GPS Module: CW55 Network Assistance Basestation






Description
The CW55 Network Assistance Basestation is a complete module specifically designed to output time,
frequency and ephemeris data that allows assisted GPS operation of the CW55 GPS receiver. The basestation is developed from a specialized version of the CW55 receiver that is designed to output the
required assist data in a format required by the tracking CW55 receivers. The basestation is a complete stand alone module with integral DC/ DC PSU and serial port and only requires an external GPS aerial with a clear view of the sky. The use of this basestation is restricted to applications where the tracking CW55 GPS receivers have a similar view of the sky as the basestation (for applications that require greater distances between the basestation and tracking CW55 GPS receivers, please contact NavSync). The basestation outputs the assist data over an RS232 serial port or USB port, and for versions of the basestation that include other communication modems, such as GSM/GPRS,please contact NavSync.

Applications
- Easy to use complete Network Assistance Basestation
- Includes all required user peripherals (RS232 and USB)
- Includes all manuals and software
- For basestation versions with GSM/GPRS, please contact NavSync


Block Diagram



CW55 Network Assist Message Format
These messages are a series of ASCII comma separated messages which are output from UART3 of the CW55 Network Assist Basestation at 38,400,8,N,1. Each message starts with a # character and ends with a <CR><LF>. Prior to the end of the message there is an & character followed by an 8-bit accumulative checksum of all bytes in-between the # and & characters in represented in ASCII hexadecimal. For simplicity, the messages which contain data normally transmitted in the GPS satellite’s Navigation Messages, contain the data formatted and scaled as closely as possible to it.

The data messages output are as follows;
- #WTP, Week, Time, Position Message
- #EPH, Ephemeris Subframe Message
- #ALM, Almanac Subframe Message
- #KLB, Klobuchar Ionospheric Parameters Message
- #UCP, UTC Correction Parameters Message
- #TIM, Time Input Message
- #LOC, Location Message



CW55 Product Brief
Ver 3.0 Date: 8/11/04
Copyright © 2004 NavSync Ltd.
All Rights Reserved Specifications subject to change without notice.