Importance Of Position Location Systems

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Register to read the introduction… The important characteristics of IR is that it can’t penetrate walls or other opaque materials. Typically, with an IR-based system, a receiver is placed in every location in which a tagged device might be found. The tagged device emits IR light, and if the tagged device is in the same room as a receiver its position is known.

The major advantage of an IR-based system is that as the oldest and most installed positioning technology, solutions are generally available from a variety of sources and support is easy to get. There are however two major disadvantages of IR-based systems. First, there must be a receiver in every room where an asset or people might be located, and these receivers must be connected using special wiring. This special infrastructure makes the installation and configuration of IR systems time-consuming and expensive.

The second major disadvantage of IR-based systems is that if its IR signal gets blocked (for example by a bathrobe or a blanket), the system fails to work. There are other disadvantages of the IR-based solution: for example the transmitters tend to consume a lot of power so battery life is shortened if transmissions are frequent.

• Network-based methods i) IEEE 802.15
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The greater the number of cells, the smaller the size of each and that translates into greater accuracy. However, more cells increase the cost of purchase and installation. Another critical consideration is the need to have a host computer (PDA, Laptop, etc) to support the Bluetooth radio to be located. This means that it is currently impractical to located people or other devices that don’t have a built-in computer.

ii) IEEE 802.11b (WiFi) The WiFi standard is a longer range, higher bandwidth communication protocol than Bluetooth. WiFi is designed to replace a wired network on a Laptop or PC. This location solution is more sophisticated than Bluetooth because the software actually tries to approximate the location of an asset or person based on some known radio propagation characteristics. These systems are still quite new and their accuracy has yet to be consistently demonstrated.

Like the Bluetooth solution, WiFi has the advantage of being able to provide a data channel as well as location methodology. WiFi also requires relatively expensive access points in any area where a person or device needs to be tracked. Similarly, any device to be tracked needs the expensive WiFi radio in it. Since WiFi was not designed to determine location, many workarounds need to be developed before it can truly be considered as option for indoor

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