3000LRS DGPS RECEIVER
OPERATOR’S MANUAL
A Product of the Fugro Group of Companies
Issue 2.00 JUNE 2003
B11203400PMBRA0 / 28
Q-Which port on the Seastar receiver do I use to connect to my GPS
receiver?
A-
Always use the Auxiliary (AUX) port to connect the Seastar receiver to a
external GPS receiver
Q-What can I use the DATA port for?
A
-The DATA port echoes the AUX NMEA input from the external GPS receiver. It
can therefore be used for example to connect to a plotter, a computer etc.
Q-What is the pin layout of the AUX port and the DATA port?
A
-The pin layouts are as follows:
AUX port
DATA port
Pin 2-Rx NMEA
Pin 2-TX NMEA
Pin 3-Tx RTCM
Pin 3-N/C
Pin 5-GND
Pin 5-GND
Q-I understand that the Seastar receiver requires a position input from the
external GPS receiver to calculate optimised corrections for the user
location, but what do I use? GGA or GLL?
A
- We prefer GGA although GLL works just as well. The latitude and longitude
have an additional decimal place in the GGA string and are therefore more
accurate. However, the Lat and Lon are not that much more accurate that it
would effect the accuracy of the VBS solution.
The reason we prefer GGA is because there is more information in that GGA
sentence which can be displayed by the Seastar receiver. Information such as:
GPS quality indicator
Number of satellites in use
HDOP
Antenna altitude
Geoidal separation
Age of differential data
Differential Reference station ID
This information is not available in a GLL string, but as stated before, the GLL
string would work just as well.
Q-My GPS receiver port can only handle RS422. Can I connect it to the
Seastar receiver anyway, since I know that the Seastar receiver can only
handle RS232?
A
-Yes, but you must use a RS232/422 converter.