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C Commands Summary
84 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2
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 SV channel and PRN, even if the assigned
satellite subsequently sets. If the satellite Doppler offset of the assigned SV 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 SV 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, Page 157, the ETSA/
B ASCII log structure and Table D-7, Page 203 for an explanation of the various channel tracking states.
NOTE: Assigning a PRN to a SV channel does not remove the PRN from the search space of the automatic
searcher; only the SV channel is removed. By default, the automatic searcher only searches for the GPS
satellites (PRNs 1-32).
The [doppler] and [search-window] parameters are optional. If [doppler] is not specified, its range value will
default to 0, and if [search-window] is not specified, its range value will default to 10,000.
There are two syntactical forms of this command, as shown below.
Syntax #1:
Example 1:
assign 0,29,0,2000
In example 1, the first SV 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 SV channel will try to acquire satellite PRN 28 at -250 Hz only.
Syntax #2:
Example 3:
assign 11,idle
In Example 3, SV channel 11 will be idled and will not attempt to search for satellites.
ASSIGN channel prn [doppler] [search-window]
Syntax Range Value Description Default Example
ASSIGN - Command unassignall assign
channel 0 - 11 Desired SV 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
ASSIGN channel keyword
Syntax Range Value Description Default Example
ASSIGN - Command unassignall assign
channel 0 - highest channel
number
Desired SV channel number from maximum SV channel number
inclusive
0
keyword IDLE Idles SV channel (not case sensitive) idle