Method for extending range and sensitivity of a fiber optic micro-doppler ladar system and apparatus therefor
US5847817A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 1997 |
| Grant date | Dec 8, 1998 |
| Priority date | — |
| Expiry date | Jan 14, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/32
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for compensating a reference signal used in a coherent receiver of a micro-doppler sensor having a transmitter includes the steps for: (a) repeatedly measuring phase differences between a signal emitted by the transmitter a first time and a previous signal emitted at a previous time so as to produce a plurality of phase error signals; (b) accumulating the phase error signals over a propagation time between the transmitter and the coherent receiver so as to produce a cumulative phase error signal; and (c) modulating a signal produced by the transmitter at the end of the propagation period so as to generate a compensated reference signal having a phase characteristic substantially identical to the signal produced by the transmitter at the beginning of the propagation period. A phase error or noise compensator, which can form part of a micro-doppler ladar system, is also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.