Pulse-Compression SDR Radar with Doppler Processing and Two-Plane Monopulse Localization Using ADALM-PLUTO

Abstract

This paper presents the design, implementation, and experimental evaluation of a low-cost pulse-compression radar based on the ADALM-PLUTO software-defined radio platform. The radar operates near 2.4 GHz and transmits 1 ms linear-frequency-modulated chirps with a bandwidth and sampling rate of 30.72 MHz. A modified dual-receive, dual-transmit ADALM-PLUTO provides coherent full-duplex acquisition, while separate patch-antenna arrays form the transmit and receive apertures. The implemented processing chain combines pulse compression, coherent Doppler processing, clutter-map subtraction, CFAR detection, and two-plane monopulse localization using amplitude comparison in elevation and phase comparison in azimuth.

The work addresses practical SDR-radar limitations, including transmit-to-receive leakage, transmitter-induced spurious components, channel-delay mismatch, acquisition-buffer timing offsets, and host-processing latency. Analytical models are developed for the antenna patterns, monopulse response, detection range, and localization accuracy.

Six outdoor experiments involving pedestrian, vehicle, maritime, and wind-turbine targets produced dominant detection groups or sequences consistent with the expected target positions and routes. The experiments demonstrate Doppler-based radial-velocity discrimination, qualitative trajectory formation, and qualitative two-plane localization in urban, coastal, and wind-turbine-plant environments. The wind-turbine experiment produced persistent detection groups corresponding to four turbines, while blade rotation generated time-varying responses across multiple nonzero-Doppler filters. Range estimation was generally more stable than cross-range and height estimation, which remained sensitive to multipath propagation, calibration errors, phase ambiguity, antenna-pattern effects, and angular-estimation uncertainty. The platform and accompanying open-source implementation provide an accessible framework for studying pulse compression, Doppler processing, micro-Doppler responses, monopulse localization, and low-cost SDR-based radar systems.