Onderwerp: Zweefportaal - Alles over zweefvliegen :: ADS-B: Het grote kabeltjestopic
Geplaatst door dingetje op 20-01-2010 17:55
Mode S Extended Squitter
The most recent and most compelling use of Mode S has been in the area of Automatic Dependent Surveillance-Broadcast (ADS-B). Under ADS-B, each aircraft periodically broadcasts its identification, position, and altitude. These broadcasts can be received by ground sensors and other aircraft for surveillance. This system of broadcast addresses the major deficiency of TCAS -- accuracy. In the TCAS system, aircraft positions are only accurate to a few degrees; thus, the accuracy of TCAS decreases with distance. Moreover, the reliance on transmission timing for range data in TCAS is error-prone. The method used by ADS-B avoids this problem.
The Mode S extended squitter (also known as the GPS squitter) is a component of ADS-B which was proposed, developed, and demonstrated by Lincoln Labs. A participating aircraft broadcasts (``squits'') positional information using a modified Mode S transponder. The positional information comes from a source of global navigation, such as a Global Positioning Satellite (GPS) receiver. The Mode S extended squitter is a smooth upgrade from traditional Mode S. According to Steve Bussolari, project leader at Lincoln Labs, ``The notion behind the Mode S extended squitter is that it works seamlessly with the existing system.'' Paul Drouilhet adds, ``The GPS squitter is an expansion of the signal...What has changed is that GPS squitter adds to the broadcast, GPS info...the previous Mode S squitter [just] broadcasts altitude. The GPS Squitter has taken [Mode S], added more bits and in those bits, transmits information as derived from GPS.'' The Mode S extended squitter was demonstrated by Lincoln Labs and the FAA in Boston and the Gulf of Mexico in 1994, and is one of three candidates being considered by the FAA for ADS-B.
Key is hierbij de kreet "periodically broadcasts". De vraag die hier dus ligt is, gaat dat automatisch of moet je daar iets voor doen?
Gezien de metingen en waarnemingen lijkt het er op dat iig de TRT800 niets extra's van zichzelf doet want anders had je dit toch moeten zien in ofwel het stroomverbruik ofwel het bovengenoemde flikkerende diamantje?
Gewijzigd door dingetje op 20-01-2010 17:56