Location: The portal on Satellite Navigation, Positioning & Timing

Mobile applications have exploded over the last decade with the roll-out of Cellular networks, Global Position System and the increased availability of costeffective mapping and spatial information. Today many people use mobile products and services such as mobile phones and PDA’s on a daily basis and will use others such as GPS devices as part of the occupation or leisure activities.

The purpose of this paper is to examine the impact on mobile applications of the continued convergence of three technologies: Position, Navigation and Timing (PNT); Geographic Information Systems (GIS) and Communications Technology (CT). The paper will describe a simple market model for convergence and will go on to discuss some of the constraints which must be overcome for the convergence to continue.

Position Navigation and Timing (PNT) includes the Global Navigation Satellite Systems (GNSS) such as GPS, Glonass, Galileo and WAAS as well as Inertial Navigation Systems (INS) and Radio Location Technologies like Loran, Wi-Fi location and Pseudolites.

Geographic Information Systems (GIS) can be defined as computer system designed to allow users to collect, manage and analyze large volumes of spatially referenced information and associated attribute data. In the context of mobile applications the aspects of GIS of most relevance are in relation to serving of maps and spatially referenced data to remote clients connected via a wireless communications link.

Communications Technology (CT) in relation to this paper refers to wireless data communications whether Satellite or Terrestrial including GPRS, Wi-Fi, and commonly used RF such as VHF/UHF and the license free bands.

Figure 1. Technology Convergence. Derived from Ackroyd and Lorimer,1990-94.

UNDERSTANDING THE MARKET
It is important from the outset to recognize that the market for mobile applications which incorporate these technologies is wide and varied. Consumer, Professional and Industrial applications are growing rapidly, each with their distinctive requirements for precision, availability, cost and features.

It is perhaps no accident that convergence has occurred most quickly in the consumer domain as these are the applications which place the highest weight on factors such as size, weight, power, ease of use and other critical factors common to consumer electronic products.

Figure 2 Migration of Applications with Time. Personal Navigation.

CONVERGENCE MODEL
The figure 1 is a simple model to illustrate the convergence of the technology domains under discussion. Geospatial Information and Communication Technology (GeoICT) is a term coined by Dr Tao, Director of the GeoICT Lab at York University in Toronto, Canada. GeoICT neatly encapsulates the concept of the convergence of PNT, GIS and CT (Indeed the concept envisions the eventual incorporation of geospatial technologies into the mainstream of ICT).

Using this simple model we can place mobile applications into the various spaces. For example, a personal GPS which only shows position coordinates would fall solely into the PNT space with no overlap with other technologies. A personal GPS with electronic maps would fit into the overlap between PNT and GIS. A PDA which downloads a map over a wireless connection would be in the shared space between GIS and CT. A mobile phone with assisted GPS (A-GPS) for 911 can be described as in overlap between CT and PNT.

A brief review of GPS applications over the last decade also demonstrates that applications migrate through the domains with time. The example of Personal Navigation used above will serve to illustrate the point and can be seen in figure 2.