System and method for frequency management in a communications positioning device
US6867734B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 2003 |
| Grant date | Mar 15, 2005 |
| Priority date | — |
| Expiry date | May 15, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J2200/11
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency management scheme for a hybrid communications/positioning device, such as a cellular/GPS or other combined device, generates a local clock signal for the communications portion of the device, using a crystal oscillator or other part. The oscillator output may be delivered to a phase locked loop to drive a high-frequency clock for the cellular or other communications portion of the hybrid device. A processor may determine frequency error between the phase locked loop and base station or other reference, to derive a digital frequency tracking message. A Doppler search or other logical control message may likewise be communicated from the processor to a GPS or other positioning receiver. The GPS receiver circuitry may consequently adjust Doppler center, window width or other parameters to enhance time to first fix or other performance. The architecture eliminates the need for a second crystal or other direct oscillator in the GPS receiver portion of the hybrid device, while still maintaining GPS performance. The architecture of the design also eliminates the need for frequency correcting elements in the crystal oscillator or other base reference oscillator or clock. The in…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.