Approach for space‐based radar manoeuvring target detection and high‐order motion parameter estimation

Abstract

The detection of manoeuvring target for space-based radar is a challenging task because of its weak energy and manoeuvring motion. Prolonging the integration time is an effective method to increase signal energy, which can improve the target detection performance. However, with the increase of integration time, the radial velocity, radial acceleration and radial acceleration rate of manoeuvring target will induce linear range walk, quadratic-range curvature, cubic-range curvature and Doppler frequency migration of echo signal, which may degrade the performance of target detection. To solve this problem, a novel method is proposed that implements a parameter separation transform to isolate the acceleration. Then, the velocity and the acceleration rate can be obtained via one-dimensional search after the compensation of linear and cubic-range migration based on Hough transform and third-order Keystone transform. The kernel steps are as follows: (i) the acceleration is isolated by multiplying the range-compressed data in range frequency domain by its timereversed data according to the symmetrical property of azimuth slow time; (ii) the cubic-range curvature is corrected by a third-order Keystone transform. The simulation results demonstrate the effectiveness of the proposed method in estimating radial velocity, radial acceleration and radial acceleration rate of a manoeuvring target, thereby the signal energy can be finely accumulated.

A fast non-searching algorithm for radar maneuvering target detection

“…Inserting (6) into 4, we obtain the slow time reversed form of the range compressed signal, i.e., Then, the PS operation is defined as [20] The expression of (8) in the range time domain is written as below where A 4 denotes the signal amplitude.…”

“…Nevertheless, there might be more than one target for radar to detect in practical situations, thus it is necessary to discuss the ability of PS-SOKT-NUSFT to suppress cross terms. Note that the number of targets is K , then the compressed signal in the range frequency domain can be expressed as where From (20) to (25), it is obvious that after conducting PS and SOKT, the energy of each self term has been relocated in one range cell, whereas range migration still exists for cross terms. What's more, the first-and thirdorder phase terms will affect the focusing performance of cross terms in the slow time domain.…”

“…As for the the energy accumulation process in the PS-AS algorithm [20], a 2-D matched filtering process is conducted in each search for acceleration, which has the computational complexity of O N s2 NM 1 + log 2 N + log 2 M , where N s2 represents the searching times of acceleration. For comparison, Table 1 shows the computational complexities of PS-SOKT-NUSFT and PS-AS.…”

“…However, there will be a residual trajectory existing after conducting KT when the maneuvering target has a complex motion, thus some extra operations are needed to compensate the residual range migration. In [20], the parameter separation (PS)-acceleration search (AS) approach is proposed for target focusing, it only needs to search for the target's acceleration after isolating it from other motion parameters.…”

Radar high-speed maneuvering target detection based on joint second-order keystone transform and modified integrated cubic phase function

“…However, because the target's energy spreads in the range frequency *Address all correspondence to: Jiancheng Zhang, E-mail: zjc7836@126.com domain, this method suffers from great signal-to-noise ratio (SNR) loss. The cubic phase function (CPF)-based methods 12,13 and the adjacent correlation function LVT 14 also face similar problems. An improved axis rotation discrete chirp Fourier transform (IAR-DCFT) method is presented in Ref.…”