Juniper Systems LandMark Mobile - Manual (Page 26)

LandMark Mobile User’s Manual
PDOP
PDOP (Position Dilution of Precision) is based on the geometric
arrangement of satellites, and indicates the quality of GPS
readings. Optimal PDOP occurs when one satellite is directly
overhead and three or more others are evenly spaced out over the
horizon. A PDOP less than 4 gives the best accuracy, between 4
and 8 is acceptable, and greater than 8 is poor.
EHE
EHE (Estimated Horizontal Error) indicates the amount of
receiver horizontal position uncertainty. This reading is an
estimate based on PDOP, HDOP, and other parameters from the
GPS receiver. The smaller the number the closer the estimate.
Note: The EHE reading appears in either feet or meters depending on the
measurement preferences that are set in the Configuration screen.
Elev
Elev (elevation) is the altitude where you are geographically
positioned. For display options, go to the Altitude Reference
section later in this chapter.
GPS Status Quality — Receiving Data
GPS status quality is shown to the right of Elev reading and
consists of the following mode indicators when receiving any data:
Mode Meaning
3D Diff
Fix from 4 or more satellites; receiving real-time
corrections from WAAS, beacon, etc.
2D Diff
Fix from 3 satellites; receiving real-time corrections
from WAAS, beacon, etc.
3D
GPS fix from 4 or more satellites; including elevation;
no real time connection.
2D
GPS fix from 3 satellites; no elevation; no WAAS.
3D PPS
Precise Positioning Service; need capability to read
PPS code; Excellent signal.
2D PPS
Precise Positioning Service; need capability to read
PPS code; Excellent signal.