Safran CORTEX CRT Quantum, User Manual

Page: 265 / 346

COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
© Safran Data Systems
This document is the property of
Safran Data Systems
.
It cannot be duplicated or distributed without expressed written consent.
Page 185
3.6.12.
PN Codes Standard (Regenerative PN Ranging)
Available under licence on Cortex CRT eXplorer
3.6.12.1.
General
The ranging sequence consists in a continuous transmission of a pseudo noise sequence, which is a logical
combination of six binary periodic PN components used for ambiguity solving. One of these PN components,
called the range clock, represents the major tone.
By means of a digital PLL, the RAU produces a phase-locked replica of the major tone. The PN components are
correlated with the demodulated code to determine the number of major tone cycles in the range.
The PLL is a second-order whose bandwidth (2Bn) is programmable from 0.001 to 32 Hz.
3.6.12.2.
Frequency Programming
The tone frequency is programmable through major tone parameters according to the following rule (in kHz):
𝐹
𝑇𝑜𝑛𝑒
= 500 ×
𝑃
𝑀𝑎𝑗𝑜𝑟_𝑇𝑜𝑛𝑒
𝑄
𝑀𝑎𝑗𝑜𝑟_𝑇𝑜𝑛𝑒
Or (
𝑃
𝑀𝑎𝑗𝑜𝑟_𝑇𝑜𝑛𝑒
in Hz and
𝑄
𝑀𝑎𝑗𝑜𝑟_𝑇𝑜𝑛𝑒
in µHz)
𝐹
𝑇𝑜𝑛𝑒
= 𝑃
𝑀𝑎𝑗𝑜𝑟_𝑇𝑜𝑛𝑒
+
𝑄
𝑀𝑎𝑗𝑜𝑟_𝑇𝑜𝑛𝑒
1 000 000
with the restrictions described in § 3.6.2.
The tone frequency is half of the Chip Rate. According to CCSDS 414.1-B-2, two chip rates are selected:
M
ODE
Q P C
ORTEX
C
HIP
R
ATES
CCSDS
C
HIP
R
ATES
P/Q 29 30 1,034,483 chips/s 1,034,295 chips/s
29 60 2,068,966 chips/s 2,068,590 chips/s
P+Q 500,000 517,147 1,034,295 chips/s 1,034,295 chips/s
0 1,034,295 2,068,590 chips/s 2,068,590 chips/s
Table 28: Available chip rates on Cortex