The Research Of Passive Time Difference Estimation Technology And The Realization Of Software System

With radio resources are widely used, the demand for electromagnetic environment monitoring and positioning equipment is increasing, especially for spectrum management equipment within a small area of environment, such as the monitoring system that prevents electromagnetic interference in airport. Thus, the design of a portable and low cost networked passive monitoring and positioning system is of great significance.Based on time difference location system, the main design and research of this subject is the software system, in addition, the time difference estimation algorithm is analyzed in the dissertation.First of all, this dissertation provides a more practical time difference estimation method of Advanced Explicit Time Delay Estimation in engineering, and analyzes the influence to the performance of location by time difference measurement error. Based on the validation of TDOA algorithm, the design of passive locating software system is realized, the software mainly completed the function of interface display, parameter configuration, data communication, and data storage. The software is developed with C++ language in the VS2010 platform.Secondly, each function module is separately designed and tested using modularized software design method. Through the design of each function module, the following work is complete:(1) the design of two-dimensional graph, histogram and colored waterfall graph are implemented through the graphic display module;(2) the remote control and management to the hardware system is realized through the parameters configuration module;(3) the network of whole passive location system is realized through the data communication module;(4) the storage of system data is implemented through the data storage module, which is for the convenience of users to analyze off-line.Finally, all the functional modules are integrated by multi-threaded design scheme, then the design and implementation of entire passive location software system is completed. The software system has good accurate timing function, under the condition of synchronization of clock source, time difference measurement error is less than 100 ns. The software has four kinds of signal scanning mode which are fixed frequency scanning, frequency scanning, channel scan and panoramic scanning, the bandwidth of these work mode is up to 20 MHz, and the working frequency range from 20 MHz to 3.6GHz. The software with multi-functions such as signal monitoring, signal detection and signal statistical analysis is designed simple and beautiful, and what’s more the software is easy to operate.