Novatel 01020347, User Manual

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28 WAAS GUS Signal Generator User Guide Rev 1
Chapter 5 Messages
Table 11: Command Message Identifier Field
Table 12: Command Message Identifier Bit Fields
5.1.3.2 Control Command
The Control Command provides for synchronous initialization of the L1 I and Q C/A code Generator states or the
L5 I and Q XB code Generator states, code modulation, symbol modulation, I channel modulation or Q channel
modulation. Upon receiving this command, the coder commences execution at the occurrence of the next 1-PPS
update pulse. If a valid Initialization Command was not received prior to receiving this command, this command is
not executed and the status message indicates the error. The Control command packet contains one byte of data.
Table 13 on Page 28 shows the L1/L5 Control Command byte field and bit order. Table 13 below shows the L1/L5
Control Command bit fields. This command must be preceded by an Initialization command to ensure that the I and
Q coders have been reset, initialized and advanced to the correct state.
Table 13: L1/L5 Control Command Bit Fields
Byte [5]
D7 D6 D5 D4 D3 D2 D1 D0
MSB LSB
Bit
Command message
(WMP to Signal Generator)
Command Message
ID Field
D0 Control Command 0x01
D1 Initialization Command 0x02
D2
Code Chip Rate and Carrier
Frequency Command
0x04
D3 Reserved for future use 0x08
D4 Reset Command 0x10
D5 Reserved for future use 0x20
D6 Reserved for future use 0x40
D7 Reserved for future use 0x80
Bit Description Range Purpose
D0 Initialize Range 0 - 1
1 = Start coders at next valid Reference 1PPS
pulse
D1 Disable PRN Code (I) 0 - 1 1 = Coder output not used in modulation
D2 Disable Message (I) 0 - 1 1 = Symbol not used in modulation
D3
BPSK/QPSK Modulation
Mode Select
0 - 1
0 = BPSK
1 = QPSK
D4 Disable NH/Manchester (Q) 0 - 1
1=Disable NH code for dataless operation and
Manchester Code for data operation
D5 Disable NH/Manchester (I) 0 - 1
1=Disable NH code for dataless operation and
Manchester Code on data for L5 (not used for
L1 I data)
D6 Disable Message (Q) 0 - 1 1=Symbol not used in modulation
D7 Disable PRN Code (Q) 0 - 1 1=Coder output not used in modulation