User's Manual

545C Operations Manual

02/10/2012 Prerelease DCN 00001789-A

5.4.2 Differential GPS

MBNET200 (ELOS protocol) may be used to broadcast differential correction

data to all Remote Stations in the network. This eliminates the need for

having a differential GPS receiver at each MCC-545C mobile unit.

Differential beacon receivers are installed at base or repeater stations

only. The base stations then transmit the RTCM correction data at periodic

intervals to all repeaters and mobiles.

The ASSIGN and SETBAUD commands are used to configure the base stations

to use a beacon receiver.

Command Description

ASSIGN,POS,p,RTCM,nn

Port selection for transmission of RTCM data.

P = Port number, normally AUX port (2)

is used.

Nn = The interval, in seconds, that the

RTCM error correction data is

transmitted. A value of 20 seconds

provides reasonable accuracy.

SETBAUD,POS,4800,N,8,1

Set up parameters for the selected port

For example:

4800 = Baud rate

N = Parity

8 = Data Bits

1 = Stop Bit

A remote station will automatically receive and process the RTCM

correction data. No other configuration commands are required.

5.4.3 GPS Report Formats

There are two position report formats used. The POS format is the basic

report and has latitude, longitude, speed, heading and altitude. The POSS

format includes all the information above but also has a 16-bit status word

and an 8-bit code for appending canned messages. An example of each type

of format is shown in Figure 4.2.