Staggered Coprime Pulse Repetition Frequencies Synthetic Aperture Radar (SCopSAR)

Abstract

High-Resolution Wide-Swath Synthetic Aperture Radar (HRWS-SAR) imaging is highly desirable since it allows one to produce high-resolution SAR images of large areas during a short visit time. In this paper, Staggered Coprime Pulse Repetition Frequencies Synthetic Aperture Radar (SCopSAR) is proposed. It divides the time during which a scatterer is illuminated by the antenna beam-pattern into two halves where, in each half, pulses are transmitted at the rate of one of two sub-Nyquist Pulse Repetition Frequencies (PRFs). Such PRFs are related to the Nyquist PRF using two coprime sub-sampling factors. This allows extending the maximum range swath width that can be imaged by a number of times that equals the smaller sub-sampling factor at the expense of a reduction in the azimuth resolution by half. It further allows for a reduction in the amount of data to be stored and communicated. SCopSAR is an imaging modality suitable for scenes that contain a small number of bright scatterers over a dark background which, for instance, is the case when imaging ships in a calm sea background. Compared to the techniques recently proposed in the literature, SCopSAR simplifies the Radar requirements since it uses only one carrier frequency, one waveform, and one channel. Simulations and real ERS-2 satellite raw data are used to validate the theoretical findings presented in this paper.

Curvilinear Flight Synthetic Aperture Radar (CF-SAR): Principles, Methods, Applications, Challenges and Trends

“…To the best of our knowledge, there are very few studies on multi-channel CF-SAR at present, and most of them focus on forward-looking imaging [82,83]. Nevertheless, some common issues of multi-channel SAR, such as efficient signal reconstruction [84], channel calibration [85], more flexible channel configurations [86][87][88][89][90][91], more novel imaging modes [91][92][93][94], etc., also need to be solved in the research corresponding to CF-SAR, making it even more difficult for CF-SAR to be solved. In addition, due to the curvilinear trajectory, some new issues are carried out for multi-channel CF-SAR, such as the failure of the assumption of 'constant-baseline' [7], serious multi-dimensional spectrum coupling [95], SV [96], etc.…”

An Efficient Algorithm for De-Interleaving Staggered PRI Signals

“…With the development of radar technology, various PRI modulation approaches have been developed for different radar applications. One of the essential PRI modulation types, the staggered PRI, can both provide high azimuth resolution and a broad SAR swath [2][3][4] while removing the blind speed of the moving target indicator (MTI) radar system [5][6][7]. Several pulse sequences with the same PRI value and various beginning phases make up the staggered PRI signal.…”