In this letter, a synthetic aperture radar (SAR) image transform method is proposed using the periodic-coded phase modulation. By modulating the intercepted radar signal with the periodic-coded phase pulse, multiple false targets can be formed along the range direction in the radar image. Then, the target of interest (TOI) can get protected by the deception jamming effect. On this basis, the jamming property and parameter design principles are further discussed. Finally, the mini-SAR data experiment indicates that multiple false targets approximately from 15 to 30 dB higher than the low-level background are generated in the SAR image and then demonstrates the validity of the proposed image transform method.

Forward scatter radar (FSR) can achieve target detection by capturing the signal disturbance caused by targets crossing the baseline, which provides a countermeasure to stealth/small targets. Firstly, the FSR net model based on the Global Navigation Satellite System (GNSS) is constructed. Then, the statistical features in the time and frequency domains are used to describe the fluctuation characteristics of the forward-scatter signal. Moreover, the influences of the relative position of the target and baseline on the statistical features are analyzed through dynamic simulations, and the change regulation of time and frequency features is revealed. Finally, a FSR experiment is carried out in an anechoic chamber and the results validate the theoretical analysis. This work provides a meaningful reference for detection and parameter estimation of targets crossing the baseline in a FSR.

Compared to the steady-state part of the extended target echo, few scholars have paid enough attention to the echo establishment and disappearance part. They contain abundant target information, but have not been fully explored and utilized. Since the pulse duration of both parts is typically short, they can be considered as instantaneous processes. Polarization is an inherent property of electromagnetic waves, which can bring information gain to the analysis of the echo instantaneous part. The objective of this study is to utilize the instantaneous polarization response (IPR) of the echo to achieve super-resolution for two targets with different polarization scattering characteristics. It is analyzed that when two target echoes are “equal-amplitude and opposite-phase", echo decoupling can be achieved, which is the precondition for achieving range super-resolution. While making full use of the polarization information is instrumental in achieving the echo with “equal-amplitude and opposite-phase". A trihedral and a dihedral are selected to verify the effectiveness of the proposed method. Multiple sets of measured data show that the two target echoes do have the instantaneous part. When the signal-to-noise ratio (SNR) of the echo data is about 6-7dB, the range super-resolution and range estimation of the two targets are achieved by using the edge threshold detector.

This letter proposes a novel algorithm to estimate the 3-D attitude using bistatic full-polarization information. First, tilt angles of bistatic Huynen target parameters are extracted from the Sinclair matrix. Then, extracted tilt angles are used to recover the linear-type target attitude by parametric space searching and noncoherent accumulation. Anechoic chamber experiment results demonstrate that the max relative error is smaller than 3% for an iron wire object with two attitude placements.

The parameter estimation in the forward scatter radar (FSR) network is the focus of attention in the radar field. In this letter, a parameter estimation method by using the crossing time difference and Doppler rate is proposed in the FSR network. The continuous position and velocity estimation of the uniform moving target is realized. Then, the factors affecting the estimation accuracy are theoretically analyzed, including parameter measurement error and receiver locations. The effectiveness and adaptability of the method are validated through Monte Carlo simulations. Compared with the parameter estimation method only based on the crossing time, higher accuracy can be achieved and fewer receivers or transmitters are needed, so it should be easier to be deployed in the real application.

Due to the high cost of obtaining echo data for space targets in real cases, most of the research usually relies on the simulation. The electromagnetic (EM) calculation is well known as one of the simulation tools. In this letter, the relationship between the calculated complex radar cross-section data and the baseband echo signal is analyzed. Then, the difference in the polarization reference plane of the radar coordinate system and EM calculation coordinate system is pointed out. For simulating the baseband echo signal with full polarization, the scattering matrix obtained by EM calculation should be rotated according to the radar position, the target position, and the target attitude. At last, a simulation of the baseband echo signal with full polarization for a cone-shaped target is given to verify the simulation algorithm.