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ESA Tone Standard
3.6.8.
3.6.8.1. General
The ranging procedure consists of a sequential transmission of tones. Initially, the highest frequency tone (called
« major tone ») is transmitted alone to allow the transponded tone to be acquired by the ground equipment (IF
receiver and RAU).
By means of a digital PLL, the RAU produces a phase-locked replica of this tone from which replicas of the lower
tones are derived by division. The first minor tone is then transmitted along with the major tone, long enough to
phase-match its synthesized replica. The minor tone is then removed, replaced by the next tone and so one.
When all minor tones have been transmitted, the RAU then continues to function only with the major tone and
measurement are performed.
3.6.8.2. Tone Frequencies
3.6.8.2.1. Virtual Tones
The frequency plan recommended by the ESA standard consists of seven sinusoidal tones:
The minor tones are derived from the major tone by division. The dividing ratio is an integer value (5), except for
the two last minor tones for which the ratio is equal to 4. The one-
3.6.8.2.2. Real Tones
Due to uplink and downlink spectrum occupancy considerations, the minor tones are transmitted according to the
following equivalent scheme (although range measurement will be based on virtual tones):
The above list corresponds to the order in which the tones are transmitted: this order is fixed. All tones are
phase-coherent.
© Safran Data Systems
COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
Major tone
100 kHz
Minor tones
20.000 kHz
4.000 kHz
800 Hz
160 Hz
32 Hz
8 Hz
Major tone
100 kHz
Minor tones
20.000 kHz
16.000 kHz
16.800 kHz
16.160 kHz
16.032 kHz
16.008 kHz
This document is the property of
It cannot be duplicated or distributed without expressed written consent.
Safran Data Systems
.
Ref.
DTU 100042
Is.Rev.
5.17
Date:
Dec.
03, 2021Sept. 30, 2021
Page 173
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