Design Of EPIRB Tester

Emergency Position Indicating Radio Beacon (EPIRB) is an important part of the global maritime distress safety systems (GMDSS), which has been widely applied in the emergency communication of sea vessel. In order to ensure that EPIRB can run stably, all the technical indexes are necessary to be tested. This paper puts forward a general planning proposal of embedded EPIRB Tester, which is based on software radio.Firstly, this paper introduces the basic principle of software radio and analyzes the key technology of the digital intermediate frequency receiver. It also puts forward the general planning proposal which combines EPIRB signal technical parameters with performance index EPRIB Tester.Secondly, for the needs of the tester, this paper puts forward a new method, which chooses software Costas and FFT algorithm as a carrier of tracking to measure the frequency in the shortest time rather than EPIRB signal's frequency measurement and duplex L demodulation algorithm, which is the most commonly used method. In the stage of signal no modulation,this method can realize frequency measurement, and in the signal modulation stage, it can realize data demodulation and decode function. In order to achieve the requirement of time-interval measurement of EPIRB signal, using electronic notation as the basic measuring principle, detecting the signal's start-stop endpoint using energy assay and phase assay method, thus produce the door-control signal for the electric counting method.Finally, the algorithm of each detection function modules was simulated and analyzed by using MATLAB, and the results showed that the tracking frequency measurement method which combined FFT with software Costas, can not only improve the phase lock loop speed, but also have the ability to get high precision carrier frequency.Furthermore, the algorithm of the signal time-interval measurement also meets the detector's accuracy. In addition, some important part of the algorithm is optimized and finished in C language, which is convenient to realize in different hardware platform.