Doppler Direction Finder (Di-Fi)

Abstract

Doppler Direction Finder (Di-Fi) systems have previously been used for aerial navigation and were a critical technology in use during the First and Second World Wars. Today, the applications of Direction Finders are in pirate radio detection and stolen vehicle localization. The project aim is to design functional hardware and a Software-based system to estimate the direction of arrival of an electromagnetic wave using the doppler effect. Currently, in Pakistan, the only solution to estimate the location of the illegal transmitter is considerably expensive and comes with huge equipment and infrastructure. We propose the design of an indigenous and cost-effective system to locate pirate FM transmitters. It consists of 4 antenna arrays connected to the RF switch and UHF receiver. Using Doppler effect and phase difference of the signals, angle of arrival of the signal is calculated. The final deliverable holds a compass module that will point in the direction of signal and GPS module that will give current location of the system. Display will be on google maps API for localization of the detected signal using triangulation.