Impacts of ADS-B Service Availability Prediction Requirements on Scheduled Airline Operations

Matt Harris and Tim Murphy

Abstract:	On May 22nd, 2010, the FAA released a final rule mandating that aircraft flown in US airspace have ADS-B capability by 2020. The rule included performance requirements specifying a Navigation Accuracy Category for position (NACp) of 8 and a Navigation Integrity Category (NIC) of 7. These requirements mean that the estimated 95% horizontal accuracy of the ADS-B position broadcast must be less than 0.05 nautical miles (92.6 meters), and the horizontal protection level that represents a bound on the position error with a 1-10-7 probability must be less than 0.2 nautical miles. While the FAA's new ADS-B rule did not include an explicit requirement for availability of ADS-B capability at the specified levels, the FAA has indicated that a pre-dispatch prediction of ADS-B service availability will be required after 2020. ADS-B Out service predictions are based on the expected GNSS satellite geometry and performance, for the scheduled flight path and time. If the predicted positioning performance does not meet the ADS-B requirements, then the scheduled flight must be cancelled or rescheduled for a time during which the requirements are predicted to be met. This paper explores ADS-B service availability and the performance of an ADS-B Service Availability Prediction Tool (SAPT) as proposed by the FAA. The paper also explores some of the operational implications of requiring dispatch prediction and illustrates the possible consequence of relatively frequent denial of dispatch for scheduled airline operations compared with dispatch availability enjoyed currently thanks to the radar infrastructure. Modeling and analysis has been done to quantify ADS-B service availability, both actual and as predicted by the proposed SAPT tool. The duration of outages is considered, and finally, the potential impact of the use of SAPT on scheduled airline operations is illustrated.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	468 - 482
Cite this article:	Harris, Matt, Murphy, Tim, "Impacts of ADS-B Service Availability Prediction Requirements on Scheduled Airline Operations," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 468-482.
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