Moving target indication

About: Moving target indication is a research topic. Over the lifetime, 2653 publications have been published within this topic receiving 32435 citations.

A New SAR–GMTI High-Accuracy Focusing and Relocation Method Using Instantaneous Interferometry

Abstract: In this paper, for a multichannel synthetic aperture radar–ground moving target indication (SAR--GMTI) system, a new high-accuracy focusing and relocating method using instantaneous interferometry, i.e., carrying out interferometry operation in the azimuth time domain before focusing, is proposed. One of the key steps of this method is to perform instantaneous interferometry to get accurate equivalent cross-track velocity (ECV) estimation for cross-track motion compensation. After that, the signal from a moving target is concentrated in range, and along-track motion compensation becomes convenient. Motion compensation transforms a moving target into a stationary one; thus, the conventional SAR imaging algorithm can be applied to focus the moving target. Finally, a strategy for accurately relocating a moving target is presented. The processing results of simulated and measured data illustrate the effectiveness of the proposed method.

Improved target detection in a littoral environment

Abstract: Radar detection of airborne targets in a littoral environment generally requires the utilization of medium to high PRF waveforms and a Doppler filter bank to attenuate the clutter and enhance the target return. In a littoral environment, with multiple interval sea and land clutter and small radar cross section targets, this processing may not be sufficient to detect the target. What is proposed in this paper is a procedure whereby with pre-transmission probing of the competing clutter an optimal waveform can be transmitted and optimally processed in the receiver. The design of this waveform implies amplitude and phase weighting of the transmitted and received pulses. Weighting of the transmitted pulses is also referred to as signal weighting. The theory of this optimization procedure is described. Typical numerical results are presented for 7-, 11-, and 14-pulse bursts, and summary performance numbers are tabulated. Typical convergence performance of the optimization procedure as a function of the number of iterations is illustrated, and our conclusions for the utilization of this technique are listed.

Noncoherent radar moving target indicator using fiber optic delay lines

Abstract: A prime candidate for detection of low flying targets over the sea surface is high resolution radar with a noncoherent delay line canceller. Fiber optic delay lines are capable of providing the required large timebandwidth (TB) product. Optimum information capacities in the spectral region around 1.3 {\mu} m are estimated theoretically to correspond to timebandwidth products of 10^8 and 10^6 for single-mode (based on 1-nm source spectral width) and graded-index multimode fibers, respectively. Pulse-to-pulse subtraction with 17-dB cancellation has been experimentally demonstrated using a 940- m graded-index multimode fiber as delay line. Higher cancellation ratios are anticipated from the use of wider bandwidth fibers.

Radar antenna pattern design for platform motion compensation

Abstract: Motion compensation techniques for coherent detection systems aboard a moving platform are discussed. Many radar and sonar systems are designed to detect moving targets within a volume of space and to reject returns from fixed objects. This can be achieved with some type of velocity (Doppler) filtering such as the moving target indicator (MTI). When the detection system is on a moving platform, both temporal and spatial processing techniques are needed to maintain good system performance. This paper presents a method for designing optimal (LMS) array correction patterns which, when used in conjunction with the primary receive pattern, minimize the effects of platform morion on the canceled clutter residue.

Moving Target Indication via Three-Antenna SAR with Simplified Fractional Fourier Transform

Abstract: Ground moving target indiction (GMTI) is of great important for surveillance and reconnaissance, but it is not an easy job. One technique is the along-track interferometry (ATI) synthetic aperture radar (SAR), which was initially proposed for estimating the radial velocity of ground moving targets. However, the measured differential phase may be contaminated by overlapping stationary clutter, leading to errors in velocity and position estimates. As effective clutter suppression can be achieved by multiple aperture or phase center antennas, this article presents a simplified fractional Fourier transform (SFrFT) for three-antenna-based SAR GMTI applications. This approach cancels clutter with three-antenna-based methods and forms two-channel signals through which moving targets are detected and imaged. Next, the Doppler parameters of the moving targets are estimated with the SFrFT-based estimation algorithm. In this way, both target location and target velocity are acquired. Next, the moving targets are focused with one uniform imaging algorithm. The feasibility is validated by theory analysis and simulation results.