Geometrics G-858BP User Manual

G-858BP Backpack Mag Operators Manual
Contact Geometrics for the availability of a cable specially designed for connecting directly to a GPS
system.
Once the GPS system is connected, you will need to actually send it the commands you have
previously programmed into the G-858BP. This is most easily done in the CHAT MODE of the EXT RS-
232 & FIELD NOTE SETUP. Select CHAT MODE, then press the desired keys to send the associated
command. You will be able to observe the response of the GPS system from within chat mode. Make sure
it is operating properly.
Now you are ready to log GPS data. Start your desired survey as usual. You will notice a bar
indicator which when moving indicates that data is coming in on the RS-232 port.
Using GPS data
The GPS data stored during a survey is embedded within the magnetometer and other positioning
data. You should upload this data into MagMap2000 where you can filter and plot GPS positions,
magnetometer data, destripe (remove heading error), contour and plot the data. Interpolating the
magnetometer data with GPS data is all done automatically and we recommend that you use the
MagMap2000 program to position the data with GPS or UTM coordinates. Visit www.geometrics.com
to
download the latest version of MagMap2000.
If you want the GPS positions and time in a separate file, you must manually extract the GPS data
from the magnetometer binary file. To manually extract the GPS positions from the file, perform the
following procedure. First, download the binary file using the MagMap2000 program. If you wish, you
can also do any other MagMap2000 function, such as locating the data or doing a diurnal correction.
Remember the name of the binary file (.BIN extension) you used as the output file name when
downloading the G-858BP data (Import / Download ). Exit the MagMap2000 program.
From the DOS prompt run the following program:
BINTOASC input.bin output.gps -R0 -M0 -D0 -P0 -U0 -F0
where
input is the name of the file containing the binary downloaded data (you must type the
.BIN extension
output is the filename you wish for the GPS data (you must give it an extension. The
GPS extension is a suggestion, however, you may use what you wish.)
-R0 ... The options tell the program not to extract everything except the RS-232
serial strings. They are a dash, a letter, and the numeral zero.
You will now have created a file of the GPS strings, along with some G-858BP formatting
information. Lines will be as shown below:
21 DATA_STRING Date Time
Example (Line is broken only to fit on page. It is actually a single line in the file.)
21 $GPGGA,175748.00,3726.0363,N,12210.0318,W,0,6,001.1, 00024.6,M,-
028.4,M,031,0000*6C 10:59:14.80 06/01/95
The 21 at the beginning of the line indicates this string came in the RS-232 port of the G-858BP.
The string is followed by a date and time stamp from the G-858BP. This may be used to correlate the
positions with the magnetometer readings, which are also time stamped.
Chapter 11: System Setup
Selecting SYSTEM SETUP from the main menu brings up the following menu.
---SYSTEM SETUP MENU---
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Geometrics G-858BP Specifications

General

Brand	Geometrics
Model	G-858BP
Category	Measuring Instruments
Language	English