Novatel 15aT Car Satellite TV System User Manual


 
Commands Chapter 5
EuroPak-15a Receiver User Manual Rev 5 61
5.3.11 POSITIONTYPE Set the Position Solution
This command sets the position filter to compute the position on either the GPS L1 or GPS L5 frequencies. You
can also obtain data from a specific frequency. Both position and navigation data are available on GPS L1 or
GPS L5. The ephemeris and almanac are decoded on the selected frequency.
When using simulated signals, if the L1 and L5 constellations are different, the receiver may drop signals that
are not in view based on the almanac. For example, if the receiver is tracking PRN 15 on L5, the position type
is set to GPSL1 and the L1 almanac indicates that PRN 15 is not in view, then the receiver stops tracking PRN
15.
To prevent this:
Use the ASSIGN command, see Page 47, to force lock on the satellites
Change the position type frequency with the POSITIONTYPE command, or
Ensure the constellations in the simulations agree with what you expect to track
This command only affects GPS satellites. Galileo satellites maintain their lock.
Syntax: Message ID: 836
Example:
POSITIONTYPE GPSL1
Table 29: Position Frequency Switch
POSITIONTYPE FREQUENCY
Field
Field
Name
Valid Values Description Format
Binary
Bytes
Binary
Offset
1 header
This field contains the Abbreviated ASCII command name. See Section
4.1 on Page 31.
H 0
2 frequency GPSL1 or GPSL5 Position frequency, see Table 29 Enum 4 H
ASCII Description
GPSL1 GPS L1 frequency
GPSL5 GPS L5 frequency