Pulsar-based navigation results: data processing of the x-ray pulsar navigation-I telescope

Abstract

Pulsar-based navigation for spacecraft is a revolutionary technology that has been researched for several decades. To validate it, China launched a small experimental satellite, the x-ray pulsar navigation-I (XPNAV-1), whose main payload was the first Chinese on-orbit grazing incidence focusing x-ray telescope, called the time-resolved soft x-ray spectrometer (TSXS). XPNAV-1/TSXS observes the x-ray pulsar at the 0.5- to 10-keV band. Based on 85-day observation data of the pulsar B0531+21 (Crab), a ground pulsar-based navigation experiment is conducted. The pulsar timing is performed to determine Crab’s spin parameters at the x-ray band. A pulse phase estimation method is designed that eliminates the influence of the Doppler effect and generates ranging measurements from 25 observations. The ranging measurements are introduced as control points into the orbit propagation of XPNAV-1. The result indicates that, in nearly three months, by observing Crab only, XPNAV-1 can locate itself with an average navigation error of 38.4 km at the control points.