Effective Urban DGPS Broadcasts for AVL

Michael SK. Sushko

Abstract:	Automatic Vehicle Location (AVL) using GPS technology in autonomous mode is not accurate enough for AVL use in urban environments. The problem is in tracking vehicles in the 100 meter range on digital maps at a control/dispatch center. As a result, some form of DGPS corrections are required. A DGPS correction broadcast can be provided, however this requires either a separate communications infrastructure or combining the DGPS broadcast on the same communications channel as vehicle position reporting. Providing a separate communication infrastructure for the broadcast of DGPS corrections is not inexpensive. A separate communications infrastructure involves the initial cost of the communications link and DGPS base station and the continued maintenance and support. Combining a DGPS broadcast on the same communications charnel used for position reporting reduces the channel bandwidth. An effective solution to providing DGPS corrections for AVL is using the new broadcast data standard defined by the National Association of Broadcasters, the Radio Broadcast Data Standard (RBDS). The RBDS defines the broadcast format for transmitting data over existing FM radio station sidebands. The RBDS format is intended for the FM broadcast industry to provide radio program information and traffic advisory information to RBS equipped radio receivers within vehicles. The RBDS standard provides for a “navigation and location” group that can be used for DGPS corrections. This paper reviews the RBDS standard, the technical aspect of the RBDS broadcast, and the RBDS groups. It also discusses the proposed broadcast format for DGPS corrections using the RBDS standard as currently defined by the Working Group for broadcasting DGPS corrections.
Published in:	Proceedings of the 49th Annual Meeting of The Institute of Navigation (1993) June 21 - 23, 1993 Royal Sonesta Hotel Cambridge, MA
Pages:	83 - 94
Cite this article:	Sushko, Michael SK., "Effective Urban DGPS Broadcasts for AVL," Proceedings of the 49th Annual Meeting of The Institute of Navigation (1993), Cambridge, MA, June 1993, pp. 83-94.
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