Traditionally, a radar apparatus mounted on a vehicle emits a transmission wave from a transmission antenna and receives a reflected wave from a target, which reflects the emitted transmission wave, at a reception antenna to thus derive position and relative speed information (hereinafter, referred to as ‘target information’) of the target with respect to the vehicle (radar vehicle). Specifically, in this time target deriving processing (hereinafter, referred to as ‘this time processing’), the reflected wave received at the reception antenna is received as a reception signal and a peak signal generated from the reception signal is subject to pairing processing. Then, when there is a target of previous time target deriving processing (hereinafter, referred to as ‘previous time processing’) having temporal continuity with the paired data, the target information of the paired data of this time processing and predicted information, which is obtained by predicting the target information of this time paired data from the target of the previous time processing, are filtered by a predetermined filter constant, so that the target information of the target of this time processing is derived (for example, (the target information of the paired data×a filter constant 0.25)+(the predicted information×a filter constant 0.75)=the target information of the target of this time processing). Here, the filter constant of the predicted information is larger than the filter constant of the target information of the paired data of this time processing. The reason is as follows: since the target information of the paired data of this time processing is derived only by this time processing but the target information of the target of the previous time processing corresponding to the predicted information is derived by filtering the target information of the paired data of the previous time processing and the target information derived in processing (processing before last) before the previous time processing, it is thought that the predicted information has higher reliability than the target information of only this time processing.
The radar apparatus outputs the target information of the target of this time processing, which is derived as a result of the filtering processing, to a vehicle control device mounted on the vehicle. When the target information input from the radar apparatus indicates a moving target that is moving in the same direction as a traveling direction of the vehicle, the vehicle control device to which the target information is input performs control such as ACC (Adaptive Cruise Control) so that the vehicle follows up the moving target (for example, a preceding vehicle that is traveling at the front of the vehicle in an own traffic lane), which is to be controlled. In the meantime, Patent Document 1 discloses a technology relating to the invention.
Patent Document 1: Japanese Patent Application Publication No. 2001-141812A
However, in a case where another target (for example, a stationary target such as a wall in a tunnel and a guard rail or a moving target (hereinafter, referred to as an ‘adjacent moving target’) moving in the same direction as the traveling direction of the vehicle in an adjacent traffic lane adjacent to the own traffic lane) (hereinafter, the ‘stationary target’ and the ‘adjacent moving target’ are collectively referred to as a ‘specific target’) exists at the periphery of the moving target, when an angle of the moving target approaches an angle of the specific target, a signal level value of an angle spectrum corresponding to the angle of the moving target may become larger than a signal level value of an angle spectrum of the specific target and at least a part of the angle spectrum of the moving target may be buried in the angle spectrum of the specific target.
When a peak signal of the specific target having a relatively large signal level value exists in the vicinity of a frequency of a peak signal of the moving target, a mis-pairing of pairing the peak signal of the moving target and the peak signal of the specific target may be caused although peak signals of the moving target should be originally paired each other. Also, when deriving the angle of the moving target, an angle (for example, an angle that is substantially the same as the specific target) different from an actual angle of the moving target may be derived due to the mis-pairing.
As a result, regarding a distance (hereinafter, referred to as a ‘transverse distance’) from the vehicle to the target in a vehicle width direction of the vehicle, which is derived by the angle of the target and a distance (hereinafter, referred to as a ‘longitudinal direction’) from the vehicle, at which the reflected wave from the target is received at the reception antenna of the radar apparatus, to the target, a transverse distance (for example, a transverse distance that is substantially the same as the specific target) different from an actual transverse distance of the moving target may be derived. In the meantime, the longitudinal distance and the transverse distance are data that is included in the position information, which is the target information.
As described above, when the transverse distance (hereinafter, referred to as ‘this time transverse distance’) of the paired data of this time processing corresponding to the target (for example, the moving target) of this time processing is different from the actual transverse distance of the target, this time transverse distance different from the actual transverse distance of the target of this time processing and information (hereinafter, referred to as ‘predicted transverse distance’), which is obtained by predicting this time transverse distance from a transverse distance (hereinafter, referred to as ‘previous time-decided transverse distance’) of the target (for example, the moving target) of the previous time processing, are filtered with predetermined filter constants, so that a transverse distance (hereinafter, referred to as ‘this time-decided transverse distance’) of the target (hereinafter, referred to as ‘this time-decided target’) of this time processing is derived (for example, (this time transverse distance of the paired data corresponding to the specific target×a filter constant 0.25)+(the predicted transverse distance of the paired data corresponding to the moving target×a filter constant 0.75)=this time-decided transverse distance of the moving target).
As a result, this time-decided transverse distance of the target (for example, the moving target) may be derived as a transverse distance different from a transverse distance of a position at which the target actually exists. As a result, the vehicle control device that performs the vehicle control on the basis of the target information of the target from the radar apparatus may not perform correct control upon performing the control such as ACC.