User Guide

Nokia Customer Care System Module

6015/6015i/6016i/6019i (RH-55), 6012 (RM-20)

GPS Engine

Figure 16: GPS Engine Block Diagram

The GPS engine (GE) major components consist of two ASICs, the RF Front End with a

Low Noise Amplifier (LNA), a voltage regulator, and a Temperature-Controlled Crystal

Oscillator (TCXO). The front end provides filtering of out-of-band signals and

amplification of the frequency band of interest. The RF ASIC provides further

amplification, AGC, down-conversion to low IF, IF filtering and analog-to-digital

conversion of the IF. The baseband ASIC is responsible for all baseband processing of the

GPS signal, including PN wipeoff, decoding, and GPS measurement calculations. The

TCXO provides a 16.368 MHz signal for down-conversion and sampling and is used by

the baseband ASIC for all the GPS processing. The RF regulator provides voltage

regulation from the battery to provide 2.8 volts for the RF components.

The GE is controlled by the Cellular Engine (CE) via the GE/CE Interface. When the CE

powers up, the GE performs a self-test and informs the CE of self-test results. If the self-

test results pass, the CE will download the operational code to the GE via the GE/CE

interface. If the self-test of the GE fails, the CE will declare a hardware failure and

increment the “Test Mode 0 Failure” PPC. The CE will receive a GPS status message from

the GE after download as to the success of the download. If the download fails, the CE

will reset the GE, increment the “Code Download Failure” PPC, and try to download the

code again. After the third unsuccessful attempt of download, the CE will declare a