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

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.

GPS Orion

12 Channel GPS Receiver Design

Product Brief

DS4808 - 1.3 August 1997