Configurable baseband in a GPS receiver

• US 8,873,692 B2
• Filed: 01/17/2012
• Issued: 10/28/2014
• Est. Priority Date: 10/19/2005
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Obermeyer, Richard
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US13/352,262
• Publication Number:
  US 20120114018A1
• Time in Patent Office: 1,015 Days
• Field of Search: 375/373, 375/371, 375/354, 375/316, 702/89, 702/85, 455/334
• US Class Current: 375/373
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: H03L 1/027 by using frequency conversion means which is variable with temperature, e.g. mixer, frequency divider, pulse add/substract logic circuit H03L1/023, H03L1/026 take precedence
• CPC Class Codes: H03L 1/028 of generators comprising piezoelectric resonators H03L1/021, H03L1/022 take precedence; oscillation generators with a piezoelectric resonator H03B5/32

Abstract

Clock compensation for GPS receivers. A receiver in accordance with the present invention comprises a Radio Frequency (RF) portion, and a baseband portion, coupled to the RF portion, wherein the baseband portion comprises a crystal, an oscillator, coupled to the crystal, wherein the oscillator generates a clock signal based on a signal received from the crystal, a counter, coupled to the oscillator via the clock signal, a comparator, coupled to the counter, a controller, at least one logic gate, coupled to the comparator and the controller, and a combiner, coupled to the at least one logic gate, the controller, and the counter and producing an accurate clock signal therefrom.

Claims

1. A Global Positioning System (GPS) receiver, comprising:

a Radio Frequency (RF) portion; and

a baseband portion, coupled to the RF portion, wherein the baseband portion comprises a crystal;

an oscillator, coupled to the crystal, wherein the oscillator generates a clock signal based on a signal received from the crystal;

a counter, coupled to the oscillator via the clock signal, a comparator, coupled to the counter;

a controller programmed to measure a physical condition of the crystal, to calculate a compensation from the measured physical condition and to apply the compensation;

at least one logic gate, coupled to the comparator and the controller; and

a combiner, coupled to the at least one logic gate, the controller, and the counter and producing an accurate clock signal therefrom.

2. The GPS receiver of claim 1, wherein the controller corrects the clock signal.

3. The GPS receiver of claim 2, wherein the controller is reprogrammable.

4. The GPS receiver of claim 1, wherein the controller is calibrated using information generated by a physically separate device.

5. The GPS receiver of claim 1, wherein the signal generated by the crystal is not accurate enough to accurately perform a geoposition calculation.

6. A Global Positioning System (GPS) receiver, comprising:

a Radio Frequency (RF) portion generating a high-speed clock signal; and

a baseband portion, coupled to the RF portion, wherein the baseband portion comprises a crystal;

an oscillator, coupled to the crystal, wherein the oscillator generates a slow-speed clock signal based on a signal received from the crystal;

a synchronization circuit, coupled to the oscillator via the slow-speed clock signal, a counter, coupled to the synchronization circuit and receiving the high-speed clock signal, and generating a value therefrom;

a controller, coupled to the counter, wherein the high-speed clock signal calibrates the slow-speed clock signal; and

a GPS digital signal processor driven by the calibrated slow-speed clock signal.

7. The GPS receiver of claim 6, wherein the RF portion and the baseband portion are on a single semiconductor chip.

8. The GPS receiver of claim 7, wherein the high-speed clock signal is generated by a Temperature Controlled Crystal Oscillator (TCXO).

9. The GPS receiver of claim 7, wherein the slow-speed clock signal is synchronized to the high-speed clock signal.

10. The GPS receiver of claim 9, wherein the controller adjusts the value to correct the slow-speed clock signal.

11. The GPS receiver of claim 10, wherein the controller is updated using information generated by a physically separate device.