码多普勒对扩频码捕获性能的影响

Influence of code Doppler on spread spectrum code acquisition performance

摘要:

为了评价高动态场景中码多普勒对捕获的影响，定量分析码多普勒对相关峰值的影响具有指导意义。引入一种有效的求解码相关结果的方法——图解法，采用此方法推导了当存在码多普勒时码相关结果，详细推导了当码搜索步进不连续时码多普勒对相关峰的影响。通过Matlab仿真了码搜索步进为连续和不连续时码多普勒对相关峰值的影响，证明前述推导是正确的。计算结果表明，当码搜索步进为二分之一码片，相关时间内码多普勒引起的码误差超过四分之一码片时将对相关峰值造成影响。

Abstract:

It shows a guiding significance to make quantitative analysis about the influence of code Doppler on correlation peak in order to evaluate the influence of code Doppler on acquisition in high dynamic scene. A graphic method is introduced，which is a kind of effective way to calculate code correlation. Correlation results are derived by this method when code Doppler exists. The influence of code Doppler on correlation peak is derived in detail when code step is discontinuous. The influence of code Doppler on correlation peak is simulated by Matlab both when the code step is continuous and discontinuous，therefore，previous derivations are verified. The calculation results show that correlation peak will be weakened under the condition that code error caused by code Doppler is above 1/4 chip during the correlation time at the code step of 1/2 chip.