ashtech DG14, Reference Manual

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232 DG14 and DG16 Board & Sensor Reference Manual
Typical GDC Message:
$PASHR,GDC,015454.00,EMER,588757.623,4136720.056,2,04,03.8,0001
2.123,M,-031.711,M,14,1010,W84*2A
Table 8.5 outline the message format:
d5 Positioning mode Indicator
• 1: Autonomous position
• 2: RTCM differential, or CPD float position
• 3: Carrier Phase differential (CPD) fixed
1, 2, 3
d6 Number of GPS satellites being used 3 to 12
f7 Horizontal Dilution of Position (HDOP) 00.0 to 99.9
f8 Altitude (meters) -9999999.999 to
+9999999.999
M Altitude units M(eters)
f9 Geoidal separation in meters w.r.t. selected datum and
Geoid Model -999.999 to
+999.999
d10 Age of differential corrections 0 to 999
s11 Differential reference station ID 0000 to 1023
s12 Datum type W84, USR
*hh Checksum 2-character hex
Table 8.6. Typical GDC Message
Item Description
015454.00 UTC time
EMER Equatorial Mercator map projection
588757.623 User Grid easting (X) coordinate
4136720.056 User Grid northing (Y) coordinate
2 RTCM differential position
04 Number of satellites used to compute position
03.8 HDOP
00012.123 Altitude
M Altitude units (M = meters)
-031.711 geoidal separation w.r.t. selected datum
Table 8.5. GDC Message Structure (Continued)
Parameter Description Range