Ground Surveillance Radar Product

Overview

A ground surveillance radar (GSR) watches a sector of terrain and reports anything that moves: a person walking at 10 km, a vehicle at 20 km, day or night, through fog, dust, and light rain that blind electro-optical sensors. Systems of this class — the AN/PPS-5 lineage, SQUIRE, Blighter, PGSR families — are carried by two or three soldiers, set up on a tripod in minutes, and used for border surveillance, base perimeter security, and reconnaissance screening. This article describes a representative man-portable Ku-band pulse-Doppler set.

The radar works by exploiting motion rather than size. Ground clutter — terrain, trees, buildings — returns echoes thousands of times stronger than a person, but clutter is stationary. A pulse-Doppler radar measures the frequency shift of each echo and filters out everything near zero velocity, leaving only movers. The practical floor is a radial velocity around 0.3 m/s; a slow crawl directly across the beam can evade it, which operators counter by repositioning.

Antenna and pedestal

The Antenna Array is a flat microstrip design: the Microstrip Patch Panel carries dozens of printed patch radiators that together form a beam roughly 2° wide in azimuth and 4° in elevation. The printed Feed Network divides transmit power across the elements with an amplitude taper that suppresses sidelobes — important, because a strong sidelobe return from a nearby road would masquerade as a main-beam target. A thin composite Radome seals the face against rain and sand.

The array sits on the Pedestal & Tripod: a Servo Motor-driven Azimuth Drive slews the head across a programmable sector at up to 36°/s, with an Encoder reporting beam azimuth to better than 0.1° so detections map to accurate grid coordinates. RF and power cross the rotating axis through the RF Rotary Joint. The Elevation Head is clamped manually to match the terrain slope, and the leveled Field Tripod holds the 30 kg head rigid in wind — pedestal wobble translates directly into false Doppler.

Transmitter and receiver

The Transmitter is entirely solid-state. The Frequency Synthesizer in the Receiver / Exciter generates a coherent, low-phase-noise waveform; the Driver Amplifier and GaN GaN Power Amplifier raise it to 5–10 W average. That is all the power a modern set needs: pulse compression and long coherent integration substitute processing gain for brute transmit power, with the side benefits of low detectability by enemy ESM, no high-voltage tube, and fanless conduction cooling through the Transmitter Heatsink.

The Circulator duplexes the single antenna between transmit and receive. Returning echoes — down to femtowatt levels — enter the Low-Noise Amplifier, whose ~2 dB noise figure fixes the sensitivity of the entire system, then pass through the Mixer stages to an intermediate frequency and onto the ADC Board for digitization. Coherence is the critical property end to end: the phase of every echo must be preserved relative to the transmitted pulse, because the Doppler measurement lives entirely in that phase history.

Signal processing

The Signal Processor turns raw echo data into tracks. The FPGA Processing Module performs pulse compression (giving ~10 m range resolution from a long, low-power pulse) and then runs an FFT bank across successive pulses in every range cell, sorting returns by radial velocity. Detections that exceed an adaptive threshold pass to tracking software on the Compute SoC Module, which associates them scan-to-scan into target tracks.

Classification uses the Doppler signature itself. A walking human modulates the return with limb micro-Doppler at a characteristic cadence; a wheeled vehicle gives a clean body line; a tracked vehicle adds the distinctive flicker of its track. The classifier labels tracks as person, group, light vehicle, or tracked vehicle, and the same signature is rendered as audio through the operator terminal's Speaker — experienced operators identify targets by ear.

Operation and power

The operator works from the Operator Terminal, a sealed magnesium Terminal Housing with a sunlight-readable LCD Panel and Touch Digitizer, showing tracks overlaid on a map. Through the Data Modem the terminal can sit up to a kilometer from the radar head, keeping the operator under cover while the antenna occupies the exposed crest.

The Power System runs the set at about 90 W from two hot-swappable 12 V Battery packs managed by a BMS Board, with the DC-DC Converter accepting any 18–32 V source — vehicle, generator, or the mains Power Supply adapter — for static, long-duration surveillance tasks.