GPS Orion
12 Channel GPS Receiver Design
Product Brief
DS4808 - 1.3 August 1997
The GPS Orion is an evaluation kit to demonstrate the
capability of the Mitel Semiconductor GP2000 Global
Positioning chip set. It is a fully functional GPS receiver design
which provides full 12 channel parallel tracking hardware and
software for GPS system integrators and designers of GPS
receiver subsystems. This new approach offers a complete
GPS receiver ‘engine’ design with the design information
being freely available, providing the ability to integrate GPS
with dedicated IC components. This allows wider design
flexibility and lower cost solutions than using third-party module-
based receivers. It enables the GP2000 chipset to be evaluated
in real applications.
FEATURES
I
Small board size - 95 mm x 50 mm
I
12 channel GPS Receiver architecture
I
Highly integrated miniature silicon Front-end IC
I
Low cost 12 Channel Correlator IC
I
32 bit RISC processor with spare processing
I
Easy to embed into host systems
I
Non-volatile data retention
I
Supported by Development System (GPS Architect)
with access to GPS software source code at minimal
cost
The GPS Orion comprises two boards : a GPS Receiver
board, and an Interface board. The Receiver board is based
on the GP2000 chip set plus complementary components
which make a complete GPS Receiver. The Interface board
provides power and data conditioning interfaces to peripheral
equipment, and long term memory backup.
GPS Receiver Board
The GPS Orion receiver architecture uses integrated
circuits manufactured by Mitel Semiconductor. The GP2000
chipset comprises the GP2015 RF downconverter, the
DW9255 35.42MHz (2MHz BW) IF SAW filter, the GP2021
correlator IC, and the 32-bit ARM60 RISC processor.
The use of a GP2015 RF downconverter offers good
immunity from out-of-band noise, especially when used with
the DW9255 surface mount SAW filter as a 2nd IF filter. The
design offers superior RF performance with a high degree of
noise rejection from digital sources. The 2-bit sampled IF, in
conjunction with triple-conversion architecture provides best-
in-class RF jamming resistance.
The GP2021 12 channel correlator can be used to track
C/A code for the Standard Positioning Service. Any channels
not used can be deselected to save power. The digital
interface is compatible with most 16 or 32-bit processors and
the IC includes interface logic to allow it to be easily coupled
to the ARM60 32 bit RISC processor.
Fig.1 GPS Orion Receiver Board with Interface Board
The ARM60-B 32-bit RISC microprocessor offers high
instruction throughput and fast real-time interrupt response.
The ARM60 offers superior performance for 12 channel
processing, which is important for applications such as vehicle
tracking and automotive applications.
Interface Board
The Interface board provides those functions which
would normally be included elsewhere in a GPS system.
These functions include : voltage regulation, battery back-up
(1000 hours memory retention), and serial interfaces to output
the information and to input commands and DGPS correction
data.
Software
The software for GPS Orion is stored in EPROM and is
self-booting. The software provides many facilities including:
NMEA 0183, or proprietary WINMON data interfaces
Navigation position filtering
Satellite Almanac and Ephemeris save and upload
Reliable satellite tracking
RTCM SC-104 Differential Correction input
Data Retention
The Receiver board includes a supercap (0.22 F) which
gives approximately 4 hours retention of volatile data
(position, satellite ephemerides, etc.) in isolation from the
Interface board. The Interface board includes a rechargeable
battery giving approximately 1,000 hours data retention.
MITEL [ MITEL NETWORKS CORPORATION ]
