Nokia 2270, 2272, 2275, 2285 Service Manual 11 GPS
CCS Technical Documentation
RH-3 Series Transceivers
Troubleshooting — GPS
Issue 1 06/2003 Confidential Nokia Corporation
RH-3
Troubleshooting — GPS CCS Technical Documentation
Page 2 Nokia Corporation Confidential Issue 1 06/2003
RH-3
CCS Technical Documentation Troubleshooting — GPS
Contents
Page No
Troubleshooting - Global Positioning System (GPS) Engine........................................ 5
Acronyms and Abbreviations......................................................................................... 6
Troubleshooting the GPS BB ......................................................................................7
Troubleshooting Flowchart....................................................................................... 7
Flowchart Notes ...................................................................................................... 10
Troubleshooting the GPS RF .....................................................................................13
Limitations .............................................................................................................. 13
GPS Receiver .............................................................................................................13
General Instructions ................................................................................................ 13
Test Equipment ..........................................................................................................14
Path of the Received Signal .......................................................................................14
GPS RF Quick Fault-finding Chart ...........................................................................15
GPS RF Circuitry and Component Placement ...........................................................16
GPS Module Test Points ............................................................................................17
GPS RF General Checking ........................................................................................18
GPS Reference Clock Checking ................................................................................21
GPS RF and GPS BB Interface Checking .................................................................23
GPS RX Chain Checking ...........................................................................................24
Issue 1 06/2003 Nokia Corporation Confidential Page 3
RH-3
Troubleshooting — GPS CCS Technical Documentation
Page 4 Nokia Corporation Confidential Issue 1 06/2003
RH-3
CCS Technical Documentation Troubleshooting — GPS
Troubleshooting - Global Positioning System (GPS) Engine
The RH-3 Model 2285 handset supports 800 CDMA / 1900 CDMA + GPS with IS 2000
capability. The RH-3P Model 2270 supports PCS and GPS functionality for Enhanced 911
(E911) services.
GPS circuitry utilizes RF signals from satellites stationed in geosynchronous orbit to
determine latitude and longitude of the handset. The GPS circuitry and the cellular
engine (CE) circuitry are completely separate in the handset. The GPS circuitry is located
exclusively on the secondary side of the PWB.
See Figure 1 for the General Block Diagram.
Figure 1: GPS Block Diagram
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RH-3
Troubleshooting — GPS CCS Technical Documentation
Acronyms and Abbreviations
AGPS Assisted GPS
AMPS Advanced Mobile Phone Service
ASIC Application Specific Integrated Circuit
E911 Enhanced 911
FCC Federal Communications Commission
BPSK Binary Phase Shift Keying
BT BlueTooth
C/A Coarse Acquisition-Code
CE Concurrent Engineering
CDMA Code Division Multiple Access
C/No Carrier to Noise ratio [dB-Hz]
DCT Digital Core Technology
DSSS Direct Sequence Spread Spectrum
FCC Federal Communications Commission
GPS Navstar Global Positioning System
HW Hardware
IC Integrated Circuit
L1 Link 1
LPRF Low Power RF
NF Noise Figure
PCS Personal Communications Service
PRN Pseudo Random Noise
PSAP Public Safety Answering Point
PWB Printed Wiring Board
Page 6 Nokia Corporation Confidential Issue 1 06/2003
RH-3
CCS Technical Documentation Troubleshooting — GPS
RF Radio Frequency
RHCP Right Hand Circular Polarized
SA Selective Availability
SPS Standard Positioning Service
UTC Universal Time Coordinated
WB Wideband
Troubleshooting the GPS BB
Figure 2: GPS RF-BB ASIC Interface
To troubleshoot the GPS BB, put the GPS engine (GE) and cellular engine (CE) in the
proper mode by selecting the GPS Testing drop-down menu item from the “Troubleshooting” dialog box. Ensure that the necessary inputs from the CE are good (e.g., power, clock,
and so on). Next, ensure that these inputs produce the proper outputs. Due to the large
level of integration (most functionality is contained in the two ASIC chips), the diagnostics that may be performed are limited.
Visually inspect the GPS circuitry to determine if the problem is physical (dislodged parts,
corrosion, poor solder joints, and so on) prior to performing any diagnostics.
Troubleshooting Flowchart
Before implementing the flowchart, turn the GPS section ON in the “GPS Receiver Control (AMS)” tab of the GPS component in Phoenix.
Reference Table 1 for GPS Test Points assignment and Figure 10 for GPS Test
Points locations.
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RH-3
Troubleshooting — GPS CCS Technical Documentation
Vcore at 1.5V?
Yes
VIO at 1.8V ?
(@ C018)
Yes
GPS_RF_CLK
(19.2MHz) OK?
(J062)
Yes
GPS_EN_RESET is
held high?
(J061)
No
No
No
Troubleshoot CE
power supply
Troubleshoot CE
VCTCXO circuit
BB ASIC being held in
reset, troubleshoot
source in CE
Yes
GPS_SLEEPCLK
(32.768KHz) OK?
(J063)
Yes
VRF_GPS OK?
Yes
No
No No
Yes
Troubleshoot CE
sleep clock circuit
VRF_GPS regulator
enable line low?
Replace regulator
N052
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CCS Technical Documentation Troubleshooting — GPS
GPS_CLK
(16.368MHz) OK?
(J010)
Yes
Test Mode 1 OK?
Yes
CE sending code
download signals?
Yes
No
No
No
Replace TCXO or
GPS RF ASIC
Replace GPS BB
ASIC
Determine why CE not
sending download
signals
SPI interface active?
Yes
RF data and clock?
Yes
Debug RF front end
No
No
Replace GPS BB
ASIC
Replace GPS RF
ASIC
Issue 1 06/2003 Nokia Corporation Confidential Page 9
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