GPS Orion - GEC Plessey Semiconductors

GPS Orion

12 CHANNEL GLOBAL POSITIONING SYSTEM RECEIVER DESIGN

The GPS Orion is an evaluation kit to demonstrate the

capability of the GEC Plessey Semiconductors 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

■Small board size - 95 mm x 50 mm

■12 channel GPS Receiver architecture

■Highly integrated miniature silicon Front-end IC

■Low cost 12 Channel Correlator IC

■32 bit RISC processor with spare processing

■Easy to embed into host systems

■Non-volatile data retention

■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 GEC Plessey Semiconductors. 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

DS4808 - 1.3

AUGUST 1997

PRODUCT BRIEF

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

PRODUCT BRIEF

Fig.2 GPS Orion Architecture

OUTLINE SPECIFICATION

RECEIVER CHARACTERISTICS

GENERAL:

DATUM:

POSITION ACCURACY:

(standard)

POSITION ACCURACY:

(DGPS)

TIME-TO-FIRST-FIX (TTFF - Ref Notes)

●Cold start:

●Warm start:

●Hot start:

RE-ACQUISITION AFTER SIGNAL LOSS:

ANTI-JAMMING RESISTANCE:

L1 frequency (1575.42MHz), C/A code direct-sequence spread-spectrum,

12 parallel channel continuous-tracking receiver, using 2-bit digital

quantization.

WGS-84 only

25 metres Spherical Error Probability (SEP);

100 metres (2D Root Mean Square) with S/A active.

3 metres SEP, with S/A active.

Typical 90%

105 seconds <165 seconds

<60 seconds

11 seconds <15 seconds

< 2 seconds (90%)

-20dBm CW to within ±7.5MHz of L1 (for <3dB degradation in GPS SNR).

Part No Description Data Sheet

Reference

DW9255 35.42 MHz SAW Filter DS3861

GP2010 GPS RF Front End DS4056

GP2015 GPS RF Front End in TQFP package DS4374

GP2021 12 Channel Correlator DS4077

ARM60 32 Bit RISC Processor DS4004

GPS Architect 12 Channel GPS Development System DS4605

RELATED PRODUCTS

PROM SRAM

LNA

ARM60

32 Bit RISC

Processor

GP2021

12 Channel

Correlator

+ Support

Functions

GPS Antenna

GP2015

RF Front End

DW9255

Clock

Crystal

TCXO

Receiver board

Back up

Battery

NMEA/Proprietary

serial I/O (RS232)

RTCM differential

correction input

Interface board

+8V to +30V

DC Power Input

GPS Orion

PRODUCT BRIEF

DATA I/O

WINMON MODE:

(J2 socket)

NMEA MODE:

(J2 socket)

UPDATE RATE:

RTCM DIFFERENTIAL CORRECTIONS:

(J1 socket)

Proprietory GEC-Plessey Semiconductors ASCII interface protocol. Full

input/output interface, controlling all user-definable options.

19200 baud, 8-bits, No Parity, 1 stop bit.

NMEA 0183 V2.01 with GGA, RMC, GSV & GSA (output only - not

configurable).

4800 baud, 8-bits, No parity, 1 stop bit.

Receiver configuration is still available in NMEA mode, by using WINMON

command protocol at 4800 baud, 8-bits, No parity, 1 stop bit.

1 per second (both modes)

RTCM SC-104 (input only) - message types 1, 2 & 9-3

9600 baud, 8-bits, No Parity, 1 stop bit

PHYSICAL CHARACTERISTICS - GPS ORION RECEIVER BOARD

PRIME POWER: Vdd into receiver board

EXTERNAL BACKUP POWER: Vdr

ACTIVE-ANTENNA POWER:

POWER CONSUMPTION: Vdd

MEMORY/RTC BACKUP POWER

CONSUMPTION: Vdr

INSTALLED SUPERCAP BACKUP LIFE:

DATA I/O LEVELS:

SIZE: (GPS Orion Receiver Board only)

SIZE: (with GPS Orion Interface Board

attached)

CONNECTORS:

+5 volts DC, +/- 10%

>+2.2 volts DC, <+5.5volts DC

+5 volts DC available

GPS Receiver Board only: 370mA 1.85W

With Antenna: 395mA 1.98W

60µA @ Vdr > +2.2volts DC

4 hours approx.

