本論文利用TDOA(Time Difference of Arrival)技術發展無線定位系統電路，並利用TDC(Time to Digital Converter)晶片作為量測時間差的工具，系統電路設計分為兩部分，一是藉由FPGA控制TDC晶片取得時間差資料至定位運算電路，此晶片採用市售acam公司生產解析度為250ps之TDC-GP1晶片；二是透過數位電路設計方式實現TDOA定位演算法運算電路與分析此電路的定位計算結果。最後由Altera Quartus II整合此兩部分電路並驗證定位系統電路之功能實現在FPGA晶片上。
在系統應用的定位環境中，模擬TDC-GP1晶片於10公尺×10公尺內平均取樣1681個位置之時間差資料，經定位運算電路之計算平均定位誤差為4.94公分與最大定位誤差為19公分。並比較若更換為假設的高解析度10ps之TDC晶片，其電路的定位誤差平均為0.206公分與最大為0.781公分。根據模擬結果得知，由於TDOA定位演算法之雙曲線定位的關係，在距離越遠處對於TDC解析度的影響也越大。因此若替換較高規格之TDC晶片，則可提升定位系統的精確度以應用於近距離的精確定位計算。
此研究為透過Quartus II程式將電路合成後達到以FPGA實現TDOA無線定位系統之目的，系統電路功率消耗為78.58mW，操作頻率為2.5MHz，定位運算電路計算時間為10us，將可取代大部分需透過電腦做定位運算的功能，進而達到低功耗、高效能等特性。未來若加入前端無線接收模組供TDC晶片量測時間差，即可更完整地實現TDOA無線定位系統。

Here we present a FPGA-based wireless positioning system using Time Difference of Arrival (TDOA) techniques. The values of TDOA were obtained using a Time to Digital Converter (TDC). The whole positioning system circuit encompasses two parts, one is a TDC controller and the other is a TDOA positioning circuit. The TDC controller used the FPGA to control the commercially available TDC-GP1, measuring the values of TDOA input to a TDOA positioning circuit. The TDC-GP1 with 250ps resolution was acquired from Acam’s company. On the other hand, the TDOA positioning circuit based on a method of digital IC design with TDOA algorithm was utilized to analyze the output results of TDOA positioning circuit. Finally, Altera Quartus II was used for verifying performance of the positioning system circuit based on FPGA.
In the environment of system application with 10m × 10m, MATLAB was used for simulating the value of TDOA by TDC-GP1 sampling of 1681 locations. After the calculation through TDOA positioning, the average of calculation positioning error is 4.94cm and maximum of calculation positioning error is 19cm. Moreover, if the experiment is replaced by the high resolution TDC with 10ps resolution, the average and maximum of calculation positioning error can be reduced to 0.206cm and 0.781cm. According to the result of TDC-GP1 and high resolution TDC, we can infer that the TDOA algorithm with hyperbolic position and in the remote location, the resolution of TDC chip can influence error in TDOA calculation. Therefore, if the system replaces high resolution TDC by TDC-GP1, the system can enhance the accuracy by TDOA positioning circuit and further apply to accurate positioning calculation within short range.
After the integration of Quartus II and the positioning system circuit, the whole system circuit with 78.58mW power consumption, 2.5MHz operation frequency and 10μs calculation time of TDOA positioning circuit can achieve low power consumption and higher efficiency than the wireless positioning system based on computing.

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