COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
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It cannot be duplicated or distributed without expressed written consent.
3.6.12.3.Code Programming
The PN sequence is defined by the parameter Code length (N = 1, 2 or 4). N = 1 for Jet Propulsion Laboratory
(JPL), N = 2 for Weighted-Voting Balanced Tausworthe (T2B), and N = 4 for T4B. The parameter Code length, in
the case of PN Codes Standard, gives a correlation degree between the range clock and the emitted ranging
sequence. The JPL PN code structure is the first structure used in PN codes history. The T2B PN code structure
is used to optimize the integration time. The T4B PN code structure is used to increase the ranging accuracy.
The periodic PN components are:
C1 = +1 –1 (the range clock)
C2 = +1 +1 +1 –1 –1 +1 –1
C3 = +1 +1 +1 –1 –1 –1 +1 –1 +1 +1 –1
C4 = +1 +1 +1 +1 –1 –1 –1 +1 –1 –1 +1 +1 –1 +1 –1
C5 = +1 +1 +1 +1 –1 +1 –1 +1 –1 –1 –1 –1 +1 +1 –1 +1 +1 –1 –1
C6 = +1 +1 +1 +1 +1 –1 +1 –1 +1 +1 –1 –1 +1 +1 –1 –1 +1 –1 +1 –1 –1 –1 –1
The periodic ranging sequence is a combination of PN components:
with length L = 2 x 7 x 11 x 15 x 19 x 23 = 1 009 470 chips
For a given chip rate, the maximum ambiguity solving is given by the following formula:
3.6.12.4.Shaping Filter
The shaping filter has the following impulse response:
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