Item | Digital | Optical fiber | Detailed description |
Closest distance | 0m@airgap=3m | 5m@airgap=3m | In HIL applications, it is hoped that a closer distance can be simulated |
Longest distance | 800m, generally unlimited | Usually 300m, if it is longer, the cost will be higher | Digital is achieved through software, and optical fiber requires hardware cost |
Distance step/accuracy | 1mm | 1cm | A. From the perspective of measurement accuracy, for 2GHz bandwidth radar, the distance resolution can reach 100mm (considering windowing), the distance measurement accuracy can reach 5mm, and it is hoped that the simulator accuracy can reach 0.5mm |
Speed step/accuracy | 0.002m/s | 0.01m/s | For most automotive radars, the speed accuracy is 0.1m/s, and the requirement for the simulator is 0.01m/s; but for some radars with high speed measurement accuracy, the accuracy can reach 0.02, and the simulator speed measurement accuracy is also required to reach 0.002 |
RCS dynamics | 110dB | 90dB | The dynamic range caused by the radar at a distance of 3-300m in the simulator reaches 80dB, and the dynamic range of the car RCS is 20dB, with a total of 100dB. It is hoped that the simulator dynamic reserve will be sufficient, and 110 is better. |
Instantaneous bandwidth | 2GHz | 5GHz | At present, the use of vehicles is basically within 2GHz. If other applications are considered, a large bandwidth can also be selected. |
Intra-band flatness | 2dB | 5dB | Provide guarantee for the waveform quality of the distance dimension. |
Target parameter update rate | 25ns, determined by FPGA clock | 1ms | From the perspective of pure data rate, under Hil application, the radar data update time is about 20ms, and it is hoped that the simulator target update rate can be less than 2ms. From the perspective of radar simulation, continuous simulation should be performed, and the distance movement within the frame must occur at high speed. It is best to reach the pulse level. Generally, the short pulse is 10us. It is hoped that the simulator data update time can be 1us. |
Multi-target | Multiple targets in a single channel | 1 target per channel | Dual targets can measure distance resolution and speed resolution. Multi-targets can simulate more scenarios. Each target of optical fiber requires a distance delay line, which is costly. |
False target | 5dB worse than fiber noise floor, higher probability of false targets at close range | Large signal also has wild value | The digital close-range compensation algorithm will cause a small deterioration of phase noise, and there is no difference between long-distance targets and optical fibers. |
Interference signal generation | √ | × | Because digital RTS has built-in ADC, FPGA, and DAC, common instrument functions can be achieved through software |
Time-frequency diagram | √ | × | |
Spectrum diagram | √ | × | |
EIRP measurement | √ | × |