INFORMATION TECHNOLOGY UNIVERSITY
COOPERATIVE WIRELESS SOURCE LOCALIZATION VIA TOA
SOURCE LOCALIZATION
Now-a-days locating and tracing different types of signal sources is an emerging wireless communication technology and an interesting research topic. In this new era of technology, the application of localization is found in many fields. For example, in robot navigation, search and rescue missions, virtual reality systems, expensive hospital equipment can be protected from theft by real time tracking, forensic investigations e.g. localizing criminals’ cellular devices. In military applications, such as localizing and tracing dangers through border security area, in detecting aircrafts and submarines. Therefore, there is a need to find new approaches that can correctly localize signal sources. In this report, we gave a brief overview of different techniques used for localization. Then we have discussed Time of Arrival based localization in detail with MATLAB simulation results. Moreover, limitations of TOA based localization are mentioned.
TOA BASED LOCALIZATION
In this type of localization transmitter transmits the signal assuming an active source and the receiver receives the signal. Moreover, few samples of the transmitted signal are already saved by the receiver. So, when the signal is received, cross-correlation is done of the received and saved signal and when maximum value of cross-correlation (x-corr) is achieved then at that instance time is being measured and the distance is being calculated by using the formula.
Moreover, in our scenario during the simulations we assumed to as zero. One thing to be mentioned is that to must be same for all receivers otherwise system will not be synchronized and error will occur in calculation. Then after calculating the distance we consider those distances as radius and make circles with sensors’ position as center point for circles. Then where all these circles intersect or overlap, we consider that point or region as the location of transmitter.
Receivers Requirement
Adding more, minimum number of receivers depends on dimensions of localization (i.e. nD = n+1 receivers at minimum). In our case as it is a 2D localization so we used 3 receivers similarly, for 3D localization 4 receivers are required and so on. To understand that why we need at minimum 1+nD receivers for n-Dimensional localization, we can take example of satellites GPS navigation system. As for 3D localization, we need 4 satellites.
FINDING SIMULATION RESULT USING TOPA - LAB VIEW RESULTS
UNDERSTANDING LOCALIZATION
LOCALIZATION IN IDEAL SCENERIO
