User Guide

10
SECTION 2
RECEIVER OPERATION
Upon power up, after initial self-test has completed, the
HI-204
III will begin satellite acquisition and tracking
process. Under normal open-sky condition, position-fix
can be achieved within approximately 35 seconds (within
10 seconds if valid ephemeris data is already collected
from recent use). After receiver position has been
calculated, valid position, velocity and time information
are transmitted through the on board serial interface.
The receiver uses the latest stored position, satellite data,
and current RTC time to achieve rapid GPS signal
acquisition and fast TTFF. If the receiver is transported over
a large distance across the globe, cold-start automatic-
locate sequence is invoked. The first position fix may take
up to 50 sec searching the sky for the GPS signal. The
acquisition performance can be improved significantly if the
host initializes the receiver with a rough estimate of time
and user position.
APPENDIX B
DEFAULT VALUES
The product has the following factory preset default values:
Datum:000 (WGS-84)
NMEA Enable Switch:GGA ON
GLL ON
GSA ON
GSV ON
RMC ON
VTG ON
Checksum ON
Baud Rate:4800 Baud
Elevation Mask:5 degrees
DOP Mask:DOP Select: Auto
GDOP: 20
PDOP: 15
HDOP: 8
Receiver Operating Mode:Normal Mode (without 1PPS)
Commands can be issued to the HI-204L to change the settings of the
receiver. The new settings will remain effective on next power-on as
long as the on-board rechargeable backup battery is not discharged.
After the backup battery is discharged, factory preset default settings
will be used.