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DO-253D Change 1
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Test results may be used by equipment manufacturers as design guidance, in preparation
of installation instructions, and, in certain cases, for obtaining formal approval of
equipment design and manufacture.
The test procedures specified in Section 2.5 provide a means to demonstrate equipment
performance in a simulated environment. Test results may be used as design guidance for
monitoring manufacturing compliance and, in certain cases, for obtaining formal approval
of equipment design and manufacture.
The installed test procedures and their associated limit requirements are in Section 3.
Although bench and environmental test procedures are not a part of installed tests, their
successful completion is normally a precondition to the completion of the installed test.
Installed tests are normally performed on the ground and in flight.
The test results may be used to demonstrate equipment functional performance in the
environment in which it is intended to operate and with the minimum service to be
Aircraft Equipment Information Vulnerabilities
This document contains minimum performance standards for GAEC D airborne equipment
to verify the VHF signal used is authentic for ground stations that support the
authentication protocols. All ground systems supporting GAST D will support the
protocols. ICAO recommends, but does not require, that air navigation service providers
use this capability for all GAST C approaches. GAEC C airborne equipment may or may
not support the authentication protocols.
This document contains minimum performance standards for unintentional interference to
GPS L1. Other types of disruption, such as spoofing, are possible. Spoofing is caused by
RF waveforms that mimic true signals in some ways, but deny, degrade, disrupt, or deceive
a receiver’s operation when they are processed. Spoofing may be unintentional, such as
effects from the signals of a GPS re-radiator, or may be intentional and even malicious.
There are two classes of spoofing. Measurement spoofing introduces RF waveforms that
cause the target receiver to produce incorrect measurements of time of arrival or frequency
of arrival or their rates of change. Data spoofing introduces incorrect digital data to the
target receiver for its use in processing of signals and the calculation of PNT. Either class
of spoofing can cause a range of effects, from incorrect outputs of PNT to receiver
malfunction. The onset of effects can be instantaneous or delayed, and the effects can
continue even after the spoofing has ended. Improperly used or installed GNSS re-
radiators act like spoofers. Re-radiators replay and GNSS emulator devices can present
misleading information to GNSS equipment and/or could cause lasting effects.
Equipment manufacturers should implement measures to mitigate processing of erroneous
data. Cross-checks of GNSS sensor data against independent position sources and/or other
detection monitors using GNSS signal metrics or data checks can be implemented in the
antenna, receiver, and/or through integration with other systems at the aircraft level. Data
validity checks to recognize and reject measurement and data spoofing should be
implemented in the receiver. Additional guidance and best practices related to GPS
equipment can be found in the U.S. Department of Homeland Security document
“Improving the Operation and Development of Global Positioning System (GPS)
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