AN/APN-81
Description of the radar set, tactical-technical characteristics
| Specifications | |
|---|---|
| frequency: | X-Band |
| pulse repetition time (PRT): | |
| pulse repetition frequency (PRF): | 8800 Hz |
| pulsewidth (τ): | 1 µs |
| receiving time: | |
| dead time: | |
| peak power: | |
| average power: | |
| instrumented range: | |
| range resolution: | |
| accuracy: | 0.1%; 0.1° |
| beamwidth: | |
| hits per scan: | |
| antenna rotation: | |
| MTBCF: | |
| MTTR: | |
AN/APN-81
The AN/APN-81 was operating in X-Band pulsed Doppler radar dedicated as radar front end for use in the Doppler navigation equipment AN/APN-66. This Doppler navigation equipment was intended for use in long-range bombers (e.g.: on SM-62 missiles, and B-47). It was operational since 1954.
In the AN/APN-66 equipment, one-microsecond radar pulses are transmitted on four beams formed by flush-mounted linear array antennas symmetrically oriented width respect to fore-aft and right-left axes of the aircraft and directed downward at an angle of 20° with respect to the vertical. The antenna array is gyro-stabilized, and its servo system ensures that the antenna system is aligned along the ground-based course of the aircraft. The Doppler shift in frequency between the signals received on one single pair of antennas is then a measure of the ground speed of the aircraft. The difference in Doppler frequency between left and right beams is a measure of the aircrafts drift.
Source:
- W. E. Frye, E. V. Stearns, '’survey of Self-contained Navigation Systems'', RM-756-1, 26 December 1951, Revised 20 May 1952 (online)