Accuracy analysis of GPS L2C signal quality assessment by different tracking methods
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摘要: 卫星信号质量好坏会影响用户的使用性能,利用软件接收机的跟踪结果可以实现信号质量评估. GPS L2C信号的伪码是由CM码和CL码时分复用(time division multiplexing,TDM)组成,根据其信号特点可以使用不同的跟踪方式进行跟踪. 针对不同跟踪方法对信号评估精度的影响,重点分析了信号一致性,信号的相关性能等指标. 通过仿真信号分析和实测数据验证,结果表明:联合跟踪相比于单分量跟踪其评估精度更高,且各项指标的评估结果都优于单条支路的评估结果,使用联合跟踪会带来更小的测距误差.
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关键词:
- GPS L2C信号 /
- 跟踪 /
- 一致性 /
- 相关损失 /
- S曲线偏差(SCB)
Abstract: The quality of satellite signals affects user performance, and signal quality evaluation can be achieved by utilizing the tracking results of software receivers. The pseudo-code of GPS L2C signal is composed of CM code and CL code time division multiplexing. According to its signal characteristics, different tracking methods can be used for tracking. The influence of different tracking methods on the accuracy of signal evaluation is analyzed, and the signal consistency and signal correlation performance are analyzed. Through simulation signal analysis and measured data verification, the results show that the joint tracking has higher evaluation accuracy than the single component tracking, and the evaluation results of each index are better than the evaluation results of a single branch. The use of joint tracking will bring smaller ranging error.-
Key words:
- GPS L2C signal /
- tracking /
- consistency /
- related losses /
- SCB
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表 1 理想信号评估结果
信号 相关损失/dB S曲线过零点偏差/ns 码载一致性/ns CM码跟踪 0.011 3 −0.030 9 0.103 6 CL码跟踪 0.011 7 0.030 8 0.102 4 联合跟踪 0.000 1 0.000 8 0.033 0 表 2 不同载噪比仿真信号相关损失
载噪比/(dB-Hz) CM码/dB CL码/dB 联合跟踪/dB 55 7.244 7 7.360 8 7.166 5 65 1.581 0 1.551 2 1.544 9 75 0.190 0 0.168 7 0.103 7 85 0.030 6 0.029 6 0.019 1 表 3 不同载噪比仿真信号SCB
载噪比/(dB-Hz) CM码/ns CL码/ns 联合跟踪/ns 55 –0.177 1 0.181 8 0.100 1 65 –0.146 2 0.152 3 –0.028 9 75 0.010 1 0.009 2 0.003 4 85 0.005 6 0.006 4 –0.003 1 表 4 不同载噪比仿真信号一致性(标准差)
载噪比/(dB-Hz) CM码/ns CL码/ns 联合跟踪/ns 55 0.253 8 0.243 2 0.162 3 65 0.126 9 0.121 6 0.060 6 75 0.103 2 0.106 3 0.036 8 85 0.104 5 0.099 5 0.033 1 表 5 三种跟踪方法的鉴相结果(标准差)
ns 序号 CM码 CL码 联合跟踪 1 0.002 3 0.002 4 0.001 8 2 0.002 4 0.002 5 0.001 9 3 0.002 4 0.002 4 0.001 8 4 0.002 5 0.002 6 0.002 0 5 0.002 4 0.002 4 0.001 8 6 0.002 3 0.002 2 0.001 8 表 6 实测信号相关损失
dB 序号 CM码 CL码 联合跟踪 1 –0.182 –0.165 –0.061 2 0.183 –0.164 –0.054 3 –0.097 0.107 0.058 4 –0.133 –0.167 0.055 5 –0.099 0.095 0.054 6 0.174 –0.167 –0.055 表 7 实测信号SCB评估结果
ns 序号 CM码 CL码 联合跟踪 1 –0.0147 0.0156 –0.0072 2 –0.0892 0.0037 –0.0018 3 –0.0399 –0.0295 –0.0028 4 –0.0350 0.0388 –0.0022 5 –0.0227 0.0091 –0.0034 6 –0.0380 –0.0290 –0.0081 表 8 实测信号一致性评估结果
ns 序号 CM码 CL码 联合跟踪 1 0.103 0.103 0.023 2 0.157 0.155 0.079 3 0.154 0.149 0.053 4 0.167 0.172 0.065 5 0.143 0.143 0.067 6 0.131 0.129 0.085 -
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