Angle-of-arrival measurement via time doppler shift
US5241313A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1992 |
| Grant date | Aug 31, 1993 |
| Priority date | — |
| Expiry date | Sep 3, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S3/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
To allow measurement of the angle-of-arrival (AOA) of the radar pulses from an uncooperative ground-based emitter, the method exploits the time doppler shift resulting from the velocity of a high performance aircraft and the high maneuver ability available to such aircraft to form initial angle calculations. These initial angle calculations along with inherent radar stability are then used for subsequent AOA measurements. The aircraft is flown at a constant velocity V.sub.B along successive legs with an angle .phi..sub.K between successive legs, and the velocity V.sub.B and the angles .phi..sub.K are found using a navigation system such as GPS or inertial navigation. The time difference T.sub.n '-T.sub.1 ' is measured between the arrival of the first and last of n pulses for each sample. A general approximation equation of T.sub.n '-T.sub.1 ' is normalized such that for any K samples the following equation applies, EQU e.sub.K =R(1-s cos .phi..sub.K)1 wherein .theta..sub.K is the angle from the line of flight for a leg K to the emitter, where e.sub.K =(T'.sub.n -T'.sub.1)/(n-1), s=V.sub.B /c(n-1), c is the velocity of light, and R=e.sub.K /(1-s cos .theta..sub.2). The value of the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.