Jianjun Zhang, PhD, is a Professor at Beijing Institute of Spacecraft System Engineering, China Academy of Space Technology. He has published more than 50 SCI/EI search papers in international journals and conferences, authorized more than 20 invention patents at home and abroad, and published 3 monographs. Jing Li, PhD, is an Associate Professor at the School of Automation, Beijing Institute of Technology. She has presided over more than 10 projects at leading institutions.

• Author Biography xiPreface xiii1 Introduction 11.1 Connotation of Inter-Satellite Link 11.2 Types of Inter-Satellite Links 51.3 Band Selection of Inter-Satellite Link 71.3.1 Selection of Link Band 71.3.2 Selection of Working Frequency 81.4 Microwave Inter-Satellite Link 101.4.1 Frequency Selection 101.4.2 Microwave Inter-Satellite Link Data Transmission System 121.5 Laser Inter-Satellite Link 141.5.1 Technical Characteristics of Laser Inter-Satellite Link 141.5.2 Future Requirements for Laser Inter-Satellite Links 151.5.3 Development Trend of Laser Inter-Satellite Links 161.5.3.1 The Development of Laser Communication Technology from Technical Verification to Engineering Application Stage 161.5.3.2 The Communication Rate Develops from Low Code Rate to High Code Rate 161.5.3.3 Deep Space Will Become an Important Place for Laser Communication Applications 171.5.3.4 Combined Use of Laser Communication and Laser Ranging 181.5.3.5 Integration and Miniaturization of Laser Communication Terminals 181.5.3.6 Networking of Laser Inter-Satellite Links 19References 192 Development History of Laser Inter-Satellite Link 212.1 Development Stage of Laser Inter-Satellite Link 212.2 Development Status of Laser Inter-Satellite Link Technology in Various Countries 222.2.1 United States 222.2.1.1 Lunar Laser Communication Demonstration 262.2.1.2 Relay Laser Communication Demonstration (LCRD) (GEO-Ground) 272.2.1.3 Integrated Laser Communication Terminal (ILLUMA-T) 302.2.1.4 Deep Space Optical Communication (DSOC) Project Terminal Reaches Level 6 Technology Maturity 302.2.1.5 Ultra-Light and Small Communication Terminal (OSCD) 332.2.2 Europe 332.2.2.1 Semiconductor Laser Inter-Satellite Link Experiment 332.2.2.2 European Data Relay Satellite System Project (EDRS) 342.2.2.3 Micro Laser Communication Terminal (OPTEL-μ) 352.2.3 Japan 362.2.3.1 Japanese Data Relay Satellite 372.2.3.2 High-Speed Communication of Advanced Laser Instruments 382.2.3.3 Miniaturized Laser Communication Terminal (SOTA) 392.3 Experience and Inspiration 392.3.1 Strengthen the Research on New Laser Inter-Satellite Links and Enhance the Innovation of Technology Research and Development 402.3.2 Strengthen the On-Orbit Verification of New Technologies and Improve the Engineering Level of New Technologies 402.3.3 Simplify the Product Spectrum and Promote the Construction of Product Pipelines 402.3.4 Respond to Commercial Product Demand and Reduce Product Cost 412.3.5 The Key Development Direction of Low-Orbit Laser Inter-Satellite Link Engineering Demonstration Work 41References 413 Spacecraft Orbits and Application 453.1 Overview 453.2 Kepler’s Laws 463.2.1 Kepler’s First Law 463.2.2 Kepler’s Second Law 473.2.3 Kepler’s Third Law 473.3 Two-Body Motion and Orbital Parameters 473.3.1 Two-Body Movement 473.3.2 Track Parameters 493.4 Near-Earth Space Orbits and Applications 533.4.1 Track Type 543.4.2 Sub-Satellite Point Trajectory 543.4.3 Several Commonly Used Tracks 553.4.3.1 Sun-Synchronous Orbit 553.4.3.2 Return to the Track 563.4.3.3 Geosynchronous Orbit 573.4.3.4 Freeze the Track 583.4.4 Overlay 593.4.4.1 Coverage Area 593.4.4.2 Minimum Observation Angle 60References 614 Basic Model of Constellation Inter-Satellite Link Networking 634.1 Application Requirements of Satellite Navigation Inter-Satellite Links 634.1.1 Constellation Precise Orbit Determination and Time Synchronization 644.1.2 Data Communication 644.1.3 Autonomous Operation 654.1.4 Extended