User's Manual

B GSOF Messages
104 SPSx80 and SPSx81 Smart GPS Antennas User Guide
PDOP
This message describes the PDOP information. It contains the following data:
• PDOP
• HDOP
• VDOP
• TDOP
SIGMA
This message describes the Position Sigma information. It contains the following data:
• Position RMS
• Sigma east, in meters
• Sigma north, in meters
• Sigma up, in meters
• Covariance east-north
• Error Ellipse Semi-major axis, in meters
• Error Ellipse Semi-minor axis, in meters
• Orientation of Semi-major axis in degrees from True North
• Unit variance
• Number of epochs
Table B.9 PDOP (Type 9 record)
Field Item Type Value Meaning
0 Output record type Char 09h PDOP information output record
1 Record length Char 10h Bytes in record
2–5 PDOP Float Positional Dilution of Precision
6–9 HDOP Float Horizontal Dilution of Precision
10–13 VDOP Float Vertical Dilution of Precision
14–17 TDOP Float Time Dilution of Precision
Table B.10 Sigma (Type 12 record)
Field Item Type Value Meaning
0 Output record type Char 0Ch Position sigma information output record
1 Record length Char 26h Bytes in record
2–5 Position RMS Float Root means square of position error calculated
for overdetermined positions
6–9 Sigma east Float Meters
10–13 Sigma north Float Meters
14–17 Covar. east-north Float number Covariance east-north (dimensionless)