Trimble Outdoors AgGPS 252 - Manual (Page 44)

5 Troubleshooting
3 8 AgGPS 252 Receiver User Guide
Global Positioning System (GPS)
Problem Possible solution
Poor accuracy
The accuracy of GPS positions is poor
because the receiver is picking up
poor quality signals from the
satellites.
The receiver always calculates the
most accurate position it can, given
the current GPS satellite differential
operating conditions.
Change some or all of the following GPS settings:
• Minimum elevation – Increase the setting
(the default is 8°).
• Minimum Signal Strength – Increase the System Mask AMU
setting (the default is 3).
• Maximum PDOP – Decrease the setting
(the default is 13).
• GPS Mode – Change to Manual 3D
(the default is Auto 2D/3D).
• DGPS Mode – Change to DGPS
(the default is DGPS Auto/On/Off ).
GPS signals are reflecting off nearby
trees and/or metal buildings and
horizontal surfaces. To reduce multipath noise, mount the GPS receiver
so that it has a clear view of the sky. The receiver
must be away from trees and large metal objects.
Intermittent loss of lock on
satellite
The receiver loses the satellite signal
from time to time. Make sure that the receiver is mounted on the
highest point of the vehicle and is clear of metal
surfaces.
Check Maximum PDOP and Minimum Signal
Strength settings (see Poor accuracy, above).
Intermittent DGPS signal
The correction signal strength can
drop to unusable levels. Causes
include tree canopy cover between
the receiver and the differential
satellite, radar sets, and microwave
transmitters. Move the receiver away from the tree cover and/or
from sources of electromagnetic interference.
Ag252_100B_UserGuide_ENG.book Page 38 Thursday, July 28, 2005 4:06 PM