Principles of Modern Radar - Volume 2 1891121537

774 CHAPTER 17 Advanced Processing Methods for Passive Bistatic Radar SystemsVelocity (km/h)Velocity (km/h)−40−30−20−10010203040−40−30−20−10010203040dB50dB5045403530−40−30−20−1045403530252015105001020304025201510500 50100150 0 50100 150Range (m)Range (m)(a)(b)dB50dB5045−404540−304035−203530−103025 02520 102015 20151030105405000 50100150 0 50100 150Range (m)Range (m)(c)(d)FIGURE 17-16 2D-CCF for a WiFi-based PBR. (a) Without disturbance cancellationusing the registered version of the transmitted signal. (b) With disturbance cancellation usingthe registered version of the transmitted signal. (c) Without disturbance cancellation usingthe recovered version of the transmitted signal. (d) With disturbance cancellation using therecovered version of the transmitted signal.Velocity (km/h)Velocity (km/h)both the range sidelobes related to the direct signal contribution and the reflections of thetransmitted signal from stationary scatterers. Each peak at zero velocity comes with thecorresponding Doppler sidelobe structure, and this yields a quite high sidelobe level allover the 2D-CCF that completely masks the two targets returns. Figure 17-16b reportsthe 2D-CCF evaluated after disturbance cancellation but without sidelobes control. Thecancellation filter (ECA-B) operates over consecutive batches of duration T b = 30 ms.The filter length was set to remove reference signal replicas with delays corresponding toranges between 0 and 330 m. The direct signal and all disturbance contributions at zeroDoppler are effectively removed, thus significantly increasing the useful dynamic rangefor target detection. The car (moving at –25 km/h) now appears as a strong peak in themap, and the human target return is significantly spread in the Doppler dimension aroundits actual location (range = 85 m, velocity =−20 km/h). This is in a measure due the