Leica GPS900 Series, Technical Reference Manual

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Managing, Creating, Editing Points/Data GPS900 34
The instrument source The instrument source describes where the coordinate triplet was measured or entered. The
option are
GPS , TPS or LGO .
The coordinate quality Description
The Coordinate Quality is:
•
computed on the rover for code solutions and phase fixed solutions.
• an indicator for the quality of the observations.
• an indicator for the current satellite constellation.
• an indicator for different environmental conditions.
• derived such that there is at least a two third probability that the computed position
deviates from the true position by less than the CQ value.
• different from the standard deviation.
CQ versus standard deviation
The standard deviation as CQ would often be too optimistic. This is why the computation of
the CQ in GPS900 is not simply based on the basic standard deviation algorithms.
For the standard deviation, there is, statistically, a 39.3 % probability in 2D that the
computed position deviates from the true position by less than the standard deviation. This
is not enough for a reliable quality indicator.
Traverse Traverse TPS
Unknown - GPS or TPS
User Application Customised application programs GPS or TPS
User Entered Manually entered point GPS or TPS
Source Originated from application program/func-
tionality Instrument
source