Pseudorandom noise ranging receiver which compensates for multipath distortion by dynamically adjusting the time delay spacing between early and late correlators
US5809064A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 1996 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | Aug 2, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/29
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A receiver for pseudorandom noise (PRN) encoded signals consisting of a sampling circuit, multiple carrier and code synchronizing circuits, and multiple digital autocorrelators. The sampling circuit provides digital samples of a received composite signal to each of the several receiver channel circuits. The synchronizing circuits are preferably non-coherent, in the sense that they track any phase shifts in the received signal and adjust the frequency and phase of a locally generated carrier reference signal accordingly, even in the presence of Doppler or ionospheric distortion. The autocorrelators in each channel form a delay lock loop (DLL) which correlates the digital samples of the composite signal with locally generated PRN code values to produce a plurality of (early, late), or (punctual, early-minus-late) correlation signals. The time delay spacing between the (early, late), and (punctual, early-minus-late) correlation signals are dynamically adjusted, such that in an initial acquisition mode, the delay spacing is relatively wide, on the order of approximately one PRN code chip time; once PRN code lock is achieved, the code delay spacing is narrowed to a fraction of a PRN cod…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.