CMOS TTL levels (0v & +5v)

95mm x 50mm x 20mm (with RF connector)

95mm x 50mm x 12mm (no RF connector)

95mm x 50mm x 30mm

RF: SMA socket

I/O: 9-pin (1 x 9), 0.1" pitch plug

PHYSICAL CHARACTERISTICS - GPS ORION INTERFACE BOARD

INPUT POWER SUPPLY:

MEMORY / RTC BACKUP BATTERY:

BATTERY CHARGE -

●RATE:

●TOTAL RECHARGE TIME:

BATTERY BACKUP LIFE (when supplying

Vdr pin on GPS Orion receiver board):

DATA I/O LEVELS:

OUTPUT DATA-MODE CHANGE:

SOFT RESET:

CONNECTORS:

+8 volts to +30volts DC

+3.6 v NiCad, 110mAhrs

7.5mA typical

18 hours approx.

8 weeks approx.

RS232 levels (±10v)

Slide switch

Push button

I/O to Orion: 9-pin (1 x 9), 0.1" pitch socket

Power: 2.5mm power socket (centre positive)

RS232: 2 x 9 pin D-type plug

ENVIRONMENTAL CHARACTERISTICS (RECEIVER BOARD ONLY)

OPERATING TEMP:

STORAGE TEMP: -40°C to +85°C

-50°C to +110°C

GPS Orion

PRODUCT BRIEF

NOTES:

1) COLD START:- A cold start results when there is no valid Almanac or Ephemeris information available for the satellite

constellation in SRAM, or when the time and/or position information is NOT known (i.e starts at 0 in both

cases).

Also a cold start will be initiated if an Almanac is valid, but a fix cannot be achieved within 10 minutes of

power-up. This could occur if the receiver position has moved significantly since it was last powered-up, but

the position change and time are NOT initialised by the user

2) WARM START:- A warm start results when there is a valid Almanac, and the initial time and position are known in SRAM,

but the ephemeris is NOT valid (i.e more than 4 - 6 hours old).

3) HOT START:- A hot start results when there is a valid Almanac, valid ephemeris (i.e. less than 4 - 6 hours old), and when

accurate time and position information are also known in SRAM (position error less than 100km, time error

less than 5 minutes). This can be simulated by a momentary Soft-Reset (i.e. press the push-button on the

GPS Orion interface Board).

Next step

The GPS Architect is available for designers who wish to develop the software further. This software, which supports the GP2000

chipset is available in both executable and source format, and is available for modification and/or embedding into the target

application. Purchase of a GPS Architect Development System provides optimum flexibility and control in the design approach

demonstrated by the GPS Orion, and includes a licence to modify the software and use it in embedded form with the target

application.

This publication is issued to provide information only which (unless agreed by the Company in writing) may not be used, applied or reproduced for any purpose nor form part of any order or contract nor to be regarded

as a representation relating to the products or services concerned. No warranty or guarantee express or implied is made regarding the capability, performance or suitability of any product or service. The Company

reserves the right to alter without prior notice the specification, design or price of any product or service. Information concerning possible methods of use is provided as a guide only and does not constitute any

guarantee that such methods of use will be satisfactory in a specific piece of equipment. It is the user's responsibility to fully determine the performance and suitability of any equipment using such information and

to ensure that any publication or data used is up to date and has not been superseded. These products are not suitable for use in any medical products whose failure to perform may result in significant injury

or death to the user. All products and materials are sold and services provided subject to the Company's conditions of sale, which are available on request.

All brand names and product names used in this publication are trademarks, registered trademarks or trade names of their respective owners.

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TECHNICAL DOCUMENTATION - NOT FOR RESALE. PRINTED IN UNITED KINGDOM.

HEADQUARTERS OPERATIONS

GEC PLESSEY SEMICONDUCTORS

Cheney Manor, Swindon,

Wiltshire SN2 2QW, United Kingdom.

Tel: (01793) 518000

Fax: (01793) 518411

GEC PLESSEY SEMICONDUCTORS

1500 Green Hills Road,

Scotts Valley, California 95066-4922,

United States of America.

Tel: (408) 438 2900

Fax: (408) 438 5576/6231

Internet: http://www.gpsemi.com