase shift amounts is set as follows on the basis of a signal corresponding to PRI1. Set to 4 combinations of (0, 0, 0), (0, π / 2, 2π / 2), (0, 2π / 2, 4π / 2), (0, 3π / 2, 6π / 2) It is assumed that Here, (a, b, c) represents a combination of phase shift amounts, where a is the phase shift amount for the signal corresponding to f1, b is the phase shift amount for the signal corresponding to f2, and c is This is the amount of phase shift for the signal corresponding to f3.
The phase shifter 373a outputs a signal phase-shifted by 0, π / 2, 2π / 2, 3π / 2 with respect to the I signal and Q signal corresponding to f2 output from the quadrature detector 372. Output sequentially. The phase shifter 373b outputs a signal phase-shifted by 0, 2π / 2, 4π / 2, 6π / 2 with respect to the I signal and Q signal corresponding to f3 output from the quadrature detector 372. Output sequentially.
The adder 374a outputs the I signal of f1 output from the quadrature detector 372, the I signal of f2 output from the phase shifter 373a, and the phase shifter 373b for each combination of the above phase shift amounts. And the I signal of f3. The adder 374b outputs the Q signal of f1 output from the quadrature detector 372, the Q signal of f2 output from the phase shifter 373a, and the phase shifter 373b for each combination of the above phase shift amounts. And the Q signal of f3. That is, the adders 374a and 374b perform phase addition for independently adding the phase-shifted I signal and Q signal for each combination of the above-described phase shift amounts.
The maximum value determiner 375 calculates the square sum square (amplitude) of the I signal and the Q signal added by the adders 374a and 374b for each combination of the four phase shift amounts, and calculates the four phase shift amounts. The I signal and Q signal having the largest square sum square root in the combination are selected and output to the inter-PRI signal synthesis unit 376.
FIG. 13 is a schematic diagram illustrating processing of the inter-frequency signal synthesizing unit 371 in the present embodiment. As shown in the figure, the signals corresponding to f1, f2, and f3, which are output from the quadrature detector 372, are phase-shifted in four ways and subjected to phase addition, and four phase additions are performed. The result having the largest square root (amplitude) is selected and output. Thereby, SNR can be improved to 2.9 dB or more. In this embodiment, there are four combinations of phase shift amounts, but the SNR can be improved to 4.8 dB when the combination of phase shift amounts (phase pattern) is increased infinitely.
Next, an example of a specific configuration of the inter-PRI signal synthesis unit 376 will be described. FIG. 14 is a schematic block diagram showing the configuration of the inter-PRI signal synthesis unit 376 in the present embodiment. As shown in the figure, the inter-PRI signal synthesis unit 376 has an adder 378.
The adder 378 adds the amplitudes of signals output from the inter-frequency signal synthesizer 371a, the inter-frequency signal synthesizer 371b, the inter-frequency signal synthesizer 371c, and the inter-frequency signal synthesizer 371d.
FIG. 15 is a schematic diagram showing an outline of processing in the radar apparatus 3 of the present embodiment. In the radar apparatus 3, as shown in the figure, the transmission unit 11 periodically transmits pulse signals in the order of carrier frequencies f1, f2, and f3 in each PRI, and receives a reflected signal reflected by an object. To do. The received reflected signal is divided by the time division unit 35 for each transmission period of PRI1, PRI2, PRI3, and PRI4, and further the first signal storage unit 361a and the second signal provided in the signal storage unit 16 for each PRI. The data is stored in the storage unit 361b, the third signal storage unit 361c, and the fourth signal storage unit 361d, respectively.
The signals received by PRI1 to PRI4 stored in the first signal storage unit 361a, the second signal storage unit 361b, the third signal storage unit 361c, and the fourth signal storage unit 361d are respectively inter-frequency signal synthesis units 371a. Are added to one signal by an inter-PRI signal synthesis unit 376 and output. In this way, the pulse signals transmitted at the carrier frequencies f1, f2, and f3 can be combined to improve the SNR, and the transmission time at each of the three carrier frequencies is a pulse required to satisfy the search performance. Even if the transmission time is shorter than the signal transmission time Trx, the search performance can be maintained.
