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DO-253D Change 1
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Detailed Test Procedures
1) Using the network analyzer, calibrate the test setup to take account of the loss in
the RF cable to be used in connecting the network analyzer to the antenna to be
tested. Then connect that cable to the antenna’s terminals.
2) Record the VSWR of the antenna over the specified frequency range and verify
compliance with the requirements in Section 22.214.171.124.2.2.
Precision Approach Navigator Tests
Definition of PAN Test Terms and Conditions
Standard Test Signals and Simulator Requirements
Simulated GPS ranging-sources shall [LAAS-212] conform with the GPS Standard
Performance Standard and Navstar GPS Interface Specification (IS-GPS-200D with IRN-
200D-001). Simulated SBAS signals (if needed) shall [LAAS-213] conform to the
specification for the Wide Area Augmentation System (FAA-E -2892B, Change 2) and
Appendix A of RTCA/DO-229().
1. The development of software to RTCA/DO-178C includes tool qualification of the
2. IS-GPS-200G dated September 2012 has been found to be equivalent to [IS-GPS-
200D with IRN-200D-001] for the purposes of simulation of the GPS constellation
in the tests in this MOPS.
Unless otherwise specified, simulated LAAS VDB signals shall [LAAS-214] conform to
the GPS/LAAS ICD, RTCA/DO-246().
Unless otherwise specified, all GPS and SBAS signals (if needed) will not indicate
unhealthy, erroneous, failed, abnormal, or marginal conditions.
When VDB data or signal is provided for testing of the PAN functions, the data may be
provided either by generating a simulated VDB RF signal and processing it using the VHF
receiver, or by generating simulated LAAS ICD messages (Types 1, 2, 3, 4, and 11) and
providing them to an appropriate input port. Unless otherwise specified, appropriate tuning
and channel selection information is provided.
The broadband noise used to simulate sky and antenna thermal noise density (Nsky,antenna),
GNSS test noise (IGNSS,Test) and external interference (IExt,Test) shall [LAAS-310] have a
bandwidth greater than the RF bandwidth of the equipment under test. IGNSS,Test is defined
as the broadband noise needed to ensure that the total effective noise (including the intra-
system noise produced by the interfering satellites actually simulated during the test
procedure) equals the values specified in Appendix D. The pulse interference source
requires an on/off ratio of 154 dB in order to achieve the necessary isolation. The CWI
generator shall [LAAS-219] be accurate to within 1 kHz.
The signal and interference levels cited in the following test procedures are defined with
respect to the input of the antenna preamplifier. The test set-up must include a test
amplifier, that has the same gain as the active portion of the antenna. If any interference is
inserted after the test amplifier, the interference level must be adjusted to reflect the
expected interference at the insertion point. The minimum or maximum installation loss
(as appropriate for the test case) must be included in the test setup, using passive devices.
This accounts for the noise generated by the aircraft cabling. When using a specific
antenna, the satellite signal levels at the test preamplifier input are adjusted based on the
minimum antenna radiation pattern above five degrees; the maximum antenna radiation
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