Real-time pulse compression radar waveform generation and digital matched filtering

Abstract

Real-time digital implementation of radar waveform pulse compression and match filtering on FPGA platform is studied. In this work, different types of radar waveforms including phase coded, linear frequency (LFM) and non-linear frequency modulated (NLFM) signals are generated digitally in Xilinx Virtex-5 FPGA platform. Waveforms with different time bandwidth products are tested both in FPGA platform and computer. Digital matched filtering implementation procedure used in FPGA is presented and comparison of theoretical calculations and FPGA implementation results along with implementation resource utilization are presented. Results indicate that precise generation of real-time waveform matched filtering implementations deviate at most 1 dB on range sidelobe levels from theoretical results. Moreover adopted segmentation and parallel implementation of the received pulse both allows processing of divided pulses without SNR degradation and uses less FPGA resources in general compared to processing full PRI at once.

Overlap-Save Commutators for High-Speed Streaming Data Filtering

“…However, for cases where the sample rate is higher than the clock frequency, several samples must be processed per clock cycle due to high bandwidths and the previous techniques cannot be used. These cases include radar [2], satellite [3], and optical communication [4], [5].…”

Sidelobe level reduction in ACF of NLFM waveform

“…In the phase coding and amplitude weighing methods, due to the phase discontinuity and variable amplitude, the mismatch loss increases in the receiver [14]; therefore, the use of LFM signals increases significantly due to continuous phase and constant amplitude. Although, the LFM method shows clear advantages over the phase coding and amplitude weighing methods, but the high sidelobe level is still annoying because of masking the smaller targets by sidelobes of bigger targets; thus, the NLFM method is used thanks to its significant decrease in peak sidelobe level (PSL) [15].…”

Generation and Digital Correlation of Barker Code for Radars and Communication Systems

“…There are several methods of pulse compression that have been used in the past. The most popular of them is frequency codes: (LFM-Costas) [1,3,6] and the phase codes (Binary phase code or Barker code and Polyphase codes: Frank, P1, P2, P3, P4 [5]). Golay complementary sequences are pairs of binary codes belonging to a bigger family of signals called complementary pairs, which consists of two codes of the same length n, whose auto-correlation functions have side-lobes equal in magnitude but opposite in sign.…”