In addition, although the structure which performs a phase addition for every combination of phase shift amount in the different frequency signal synthetic | combination part 371a-d was demonstrated, the amplitude (square sum square root) of each signal shifted without phase addition was demonstrated. The sum may be calculated (amplitude synthesis). In this case, among the combinations of phase shift amounts, the sum of the largest amplitudes may be selected by the maximum value determiner and output.
(Fourth embodiment)
The radar device according to the fourth embodiment is different from the radar device 3 according to the third embodiment in the different frequency signal synthesis units 371a to 371d provided in the radar device 3, and thus different configurations will be described. Description is omitted.
FIG. 16 is a schematic block diagram showing a configuration of the inter-frequency signal synthesizing unit 471a provided in the radar apparatus according to the present embodiment. The inter-frequency signal synthesizer 471a is provided in place of the inter-frequency signal synthesizer 371a in the third embodiment. Similarly to the inter-frequency signal synthesizing unit 471a, the inter-frequency signal synthesizing units 471b, 471c, and 471d are provided instead of the inter-frequency signal synthesizing units 371b, 371c, and 371d in the third embodiment. Moreover, since the inter-frequency signal synthesizing units 471b, 471c, and 471d have the same configuration as the inter-frequency signal synthesizing unit 471a, description thereof is omitted.
As shown in FIG. 16, the inter-frequency signal synthesizer 471 a includes a quadrature detector 472 and an FFT calculator 473. The FFT calculator 473 reads out signals corresponding to the three carrier frequencies f1, f2, and f3 in the first PRI stored in the first signal storage unit 361a, and the three carrier frequencies in the read one PRI. The signal is converted to a frequency domain signal by fast Fourier transform. The maximum value selector 474 selects a signal having the highest power among the frequency domain signals converted by the FFT calculator 473, and outputs the selected signal to the inter-PRI signal synthesizer 376.
Note that the configuration in which the FFT calculator 472 performs fast Fourier transform on a signal corresponding to three carrier frequencies has been described, but a signal having zero amplitude is added to the signal corresponding to three carrier frequencies, and the number of FFT points is calculated from four. You may make it enlarge and perform a fast Fourier transform.
As described above, the radar apparatus 3 in the third and fourth embodiments performs coherent synthesis over a plurality of carrier frequencies with respect to the reflected signal for each carrier frequency stored in the signal storage unit 36 for each PRI. Further, the SNR of the reflected signal is improved by performing synthesis over a predetermined PRI. Thereby, even if each of the transmission times at a plurality of carrier frequencies is shorter than the transmission time Trx of the pulse signal required to satisfy the search performance, the search performance can be maintained.
In the third and fourth embodiments, the signal storage unit 36 includes the first signal storage unit 361a, the second signal storage unit 361b, the third signal storage unit 361c, and the fourth signal storage unit 361d based on FIG. The parallel processing stored in the four storage units and further combined in parallel by the four different frequency signal combining units has been described. However, for example, serial processing using a ring buffer is also possible. For example, the time division unit 35 divides sequentially input signals and outputs them to the signal storage unit 36. After the signal is temporarily stored in the signal storage unit 36, the signal output from the time division unit 35 is newly stored in the storage unit in which the signal output to the signal synthesis unit 37 is stored. The same signal processing result can be obtained with a relatively simple configuration.
As described above, the radar apparatus according to each of the above-described embodiments uses a plurality of carrier frequencies in a time-division manner in the pulse signal transmission time Trx required for satisfying the search performance required for detecting the target. Are sent periodically. When the pulse signal transmitted from the radar apparatus 1 corresponds to an image frequency in a receiving apparatus used in another communication system, it appears as a signal dispersed at the image frequency. Thereby, since the interference which a pulse signal gives in an image frequency can be disperse | distributed to several frequencies, the influence which it has on other communication systems can be reduced.
Further, in each of the above-described embodiments, as shown in FIG. 9, the frequency band assigned to the radar apparatus is an image frequency band at the baseband frequency stage or the intermediate frequency stage in the receiving apparatus of another communication system. The carrier frequencies f1, f2, and f3 may be set as follows.
