Tracking filter for frequency measurement in a Doppler type navigation guidance system or the like
US3977002A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 6, 1975 |
| Grant date | Aug 24, 1976 |
| Priority date | — |
| Expiry date | Feb 6, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S1/40
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A Doppler type radio navigation system in which each element of a linear array is energized discretely and sequentially to produce a simulated Doppler effect at a remote location such as an aircraft on landing approach. A reference signal is also transmitted, and a receiver at the remote location "sees" a Doppler frequency shift proportional to the sine of the angle subtended by the receiver normal to the axis of the array by processing of the commutated data against the received reference signal to obtain a beat. A sum and difference transversal tracking filter arrangement is included for tracking the desired beat signal to exclude multi-path spurious beat signals. The tracking arrangement includes a voltage controlled oscillator, the detected beat signal being taken therefrom. Low noise bandwidth is obtained and performance under severe multipath conditions is improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.