Installation guide

LMU Users Guide

V1.0.6 December 10 2009

- 61 - CalAmp Proprietary & Confidential

9.2.3 GPS Restart

In some cases it may be desirable to have the LMU automatically reset the GPS Receiver

outside of the PEG script. This timer, which is controlled by S-Register 144, is the length of

time the LMU will wait after losing GPS signal before resetting the GPS Receiver. The value

of this Register ranges from 1 to 255 minutes with a value of 0 disabling the reset. It is

VERY important that this value be long enough to allow the LMU to gain GPS lock. For

instance a value of 1 minute could ensure that the LMU never gains a GPS lock while in a

challenging GPS environment. A value of 5 minutes is the recommended minimum.

9.3

When a GPS receiver is stationary the position it produces does not remain static. That is,

the position will actually drift and move over time. The idea behind Pinning is to only update

the LMU’s current position when a ‘better’ position is received. This is to help prevent drift

that could give false moving reports or other GPS events.

Pinning

Pinning is controlled by 3 S-Registers, 156, 142 and 174.

9.3.1 Enable / Disable pinning

Pinning is turned on or off by setting or clearing bit 0 of S-Register 156. To enable Pinning

you would use:

AT$APP PARAM 1024,36,1,1

To disable Pinning you would use:

AT$APP PARAM 1024,36,1,0

9.3.2 Using Ignition to control Pinning

The LMU can use its ignition line to decide if it should apply its Pinning logic. When ignition

control is enabled, the LMU will Pin the position when the ignition off. Pinning will not be

used when the ignition is on.

If ignition control is disabled then Pinning begins once the LMU drops below its Moving

Speed Threshold

Ignition control is enabled by clearing bit 1 of S-Register 156.

. Pinning is stopped when the LMU exceeds its Moving Speed Threshold.

AT$APP PARAM 1024,36,2,0

It is disabled by setting bit 1.

AT$APP PARAM 1024,36,2,2

See the PEG Programming Guide for details on the Moving Speed Threshold