FIG. 9 is a diagram illustrating an example of setting the carrier frequencies f1, f2, and f3 in the above-described embodiments. In another communication system, when communication is performed by dividing the frequency band assigned to the communication system into n sub-frequency bands (channels), each of the carrier frequencies f1, f2, and f3 is down-converted. In order to appear as image signals in different sub-frequency bands (ch.1, ch.2, ch.3).
That is, the frequency intervals between the carrier frequencies f1, f2, and f3 may be set according to the channel allocation frequency interval in another communication system. As a result, the pulse signals transmitted from the radar device at the carrier frequencies f1, f2, and f3 appear dispersed as image signals in different channels in other communication systems, so that the interference applied can be further reduced.
In another communication system, when a signal that has been subjected to error correction coding is used for communication, the length of the pulse signal transmitted using the carrier frequencies f1, f2, and f3 is set to the error correction coding. A shorter burst error duration may be set. That is, the pulse signal transmission time at the carrier frequencies f1, f2, and f3 may be set according to the burst error duration allowed in other communication systems.
When the transmission time is set in this way, even if the pulse signal transmitted from the radar device interferes as an image signal in a receiving device of another communication system, an error caused by the interference is corrected by error correction decoding of the communication system. can do. Thereby, it can prevent that an error arises with the pulse signal transmitted from the radar apparatus, and the interference which the pulse signal transmitted from the radar apparatus gives can be reduced.
Note that the above-described radar apparatus may have a computer system therein. In that case, the processes of the A / D conversion units 14 and 34, the frequency division unit 15 or the time division unit 35, the signal storage units 16 and 36, and the signal synthesis units 17 and 37 described above are computer-readable in the form of a program. The above processing is performed when the computer reads out and executes the program stored in the recording medium. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.
In each of the embodiments described above, the case where the pulse signal is transmitted using three carrier frequencies has been described. However, the present invention is not limited to this, and the pulse signal may be transmitted using two or more carrier frequencies.
Further, in each of the embodiments described above, the configuration for synthesizing 4 PRI signals has been described, but the number of PRIs to be synthesized may be other than 4. When the radar apparatus is operated by rotating the antenna, the number of PRIs to be combined may be set based on the rotation angular velocity of the antenna, the half width of the antenna directivity gain, and the PRI. Thereby, the improvement of the sensitivity by the synthesis and the decrease in the azimuth resolution can be prevented.
In each of the above-described embodiments, the configuration in which one radar apparatus transmits a pulse signal and receives a reflected signal has been described. However, the radar apparatus is divided into an apparatus that transmits a pulse signal and an apparatus that receives a reflected signal. Alternatively, a bistatic or multistatic radar system including two or more devices may be used.
As described above, the present invention is not limited to the above-described embodiments, and various configurations of the embodiments are possible within the scope of the present invention, and any improvement may be applied to all or some of the components.
DESCRIPTION OF SYMBOLS 1,3 ... Radar apparatus 11,31 ... Transmission part 12,32 ... Antenna 13,33 ... Reception part 14,34 ... A / D conversion part 15 ... Frequency division part 16 ... Signal storage part 17 ... Signal synthesis part 18,38 ... Output processing unit 161a ... First signal storage unit 161b ... Second signal storage unit 161c ... Third signal storage unit 171 ... Phase synthesis unit 171a, 171b, 171c, 271a, 271b, 271c ... Inter-PRI signal synthesis unit 172 ... Orthogonal Detectors 173a, 173b ... Accumulator 175 ... Inter-frequency signal synthesizer 176, 177 ... Phase shifters 178a, 178b ... Adder 179 ... Maximum value determiner 272 ... FFT calculator 273 ... Maximum value selector 35 ... Hour Dividing unit 36... Signal storage unit 37... Signal synthesis unit 361 a... First signal storage unit 361 b... Second signal storage unit 361 c... Third signal storage unit 361 d. Storage units 371a, 371b, 371c, 371d, 471a, 471b, 471c, 471d ... Inter-frequency signal synthesis units 372 ... Quadrature detectors 373a, 373b ... Phase shifters 374a, 374b ... Adders 375 ... Maximum value determiners 376 ... PRI Inter-signal synthesizer 378 ... adder 472 ... quadrature detector 473 ... FFT calculator 474 ... maximum value selector
A transmitter that sequentially transmits a pulse signal of each of a plurality of carrier frequencies at a predetermined period;
