Novatel 01020347, User Manual

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34 WAAS GUS Signal Generator User Guide Rev 1
Chapter 5 Messages
Table 27: L1/L5 Code Chip Rate and Carrier Frequency Command Fields
CODE CHIP RATE FIELD
The Code Chip Rate field specifies the absolute initial code clock frequency. Table 28 shows the byte and bit
ordering for the Code Chip Rate field.
Table 28: Code Chip Rate Field
CODE CHIP RATE RAMP FIELD
This field is a 16 bit signed value (2’s complement) where D15, the most significant bit is the sign bit. See Table 29
for the Code Chip Rate Ramp field bit format.
Table 29: Code Chip Rate Ramp Field
CARRIER FREQUENCY FIELD
The Carrier Frequency Command specifies in absolute terms, the new Carrier Frequency (for either L1 or L5) to be
assigned at the next 1PPS update pulse. See
Table 30 for the Carrier Frequency field byte and bit order format.
Table 30: Carrier Frequency Field Bit Format
Byte Position Description Valid Range Scale Factor
Data Byte [17:22]
Code Chip
Rate
1.023 ±0.25/1540 Mcps (L1)
10.23 ±0.25/115 Mcps (L5)
LSB = 75 x 2
-48
Mcps
Data Byte [23:24]
Code Chip
Rate Ramp
±8.525 × 10
-6
cps/250 ms (L1)
±8.525 × 10
-5
cps/250 ms (L5)
LSB = 75 x 2
-50
Mcps/250 ms
Data Byte [25:30]
Carrier
Frequency
70 ±0.25 MHz
LSB = 300 x 2
-48
MHz
Data Byte [31:33]
Carrier
Frequency
Ramp
±0.025 Hz/250 ms
LSB = 300 x 2
-50
MHz/250 ms
Byte [17] Byte [18] Byte [19] Byte [20] Byte [21] Byte [22]
D7 – D0 D15 – D8 D23 – D16 D31 – D24 D39 – D32 D47 - D40
D0 = LSB D47 = MSB
LS Byte [23] MS Byte [24]
D7 D6 D5 D4 D3 D2 D1 D0 - D14 D13 D12 D11 D10 D9 D8
LSB MSB(sign)
Byte [25]
LS Byte
Byte [26] Byte [27] Byte [28] Byte [29]
Byte [30]
MS Byte
D7 – D0 D15 – D8 D23 – D16 D31 – D24 D39 – D32 D47 - D40
D0 = LSB D47 = MSB