A Study on the Application of Phase Coded Waveform for Reentry Capsule in the Blackout Area

Aiming at the poor tracking performance of radar using conventional linear frequency modulation (LFM) signal for reentry flight target under strong sheath environment, the detection and tracking performance of radar using phase-encode waveform for spacecraft during the process from sheath appearance to continuous enhancement was studied. Compared with LFM signal, the ambiguity function of phase-coded signal is pushpin shape, and the range and Doppler resolution of phase-encode signal are higher, so there is no range-Doppler coupling effect. When the sheath signal is weak and the body signal is strong, the Doppler filter of the body can be used to detect the target. When the signal intensity of the sheath is stronger than the signal intensity of the body, the channel of the strongest Doppler filter of sheath can be selected to detected the target, so the target can be accurately located by detecting the sheath, and complete the tracking measurement of the target. The phase coded signal can provide a powerful supplement to the conventional LFM signal to detect the sheath target and improve the tracking and measurement for the spacecraft in blackout area.