全球定位系統軟體接收機的信號獲取

Abstract

在現今的社會裡，全球定位系統是一種相當普及的科技。而在獲取信號全球定位系統的軟體接收機中最重要的是如何提升速度，在全球定位系統中最耗時間的是快速複利葉轉換，因此我們提出了三種演算法來提升全球定位系統的軟體接收機的速度。第一種方法是基數-2 快速複立葉轉換，第二種是分離式基數-2/4 快速複立葉轉換，第三種是分離式基數2/8快速複立葉轉換，然後比較彼此之間的暫存和負載來比較哪一個演算法比較快，同時比較省加法器和乘法器。我們後來模擬後的結果跟比較後發覺分離式基數2/8快速複立葉轉換比分離式基數-2/4快速複立葉轉換省了25%的暫存器，負載，加法器，和乘法器。而分離式基數-2/4快速複立葉轉換也比基數-2快速複立葉轉換更加的省暫存器，負載，加法器，和乘法器。我們也比較了浮點和定點的兩種運算結果的差距，同時我們為了確定獲取的訊號是正確的，所以我們也提出了新的演算法來確定抓取的訊號是正確 , 之後也採用了唐式偵測法來確保acquisition 的訊號是正確的, 我們也模擬出錯誤警告和偵測還有錯失的機率. 我們將在這一本論文裡面詳加介紹.

In the modern society today, GPS is known to be a popularized universal technology. The most crucial factor in the acquisition of GPS software receiver is to accelerate the speed of the operation. Among the many different variety of GPS blocks, FFT is the most time consuming technology. In order to successfully enhance the speed of GPS software receiver, we have investigated 3 different algorithms to compare the speed and capability saving the most additions and multiplication. The first algorithm is called radix-2 FFT, the second is called split-radix-2/4 FFT and the third is called split-radix-2/8 FFT. After comparing the simulation result, we have realized the split-fadix-2/8 FFT saves stores, additions and multiplication 25% more than the split radix-2/4. The split-radix-2/4 FFT also can save significantly more stores, loads, additions and multiplications than the radix-2. We have also compared the difference between the floating point and fixed point operations. In order to confirm the accuracy of acquired signal, we not only claimed a brand new algorithm, but the Tong search detector was also employed at this stage. Simulations such as false alarm, detection and the probability of missing have also been introduced more thoroughly in the content of my thesis.