This and the following six papers were selected from the many papers presented at the 9th World Congress of the International Association of Institutes of Navigation (IAIN) held in Amsterdam, The Netherlands, 17–21 November 1997.

During the past several years, a number of important investigations, policy initiatives and national commitments relating to the future of GPS, GLONASS and their augmentations have occurred. Substantive and on-going studies of the character and configuration of a Global Navigation Satellite System (GNSS) have also been evaluated worldwide, especially by the International Civil Aviation Organization (ICAO). These efforts have been principally directed toward the definition of near- and far-term GNSS implementations that meet the needs and concerns of the international community. This paper briefly reviews some of the investigations and addresses, in particular, the concerns and requirements that may affect the future capabilities and the dual (civil/military) character of GPS. The main issues relating to the modernisation of GPS and its subsequent transition to a component of a GNSS with a viable international character are presented. These include a discussion of new signal structure options, certain changes in operating frequencies, increased signal power levels, other system alternatives and their potential impact on system performance. International issues are briefly addressed, including future performance capabilities, assurance of service, economic participation and benefit, reasonable cost, standards and international participation.

As new technologies contribute to the expanded functionality of Loran-C, and as concerns for limitations in GPS and its augmentations are raised, specific aspects of Loran-C have been developed and applied to ameliorate those limitations. Specifically, GPS availability is a concern, particularly in over-land applications. This paper discusses recent developments using very high-precision synchronisation of Loran-C transmissions, new data compression and Loran-C signal modulation techniques to augment GPS accuracy, availability and integrity over a very wide area at very low cost.

Marine radiobeacons have been used to broadcast differential corrections for global navigation satellite systems (DGNSS) for nearly a decade. The method has become the accepted international standard for maritime applications. The background to the development of the system is described and the current status of radiobeacon DGNSS services around the world reported. The applications are discussed, including the function of radiobeacon DGNSS as the position sensor within integrated systems, together with the performance requirements imposed by associated systems such as ECDIS and Automatic Identification Systems. The advantages and disadvantages of the radiobeacon system in regulatory, administrative and technical terms are discussed and the potential for development of the system is considered. The future role of radiobeacon DGNSS in the overall mix of systems is assessed taking into account the introduction of geo-stationary overlays, and possibly Loran-C, for provision of DGNSS corrections.

This paper gives details of the failure rates and the failure modes experienced with SPS GPS receivers certificated for aviation use to the TSO-C129 specification. These failure rates are significant compared to those from other modern avionics and the rates are comparable to that currently experienced from un-scheduled failures in the GPS signals-in-space. To achieve certification, Flight Management System (FMS) design should consider the way in which the satellite navigation receivers fail. The paper also gives details concerning the 2-D errors that have been experienced with these receivers, and indicates further work that needs to be done with C 129a receivers.

After a brief overview of Loran-C system operation and performance, the present situation of the system in Europe is described. Loran-C is now in operation under the NELS agreement in north-western Europe in newly established chain configurations with old and new transmitter positions. Parallel to Loran-C the Russian equivalent, Chayka, is also operating, with three chains in Europe. There is an agreement between Norway and Russia concerning cooperation and possibly joint chain operations between the two system providers in the north; similar agreements in the Baltic and Mediterranean/Black Sea areas are being worked on. The situation around the Iberian peninsula has not yet been clarified. Being the only long/medium-range terrestrial system in Europe in the 2000+ time frame, Loran-C could be seen as a supplement to satellite systems. Due to the good penetration properties of its low-frequency signals, it can be used in many circumstances where satellite systems fail because of limited satellite visibility. Integration of Loran-C and (differential) satellite receivers, where Loran-C is calibrated by the satellite system as long as there are enough visible satellites, could in fact give the best of both worlds. For this reason, Loran-C is being considered in the perspective of a future international, civil satellite navigation system, initiated in Europe.

This paper, and the following five papers, were presented during the NAV 97 Conference held at Church House, Westminster, London on 11th and 12th November 1997. A full listing of the Conference, and how to obtain a copy of the proceedings, is shown on Page 279.

The Government of the Russian Federation has made available, subject to certain conditions, the GLONASS satellite radionavigation system for civil use. Use of the system is free and there is no intention to introduce coding or to cause any deterioration to the accuracy of the signals. Discussions are currently taking place between the European Commission and the Russian Federation on cooperation concerning the implementation of a navigation satellite system for civil purposes. Discussions are also taking place between interested European Governments and the Russian Federation into the possibility of developing joint Chayka/Loran-C chains wherever this is feasible, and in particular, to cover the Barents Sea, the Baltic Sea and the Black Sea. The development of a concept on integration of radionavigation systems would probably be a significant contribution to the European Radionavigation Plan.

This paper covers the wide area and short range locational technologies that are available for vehicle tracking in particular and mobile user security in general. It also summarises the radio communications services that can deliver information to the user. It considers the use that can be made of these technologies, when combined with procedures for delivering a response, in the security field, notably in relation to personal security, high-value load protection and the after-theft tracking markets.