Home' RTCA Documents for Review : C2 Link Systems MASPS_Draft Contents Appendix D
© 2018 RTCA, Inc.
monitoring application that interfaces to the remote pilot and/or the UA, which would be
specific to each UAS design.
The fundamental requirement of the C2 Link System Status Reporting is to provide the
remote pilot or CS applications supporting the remote pilot and the UA with real-time
information on the C2 Link System’s ability to support information exchanges, i.e., is the
C2 Link System currently operating as required or is it interrupted?
Based on the MASPS definition of an interruption given in Subsection E.1, the C2 Link
System must be statused to see if:
1. Information is flowing at the required rate (the C2 Link System is “unavailable and/or
2. Information is arriving late (the C2 Link System “introduces too much latency”).
3. Information is not being accurately received the C2 Link System (“lacks integrity”).
Note D-19: Although it is anticipated that error detection and correction capabilities are
included in the C2 Link System design, information exchanges that are
delivered to the security algorithms with errors will be rejected, and thus they
will not exit from the C2 Link System. Consequently, uncorrected errors in
received information will manifest themselves as interruptions with a
consequent reduction in the delivered information rate affecting Item 1 in the
above list and not Item 3. Item 3 requires the C2 Link System Status Reporting
to report that it has received errored information so that the CS and UA will
know if the information is missing because of lack of signal strength or because
of a lack of integrity.
Note D-20: This MASPS assumes that the information provided by the C2 Link System
Status Reporting will, for example, be continuously monitored by a CS or UA
application external to the C2 Link System to determine if the information flow
from Item 1 above has been interrupted for longer than the appropriate TET.
If this occurs, then this MASPS again assumes that this monitoring external to
the C2 Link System will then annunciate that condition to the remote pilot
and/or the CS applications supporting the remote pilot, or the UA as dictated
by the UAS design.
Latency of the C2 Link System Status Reporting
Since the occurrence of an interruption will be used to start and clear TET timers (this
MASPS assumes such applications are outside the C2 Link System), the latency of the
Status Reporting will affect how accurately these TET timers reflect the true length of the
C2 Link System interruptions.
As has already been determined in the previous sections of this Appendix (see E.3, 4, 5 and
6), TETs for C2 Link Systems are measured in a small number of seconds. So, UAS
designer Subject Matter Experts determined that the latency of the C2 Link System Status
Reporting could be no greater than 0.5 seconds to ensure adequate accuracy of the
measurement of the C2 Link Systems interruptions.
C2 Link System Status Reporting Interruptions
Because the TETs for the other remote pilot activities are measured in only a few seconds
(see E.3, 4, 5 and 6), any interruption in the Status Reporting by the C2 Link System for a
time that is significant compared these TETs is not acceptable. Consequently, it was the
opinion of UAS designer Subject Matter Experts that any interruption longer than 2
Links Archive DO-XYZ_ED-ABC_FRAC_SC236_MASPS Navigation Previous Page Next Page