PosArc: A Layered Architecture for Development of Seamless Positioning Systems Kavi Kumar Khedo Faculty of Engineering, University of Mauritius, Réduit, Mauritius k.khedo@uom.ac.mu Danraz Meetoo Faculty of Engineering, University of Mauritius, Réduit, Mauritius meetood@mx.uom.ac.mu Abstract Position location systems are becoming increasingly important as add-ons to today’s pervasive wireless technology. Positioning systems enable context-aware computing with location awareness. Moreover, Location awareness is a key ingredient to many applications of mobile devices. Devices with the ability to determine their own position in space can retrieve, filter or present information depending on this position. There are, however, different ways to look at this situation resulting in different distributions of computational resources. In this paper, PosArc a new cost-effective and easily deployed layered architecture to provide seamless positioning using GPS and Bluetooth is proposed. It enables users to obtain location information available from nearby devices and access points. The raw location data obtained is transformed into useful position information using local or remote map and web services. Layers in the architecture interact using HTTP and XML protocols. The challenges and related work in the field of positioning systems are also discussed. 1. Introduction Location awareness is a key component in ubiquitous computing. During the past few years, much research and interest has been focused on location sensing technologies, location based services and location aware computing. A number of location sensing systems have emerged that differ with respect to precision, accuracy, cost of deployment and maintenance. The Global Positioning System (GPS) is the most popular and widely used outdoor positioning technology. In addition, the recent explosion of Bluetooth, Wi-Fi and other wireless networking technologies has led to many end- user devices being equipped with Radio Frequency hardware that can be used for location sensing [3]. Allowing users to discover and communicate their positions in the physical world has long been identified as a key component in emerging mobile computing applications [1, 2]. Dozens of research and commercial location systems have been built using sensing technologies including ultrasonic time-of-flight, infrared proximity, radio signal strength and time-of-flight, optical vision, and electro-magnetic field strength. There have been many research and commercial efforts to improve accuracy and precision, shrink the size of the sensing hardware, simplify deployment and calibration of sensors, and provide more convenient middleware. Despite these efforts, building and deploying location-aware applications that are usable by a wide variety of people in everyday situations is arguably no easier now than it was ten years ago. First and foremost, current location systems do not work where people spend most of their time; coverage in current systems is either constrained to outdoor environments or limited to a particular building or campus with installed sensing infrastructure. Applications like location-aware instant messaging fall flat if they only work for a fraction of users or only during a fraction of a user’s day. Second, existing location technologies have a high cost of entry to both users and application developers. Many location systems require expensive infrastructure, time consuming calibration, or special tags, beacons, and sensors. The privacy cost to the many stakeholders is also typically ignored or considered only after deployment. These barriers leave location-aware computing in an unfortunate cycle: There are very few users due to a dearth of applications; developers are not interested in writing applications for nonexistent infrastructure; infrastructure investments are based on user demand, of which there is little. This cycle has not prevented researchers from prototyping and innovating in the application space. It has, however, prevented the widespread experimentation and adoption of these applications by real users. The result is that while we can give compelling demonstrations of location-based applications, few can be used in the places they are most useful. This paper presents a layered architecture, PosArc, for seamless positioning with GPS and Bluetooth where location information can be interchanged and combined to achieve a more available service. The architecture 0-7695-2629-2/06/$20.00 (c) 2006 IEEE