Methods and systems for acquisition, reacquisiton and tracking of weak navigational signals
US7477189B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 2007 |
| Grant date | Jan 13, 2009 |
| Priority date | — |
| Expiry date | Mar 30, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/29
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Provided herein are systems and methods for achieving long coherent integration in a navigational receiver to improve the sensitivity of the receiver and enable the receiver to acquire, reacquire and track signals under very weak signal conditions. In an embodiment, phase compensation is computed based on estimated Doppler frequency, rate of change of the Doppler frequency with time, and second order rate of change of the Doppler frequency. The Doppler frequency may be computed from an orbital model or ephemeris. This phase compensation is used to compensate samples of the input signal for changes in the phase due to the Doppler frequency. Frequency components of the phase-compensated samples are then computed using a frequency analysis such as a Fast Fourier Transform (FFT). The maximum frequency component is taken as an error frequency and used to compensate the samples of the input signal for residual frequency error.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.