A receiving unit that receives a reflected signal reflected by a target to be detected, the pulse signal transmitted from the transmitting unit;
A frequency divider that divides the reflected signal received by the receiver into signals corresponding to the plurality of carrier frequencies;
A signal synthesizing unit that synthesizes a time-series signal composed of reflected signals divided by the frequency dividing unit for each of the plurality of carrier frequencies, and further synthesizes the phase-synthesized signals of the plurality of carrier frequencies. A radar apparatus comprising:
The signal synthesizer
A phase synthesizer that outputs a signal obtained by performing quadrature detection on the reflected signal divided by the frequency divider for each of the plurality of carrier frequencies over a predetermined number of transmission periods and outputs the result. ,
For each combination of a plurality of phase shift amounts determined in advance, each of the signals for each of the plurality of carrier frequencies output from the phase synthesizer is phase-shifted and added, and for each combination of the plurality of phase shift amounts The radar apparatus according to claim 1, further comprising: a signal synthesizing unit between different frequencies that selects and outputs the largest addition result among the addition results.
For each of the plurality of carrier frequencies, phase synthesis is performed by selecting and outputting a signal corresponding to the frequency spectrum having the largest power among the frequency spectrum obtained by Fourier transform with respect to the reflected signal divided by the frequency dividing unit. And
For each combination of a plurality of phase shift amounts determined in advance, each of the signals for each of the plurality of carrier frequencies output from the phase synthesizer is phase-shifted and added, and for each combination of the plurality of phase shift amounts An inter-frequency signal synthesizer that selects and outputs the largest addition result among the addition results of
The radar apparatus according to claim 1, further comprising:
A time division unit that divides the reflected signal received by the reception unit every predetermined period;
The signals of the plurality of carrier frequencies are synthesized for each time-series signal composed of the reflected signals divided by the time division unit, and further, the synthesized signals are synthesized over a plurality of the predetermined periods. A radar apparatus comprising: a signal synthesis unit.
For each combination of a plurality of phase shift amounts determined in advance, each of the signals for each of the plurality of carrier frequencies output from the time division unit is phase-shifted and added, and for each combination of the plurality of phase shift amounts An inter-frequency signal synthesizer that selects and outputs the largest addition result among the addition results of
A synthesis unit that adds and outputs the signals output from the inter-frequency signal synthesis unit;
A different frequency for selecting and outputting a signal corresponding to a frequency spectrum having the largest power among frequency spectra obtained by Fourier transform for the reflected signal divided by the time division unit for each of the plurality of carrier frequencies. Inter-signal synthesis unit;
The frequency interval between the plurality of carrier frequencies is set according to a frequency interval of channel assignment in a communication system in which a frequency band assigned to the own device appears as an image frequency. The radar apparatus according to any one of 6.
The transmission time of the pulse signal in each of the plurality of carrier frequencies is set according to the duration of a burst error that can be error-corrected in a communication system in which the frequency band allocated to the device appears as an image frequency. The radar apparatus according to any one of claims 1 to 7.
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text:
Framing toolkit: Talking about poverty
Part of Talking about poverty
Paul Brook
Compassion and justice are values that underpin our society – we believe in helping each other out when we're having a tough time. We need to make sure those values underpin the way we talk about poverty too.
At JRF, we want to inspire action and change to solve UK poverty, but we know there's a lot of work to do if more people are to understand it and call more loudly for solutions.
To help with this challenge, we're changing the story we tell about poverty, using framing recommendations from the FrameWorks Institute's research into public attitudes to poverty in the UK, involving 20,000 people.
This toolkit explains what framing is, why we're using it, and how you can put it into action yourself.
DownloadFraming Toolkit (1.08 MB)
How to build lasting support to solve UK poverty
This summary explores public attitudes towards poverty in the UK. It recommends a set of tested strategies to build a deeper understanding of how poverty happens and the changes needed to address it.
Talking about poverty in the UK - what works?
A ten-step guide to communicating more effectively about UK poverty.
