Automatic gain control in system simultaneously receiving GPS and GLONASS signals

• US 8,018,379 B1
• Filed: 04/05/2010
• Issued: 09/13/2011
• Est. Priority Date: 01/25/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm Atheros Incorporated (Qualcomm, Inc.)
• Inventors: Huang, Justin, Sun, Qinfang
• Primary Examiner(s): Tarcza; Thomas
• Assistant Examiner(s): Galt; Cassie
• Application Number:
  US12/754,562
• Time in Patent Office: 526 Days
• Field of Search: 342/357.62, 342/357.73, 342/357.75, 342/357.76, 342/357.77, 375/345
• US Class Current: 342/357.75
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/33 Multimode operation in different systems which transmit time stamped messages, e.g. GPS/GLONASS
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain

Abstract

A receiver for receiving both GPS signals and GLONASS signals is provided. This receiver includes an analog front end (AFE), a GPS digital front end (DFE) and a GLONASS DFE for receiving an output of the AFE, and a dual mode interface (DMI) for receiving outputs of the GPS and GLONASS DFEs. Search engines are provided for receiving outputs of the DMI. Notably, certain front-end components of the AFE are configured to process both the GPS signals and the GLONASS signals.

Claims

1. A method of providing automatic gain control (AGC) for a receiver configured to receive both GPS signals and GLONASS signals, the method comprising:

initializing GPS-specific amplifiers, GLONASS-specific amplifiers, and any shared GPS/GLONASS amplifiers;

correcting a gain of the GPS-specific amplifiers and any shared GPS/GLONASS amplifiers using outputs of a GPS digital front end; and

following a GPS AGC lock, correcting a gain of the GLONASS-specific amplifiers using outputs of a GLONASS digital front end.

2. A method of operating a receiver configured to receive GPS signals and GLONASS signals, the method comprising:

providing automatic gain correction (AGC) to amplifiers in an analog front end (AFE) of the receiver, the providing AGC including;

initializing GPS-specific amplifiers, GLONASS-specific amplifiers, and shared GPS/GLONASS amplifiers;

correcting a gain of GPS-specific amplifiers and a shared GPS/GLONASS amplifier using outputs of a GPS digital front end (DFE) of the receiver; and

following a GPS AGC lock, correcting a gain of GLONASS-specific amplifiers using outputs of a GLONASS DFE of the receiver.

3. The method of claim 2, wherein correcting the gain of GPS-specific amplifiers and shared GPS/GLONASS amplifiers as well as correcting the gain of GLONASS-specific amplifiers is performed by an interface counter device (ICD).

4. The method of claim 3, wherein the outputs of the GPS DFE and the GLONASS DFE are quantized outputs in which only magnitude bits are counted.

5. The method of claim 4, further including debugging the ICD by measuring other quantized outputs in the receiver.