Safran CORTEX CRT Quantum User Manual page 255

Steps 2 and 3 are repeated for minor tones 2, 3, 4 and 5.

4. Transmission of the sixth minor tone along with the major tone.

5. Average phase measurement for the sixth minor tone. The major tone is then transmitted alone
during Ts seconds.

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.
Phase measurements on the major tone are performed at regular time interval (One measurement every 250
ms). These measurements are corrected as described in § 3.6.3.4. For each measurement on the major tone is
calculated a « distance » in nanoseconds. The calculation takes into account (ambiguity solving) phase drift due
to spacecraft motion during major tone transmission.
The total duration of the ranging sequence depends on four factors:

the measurement sampling ratio,

the minor tone integration time,

the number of measurements on the major tone,

the tone set time (based on the PLL bandwidth and the maximum satellite distance).
Assuming that these parameters are: 1 (no measurement under-sampling), 250 ms (integration time), 10
measurements on the major tone and default tone set time (see scenario 1, section 3.6.4.7.1) with the RAU
bandwidth in the range 1 to 8 Hz, the sequence duration is (tone definition tables computation time not included):

Transmission of the major tone alone

Minor tone 1 (set time + integration)

Minor tones 2, 3, 4, 5 & 6 (0.75 x 5)

Transmission of the major tone alone

10 measurements on the major tone (0.25 x 9) : 2.25 s
Total sequence duration
If the sampling ratio is set to 2 (1 measurement out of 2 is transmitted to the Ranging Client), the sequence
duration is augmented accordingly:

Transmission of the major tone alone

Minor tone 1 (set time + correlation)

Minor tones 2, 3, 4, 5 & 6 (0.75 x 5)

Transmission of the major tone alone

10 measurements on the major tone (0.25 x 18) : 4.5 s
Total sequence duration
© Safran Data Systems
COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
This document is the property of
It cannot be duplicated or distributed without expressed written consent.
: 2 s
: 0.75 s
: 3.75 s
: 2 s
: 10.750 seconds
: 2 s
: 0.75 s
: 3.75 s
: 2 s
: 13 seconds
Safran Data Systems
.
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
Page 175