Pentek provides SDR interface for NeXtRAD multistatic radar

June 01, 2017 //By Jean-Pierre Joosting
NeXtRAD is a dual-band, dual-polarization, multistatic radar system under development at the University of Cape Town (UCT) in collaboration with University College London (UCL). The primary mission of the system is to collect multistatic data of small radar cross-section maritime targets embedded in sea clutter.

“Pentek's Cobalt® Model 71621 was selected as the SDR interface because it is well suited to the radar's requirements, providing three A/D converters and a dual-channel 800 MHz D/A converter,” said Mr. Dane du Plessis, member of the system integration team for NeXtRAD.

NeXtRAD is a multi-sensor network comprised of three stations (or nodes) separated by several hundred meters, all focusing on a common target area. The system requires a usable bandwidth of 50 MHz to achieve a range resolution of three meters. Each node has dual-polarized L- and X-band antennas (IEEE definition) with a 10-degree beamwidth.

This arrangement effectively forms a pair of bistatic radars in combination with a monostatic radar, which means that target data can be simultaneously acquired from three perspectives. This topology has advantages over single-sensor radars. NeXtRAD is a more capable version of NetRAD, a single-frequency multistatic radar developed by UCT and UCL.

NeXtRAD requires that waveform generation and digitization be fully coherent at each node. To achieve coherency, each node is supplied a very stable 10 MHz reference signal from a local GPS-disciplined oscillator (GPSDO), which is distributed via a frequency distribution unit (FDU) to the Cobalt module and to the receiver exciter (REX). This ensures that there is no phase drift between oscillators in a given node and that the relative phase of oscillators between any two nodes is constant.