GPS Module: CW55

Description
The CW55 Network Assistance Base Station is an integrated module designed specifically to output time and ephemeris data that allows assisted GPS operation of the CW25 GPS receiver. The CW55 provides assist data in a usable format for tracking CW25 receivers in less-than-optimal GPS environmentssuch as indoors or in other areas of restricted GPS coverage.

The CW55 is a complete stand-alone module with integral DC/DC PSU and serial port, requiring only an external GPS antenna with a clear view of the sky. This use of this base station is intended for applications where tracking CW25 GPS receivers have a limited of the sky. The base station outputs the assist data over an RS232 serial port.

For versions of the base station for applications that require greater distances between the base station and tracking CW25 receivers OR for versions that include other communications modems, such as GSM/GPRS, please contact NavSync.

Features
- Easy to use complete Network Assistance Base Station
- Includes all required user peripherals (RS232)
- Includes all manuals and software


Block Diagram



CW55 Network Assist Message Format
These messages are a series of ASCII comma separated messages, output from UART3 of CW55 Network Assist Base Station at 38,400,8,N,1. Each message starts with a # character and ends with a . Prior to the end of the message there is a character followed by an 8-bit accumulative checksum of all bytes in between the # and the & characters in represented in ACSII hexadecimal. For simplicity, the messages that contain data normally transmitted in the GPS satellite\u2019s 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