GPS-free Localization technique using a Wireless Sensor Network

Improvements in localization based technologies have led to a growing business interest in location-based applications and services. Nowadays, locating the physical belonging indoor and outdoor environment become one of the application requirements. Localization is the technique to obtain the location information of objects. The location information of objects can be obtained by using wireless sensor networks in the sensor localization. Global Positioning System (GPS) is one of the device that use wireless networks to obtain location information. However, due to the expensive cost and it is unable to be used in indoor environment, an alternatives need to be figured out. Thus, the aim of this project is to build a reliable and cheaper local positioning system, which can function in indoor and outdoor setting. Literature review on some techniques has been done and from the review, the features, advantage and disadvantage of all techniques discussed are compared. The techniques that have been discussed in this study are time of arrival (TOA), time different of arrival (TDOA), angle of arrival (AOA) and received signal strength indicator (RSSI).Based on the comparison of 4 techniques above, the TOA approach has been selected to be focus further and will be implement in Matlab software for future work. The parameters are varied to compare the performance of node localization. By using the baseline value, the performance comparison is done by varying some parameters which are network area, numbers of anchors, anchors arrangements, and number of run. From the results obtained, four conclusions can be made. First, percentage of accuracy is higher with smaller network area. Second, less number of anchors will increase the percentage error, third, increase in the number of run will yield lower percentage error and the final one is the best topology of anchor are in hexagon arrangement.