This paper describes three different antenna systems for mobile vehicle applications. The antennas are either patches or derivatives in all cases. The first is a dual-band telephone antenna with a low profile and wide bandwidth. Operating at 900 MHz and 1800 MHz, with a VSWR of better than 1·7, it is a hybrid construction combining a monopole with a top-loading patch shorted to the ground-plane. Extra-shorted pins provide the upper frequency band coverage. It provides monopole radiation characteristics and can be hidden under a plastic panel or mounted on the vehicle roof. The second is a microstrip patch antenna integrated into a laminated glass windscreen for a vehicle. It is fed using a coplanar waveguide feed printed on the innermost layer of the glass, avoiding the need for a contacting feed within the laminate. The patch and ground plane are meshed for manufacturing in the glass to avoid distorting the heat profile when the glass is shaped and laminated. The patch is easily fed from inside the vehicle and is potentially a very low cost design. The final antenna discussed is a dual-band patch antenna specifically designed for the Globalstar satellite telephone system at 1·6 GHz and 2·45 GHz. It also covers the Iridium band at 1·6 GHz. A single circularly polarised patch is used. Dual-band operation results from truncating the corners of the square patch and judiciously placed slots to achieve a band spacing of 1·5.

Navigation map databases have evolved during the last 10 years in coverage, content and accuracy to such a degree that they are being used (and considered) for applications beyond vehicle navigation. For a number of advanced driver assistance systems (ADAS) in Europe and North America, the navigation maps are being enhanced to offer new functions. This will complement dynamic route guidance, with location referencing, descriptions of delays, floating car data and re-routeing, all requiring developments in traffic management, road capacity balancing and routing algorithms.

This paper presents the results of a study carried out in the Greater London area to assess and characterise the performance of the Global Positioning System (GPS) for vehicle positioning in urban areas. The performance assessment addresses, in varying levels of detail, the issues of service coverage, positioning accuracy, integrity and availability of service. The project was supported by Racal Survey Limited and is part of the wider research at Imperial College in the area of architectural design and testing of Advanced Transport Telematics (ATT) systems. The results highlight the shortcomings of GPS as the sole means for in-car navigation in urban areas and details the temporal and spatial considerations to be taken into account in the process of designing an integrated positioning system capable of meeting navigation requirements placed on ATT systems.