15.12.2012 Views

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

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

DRAFT - Working Paper ASP TSGWP11-01 <strong>for</strong> review by the TSG during the meeting in June 2011 in Paris<br />

B-28 <strong>Technical</strong> <strong>Provisions</strong> <strong>for</strong> <strong>Mode</strong> S <strong>Services</strong> <strong>and</strong> <strong>Extended</strong> <strong>Squitter</strong><br />

B.2.5.2 LOSS OF INPUT DATA<br />

The GFM shall h<strong>and</strong>le loss of input data as specified in §A.2.5.2.<br />

B.2.5.3 SPECIAL PROCESSING FOR FORMAT TYPE CODE ZERO<br />

Special processing <strong>for</strong> <strong>for</strong>mat TYPE Code zero shall be per<strong>for</strong>med as specified in §A.2.5.3.<br />

B.2.5.4 TRANSPONDER CAPABILITY REPORTING<br />

Transponder capability reporting shall be per<strong>for</strong>med as specified in §A.2.5.4.<br />

B.2.5.5 HANDLING OF EVENT-DRIVEN PROTOCOL<br />

The event-driven interface protocol provides a general purpose interface into the transponder function <strong>for</strong> messages<br />

beyond those that are regularly transmitted all the time (provided input data are available). This protocol shall operate by<br />

having the transponder broadcast a message once each time the event-driven register is loaded by the GFM.<br />

Note.— This gives the GFM complete freedom in setting the update rate (up to a maximum) <strong>and</strong> duration of<br />

broadcast <strong>for</strong> applications such as emergency status <strong>and</strong> intent reporting.<br />

In addition to <strong>for</strong>matting, the GFM shall control the timing of message insertion so that it provides the necessary pseudor<strong>and</strong>om<br />

timing variation <strong>and</strong> does not exceed the maximum transponder broadcast rate <strong>for</strong> the event-driven protocol.<br />

B.2.5.5.1 TRANSPONDER SUPPORT FOR EVENT-DRIVEN MESSAGES<br />

Transponder support <strong>for</strong> event-driven messages shall be as specified in §A.2.5.5.1.<br />

B.2.5.5.2 GFM USE OF EVENT-DRIVEN PROTOCOL<br />

GFM use of the event-driven protocol shall be as specified in §A.2.5.5.2.<br />

B.2.5.5.3 EVENT-DRIVEN MESSAGE TRANSMISSION SCHEDULING FUNCTION<br />

Draft<br />

The event-driven message scheduling function shall ensure that the total event-driven message rate does not exceed 2<br />

transmitted messages per second.<br />

The event-driven message scheduling function shall apply the following rules as a means of prioritizing the event-driven<br />

message transmissions <strong>and</strong> limiting the transmission rates:<br />

a) the event-driven message scheduling function shall reorder, as necessary, pending event-driven messages<br />

according to the following message priorities, listed below in descending order from highest to lowest priority.<br />

1) When an extended squitter aircraft status message is active <strong>for</strong> the broadcast of an emergency/priority<br />

condition (type=28 <strong>and</strong> subtype=1), or an ACAS RA broadcast (type=28, subtype=2), that message shall<br />

continue to be transmitted at r<strong>and</strong>om intervals that are uni<strong>for</strong>mly distributed over the range of 0.7 to 0.9<br />

DRAFT - Working Paper ASP TSGWP11-01 <strong>for</strong> review by the TSG during the meeting in June 2011 in Paris

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!