COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
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It cannot be duplicated or distributed without expressed written consent.
3.6.3.3. Phase-shift Measurement
Phase measurements transmitted to the Ranging Client are raw phase measurements (), whatever the
selected ranging standard:
In the ESA, ESA-like and USB standards, raw phase measurements are then corrected to obtain net phase
measurements for ambiguity solving and distance computation. Phase correction depends on the ranging
request contents:
If the ranging request is a « range measurement request », the following correction applies:
If the ranging request is a « calibration request », the following correction applies:
where:
-offset.
Compensation for contribution to phase measurement of ground
equipment that are inserted in the station calibration loop but not used
during satellite range measurement (example: Test Loop Translator).
Compensation for satellite contribution to range measurement.
The above correction parameters are programmable by commands received on the Control port.
3.6.3.4. Phase-shift Correction for Ambiguity Solving
IMPORTANT:
PHASE-SHIFT CORRECTION ONLY APPLY TO TONE STANDARDS WITH AMBIGUITY SOLVING
(ESA AND ESA-LIKE).
3.6.3.4.1. “Spectrum Correction”
Parameter Spectrum Correction () allows to compensate for phase offset due to frequency
mixing and FM/PM ranging loops. Any of the following scenario can be selected:
No spectrum correction.
Spectrum inversion due to the presence of an IF or RF frequency mixer in the ranging loop.
Phase measurements are corrected by 180°.
FM (uplink) and PM (downlink) modulation schemes. Phase measurements are corrected
by + 90°.
Spectrum inversion and FM/PM loop: phase measurements are corrected by - 90°.
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