论文标题
LiteBird的验证计数据压缩的板上数据压缩的设计
Design of the on-board data compression for the bolometer data of LiteBIRD
论文作者
论文摘要
Litebird是一种空间传播实验，用于检测大规模$ b $ mmode各向异性在宇宙微波背景（CMB）的线性极化中，这是通过通货膨胀理论预测的。它计划在2020年代后期推出到Sun-Earth系统的第二个Lagrange Point（L2）。 Litebird将以15个频带绘制天空。与$ \ it {planck} $ hfi相比，先前基于低温测量计的CMB观测卫星，检测器的数量已增加了两个数量级，总计$ \ sim $ 5000检测器。来自每个检测器的数据速率为19 Hz。每天使用X波段几个小时，地面的带通限制为10 Mbps。这些要求将数据压缩超过50％。确切的值取决于实际数据中包含多少信息熵。因此，我们通过模拟了极化敏感辐射计的时序数据来评估压缩。模拟了前景发射，检测器噪声，宇宙射线故障，从CMB强度到极化等泄漏等。我们研究了几种算法，并证明其中一些算法可以达到所需的压缩比。我们描述了该评估的细节，并提出了可以在LiteBird的车载数字电子中使用的算法。
LiteBIRD is a space-borne experiment dedicated to detecting large-scale $B$-mode anisotropies in the linear polarization of the Cosmic Microwave Background (CMB) predicted by the theory of inflation. It is planned to be launched in the late 2020s to the second Lagrange point (L2) of the Sun-Earth system. LiteBIRD will map the sky in 15 frequency bands. In comparison to $\it{Planck}$ HFI, the previous low-temperature bolometer-based satellite for CMB observations, the number of detector has increased by two orders of magnitude, up to $\sim$5000 detectors in total. The data rate is 19 Hz from each detector. The bandpass to the ground is limited to 10 Mbps using the X-band for a few hours per day. These require the data to be compressed by more than 50 %. The exact value depends on how much information entropy is contained in the real data. We have thus evaluated the compression by simulating the time-ordered data of polarization sensitive bolometers. The foreground emission, detector noise, cosmic ray glitches, leakage from the CMB intensity to polarization, etc. are simulated. We investigated several algorithms and demonstrated that the required compression ratio can be achieved by some of them. We describe the details of this evaluation and propose algorithms that can be employed in the on-board digital electronics of LiteBIRD.
