Type 791-A Precision Approach Radar
Description of the radar set, tactical-technical characteristics
Figure 1: Type 791-A Precision Approach Radar (1991)
| Specifications | |
|---|---|
| frequency: | X-Band |
| pulse repetition time (PRT): | |
| pulse repetition frequency (PRF): | |
| pulsewidth (τ): | |
| receive time: | |
| dead time: | |
| peak power: | |
| average power: | |
| instrumented range: | 35 km |
| range resolution: | 200 m |
| accuracy: | r= 60m; β= 0.5°; ε= 0.35° |
| beamwidth: | both: 1.2° |
| hits per scan: | |
| antenna rotation: | |
| MTBCF: | |
| MTTR: | |
Type 791-A Precision Approach Radar
The Chinese-manufactured Type 791-A Precision Approach Radar is a typical military mobile radar equipment operating in X-Band. It is mounted on a six-wheeled truck, although the manufacturers state that both mobile and fixed installations were available. It closely resembles the former Soviet RSP-7 PAR (NATO reporting name “Two Spot”) and it could well be a licence-made version although there are slight differences.
Like the RSP-7 the Type 791-A PAR uses two scanners, a 20-degree left/right swinging antenna for search and azimuth guidance and a by six degree nodding elevation antenna for elevation guidance. These Orange-peel-antennas are co-located on a mounting at the rear of the vehicle. Circular polarisation is provided to combat weather clutter and the receiver includes a logarithmic intermediate frequency amplifier. Dual transmitter/receivers are provided to ensure continuity of service. For the same reason the display indicators are also duplicated. Double B scope displays are used to improve the accuracy at short range.
There is an operators' cab in front of this which also contains communications facilities. For VHF and ultrahigh frequency (UHF) air communications it used a cone-shaped dipol antenna. When operating the antenna is able to change direction rapidly to cope with aircraft landing on different runways.