# A Waveform and Velocity Ambiguity Resolution Method for Corner Radar
## 4 Simulation Experimental Verification
Simulation utilizes data after a constant false alarm rate (CFAR), which enhances the velocity of data processing. The three simulation targets are all selected at the junction of the three waveforms, but due to the use of a single waveform, simulation will not encounter significant difficulties. Matching distance and velocity using a single waveform is more consistent with real-world scenarios. If composite waveforms are used, a more appropriate approach would be to place velocity disambiguation after tracking. This involves adding more matching information, such as angle, signal-to-noise ratio (SNR), etc. This approach would provide more reliable results in complex situations but would consume more computing resources. The experiment utilized a radar designed by the Alps Pro chip to verify the waveform and velocity ambiguity resolution method. The Alps Pro chip supports DDMA transmission mode, with a maximum support of 4T4R (4 transmitters and 4 receivers). The road test scenario was selected at Nameless Road in Nanjing, which is a semi-closed road that is relatively safe and will not interfere with traffic. The corner radar (uncovered) was installed at a 45\({}^{\circ}\) corner in the left rear direction of the main vehicle, as illustrated in Figure 10. Since this article does not involve antenna layout, array layout information is not displayed. The maximum unambiguous velocity represents the radial velocity of the target towards the radar. However, corner radars primarily detect lateral oncoming vehicles, meaning the direction of the target's movement is often not radial. As a result, even when the actual vehicle velocity exceeds the maximum unambiguous velocity, the mapping to the radial velocity may still not become ambiguous. This phenomenon leads to an increase in the unambiguous range due to the change in direction, posing significant difficulties for testing. To address this challenge and ensure the safety and feasibility of the experimental verification, the method \(T_{c}\) was set to 42 us. This adjustment successfully verified the unambiguous method in an operable experimental environment. However, it is important to note that there is a slight difference between the set parameters and those listed in Table 4. Due to the increase in \(T_{c}\), the maximum unambiguous velocity during actual testing decreased from 27.2 m/s to 23.3 m/s. Figure 10: (**a**) Test scenario. (**b**) Test radar. During the experiment, the main vehicle was parked at one end of the open road, and the target vehicle accelerated from a distance towards the vicinity of the main vehicle. Upon entering the radar detection range, the distance was calculated. As the target vehicle approached the safe braking point, braking was initiated. At this point, the target vehicle reached its maximum velocity and gradually decelerated to 0 m/s. The radar detection data is illustrated in Figures 11a-14a. To ensure the authenticity of the radar data verified in the experiment, a mature commercial radar was also installed in the right rear of the vehicle during testing. This radar served as a comparative reference for validating the algorithm. The test results of the mature radar were utilized as a reliable source for extracting information from the target vehicle. The algorithm validation radar is referred to as the validation radar, while the mature radar is known as the comparative radar. The test results of the comparative radar are displayed in Figures 11b-14b. Figure 11 illustrates the motion trajectory of the target in the radar coordinate system, specifically capturing the trajectory of the target near its maximum velocity. Figure 12 displays the relationship between target distance and energy. The energy points detected and returned by the two radars for the target vehicle closely match, fluctuating within a reasonable range. Figure 11: Test target trajectory. (**a**) Validation radar. (**b**) Comparative radar. Figure 13 depicts the relationship between distance and match points.