Five doodles that help to make sense of UK poverty
It's all very well having robust, reliable evidence of what causes poverty in the UK – but facts and figures alone aren't enough to build support for solving it, says Paul Brook.
Effective poverty and obesity campaigns need more than just stats
It's time for anti-poverty and anti-obesity campaigners to tell a new story, says Abigail Scott Paul.

redpajama_set_name: RedPajamaCommonCrawl


For a decade, CDW Canada has been helping Canadian educators employ technology to create more engaging learning environments through its Digitize Your Classroom Contest. The contest offers K-12 teachers and administrators across the country an opportunity to win $10,000 worth of technology, such as laptops, software, screens and projectors for their classrooms.
One of the winners of our Digitize Your Classroom was Bnei Akiva Schools of Toronto. The faith-based Jewish high school has approximately 270 students across its two Toronto campuses – one for boys and one for girls.
The school is dedicated to employing technology to deliver a robust program for its students, said Mordechai Sabeti, the school's executive director, and will use the technology it received from the Digitize Your Classroom Contest, including a Lenovo N23 Chromebook; 18 Lenovo N24 (Touch & Pen) Windows 10 S 4GB/64GB Notebooks; a Lexmark MX310DN Multi-function printer; and an InFocus INF6500e 65-inch capacitive touch display, to boost its existing digital programs.
Ensuring each student has their own device enables Bnei Akiva to employ blended learning that combines digital media with traditional face-to-face classroom instruction. For example, a math teacher could record a lesson with audio and video and make it available to students. Students could watch the lesson at home, then come to school the next day and apply what they learned from the video in the classroom.
Blended learning has boosted student engagement, Sabeti said, but it hasn't been an entirely smooth journey. Until now the school has been unable to administer year-end exams on student devices because the software Bnei Akiva uses for the exams does not support Chromebooks. Thanks to Digitize Your Classroom, the school has loaded its new Lenovo notebooks with its testing software and plans to issue the machines to students with Chromebooks so the entire class can use laptops at exam time.
The school is also exploring ways to incorporate stylus capability into its lessons. Until now it hasn't had machines that incorporate a stylus, Sabeti noted. The school is considering two possibilities.
The school is also looking forward to employing its new touch display. The capacitive touch capability makes it an ideal tool for the front of the classroom, Sabeti said, where it can boost student interaction.


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Mad Addy is petite and uncommonly thin and wiry. At 4′-9″ she looks like a child next to the rest of the crew, an image that is reinforced by her angelic face. She has a cute little upturned nose, and bright blue eyes, and her cheeks are always just a bit flushed. However, she scares even the dodgiest pirate when she gets angry, her cute face contorting into a mask of fury. If she bothered to wash up, her skin would be a creamy white. Her hair would be golden blonde apart from the dirt, but she doesn't wash or comb it and it resembles a sickly grayish color most of the time. She cuts it short with a knife so it doesn't get in her way. The only feature she prides herself on is her teeth, and she brushes and cleans them at least four times a day. She also is not afraid to use them in a fight.
The clothes she wears are boy's garments dyed startlingly bright colors, like purples and greens and oranges and pinks and blues, and typically clash horribly with each other. Some of the deckhands call her the captain's parrot behind her back, due to her bright clothing and her tendency to yell at everyone and everything around her. Her clothes, too, are ripped and stained. She carries a pair of knives, one on a belt at her waist and the other strapped to her lower leg on the right side. Both are kept razor sharp.
She's a contortionist and can climb the rigging like a monkey, and therefore goes barefooted and her hands and feet are both calloused from climbing. She has scars on her legs and arms from the ropes, and one angry red scar on her throat where she nearly hung herself in the rigging her first year at sea. She spends most of her time in the rigging, even napping on the beams during the day. She'll climb things like a monkey rather than walk down a street, always preferring to be above the crowd. If she does walk, she darts in random directions in spurts, pausing nervously between outbursts.
The only time she seems at peace is when she's had a good meal and can settle herself in the rigging to watch the deckhands sing and dance in the lantern light on a peaceful night at sea. She never joins in the dancing with the group, but a few have caught her twirling to unheard music across the railing of the ship or on top of the crow's nest.
