Technical Provisions for Mode S Services and Extended Squitter
Technical Provisions for Mode S Services and Extended Squitter
Technical Provisions for Mode S Services and Extended Squitter
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DRAFT - Working Paper ASP TSGWP11-01 <strong>for</strong> review by the TSG during the meeting in June 2011 in Paris<br />
Appendix C C-7<br />
C.2.3.1.1 Airborne Position Message TYPE Code<br />
C.2.3.1.1.1 Airborne Position Message TYPE Code if Containment Radius is Available<br />
Note.— If the position in<strong>for</strong>mation comes from a GNSS receiver that con<strong>for</strong>ms to the ARINC 743A<br />
characteristic, a suitable source of in<strong>for</strong>mation <strong>for</strong> the containment radius (RC), is ARINC 429 label 130 from<br />
that GNSS receiver.<br />
If RC (containment radius) in<strong>for</strong>mation is available from the navigation data source, then the transmitting<br />
ADS-B subsystem shall determine the TYPE Code (the value of the TYPE subfield) of Airborne Position<br />
Messages as follows.<br />
a. If current valid horizontal position in<strong>for</strong>mation is not available to the ADS-B Transmitting<br />
Subsystem, then the TYPE Code subfield of Airborne Position Messages shall be set to ZERO (0).<br />
b. If valid horizontal position <strong>and</strong> barometric pressure altitude in<strong>for</strong>mation are both available to the<br />
ADS-B Transmitting Subsystem, then the ADS-B Transmitting Subsystem shall set the TYPE Code<br />
subfield of Airborne Position Messages to a value in the range from 9 to 18 in accordance with<br />
Table C-2.<br />
c. If valid horizontal position in<strong>for</strong>mation is available to the ADS-B Transmitting Subsystem, but valid<br />
barometric pressure altitude in<strong>for</strong>mation is not available, <strong>and</strong> valid geometric altitude in<strong>for</strong>mation is<br />
available, the ADS-B Transmitting Subsystem shall set the TYPE Code subfield of Airborne<br />
Position Messages to a value in the range from 20 to 22 depending on the radius of containment<br />
(RC ) in accordance with Table C-2.<br />
d. If valid horizontal position in<strong>for</strong>mation is available to the ADS-B Transmitting Subsystem, but neither<br />
valid barometric altitude in<strong>for</strong>mation nor valid geometric altitude in<strong>for</strong>mation is available, the ADS-B<br />
Transmitting Subsystem shall set the TYPE Code subfield in Airborne Position Messages to a value<br />
in the range from 9 to 18 depending on the radius of containment RC in accordance with Table C-2.<br />
(In that case, the ALTITUDE subfield of the Airborne Position Messages shall be set to all ZEROs<br />
in order to indicate that valid altitude in<strong>for</strong>mation is not available.)<br />
C.2.3.1.1.2 Airborne Position Message TYPE Code if Containment Radius is Not<br />
Available<br />
Draft<br />
If RC (radius of containment) in<strong>for</strong>mation is NOT available from the navigation data source, then the ADS-B<br />
Transmitting Subsystem shall indicate NIC=0 by selecting a TYPE Code of 0, 18, or 22 in the Airborne<br />
Position Messages, as follows:<br />
a. The ADS-B Transmitting Subsystem shall set the TYPE Code subfield to ZERO (0) if valid<br />
horizontal position in<strong>for</strong>mation is not available.<br />
b. The ADS-B Transmitting Subsystem shall set the TYPE Code subfield to 18 if valid pressure<br />
altitude in<strong>for</strong>mation is available, or if neither valid pressure altitude nor valid geometric altitude<br />
in<strong>for</strong>mation is available.<br />
If valid pressure altitude is not available, but valid geometric altitude in<strong>for</strong>mation is available, the ADS-B<br />
Transmitting Subsystem shall set the TYPE Code subfield to 22.<br />
DRAFT - Working Paper ASP TSGWP11-01 <strong>for</strong> review by the TSG during the meeting in June 2011 in Paris