Generalized Dechirp-Keystone Transform for Radar High-Speed Maneuvering Target Detection and Localization

Abstract

The multivariate range function of the high-speed maneuvering target induces modulations on both the envelop and phase, i.e., the range cell migration (RCM) and Doppler frequency migration (DFM) which degrade the long-time coherent integration used for detection and localization. To solve this problem, many long-time coherent integration methods have been proposed. Based on mechanisms of typical methods, this paper names two signal processing modes, i.e., processing unification (PU) mode and processing separation (PS) mode, and presents their general forms. Thereafter, based on the principle of the PS mode, a novel long-time coherent integration method, known as the generalized dechirp-keystone transform (GDKT), is proposed for radar high-speed maneuvering target detection and localization. The computational cost, energy integration, peak-to-sidelobe level (PSL), resolution, and anti-noise performance of the GDKT are analyzed and compared with those of the maximum likelihood estimation (MLE) method and keystone transform-dechirp (KTD) method. With mathematical analyses and numerical simulations, we validate two main superiorities of the GDKT, including (1) the statistically optimal anti-noise performance, and (2) the low computational cost. The real radar data is also used to validate the GDKT. It is worthwhile noting that, based on closed analytical formulae of the MLE method, KTD method, and GDKT, several doubts in radar high-speed maneuvering target detection and localization are mathematically interpreted, such as the blind speed sidelobe (BSSL) and the relationship between the PU and PS modes.

Frequency Diversity Gain of a Wideband Radar Signal

“…When the two are combined, more complex problems will appear, and more factors need to be considered to determine the optimal bandwidth. In reference [23,24], several classical radar target azimuth echo accumulation methods are given. Combining the theory studied in this paper with such methods, the diversity gain of azimuth can be further studied.…”

Long-time coherent integration algorithm for high-speed maneuvering target detection

“…Furthermore, the blind speed side lobe effect may appear in RFT and GRFT inducing a protruding false alarm problem due to discrete pulse sampling, finite range resolution, and limited integration time. 13,14 KT-class algorithms, including the generalized dechirp-KT (GDKT), 15 KT-matched filtering process (KT-MFP), 16 and other algorithms, [17][18][19][20] can correct the LRM without requiring any prior information about the target's velocity. In Refs.…”

“…We should emphasize that it is very difficult to conduct radar experiments against real highspeed maneuvering targets, so in recent works, unmanned aerial vehicles (UAVs) were usually taken as the targets in practical radar experiments. 4,15,27,29 From the signal modeling and processing points of view, the RM and DFM should be the two most important problems for maneuvering target detection regardless of target speed. In the practical experiment of this work, an airplane is taken as the target whose equivalent motion parameters are significantly larger than that of the UAVs in published works.…”

Long-Time Coherent Integration for Maneuvering Target Based on Second-Order Keystone Transform and Lv’s Distribution

“…Over the past few years, radar has been widely applied in civil and military due to its all-day and all-weather target detection capability. However, the gradual development of stealth technology makes the signal-to-noise ratio (SNR) of radar echoes extremely low, posing a significant challenge to the traditional radar detection technology [1][2][3][4][5]. It is known that integrating the energy of multiple echoes can effectively improve the ability of weak target detection without changing the radar hardware.…”