卫星接收信号的同步设计性实验开发与教学实践

Designing Experiment Development and Practice of Synchronization of Satellite Received Signals

为了提升本科生创新实践能力,开发了一个设计性实验项目——卫星接收信号的同步。该教学实验包括基带信号同步技术验证的方案设计、现场可编程门阵列(FPGA)的实现及系统测试。实验对信号进行采样处理;利用快速傅里叶变换(FFT)进行载波的粗同步;将信号的频点牵引到同相正交环(Costas环)的捕捉范围中,通过Costas环进行精细同步;采用超前滞后位同步技术的方法,实现码元同步;并对星基信号检测。教学实践表明,这种渐进式的设计性实验教学方式,可以激发学生的实验兴趣和创新意识,增强学生解决工程问题的能力,从而提高实验教学质量。

In order to improve the innovation and practice ability of the undergraduate,a designing experiment of synchronization of received satellite signals is developed.The experiment includes the scheme design of baseband signal synchronization,the realization of FPGA and the system tests.In the experiment,the signal is down-sampled first.Then perform carrier synchronization.It uses FFT(Fast Fourier Transformation)to perform coarse synchronization of the carrier,and pulls the frequency points of the signal into the capture range of the Costas ring(in-phase quadrature ring),and then lets the Costas ring perform fine synchronization.The next step is the symbol synchronization,which adopts the method of leading and lagging bit synchronization technology.Finally,the experimental system is tested to detect satellite-based signals.Teaching practice has proved that this teaching method of synthetic and designing experiment can stimulate students'experimental interest and innovative consciousness,enhance students'ability to solve engineering problems,and thus improve the quality of experimental teaching.