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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 />

C-58 <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 />

2. The update <strong>and</strong> output of both ADS-B Reports when <strong>Extended</strong> <strong>Squitter</strong> Messages are received<br />

with the duplicate ICAO 24-bit address results in additional overhead since output of both ADS-B Reports<br />

possibly occurs upon message reception. However, this approach gives ADS-B applications the ability to<br />

associate in<strong>for</strong>mation with the correct ADS-B Report if they choose to attempt to correlate using the<br />

additional provided in<strong>for</strong>mation.<br />

The duplicate address condition shall be cleared after 60 seconds has elapsed with no Position Message<br />

update <strong>for</strong> a Participant with an ADS-B Report identified in the duplicate address condition. The relevant<br />

ADS-B Report <strong>for</strong> the Participant shall be deleted from the Report Output Storage Buffer. Output of the<br />

remaining ADS-B Report shall contain a State Vector Report with the Duplicate Address Flag set to “OFF”.<br />

Note.— After clearing the duplicate address condition, the ADS-B Report <strong>for</strong> the aircraft/vehicle that<br />

continues to receive Position Messages that pass the local CPR reasonableness test, as well as other<br />

1090ES ADS-B Messages, is retained <strong>and</strong> updated as per RTCA DO-260B, §2.2.10.4.<br />

C.2.6.10.4.3 Duplicate Address Report Capacity<br />

The ADS-B Receiving Subsystem shall be capable of maintaining <strong>and</strong> processing a minimum of three<br />

concurrent duplicate address Reports.<br />

Note.— The required capacity includes duplicate address Reports from both ADS-B <strong>and</strong> ADS-R targets.<br />

Since duplicate address situations are expected to be infrequent events, the ability to h<strong>and</strong>le three duplicate<br />

address Reports is expected to be sufficient.<br />

C.2.7 FORMATS FOR EXTENDED SQUITTER<br />

The <strong>Extended</strong> <strong>Squitter</strong> messages shall be <strong>for</strong>matted as defined in the following tables.<br />

Note.— In some cases, ARINC 429 labels are referenced <strong>for</strong> specific message fields. These references<br />

are only intended to clarify the field content, <strong>and</strong> are not intended as a requirement to use these ARINC 429<br />

labels as the source <strong>for</strong> the message field.<br />

Draft<br />

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

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