Service 654.2 Basic Requirement Model of Inter-Satellite Link Network Application 664.2.1 Basic Configuration of Constellations 664.2.2 Inter-Satellite Transmission Network Based on STDMA 674.2.3 Antenna Solution 714.2.4 Inter-Satellite Link Application Mode 724.3 Inter-Satellite Link Network Chain Topology Model 744.3.1 Analysis of Topological Attribute of Inter-Satellite Links 744.3.2 Inter-Satellite Visibility Analysis 744.3.3 Inter-Satellite Link Topology Cost 774.3.3.1 Path Loss 784.3.3.2 Transmission Loss 794.3.3.3 Protocol Overhead 824.4 Inter-Satellite Link Network Protocol Model 834.4.1 Inter-Satellite Network Protocol Model 834.4.2 Transport Layer Protocol 84References 855 Principles of Laser Inter-Satellite Ranging 875.1 Principle of Inter-Satellite Ranging 875.2 Inter-Satellite Ranging Accuracy 885.3 Principle of Microwave Inter-Satellite Ranging 895.3.1 Principle of Pseudo-Range Two-Way Ranging 895.3.2 Analysis of Error Sources in Microwave Ranging 915.3.2.1 Antenna Phase Center Error 915.3.2.2 Device Circuit Delay Error 935.3.2.3 Multipath Effect Error 935.3.2.4 Ionospheric Delay Error 935.3.2.5 Relativistic Effect Error 945.4 Principle of Laser Inter-Satellite Ranging 955.4.1 Principle of Laser Pulse Ranging 955.4.2 Analysis of Error Sources in Laser Ranging 96References 976 Composition of Laser Inter-Satellite Link 996.1 Basic Structure of Laser Inter-Satellite Link 996.1.1 Optical Transmitting Subsystem 996.1.2 Light Receiving Subsystem 1006.1.3 Align, Capture, Track Subsystem (PAT) 1016.2 Workflow of Laser Inter-Satellite Link 1016.3 Constraints 1036.3.1 Satellite Orbit 1036.3.2 Satellite Attitude 1046.3.3 Uncertain Angle of Pre-Cover 1056.3.4 Satellite Vibration Problem 1066.3.5 Dynamic Coupling Problem 1076.3.6 Influence of Background Stray Light 1076.4 Transmitter Design 1106.4.1 Choice of Laser 1106.4.2 Wavelength Selection 1116.4.3 Selection of the Diameter of the Transmitting Antenna 1126.4.4 Calculation of Transmitting Antenna Gain 1126.5 Receiver Design 1136.5.1 Selection of Receiver Detector 1136.5.2 Selection of Receiving Antenna Aperture 1146.5.3 Calculation of Receiving Antenna Gain 1146.5.4 Calculation of Received Power 115References 1157 Inter-Satellite Laser Capture, Aiming, and Tracking System 1177.1 Introduction 1177.2 Acquisition 1197.2.1 Capture Scheme 1207.2.1.1 Stare-Scan 1207.2.1.2 Scan-Scan 1217.2.2 Capture Path 1227.3 Pointing 1237.4 Tracking 1247.4.1 Analysis of Tracking System Beacon Beam Divergence 1247.4.2 The Role of the Tracking System in the APT System 1267.5 APT System Terminal Structure 1287.5.1 Coarse Sight Subsystem Design 1297.5.1.1 Coarse Sight Subsystem Composition 1297.5.1.2 Coarse Aiming Control Subsystem Design 1327.5.2 Design of Precision Sighting Subsystem 1337.5.2.1 The Composition of the Precision Aiming Subsystem 1337.5.2.2 Design of Precision Aiming Control System 135References 1368 Inter-Satellite Laser Link Tracking Error 1398.1 Definition of Alignment Error 1398.2 Alignment Error Model and Factor Analysis 1408.2.1 Mathematical Modeling of Alignment Errors 1408.2.2 Factors Causing Alignment Errors 1438.2.3 Influence of Tracking Error on Beam Distribution at Receiver 1448.2.3.1 The Effect of Tracking Error on the Beam Intensity at the Receiving End 1458.2.3.2 Influence of Tracking Error on Beam Power at Receiver 1468.2.4 Influence of Tracking and Pointing Error on Communication Error Rate 1478.3 Analysis of Tracking and Pointing Error Sources of Inter-Satellite Laser Communication System 1498.3.1 Satellite Platform Vibration 1518.3.2 Detector Noise 1528.3.2.1 Characteristics and Types of Detector Noise 1528.3.2.2 Effect of Detector Noise on System Performance 1558.4 Satellite Platform Vibration Suppression Scheme 1578.4.1 Satellite Platform Vibration Suppression Scheme 1578.4.1.1 Passive Vibration Isolation 1578.4.1.2 Active Control 1588.4.2 Feedforward Vibration Suppression Algorithm 1598.4.2.1 