3-D Pseudo-Noise Interferometry for a Novel Bistatic Aperture Lidar

We reported an unconventional coherent Pseudo-Noise (PN) interferometry with true 3-D lidar imaging capability by recording multiple fast-time acquisition for parallel 2-D ranging while achieving azimuth compression for the third dimension without using a filled aperture. Two transmitters broadcast the same but mutually time-delayed Binary Phase Shift Keyed (BPSK) PN-code riding on shifted RF carrier frequencies to track the quadratic phase trajectory of the target in azimuth using synthetic wavelength. The range/cross-range is obtained while two time-delayed backscattered BPSK signals interfere at the receiver through code-multiplexing of the interferometric PN-modulation that encodes time-difference-of-arrival (TDOA) and time-of-flight (TOF) delay in parallel using the shift-and-add property of the maximum-length (ML) sequences. The simulation and proof-of-concept experiment demonstrate synthetic aperture (SA) imaging in azimuth dimension in addition to the 2-D parallel ranging from the PN interferometry.