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
2week GPS week number 637
3seconds GPS seconds into the week 512473.00
4gdop Geometric dilution of precision - assumes 3-D position and receiver clock offset (all
4 parameters) are unknown 2.9644
5pdop Position dilution of precision - assumes 3-D position is unknown and receiver clock
offset is known 2.5639
6htdop Horizontal position and time dilution of precision. 2.0200
7hdop Horizontal dilution of precision. 1.3662
8tdop 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]