Contents1 Introduction 11.1 Basic Concept of Spacecraft Autonomous Navigation System 11.1.1 Definition of Spacecraft Autonomous Navigation System 11.1.2 Necessity of Autonomous Navigation Systems 11.2 Three Main Types of Spacecraft Autonomous Navigation Systems 31.2.1 Inertial Navigation System 31.2.2 Celestial Navigation System 41.2.3 Navigation Satellite System 61.3 Review of X-Ray Pulsar-Based Navigation 91.3.1 Brief Introduction of Pulsar 91.3.2 Brief Introduction of X-Ray Pulsar-Based Navigation 101.3.3 Famous Programs on XPNAV 111.3.4 Progresses of Key Techniques 13References 222 Fundamential of the X-Ray Pulsar-Based Navigation 252.1 Space-Time Reference Frame 252.1.1 Coordinate System 252.1.2 General Relativistic Time System 272.2 Timing Model 322.2.1 Time and Phase Model 332.2.2 Time Transfer Model 352.3 Spacecraft Orbital Dynamics and Attitude Dynamics Models 372.3.1 Spacecraft Orbital Dynamics Model 372.3.2 Spacecraft Attitude Dynamics Model 402.4 X-Ray Pulsar-Based Spacecraft Positioning 432.4.1 Basic Principle 432.4.2 Working Flow 452.4.3 Analysis on the X-Ray Detector Configuration Scheme 462.5 X-Ray Pulsar-Based Spacecraft Time Keeping 482.5.1 Basic Principle 482.5.2 System Equation 492.5.3 Feasibility Analysis of Time-Keeping via the Observation of One Pulsar 502.6 X-Ray Pulsar-Based Spacecraft Attitude Determination 522.6.1 Basic Principle 522.6.2 Means of Realizing Direction via the Observation of Pulsar 56References 583 X-Ray Pulsar Signal Processing 613.1 X-Ray Pulsar Signal Model 613.2 Profile Recovery 623.2.1 Epoch Folding 623.2.2 Period Search 633.2.3 Enhancing the Signal to Noise Ratio of Profile 683.3 Pulse TOA Calculation for Stationary Case 783.3.1 Pulse TOA Calculation Methods 783.3.2 Performance Analysis 803.4 Pulse TOA Calculation for Dynamics Case 813.4.1 Improved Phase Propagation Model 813.4.2 Linearized Phase Propagation Model 833.4.3 Estimation of Phase and Doppler Frequency 873.4.4 Simulation Analysis 913.5 Data Processing of XPNAV-1 Data 1003.5.1 Introduction of the Measured Data of XPNAV-1 1003.5.2 Data Processing for the Measured Data 1013.6 Summary 106References 1074 Errors Within the Time Transfer Model and Compensation Methods for Earth-Orbing Spacecraft 1094.1 Modeling of Error Sources Within Time Transfer Model 1094.1.1 Position Error of Central Gravitational Body 1104.1.2 Position Error of the Sun 1104.1.3 Position Error of Other Celestial Bodies 1114.1.4 Angular Position Error of Pulsar 1124.1.5 Distance Error of Pulsar 1124.1.6 Error Within Proper Motion Velocity of Pulsar 1134.1.7 Error Within Spacecraft-Borne Atomic Clock 1134.2 Impact of Error Sources 1134.2.1 Impact of Error Sources on Time Transfer Model 1144.2.2 Impact of Error Source on Template 1204.2.3 Impact of Error Source on Positioning Performance 1224.3 Analysis of Propagation Property of Major Error Sources 1254.3.1 Propagation Property of Planet Ephemeris Error 1254.3.2 Propagation Property of Pulsar Angular Position Error 1294.3.3 Propagation Property of Pulsar Distance Error 1304.3.4 Propagation Property of Clock Error of Spacecraft-Borne Atomic Clock 1314.4 Systematic Biases Compensation Method Based on Augmented State 1334.4.1 Navigation System 1334.4.2 Observability Analysis 1354.4.3 Simulation Analysis 1384.5 Systematic Biases Compensation Method Based on Time-Differenced Measurement 1394.5.1 Time-Differenced Measurement Model 1394.5.2 Observability Analysis 1394.5.3 Modified Unscented Kalman Filter 1414.5.4 Simulation Analysis 1444.6 Summary 148References 1495 X-Ray Pulsar/Multiple Measurement Information Fused Navigation 1515.1 XNAV/CNS Integrated Navigation Framework 1515.1.1 Traditional Celestial Measurement Model 1525.1.2 Information Fusion Method 1545.1.3 Error Compensation Method Based on Error Separation Principle 1595.1.4 Simulation Analysis 1615.2 XNAV/INS Integrated Navigation Framework 1675.2.1 Composition of XNAV/INS Integrated Navigation System 1685.2.2 Dynamic Model 1695.2.3 Observation Model 1695.2.4 Simulation Analysis 1705.3 Summary 173References 1736 Spacecraft Autonomous Navigation Using the X-Ray Pulsar Time Difference of Arrival 1756.1 Shortcomings of Autonomous Navigation Using Inter-satellite Link 1756.1.1 Inter-satellite Link Ranging Measurement 1756.1.2 Mathematical Analysis for Orbit Determination Using Inter-satellite Link Ranging 1776.2 System Observation Model and Observability Analysis 1806.2.1 Measurement Model for Multiple Spacecraft Observing One Pulsar 1806.2.2 Ranging Measurement Using Inter-satellite Link 1826.2.3 Observability Analysis 183<