Influence of Satellite Platform Vibration on Precision Aiming Control System 1598.4.2.2 Analysis of Feedforward Vibration Suppression Algorithm 161References 1659 Inter-Satellite Link Laser Modulation Mode 1679.1 Block Diagram of Inter-Satellite Link Optical Communication System 1679.2 Typical Incoherent Optical Modulation (IM/DD) 1689.2.1 On-Off Key Control 1699.2.2 Pulse Position Modulation 1699.2.3 Differential Pulse Position Modulation 1699.2.4 Digital Pulse Interval Modulation 1719.2.5 Double Head Pulse Interval Modulation 1719.3 Coherent Optical Communication Modulator and Modulation Principle 1729.3.1 Optical Modulator 1739.3.2 Coherent Optical Communication Modulation Format 1749.3.2.1 Binary Phase Shift Keying 1749.3.2.2 Quaternary Phase Shift Keying 1759.3.2.3 8psk 1769.3.2.4 8qam 1789.4 Comparison of Communication Performance of Laser Modulation Schemes 1799.4.1 Average Transmit Power 1799.4.1.1 OOK 1799.4.1.2 PPM 1799.4.1.3 DPPM 1799.4.1.4 DPIM 1809.4.1.5 DH-PIM 1809.4.1.6 Coherent PSK 1809.4.2 Transmission Bandwidth 1809.4.2.1 PPM 1809.4.2.2 DPPM 1819.4.2.3 DPIM 1819.4.2.4 DH-PIM 1819.4.2.5 Coherent PSK 1819.4.3 Bit Error Rate 1819.4.3.1 OOK 1829.4.3.2 PPM 1829.4.3.3 DPPM 1829.4.3.4 DPIM 1839.4.3.5 DH-PIM 1839.4.3.6 BPSK 1839.4.4 Summary 183References 184Index 187

Jianjun Zhang, PhD, is a Professor at Beijing Institute of Spacecraft System Engineering, China Academy of Space Technology. He has published more than 50 SCI/EI search papers in international journals and conferences, authorized more than 20 invention patents at home and abroad, and published 3 monographs. Jing Li, PhD, is an Associate Professor at the School of Automation, Beijing Institute of Technology. She has presided over more than 10 projects at leading institutions.

• Author Biography xiPreface xiii1 Introduction 11.1 Connotation of Inter-Satellite Link 11.2 Types of Inter-Satellite Links 51.3 Band Selection of Inter-Satellite Link 71.3.1 Selection of Link Band 71.3.2 Selection of Working Frequency 81.4 Microwave Inter-Satellite Link 101.4.1 Frequency Selection 101.4.2 Microwave Inter-Satellite Link Data Transmission System 121.5 Laser Inter-Satellite Link 141.5.1 Technical Characteristics of Laser Inter-Satellite Link 141.5.2 Future Requirements for Laser Inter-Satellite Links 151.5.3 Development Trend of Laser Inter-Satellite Links 161.5.3.1 The Development of Laser Communication Technology from Technical Verification to Engineering Application Stage 161.5.3.2 The Communication Rate Develops from Low Code Rate to High Code Rate 161.5.3.3 Deep Space Will Become an Important Place for Laser Communication Applications 171.5.3.4 Combined Use of Laser Communication and Laser Ranging 181.5.3.5 Integration and Miniaturization of Laser Communication Terminals 181.5.3.6 Networking of Laser Inter-Satellite Links 19References 192 Development History of Laser Inter-Satellite Link 212.1 Development Stage of Laser Inter-Satellite Link 212.2 Development Status of Laser Inter-Satellite Link Technology in Various Countries 222.2.1 United States 222.2.1.1 Lunar Laser Communication Demonstration 262.2.1.2 Relay Laser Communication Demonstration (LCRD) (GEO-Ground) 272.2.1.3 Integrated Laser Communication Terminal (ILLUMA-T) 302.2.1.4 Deep Space Optical Communication (DSOC) Project Terminal Reaches Level 6 Technology Maturity 302.2.1.5 Ultra-Light and Small Communication Terminal (OSCD) 332.2.2 Europe 332.2.2.1 Semiconductor Laser Inter-Satellite Link Experiment 332.2.2.2 European Data Relay Satellite System Project (EDRS) 342.2.2.3 Micro Laser Communication Terminal (OPTEL-μ) 352.2.3 Japan 362.2.3.1 Japanese Data Relay Satellite 372.2.3.2 High-Speed Communication of Advanced Laser Instruments 382.2.3.3 Miniaturized Laser Communication Terminal (SOTA) 392.3 Experience and Inspiration 392.3.1 Strengthen the Research on New Laser Inter-Satellite Links and Enhance the Innovation of Technology Research and