RANGE MEASUREMENT METHOD AND APPARATUS HAVING SCANNING INTERFEROMETERS AND RANGE SIGNAL PROCESSOR

Assignee

BOEING COMPANY THE, A CORP. OF DE

Filed

Sep 28, 1984

Granted

Sep 13, 1988

Location

SEATTLE WA US

Abstract

An array of antenna elements is arranged along a common, rotating platform so as to form a pair of mechanically scanned interferometers exhibiting spaced, parallel receiving axes for ranging on a distance emitter. As the receiving lobes of the pair of interferometers scan across the emitter, lobe modulated signals are received having a relative time difference t21 that varies as a sinusoidal function of time due to the platform's rotation and includes a dc error value due to slight but unavoidable nonparallelism of the interferometer beams. The rate of change of t21 is derived to produce a signal t21 which drops the dc error component of t21, and which is applied as an input to a rate dependent range signal processor producing an output signal of range R as a function of the relationship ##EQU1## In this relationship d is the separation of the interferometer centers along the base line, and φ is the varying angle of arrival of the emitter relative to the rotating base line of the antenna array. In a preferred embodiment, the individual antenna elements that form the pair of interferometers, are mounted and servo controlled on the rotating platform so as to maintain tracking alignment of the principal antenna beams on an emitter of interest, independently of the rotating platform so as to optimize received signal strength.

Source: Google Patents