Wireless Positioning Systems: Operation, Application, and Comparison

Abstract

Recent years have seen rapidly increasing demand for services and systems that depend upon accurate positioning of people and objects. This has led to the development and evolution of numerous positioning systems. This chapter provides an overview of the main positioning techniques: time-of-arrival (TOA), direction-of-arrival (DOA) and received signal strength indicator (RSSI). It then introduces positioning systems that are either in use or being developed ßfor a variety of applications. Operations of these positioning systems are summarized using flowcharts and figures. In addition, the chapter compares positioning systems on the basis of system characteristics and performance parameters. Many of these positioning techniques and systems are introduced in greater details throughout different parts of this handbook. The chapter concludes by reviewing a number of emerging positioning systems and outlining some future applications. Received Signal Strength Indication (RSSI):Similar to the TOA, in RSSI, multiple base nodes collaborate to localize a target node via triangulation (see Figure 2 (a)). However, instead of measuring TOA at base nodes, the estimation is carried out using the received signal strength [3]. In this method, the strength of the received signal indicates the distance travelled by the signal. Assuming that the transmission strength and channel (or environment in which the signal is traveling) characteristics are known, for a co-planar case, three base nodes and three RSS measurements are required. Part III of this handbook studies RSS-based methods in detail.

A methodology for design space exploration of real-time location systems

“…Programming effort for increasing it (e.g., applying a complex filtering technique) could be considerably bigger. For a more detailed comparison we refer the interested reader to [6,8].…”

“…Another powerful method is angle-of-arrival (AOA) [5], though it typically requires complex antenna hardware. A detailed survey of range-based methods can be found in [6]. Several performance improvements have been developed, for example, Least Squares [4] and Kalman filtering [7].…”

“…Several performance improvements have been developed, for example, Least Squares [4] and Kalman filtering [7]. Distances provided by rangebased methods are used in calculating moving object's coordinates, for example, by using trilateration [6].…”

Hierarchical Area-Based Address Autoconfiguration Protocol for Self-organized Networks

“…In other terms, the neighborhood is formed by all nodes reachable within one hop. The relative position of a node to one of its neighbor must be taken in a geographic sense and can be obtained using techniques similar to those surveyed in [16]. We call prefix at level n the two bits corresponding to the label of an area of level n. The address of a particular node is then the concatenation of all prefixes of all levels.…”

“…Each node chooses as address the label of the region where it is located using its absolute coordinates. -If the nodes have only access to their relative geographic position [16], the address assignement needs communication between nodes. From now on, we will focus on this second case.…”