Addy is a contradictory sort. She acts very tough and independent, and is always shying away from social situations. But if you look closely you can catch her watching groups of people with a yearning expression on her face. She is a lonely young woman, and very defensive. She's always had to be tough, and she thinks that opening up to someone would jeopardize that.
In a fight, she is ruthless. There's a history in her eyes that makes her fury almost sad to behold. Something has broken her trust in her fellow man, and now when she fights she is striking out at everything that ever hurt her each time she strikes her foe. She sometimes hides away after battle, sobbing with the emotions that her fury brings to the surface.
And around the crew, she is loud and obnoxious. She hounds them, chastises them, insults them, and teases them. She sometimes chatters loudly to herself when they're around, occasionally confusing one of them by asking them a question in the middle of her ranting.
She loves the ocean and the wild depth it represents. She loves the ship and the crew because it allows her to get as close to the depths of the ocean as possible. She hates being pinned down, pigeon-holed, told what's proper. She's wild and free, and fights everyday for that privilege.
Addy is obsessed with the ocean and will spend hours staring into its depths. She sees freedom there, along with temptation and power. The ocean represents the ultimate freedom and the ultimate release. Ever since she was a tiny girl she was fascinated by the stories of Davy Jones's Locker. She views the ocean as the release from the life she hated, but she isn't quite willing to give herself over to it completely so she remains as close as she can to it.
Publicly she crows the freedom that piracy gives her. She'll eagerly tell her crewmates that she's a pirate because she WANTS to be, and there isn't anyone that can tell her any different. Pirate women belong to no man, they're mean and deadly and they are the daughters of the sea. No one commands her, and no one controls her. She follows the captain because he understands that she is a wild thing and can't be controlled.
For the most part she is quite content to stay on the ship and nest in the rigging. She will go ashore when told, and usually stays out of the way during those times. She can, however, be roused to fight if she sees a woman being mistreated or insulted. She also defends her ship viciously. She sees the ship and crew as hers, and would give her life to protect them.
Adaline was a proper young lady, daughter of a landed lord. Her days consisted of being pampered by her wet nurse and learning silly crafts that every noble woman should know. On her 16th birthday she was married to an insignificant baron nearly 20 years her senior. She was a trophy, a doll for him to abuse and parade around with. For months she silently put up with his abuse, his drunken advances, and his disgusting habits.
One evening he came to her chambers after a night of drinking. She cried the entire night once he passed out in the bed. She was aching and covered in bruises, wishing her life would end. Taking up the pretty knife the baron had left in his piled clothing, she calmly thought about ending her suffering. It was a loud snorting snore that turned her attention to the baron instead. Without another thought she plunged the dagger to its hilt in his chest and ran from the manor in her ripped and bloodied nightgown.
She intended to throw herself to the sea as she reached the docks, but an old seaman clucked at her and told her to change her clothes if she wanted to leave. He took her along on a pirate ship, and she never looked back.


Someone asked me how my boys were doing the other day. It's interesting because I always hesitate to say they are doing well. It seems that everytime I do that some huge meteor appears in the nightsky presaging the beginning of a period of doom. So I simply answered her "At this moment, at this time, in this second of my reality, everything is OK." She actually laughed because she understood exactly what I was talking about.
No she is not the parent of a special needs child, she is just a mother, wife, daughter and citizen of the world. When you are alive you have problems. She has an elderly parent living at home with her and her husband. Her husband's elderly parents (both with medical issues) live down the street and her son just got flooded out in the huge hurricane. He and his girlfriend now live in her basement. She also just went through major back surgery. It's called life. There is always something, no matter who you are.
It's why I never really understood people who have to create problems for themselves. Doesn't life just give you enough to handle on its own? Why are there people who have to cheat, steal, lie and break every commandment? Is life not spicy enough for them? What more do they need? Are they so bereft of values and morals that nothing makes them happy? You can't claim poverty or single parenting for every ill in the world. In fact some of the most unhappy people I know have more material goods and disposable income than anyone else on the planet (these people I really can't understand). Of course I would like the opportunity to test the hypothesis that "money can't buy happiness." I would write a great scientific paper on the subject, worthy of a Nobel Prize, and let everyone in on my findings.
