Global positioning system (GPS) assembly test using wireless transmission

• US 7,889,123 B1
• Filed: 08/28/2008
• Issued: 02/15/2011
• Est. Priority Date: 08/28/2008
• Status: Expired due to Fees

• Current Assignee: Qualcomm technologies international, ltd. (Qualcomm, Inc.)
• Original Assignee: RF Micro Devices Incorporated (Qorvo, Inc.)
• Inventors: Warloe, Andreas
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): MCGUE, FRANK J
• Application Number:
  US12/200,342
• Time in Patent Office: 901 Days
• Field of Search: 342/357, 342/165, 342/173, 455/115.1, 455/115.2
• US Class Current: 342/357.62
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements

Abstract

A GPS assembly test system and method for a wireless communications device, such as a mobile telephone, having an integrated GPS receiver. The GPS assembly test can be performed without the requirement of external testing equipment. The GPS assembly test activates the wireless communications device transmitter during testing to increase GPS in-band noise. If the GPS receiver components are installed and operating properly, a change in noise is expected and can be detected. Embodiments include test software to initiate the transmitter during testing. Different methods can be used to detect a change in noise density. For example, an expected automatic reduction in gain control to a low noise amplifier (LNA) can be detected when the transmitter is activated. Another example includes setting LNA gain to a fixed gain and detecting expected changes in data generated an analog-to-digital (A/D) converter in response to the increased noise.

Claims

1. A wireless communications device, comprising:

a GPS receiver adapted to receive GPS in-band radio-frequency (RF) signals in a GPS band;

transmit circuitry onboard the wireless communications device adapted to transmit a radio-frequency (RF) signal in a wireless communications band that is different from the GPS band, wherein transmission of the RF signal causes a GPS in-band signal to be generated and received by the GPS receiver; and

a control system onboard the wireless communications device adapted to test the GPS receiver by being adapted to;

instruct the transmit circuitry to transmit the RF signal;

determine a transmission noise level in the GPS receiver caused by receipt of the GPS in-band signal from the RF signal when the transmit circuitry is transmitting; and

compare a nominal noise level representing a noise level in the GPS receiver based on the transmit circuitry not transmitting to the transmission noise level.

2. The wireless communications device of claim 1, wherein the control system is further adapted to determine the nominal noise level by measuring the noise level in the GPS receiver when the transmit circuitry is not transmitting.

3. The wireless communications device of claim 1, wherein the control system is further adapted to determine the nominal noise level by retrieving a nominal noise level pre-programmed into memory in the wireless communications device.

4. The wireless communications device of claim 1, wherein the control system is further adapted to test the GPS receiver without any external test equipment being coupled to the wireless communications device.

5. The wireless communications device of claim 1, wherein the wireless communications device comprises a mobile telephone.

6. The wireless communications device of claim 1, wherein the control system is further adapted to determine if the GPS receiver is operating properly based on the comparison of the nominal noise level to the transmission noise level.

7. The wireless communications device of claim 6, wherein the control system is further adapted to determine the GPS receiver is operating properly if the transmission noise level is greater than the nominal noise level.

8. The wireless communications device of claim 7, wherein the control system is adapted to determine the GPS receiver is operating properly if the transmission noise level is greater than the nominal noise level by at least a minimum threshold noise level.

9. The wireless communications device of claim 7, wherein the control system is further adapted to generate a test signal indicating the GPS receiver is operating properly if the transmission noise level is greater than the nominal noise level.

10. The wireless communications device of claim 7, wherein the control system is further adapted to generate a test signal indicating the GPS receiver is not operating properly if the transmission noise level is not greater than the nominal noise level.

11. The wireless communications device of claim 1, wherein the radio-frequency (RF) signal transmitted by the transmit circuitry further comprises a GPS out-of-band signal, wherein the GPS receiver is adapted to filter out the GPS out-of-band signal.

12. The wireless communications device of claim 1, wherein the GPS receiver comprises:

an amplifier adapted to amplify a received GPS in-band signal based on a gain level to produce an amplified GPS in-band signal; and

a signal processor adapted to process the amplified GPS in-band signal, wherein the signal processor is adapted to set the gain control level for the amplifier based on the noise present on the amplified GPS in-band signal;

wherein the nominal noise level comprises a floor gain level for the amplifier based on the transmit circuitry not transmitting; and

wherein the control system is adapted to determine the transmission noise level in the GPS receiver by being adapted to detect a transmission gain control level set by the signal processor when the transmit circuitry is transmitting.

13. The wireless communications device of claim 12, wherein the control system is further adapted to determine if the GPS receiver is operating properly based on a comparison of the floor gain level to the transmission gain control level.

14. The wireless communications device of claim 13, wherein the control system is adapted to determine if the GPS receiver is operating properly if the transmission gain control level is less than the floor gain level by a threshold gain level.

15. The wireless communications device of claim 1, wherein the GPS receiver comprises:

an amplifier adapted to amplify a received GPS in-band signal to produce an amplified GPS in-band signal based on a gain level;

an analog-to-digital (A/D) converter adapted to convert the amplified GPS in-band signal into digital data representing the amplified GPS in-band signal;

a signal processor adapted to process the digital data, wherein the signal processor is adapted to set the gain control level for the amplifier based on the noise present in the digital data;

wherein the nominal noise level comprises a floor data output by the A/D converter based on the transmit circuitry not transmitting;

wherein the control system is further adapted to set the gain control level to a fixed gain level; and

wherein the control system is adapted to determine the transmission noise level in the GPS receiver by being adapted to detect a transmission data generated by the A/D converter when the transmit circuitry is transmitting.

16. The wireless communications device of claim 15, wherein the control system is further adapted to determine if the GPS receiver is operating properly based on a comparison of the floor data to the transmission data.

17. A method of testing a GPS receiver in a wireless communications device, comprising the steps of:

instructing transmit circuitry onboard a wireless communications device to transmit a radio-frequency (RF) signal in a wireless communications band that is different from a GPS band, wherein transmission of the RF signal causes a GPS in-band signal to be generated and received by a GPS receiver integrated into the wireless communications device;

determining a transmission noise level in the GPS receiver caused by receipt of the GPS in-band signal from the RF signal when the transmit circuitry is transmitting; and

comparing a nominal noise level representing a noise level in the GPS receiver based on transmit circuitry not transmitting to the transmission noise level.

18. The method of claim 17, further comprising determining if the GPS receiver is operating properly based on the comparing of the nominal noise level to the transmission noise level.

19. The method of claim 18, further comprising determining the GPS receiver is operating properly if the transmission noise level is greater than the nominal noise level.

20. The method of claim 19, wherein determining the GPS receiver is operating properly comprises determining the GPS receiver is operating properly if the transmission noise level is greater than the nominal noise level by at least a minimum threshold noise level.

21. The method of claim 19, further comprising generating a test signal indicating the GPS receiver is operating properly if the transmission noise level is greater than the nominal noise level.