Chapter 12 – Postion Determination (GPS) Commands
Multi-Tech Systems, Inc. CDMA Wireless AT Commands (PN S000294J)
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Position Determination Start Session +WPDSS
Description:
This command is used to start a position determination session. Configuration settings, either default or as
set by a PD related AT command, will be used. For an ephemeris/almanac data download session, the data
is returned to the module PD software and not displayed. For all other PD session types, position data will
be returned using +WPDSS unsolicited responses. The content of the unsolWPDSS responses is
dependent on the service requested by the +WPDSS command. Only one PD session may be active at a
time.
Values:
<service>
“P”
Position only
“PV”
Position and Velocity; velocity includes heading data.
“PH”
Position and Elevation
“PVH”
Position, Velocity, and Elevation; velocity includes heading data.
Note:
Multiple letter codes for the service parameters must be ordered as shown.
<performance>
0
No time allowed for GPS search. Use
Advanced Forward Link Trilateration
(AFLT) only.
1-255
Upper bound of permitted GPS search time in seconds. Note that this does not correspond to
overall
session
time, but only the amount of time spent searching in GPS mode.
<accuracy>
Accuracy threshold in meters; only used in MS-based position determination sessions. If the position
uncertainty is higher than the accuracy threshold, the session will fall back to PDE-calculated fixes if
permitted by the current privacy setting (+WPDPL <level> not 2). The PDE-calculated fixes will not be
checked to the accuracy threshold. If the privacy setting prohibits PDE-calculated fixes, the accuracy
threshold exceeded fix will be used.
Syntax:
Command syntax:
AT+WPDSS=<service>,<performance>,<accuracy>
Command
Possible responses
AT+WPDSS=”PV”
Note: Start a PD session for position and velocity.
Use AFLT with no accuracy threshold.
OK
Note: Command accepted.
AT+WPDSS=”PVH”,20,50
Note: Start a PD session for position, velocity, and
elevation. GSP search time limited to within 20
seconds. Desired accuracy within 50 meters.
OK
Note: Command accepted.
AT+WPDSS?
+WPDSS: ”PVH”,20,50
OK
Note: “PVH” session in progress.
+WPDSS:
OK
Note: No active session.
Position Determination End Session +WPDES
Description:
This command is used to end a position determination session prior to its normal termination. For example,
the termination of a PD session before the +WPDFR command specified number of fixes have been
returned.
Syntax:
Command syntax:
AT+WPDES
Command
Possible responses
AT+WPDES
Note: End current PD session
OK
Note: Command accepted. PD session ended.
+CME: ERROR: 604
Note: No active session.