No this is not a religious tirade. We are not particularly a religious family, albeit a culturally Jewish one. We do have a strong sense of our history coupled with understanding rights and wrongs and ethics and moral value. We know what a person is supposed to do by law and what a person is required to do to be a good person. Interestingly, they are not always one in the same.
You might be surprised just how lacking in moral fiber our legal code actually happens to be (I am not talking about some of the inherent racist or economic disparities within our legal system, but the laws itself.). The fact that our legislatures had to pass "Good Samaritan" laws to protect those who would come to anothers rescue from legal imprisonment or a civil lawsuit, should in and of itself say something about our society.
But it is even more than that. There is "something rotten in Denmark." People are angry, so very angry. When the world that you have built over decades comes crashing down around you you need to lash out and you need to blame someone. It almost seems like noone takes any responsibility for their mistakes anymore. No one from the top down can say "the buck stops here." It's always someone else's fault. It's easier to scapegoat someone rather than except that you or your perspectives could be wrong.
I think this goes back to the class that CM2 is taking on prejudice. He is learning how society scapegoats others to find a reason to not take blame for their own poor choices. He is studying the rights and wrongs of the world and how they go belly up so often. It's been part and parcel of CM1's existence for years now and unfortunately it only makes him angry when he thinks about it. Luckily CM2 hasn't become angry, not yet, but his way of dealing with the dichotomy of societal reality is to be a very cynical 17 year old.
You used to find such cynicism in older folks, like me, but it is a huge aspect of the way CM2 deals with the present situation. It is a loss of innocence and in many ways I resent that the world has done that to him. But then again he never blames others for his mistakes. He accepts responsibility and he knows what is expected of him. He just doesn't understand why others, especially those in power, don't feel obligated to adhere to the same ethical and moral rules bywhich he has to abide.
Whose fault is it when things do not go as planned? Whose fault is it when people don't agree with you and kowtow to your perspectives and thought processes? Whose fault is it when life takes a huge bite out of your future and sets you on a tailspin? Whose fault is it if you don't pull yourself together and fix your problems? Once again our elected officials exemplified the inadequate in our society. A Jewish California Congressman just blamed the democratic loss in New York 9 on "Jews who were only interested in keeping their own wealth..." I kid you not. While the head of the DNC said that the Orthodox Jewish community of NY9 are a fringe element not really part of American-Jewry. It makes your head spin. No real need to wonder why CM2 is so cynical.
I suppose the issue becomes what kind of world do you want to live in? Do you want to live in a world where there are no boundaries and everyone does just what they want? Or do you want to live in a world where there are expectations and requirements? According to a recent poll, those who have a moral code and are permitted to ask questions about that code, and the world around them, are the most content people in the world (OK yes the poll did say that Jewish people are the happiest, with atheists coming in second. Since we are Jewish, with CM1's atheism thrown in, I confess the poll made me happy). Understanding what is expected of a person brings happiness, especially when you fulfill that obligation. Knowing boundaries helps society to flourish and to grow. The ability to question authority also allows for growth and development as a person and as a society.
I suppose that is why my friend with all going on in her life is well, quite happy. She understands the world around her and is fulfilling her obligations. The boys are happy, at this moment, at this time, in this second of their reality because they understand their obligations and are fulfilling them. I am happy because as the old saying goes you are only as happy as your least happy child.
While picking up CM2 from school I received a call from CM1. He had just had a seizure, ended up on the floor and hit his head. I stayed on the phone with him for awhile and periodically called while on my mommy-taxi trip to make sure he remained lucid. I then took CM1 directly to the ER once I got home. After three hours of blood tests and catscans (everything showed that he was fine) he was released with a caveat that if he was feeling poorly he should call his doctor right away. But that he needs to follow up with his neurologist.
It is always something isn't it?


