User's Manual

AD Plus2.0 User Manual
Page 47 of 66
then, click send and save to stop recording the GPS original data into the black box.
In addition, when the device detects that the GPS signal quality is poor, it makes
prompts via the LED light on the front panel of the device. At this time, the LED
light indicating GPS on the front panel flashes repeatedly (at intervals of 1s), and it
stops flashing when the positioning signal is recovered.
1) Choose Preferences > Collection > General > Mileage. The screen for
setting the Mileage is displayed. On this screen, you can specify the Base
Value, and correct or clear the mileage data, as shown in the following figure:
2) Choose Preferences > Collection > General > A-GPS. The screen for setting
the A-GPS is displayed.
In a strong signal environment, the autonomous GNSS receiver can cold start
positioning in about 30 seconds; however, in a weak signal environment (such as
under an elevated road, on a tree-lined path, between urban high-rise buildings, just
out of a tunnel, just out of an underground garage, etc.), receivers without external
assistance are slow to acquire satellites, and they have difficulty in acquiring a text
from satellites; therefore, it will take a long time to locate, or even impossible to
locate. The AGNSS (AGPS) service can provide the receiver with auxiliary
information necessary for positioning, such as text, rough position, and time.
Whether in a strong signal or weak signal environment, the information can
significantly shorten the time of first positioning time to achieve fast startup and fast
positioning.
When in use, the AGPS proxy server regularly obtains all ephemeris data from
various chip manufacturers and stores the data on the server. The device connects to
the proxy server through the default IP/domain name and port of the proxy server
(parameters can be modified manually). After the device is started, check whether
the AGPS auxiliary information file expires (different chip files have different due
time). If it expires, request the AGPS proxy server to obtain the latest ephemeris
data, and download it to the local by overwriting. If the data can not be obtained,
keep trying.