ROC Performances of Constant False Alarm Coded Anti-collision Radar in Multi-user Environment
Résumé
Active safety systems such as anticollision radar play a major role in reducing traffic accidents. The principal task of the radar is to detect the presence of targets and estimate their positions. To make this task, the system called coded anticollision radar use a code at transmission and correlation at reception. The actual used codes are the BPRS sequences but they are not sufficient to share the channel between a large number of users. On other hand, the detection of correlation peak, previous approach, is not able to detect multiple targets simultaneously . In this paper, we present new codes that can be used and develop the probabilities of detection and false alarm. By these developments we can determine the threshold to have a fixed false alarm probability that gives a good performances . Thus, the new system is called constant false alarm coded anti-collision radar (CFACAR). To determine what is the best code, the receiver operating characteristics (ROCs) are plotted for different signal to noise ratio, codes and cases. We found that, in all time, the theoretical ROCs exactly match with the simulated ones. The most important case is also studied that represents the multi-user case where the user is confronted to interference caused by other users. The comparison of ROCs in different cases shows that the best code for CFACAR system is the Kasami type 2.