Today I love second place and coming in a solid second in both of our playoff curling games. I love that we had a lot of fun on Monday night and again on Wednesday night, that my two teams had less cumulative years of curling and still tried their hardest, and that we all are charged up to return next year. I love that I am playing in one last game tonight, and then I'll likely hang up my curling shoes until next autumn when we start again. I love having something to look forward to. I love that some of my friends from curling are also dragon boaters and some more of them are going to come out and try dragon boating this year. I love that I am hoping to do more walking, swimming and bicycling this year, though I intend to do all those things casually. I love that there are some things I wish to do this year that are work like things but that are not for clients, just for us and the house and the cottage. I love all the things I do and all the things I get to participate in. I love that in a way, no activity I am engaged in ever ends, they just take breaks for different seasons.
Today I love that this week is rolling along and that the coming weekend is a busy one. I love keeping pace with the world, listening to the rythym of the days and hours and minutes and matching that with my heart beats. I love the way things move forward and I love the way they take me with them when they do. I love that I am feeling better about my heart tests now that they are in the past. I love being alive. I love that my will has been updated.
Today I love resilient house plants, because heaven knows I ain't much help to them. I love strawberry jam on fresh baked rolls. I love that I just remembered that there's banana bread in the fridge, and that is definitely going to be my mid morning, post blogging snack. I love how much improvement we've managed here in this house lately with new storage systems and changes to the way rooms are furnished. I love stretching like a cat. I love that so much snow has melted already. I love that this is the first full day of Spring, but there are better days yet to come.
Today I love drinking coffee and chatting with the resilient house plants about their concerns and demands for better living conditions.


text:
By Ezinwanne Onwuka (Senior Reporter)
Ezinwanne Onwuka, senior staff reporter and columnist with WAP is a Nigerian-based writer and content developer. She holds a Bachelor of Arts degree in Philosophy from the prestigious University of Nigeria, Nsukka. Her interests include reading, writing, researching and graphic designing.
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NewsNigeriaPoliticsINEC Fixes Election Expenses for Presidential Candidates at N5bn
By Ezinwanne Onwuka (Senior Reporter)November 26, 2022
The maximum amount of money political parties and candidates can spend ahead of the 2023 presidential election is N5 billion, the Independent National Electoral Commission (INEC) says.
This is contained in the guidelines on the finances and election expenses for political parties and their candidates approved for publication and release by INEC.
"The commission approved the publication and release of the guidelines for the conduct of political rallies, processions and campaigns, as well as that of finances and election expenses of political parties, candidates and aspirants," Festus Okoye, INEC's National Commissioner and Chairman, Information and Voter Education Committee, said in a press release on Thursday.
Okoye added that the commission uploaded the two documents on its website and social media handles, while copies would be made available to political parties, civil society groups, the media and other critical stakeholders.
While INEC fixed the maximum election expenses for presidential candidates at N5 billion, that of candidates for governorship elections was pegged at N1 billion.
Also, the maximum amount of money or other assets that an individual, a group of individuals or an entity can donate to a political party or aspirant for an election is N50 million.
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text:
Plans to turn former Rat and Parrot pub in Liverpool into supermarket and restaurant
Developers have submitted a planning application to bring the Liverpool city centre site back into use
Rat & Parrot pub in Queen's Square
The old Rat and Parrot pub in Queens Square could be turned into a new supermarket, restaurant and coffee shop complex.
Developers have submitted a planning application to bring the city centre site back into use – just over three years after the pub closed.
Details of the scheme are limited, but documents submitted to Liverpool council reveal the intended use of the site, if planning chiefs give the green light to proposals.
The three-storey property, on the corner of Whitechapel and Hood Street, has been empty since the Rat and Parrot closed for business just before Christmas 2011.
Plans submitted to the council's planning department, including designs by DK-Architects, reveal proposals for the ground floor to be converted into a supermarket and a separate coffee shop and the upper two levels to become a restaurant.
While they were submitted to the council just before Christmas, the details of the application have only just been made public.
The application details a bid for a change of use for the premises and a remodelling of the facade.
According to proposals, pre-planning advice has been sought from the council, with the applicants claiming the authority had no objection to the proposal in principle, though further clarification of the layout and uses was requested.
A spokesman for the Liverpool BID Company welcomed the proposals and said: "Queens Square is an integral part of the city centre and the fact that this site has been vacant for some time has had a detrimental effect on that area, so any development would be welcome."
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