High Range Resolution Profile Construction Exploiting Modified Fractional Fourier Transformation

Abstract

This paper addresses the discrimination of closely spaced high speed group targets with radar transmitting linear frequency modulation (LFM) pulses. The high speed target motion leads to range migration and target dispersion and thereby the discriminating capability of the high range resolution profile (HRRP) deteriorating significantly. An effective processing approach composed of stretch processing (SP), modified fractional Fourier transform (FrFT), and multiple signal classification (MUSIC) algorithm is proposed to deal with this problem. Firstly, SP is adopted to transform the received LFM with Doppler distortions into narrow band LFM signals. Secondly, based on the two-dimensional range/velocity plane constructed by the modified FrFT, the velocity of the high speed group target is estimated and compensated with just one single pulse. After the compensation of range migration and target dispersion simultaneously, the resolution of the HRRP achieved by single pulse transmission improves significantly in the high speed group targets scenarios. Finally, MUSIC algorithm with superresolution capability is utilized to make a more explicit discrimination between the scatterers in comparison with the conventional SP method. Simulation results show the effectiveness of the proposed scheme.

Steady-State Performance Analysis of Tracking Filter Using LFM Waveforms and Range-Rate Measurement

“…Tracking filters for robots and aircrafts predict the trajectory and velocity of a maneuvering target based on the measurements by remote sensors, such as radars, lidars, and/or sonars. For certain applications in such fields, linear frequencymodulated (LFM) waveforms are used for improving the resolution of the range measurements and imaging [1][2][3][4]. In measurements using LFM waveforms, a bias error occurs due to the Doppler effect, known as range-Doppler coupling [4,5], which must be compensated.…”

“…Most conventional studies on steady-state LFM tracking filters have considered the measurement of the range (distance) alone [5,[8][9][10], neglecting the measurement of the range-rate. However, owing to technical advancements, recent LFM radar systems can generally measure the range and range-rate with sufficient accuracy [1][2][3][4]11]. In [4], a measurement model incorporating compensation for range-Doppler coupling using the measured range-rate was presented and applied to radar ship tracking.…”