GPS receiver having RF front end power management and simultaneous baseband searching of frequency and code chip offset
First Claim
1. A GPS receiver, comprising:
- an RF front end including an IF stage and an analog-to-digital converter;
a digital baseband processor coupled to receive a digital baseband signal from the analog-to-digital converter of the RF front end; and
control circuitry coupled to the RF front end and the digital baseband processor,wherein a frequency of the IF stage is operable to be increased or decreased responsive to the control circuitry, a sample rate of the analog-to-digital converter is operable to be increased or decreased responsive to the control circuitry, and a bandwidth of the RF front end is operable to be increased or decreased responsive to the control circuitry, andwherein during a signal acquisition mode the control circuitry sets the RF front end bandwidth to approximately 2 MHz, the intermediate frequency to approximately 3 MHz, and the ADC sample rate to greater than 10 MHz;
during an ephemeris download mode the control circuitry sets the RF front end bandwidth to approximately 2 MHz, the intermediate frequency to approximately 8 MHz, and the ADC sample rate to approximately 2 MHz.
1 Assignment
0 Petitions
Accused Products
Abstract
A GPS receiver includes baseband resources for simultaneous determination of carrier frequency shift and code chip offset. Reduction in the power consumption of a receiver is achieved by managing the sampling rate of an analog-to-digital converter, the intermediate frequency of the RF front end, and the front end bandwidth so these are appropriate to the current function of the receiver. In a GPS receiver during signal tracking, the IF, front end bandwidth, and ADC sampling rate are set as high as possible; during signal acquisition, the IF and front end bandwidth are set to relatively low values, and the ADC sample rate is set to a high value; and during ephemeris download, the IF, front end bandwidth, and the ADC sample rate are set to relatively low values. When a low battery condition is detected, the IF, front end bandwidth, and the ADC sample rate are set to relatively low values regardless of whether the GPS receiver is in the signal acquisition mode, signal tracking mode, or ephemeris download mode.
86 Citations
15 Claims
-
1. A GPS receiver, comprising:
-
an RF front end including an IF stage and an analog-to-digital converter; a digital baseband processor coupled to receive a digital baseband signal from the analog-to-digital converter of the RF front end; and control circuitry coupled to the RF front end and the digital baseband processor, wherein a frequency of the IF stage is operable to be increased or decreased responsive to the control circuitry, a sample rate of the analog-to-digital converter is operable to be increased or decreased responsive to the control circuitry, and a bandwidth of the RF front end is operable to be increased or decreased responsive to the control circuitry, and wherein during a signal acquisition mode the control circuitry sets the RF front end bandwidth to approximately 2 MHz, the intermediate frequency to approximately 3 MHz, and the ADC sample rate to greater than 10 MHz;
during an ephemeris download mode the control circuitry sets the RF front end bandwidth to approximately 2 MHz, the intermediate frequency to approximately 8 MHz, and the ADC sample rate to approximately 2 MHz.
-
-
2. A method of operating a GPS receiver having a front end, and a digital baseband processor, the front end including an IF (Intermediate Frequency) stage and an ADC (Analog to Digital Converter), the method comprising:
-
setting, if in a signal tracking mode, a front end bandwidth to a first value, an IF frequency to a second value, and an ADC sample rate to a third value; setting, if in a signal acquisition mode, a front end bandwidth to a fourth value, an IF frequency to a fifth value, and an ADC sample rate to a sixth value; and setting, if in an ephemeris download mode, a front end bandwidth to a seventh value, an IF frequency to an eighth value, and an ADC sample rate to a ninth value. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A GPS receiver comprising:
-
a front end including an IF (Intermediate Frequency) stage and an ADC (Analog to Digital Converter); and a digital baseband processor coupled to the front end to control the front end bandwidth, the IF frequency and the ACD sample rate; wherein the digital baseband processor; sets, if in a signal tracking mode, a front end bandwidth to a first value, an IF frequency to a second value, and an ADC sample rate to a third value; sets, if in a signal acquisition mode, a front end bandwidth to a fourth value, an IF frequency to a fifth value, and an ADC sample rate to a sixth value; and sets, if in an ephemeris download mode, a front end bandwidth to a seventh value, an IF frequency to an eighth value, and an ADC sample rate to a ninth value. - View Dependent Claims (12, 13, 14, 15)
-
Specification