Study on a high performance and multifunictional software receiver for plasma wave instrument

研究了科学卫星软件接收机的优化算法。为了设计出最优的星载软件，以获得最大的等离子体物理科学输出，我们研究了星载等离子体波仪的数据选择、数据压缩和频谱分析信号处理的几种算法。主要结论总结如下：1。为了利用安装在板载CPU上的软件从宽带波形捕获中获取频谱数据，我们提出了一种优化分析方法，特别是在高频分辨率非常低的频率范围内。数据压缩算法对于实现更高的数据压缩比以及保证科学目标的数据质量也很重要。对频谱数据采用了无损和有损两种算法。我们证明，与自适应距离编码器应用于标称分辨率数据相比，JPEG应用于更高时间分辨率数据可以获得更高的数据质量。对于波形数据，我们提出了一种新的分带方法。利用与科学卫星兼容的小型CPU对机载软件处理进行了模拟。我们测量了所提出的数据处理方法的执行时间，并给出了数据处理的最佳参数。研制了雷电啸声色散特性的自动数据检测与估计方法。结果表明，该方法适用于闪电哨声的数据选择，所得色散特性可用于重建等离子体球中电子密度的空间分布。

We studied optimal algorithms for a software receiver onboard scientific satellite. For the purpose of designing optimal onboard software which obtains the maximum scientific output of the plasma physics, we examined several algorithms for data selection and data compression as well as signal processing for spectral analysis to be performed on a plasma wave instrument onboard the satellite. The main conclusions are summarized as follows:1. In order to obtain spectral data from wideband waveform capture using software installed on an onboard CPU, we proposed an optimal analyses method, especially for very low frequency range with a high frequency resolution.2. Data compression algorithm is also important to achieve higher data compression ratio as well as to keep fine data quality for scientific objectives. Both lossless and lossy algorithms are taken into account for the spectrum data. We demonstrated that higher data quality can be obtained by JPEG applying to higher time resolution data than by adaptive range-coder applying to nominal resolution data. As for the waveform data, we proposed a new sub-band ceding method.3. Onboard software processing was simulated using a small CPU, which is compatible to the one used for a scientific satellite. We measure execution times for the proposed data processing methods, and showed optimal parameters for the data processing.4. Automatic data detection and estimation of the dispersion characteristics of the lightning whistlers was developed. We demonstrated that the proposed method is applicable for the data selection for lightning whistlers, and the derived dispersion properties are useful for the reconstruction of a spatial profile of electron density in the plasma sphere.