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C Commands Summary
MiLLennium Command Descriptions Manual 69
ASSIGN
This command may be used to aid in the initial acquisition of a satellite by allowing you to override the automatic
satellite/channel assignment and reacquisition processes with manual instructions. The command specifies that the
indicated tracking channel search for a specified satellite at a specified Doppler frequency within a specified
Doppler window. The instruction will remain in effect for the specified channel and
PRN, even if the assigned
satellite subsequently sets. If the satellite Doppler offset of the assigned channel exceeds that specified by the
Search-Window parameter of the
ASSIGN command, the satellite may never be acquired or re-acquired. To cancel
the effects of
ASSIGN, you must issue the UNASSIGN or UNASSIGNALL command, or reboot the GPSCard.
When using this command, NovAtel recommends that you monitor the channel tracking status (
ETSA/B) of the
assigned channel and then use the
UNASSIGN or UNASSIGNALL commands to cancel the command once the channel
has reached channel state 4, the Phase Lock Loop (
PLL) state. See Appendix D, the ETSA/B ASCII log structure and
Table D-7 for an explanation of the various channel tracking states.
Syntax:
Example 1:
assign 0,29,0,2000
In example 1, the first channel will try to acquire satellite
PRN 29 in a range from -2000 Hz to 2000 Hz until the
satellite signal has been detected.
Example 2: assign 11,28,-250,0
The twelfth channel will try to acquire satellite
PRN 28 at -250 Hz only.
ASSIGN channel prn doppler search-window
Syntax Range Value Description Default Example
ASSIGN - Command unassignall assign
channel 0 - 11 Desired channel number from 0 to 11 inclusive (channel 0
represents first channel, channel 11 represents twelfth
channel)
0
prn 1 - 32 A satellite PRN integer number from 1 to 32 inclusive 29
doppler -100,000 to 100,000
Hz
Current Doppler offset of the satellite
Note: Satellite motion, receiver antenna motion and
receiver clock frequency error must be included in the
calculation for Doppler frequency.
0
search-window 0 - 10,000 Error or uncertainty in the Doppler estimate above in Hz
Note: Any positive value from 0 to 10000 will be
accepted. Example: 500 implies ± 500 Hz.
2000