Figure 81: Ranging Sequence - Safran CORTEX CRT Quantum User Manual

TONE 1
1 2

1. RAU in idle state: mute output.

2. On reception of a ranging request from the Ranging Client, the RAU computes the tone definition
tables (only the first time a ranging request is received for the current RAU configuration. Duration: < 3
seconds). Then, if the computation is successful the RAU starts transmitting the first tone (major tone or
19-kHz or 27.778-kHz sub-carrier phase-modulated by any of the four minor tones).

3. 6 seconds later (tone set time), the RAU instantaneously performs the first phase measurement and
simultaneously acquires the current time from the Time Code Reader for further time-tagging of the
ranging transaction response message. Next measurements on the first tone take place every 100 ms.

4. For the second, third and fourth tones, the process is similar.

5. End of phase measurement on the fourth tone. Idle state.
The total duration of the ranging sequence depends on the measurement sampling ratio and the number of
measurements on each tone. Assuming 10 measurements per tone and a sampling ratio of 1 (all measurements
transmitted), the sequence duration (computation time for tone definition tables not included) is:
 st
1 tone set time

Measurement on 1

nd
2 tone set time

Measurement on 2

rd
3 tone set time

Measurement on 3
 th
4 tone set time

Measurement on 4
Total sequence duration
© Safran Data Systems
COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
6 seconds
100 ms
3
Figure 81: Ranging Sequence (INMARSAT/LMCO Standards)
6 seconds
st
tone 0.9 second
6 seconds
nd
tone 0.9 second
6 seconds
rd
tone 0.9 second
6 seconds
th
tone 0.9 second
27.6 seconds
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It cannot be duplicated or distributed without expressed written consent.
6 seconds
TONE 2
4
Safran Data Systems
.
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
TONE 4
5 6
Page 180