COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
This document is the property of Safran Data Systems.
It cannot be duplicated or distributed without expressed written consent.
3.7.4. Dopple Compensation Instruction Set
The following instructions can be identified with a Doppler ID which will set a particular Doppler Compensation
profile, this feature will enable you to handle two satellites at the same time.
3.7.4.1. Doppler Table Initialization
Constructs a new internal Doppler Compensation table. If a Doppler Compensation is in progress, the current
internal Doppler Compensation is stopped and is cleared (the last time/frequency offset couple processed is
applied until the new Doppler Compensation table is effective).
The new internal Doppler Compensation table will be effective at the used-defined Start time and will end when
all time offsets of the table have been processed.
The time offsets will represent, as shown in Figure 75, the time difference between two samples on the Doppler
Compensation curve whereas the frequency offsets represent the difference between the programmed IF carrier
or sub-carrier and the compensated IF carrier or sub-carrier.
Error Code:
Invalid instruction: frequency offset result is less than –7,812,500 Hz, or larger than 7,812,500 Hz.
Invalid date / time: starting time is close to the current time (if CheckTime is enabled).
Invalid license: current license does not support Doppler Compensation
3.7.4.2. Append Doppler Table
This instruction allows you to append new Doppler Compensation values to the existing internal Doppler
Compensation Table. The effective ending time of the internal Doppler Compensation table will be re-computed.
This instruction should always be executed after the Doppler Compensation Initialisation instruction, otherwise
the Cortex will send back a bad acknowledge.
Error Code:
Invalid instruction: frequency offset result is less than –7,812,500 Hz, larger than or equal to
7,812,500 Hz.
Invalid date / time: last Doppler Compensation date of the existing table added to the first offset time
is close to the current time (if CheckTime is enabled).
Append Instruction Rejected: no Internal Doppler Compensation table exist, or the sequence counter
is not following the current sequence counter, or the number of values of the current Doppler
Compensation table plus the number of Doppler compensation values of Append instruction is larger
than 32,000.
Invalid license: current license does not support Doppler Compensation
Invalid sequence: only one Append request can be sent
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