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3.6.13.4.Integration Time
The minor tone duration is imposed by the satellite and is expressed as an integer M Epoch periods.
This configuration is programmable in the Cortex CRT (cf. parameter at offset 2 of the Ranging Unit Table
0x1034).
The actual integration time for ambiguity resolution is about (M-2) Epoch periods but the operation lasts for M
Epoch due to the fact the sequence is imposed by the satellite.
3.6.13.5.Ranging Sequence
Next figure illustrates the ranging measurement sequence:
1
Major tone
Minor tones
1 2 3 4 5 6 1 2
There is a continuous transmission of a minor tones sequence along with the major tone.
1. On reception of a ranging request from the Ranging Client, the RAU computes the tone definition
table (only the first time a ranging request is received for the current RAU configuration). Then, if the
computation is successful, the RAU continues processing otherwise returns an error code.
2. Determination of the beginning of the sequence: the RAU waits for an entire minor tones sequence
and estimates the uplink epoch that corresponds to a new sequence. The beginning of the sequence
is therefore estimated with an uncertainty of one Epoch.
3. Waiting for the beginning of the next minor tones sequence.
4. Status Measurement Progress in the RAU monitoring table starts incrementing.
5. Average phase measurement for the first minor tone, then for minor tones 2, 3, 4, 5 and 6.
6. First phase measurement on the major tone and ambiguity solving. The RAU simultaneously
acquires the current time from the Time Code Reader for further time-tagging of the ranging
transaction response message.
7. Status Measurement Progress is equal to 100. Phase and « distance » measurements are
returned to the Ranging Client(s) in a ranging transaction response message.
© Safran Data Systems
COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
2
3
3 4 5 6 1
IT
IT
IT
IT
IT = Integration Time
Figure 84: Ranging Sequence (Hybrid Ranging Standard)
This document is the property of
It cannot be duplicated or distributed without expressed written consent.
6
4
5
Major tone
2 3 4 5 6 1
Safran Data Systems
.
Ref.
DTU 100042
Is.Rev.
5.17
Date:
Dec.
03, 2021Sept. 30, 2021
N measurements on the major tone
One measurement every 250 ms
2 3 4 5
6 1
2 3 4
Page 194
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