of the HDOP varies with geographic location only a little, VDOP value is changing a lot with geographic latitude. The latitude of ± 56 ° VDOP reaches its minimum and with latitude increasing VDOP significantly increases. This error increase at higher latitudes is due to the fact that after crossing the latitude, which is equal to the track inclination, already below the overhead satellites, culminating in increasingly lower elevations. Three-dimensional positioning error almost follows track of the dominant height error. Figure 9: Satellites position and movement over time Using simulation tools there is possible to model various geometric distribution of satellites typical example for different latitudes. There is possible to simulate conditions of high and low levels of DOP indicators. For each of the satellites there is possible to simulate the signal level, or to switch off the satellite which leads to a situation of broadcast only n satellites. The combination of these settings allows assembling many different test scenarios for testing GNSS signal reception, depending on the constellation of satellites. Figure 10: Display of received signal levels Figure 11: Display of setting concerning signal levels This feature can also be used to simulate a particular constellation of GNSS satellites in the defined period of time in the past. This includes re-induction (replay) of the situation that leads to the application or device error. This is possible for the GPS signal, which is governed by the so-called GPS weeks. For each GPS week almanac generated file that defines the current position of the GPS satellites. This information is freely available in the internet. This file is imported into the simulation software tools and the position of the satellite after that corresponds to the required time. GNSS signal emulation Process through the generation of GNSS signal in the simulator is in several steps (and is shown on the picture below): Operator in the simulation program sets the course (manually or pre-prepared set of positional data, such as NMEA data) and all parameters of the generated signal (e.g. number
of the HDOP varies with geographic location only a little, VDOP value is changing a lot with geographic latitude. The latitude of ± 56 ° VDOP reaches its minimum and with latitude increasing VDOP significantly increases. This error increase at higher latitudes is due to the fact that after crossing the latitude, which is equal to the track inclination, already below the overhead satellites, culminating in increasingly lower elevations. Three-dimensional positioning error almost follows track of the dominant height error. Figure 9: Satellites position and movement over time Using simulation tools there is possible to model various geometric distribution of satellites typical example for different latitudes. There is possible to simulate conditions of high and low levels of DOP indicators. For each of the satellites there is possible to simulate the signal level, or to switch off the satellite which leads to a situation of broadcast only n satellites. The combination of these settings allows assembling many different test scenarios for testing GNSS signal reception, depending on the constellation of satellites. Figure 10: Display of received signal levels Figure 11: Display of setting concerning signal levels This feature can also be used to simulate a particular constellation of GNSS satellites in the defined period of time in the past. This includes re-induction (replay) of the situation that leads to the application or device error. This is possible for the GPS signal, which is governed by the so-called GPS weeks. For each GPS week almanac generated file that defines the current position of the GPS satellites. This information is freely available in the internet. This file is imported into the simulation software tools and the position of the satellite after that corresponds to the required time. GNSS signal emulation Process through the generation of GNSS signal in the simulator is in several steps (and is shown on the picture below): Operator in the simulation program sets the course (manually or pre-prepared set of positional data, such as NMEA data) and all parameters of the generated signal (e.g. number
001-HeEROWP4DELD42V11Final.docx