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D Logs Summary
MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2 155
DOPA/B Dilution of Precision
The dilution of precision data is calculated using the geometry of only those satellites that are currently being
tracked and used in the position solution by the GPSCard and updated once every 60 seconds or whenever a change
in the constellation occurs. Therefore, the total number of data fields output by the log is variable, depending on
the number of SVs tracking. Twelve is the maximum number of SV PRNs contained in the list.
NOTE: If a satellite is locked out using the LOCKOUT command, it will still be shown in the PRN list, but is
significantly deweighted in the DOP calculation.
DOPA
Structure:
Example:
$DOPA,637,512473.00,2.9644,2.5639,2.0200,1.3662,1.4880,6,18,6,11,2,16,19
*29[CR][LF]
$DOPA week seconds gdop pdop htdop hdop tdop # sats
prn list *xx [CR][LF]
Field # Field type Data Description Example
1 $DOPA Log header $DOPA
2 week GPS week number 637
3 seconds GPS seconds into the week 512473.00
4 gdop Geometric dilution of precision - assumes 3-D position and receiver clock offset (all
4 parameters) are unknown
2.9644
5 pdop Position dilution of precision - assumes 3-D position is unknown and receiver clock
offset is known
2.5639
6 htdop Horizontal position and time dilution of precision. 2.0200
7 hdop Horizontal dilution of precision. 1.3662
8 tdop Time dilution of precision - assumes 3-D position is known and only receiver clock
offset is unknown
1.4880
9 # sats Number of satellites used in position solution (0-12) 6
10... prn list PRN list of SV PRNs tracking (1-32), null field until first position solution available 18,6,11,2,16,
19
variable *xx Checksum *29
variable [CR][LF] Sentence terminator [CR][LF]