Ranging Sensor Fusion in LISA Data Processing: Treatment of Ambiguities, Noise, and On-Board Delays in LISA Ranging Observables
Jan Niklas Reinhardt Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Callinstraße 38, 30167 Hannover, Germany Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany Martin Staab Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Callinstraße 38, 30167 Hannover, Germany Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany Kohei Yamamoto Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Callinstraße 38, 30167 Hannover, Germany Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany Jean-Baptiste Bayle University of Glasgow, Glasgow G12 8QQ, United Kingdom Aurélien Hees SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, 61 avenue de l’observatoire 75014 Paris, France Olaf Hartwig Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Callinstraße 38, 30167 Hannover, Germany Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, 61 avenue de l’observatoire 75014 Paris, France Karsten Wiesner Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Callinstraße 38, 30167 Hannover, Germany Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany Sweta Shah Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Callinstraße 38, 30167 Hannover, Germany Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany Gerhard Heinzel Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Callinstraße 38, 30167 Hannover, Germany Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
Abstract
Interspacecraft ranging is crucial for the suppression of laser frequency noise via time-delay interferometry (TDI). So far, the effects of on-board delays and ambiguities on the LISA ranging observables were neglected in LISA modelling and data processing investigations. In reality, on-board delays cause offsets and timestamping delays in the LISA measurements, and pseudo-random noise (PRN) ranging is ambiguous, as it only determines the range up to an integer multiple of the PRN code length. In this article, we identify the four LISA ranging observables: PRN ranging, the sideband beatnotes at the interspacecraft interferometer, TDI ranging, and ground-based observations. We derive their observation equations in the presence of on-board delays, noise, and ambiguities. We then propose a three-stage ranging sensor fusion to combine these observables in order to gain accurate and precise ranging estimates. We propose to calibrate the on-board delays on ground and to compensate the associated offsets and timestamping delays in an initial data treatment (stage 1). We identify the ranging-related routines, which need to run continuously during operation (stage 2), and implement them num
中文速览
激光干涉空间天线（LISA）要探测引力波，必须靠"时延干涉"（TDI）技术把激光频率噪声压低八个数量级以上，而这需要精确知道三颗卫星之间的距离；然而现实中，星载设备的内部延迟会引入测距偏差和时间戳误差，伪随机噪声（PRN）测距又因码长有限而存在整数倍的模糊性，使得真实测距精度大打折扣。为此，作者系统推导了LISA四种测距观测量——PRN测距、星间干涉仪的边带拍频、TDI测距以及地面观测——在星载延迟、噪声和模糊性共同作用下的观测方程，并提出一套三阶段"测距传感器融合"方案：第一阶段在地面标定并补偿星载延迟引入的偏差；第二阶段用卡尔曼滤波器持续融合PRN测距与边带拍频来降低测距噪声；第三阶段利用地面观测和TDI测距对PRN模糊性与偏移量进行交叉验证和修正。数值仿真结果表明，该方案能够可靠解算模糊性、有效抑制测距噪声，为LISA数据处理流水线提供了切实可行的精密测距解决方案，对整个引力波探测任务的成败至关重要。
原文 arXiv:2307.05204;中英对照 + 大白话阅读 https://aha.fim.ai/paper/2307.05204v3