Development 402.3.2 Strengthen the On-Orbit Verification of New Technologies and Improve the Engineering Level of New Technologies 402.3.3 Simplify the Product Spectrum and Promote the Construction of Product Pipelines 402.3.4 Respond to Commercial Product Demand and Reduce Product Cost 412.3.5 The Key Development Direction of Low-Orbit Laser Inter-Satellite Link Engineering Demonstration Work 41References 413 Spacecraft Orbits and Application 453.1 Overview 453.2 Kepler’s Laws 463.2.1 Kepler’s First Law 463.2.2 Kepler’s Second Law 473.2.3 Kepler’s Third Law 473.3 Two-Body Motion and Orbital Parameters 473.3.1 Two-Body Movement 473.3.2 Track Parameters 493.4 Near-Earth Space Orbits and Applications 533.4.1 Track Type 543.4.2 Sub-Satellite Point Trajectory 543.4.3 Several Commonly Used Tracks 553.4.3.1 Sun-Synchronous Orbit 553.4.3.2 Return to the Track 563.4.3.3 Geosynchronous Orbit 573.4.3.4 Freeze the Track 583.4.4 Overlay 593.4.4.1 Coverage Area 593.4.4.2 Minimum Observation Angle 60References 614 Basic Model of Constellation Inter-Satellite Link Networking 634.1 Application Requirements of Satellite Navigation Inter-Satellite Links 634.1.1 Constellation Precise Orbit Determination and Time Synchronization 644.1.2 Data Communication 644.1.3 Autonomous Operation 654.1.4 Extended Service 654.2 Basic Requirement Model of Inter-Satellite Link Network Application 664.2.1 Basic Configuration of Constellations 664.2.2 Inter-Satellite Transmission Network Based on STDMA 674.2.3 Antenna Solution 714.2.4 Inter-Satellite Link Application Mode 724.3 Inter-Satellite Link Network Chain Topology Model 744.3.1 Analysis of Topological Attribute of Inter-Satellite Links 744.3.2 Inter-Satellite Visibility Analysis 744.3.3 Inter-Satellite Link Topology Cost 774.3.3.1 Path Loss 784.3.3.2 Transmission Loss 794.3.3.3 Protocol Overhead 824.4 Inter-Satellite Link Network Protocol Model 834.4.1 Inter-Satellite Network Protocol Model 834.4.2 Transport Layer Protocol 84References 855 Principles of Laser Inter-Satellite Ranging 875.1 Principle of Inter-Satellite Ranging 875.2 Inter-Satellite Ranging Accuracy 885.3 Principle of Microwave Inter-Satellite Ranging 895.3.1 Principle of Pseudo-Range Two-Way Ranging 895.3.2 Analysis of Error Sources in Microwave Ranging 915.3.2.1 Antenna Phase Center Error 915.3.2.2 Device Circuit Delay Error 935.3.2.3 Multipath Effect Error 935.3.2.4 Ionospheric Delay Error 935.3.2.5 Relativistic Effect Error 945.4 Principle of Laser Inter-Satellite Ranging 955.4.1 Principle of Laser Pulse Ranging 955.4.2 Analysis of Error Sources in Laser Ranging 96References 976 Composition of Laser Inter-Satellite Link 996.1 Basic Structure of Laser Inter-Satellite Link 996.1.1 Optical Transmitting Subsystem 996.1.2 Light Receiving Subsystem 1006.1.3 Align, Capture, Track Subsystem (PAT) 1016.2 Workflow of Laser Inter-Satellite Link 1016.3 Constraints 1036.3.1 Satellite Orbit 1036.3.2 Satellite Attitude 1046.3.3 Uncertain Angle of Pre-Cover 1056.3.4 Satellite Vibration Problem 1066.3.5 Dynamic Coupling Problem 1076.3.6 Influence of Background Stray Light 1076.4 Transmitter Design 1106.4.1 Choice of Laser 1106.4.2 Wavelength Selection 1116.4.3 Selection of the Diameter of the Transmitting Antenna 1126.4.4 Calculation of Transmitting Antenna Gain 1126.5 Receiver Design 1136.5.1 Selection of Receiver Detector 1136.5.2 Selection of Receiving Antenna Aperture 1146.5.3 Calculation of Receiving Antenna Gain 1146.5.4 Calculation of Received Power 115References 1157 Inter-Satellite Laser Capture, Aiming, and Tracking System 1177.1 Introduction 1177.2 Acquisition 1197.2.1 Capture Scheme 1207.2.1.1 Stare-Scan 1207.2.1.2 Scan-Scan 1217.2.2 Capture Path 1227.3 Pointing 1237.4 Tracking 1247.4.1 Analysis of Tracking System Beacon Beam Divergence 1247.4.2 The Role of the Tracking System in the APT System 1267.5 APT System Terminal Structure 1287.5.1 Coarse Sight Subsystem Design 1297.5.1.1 Coarse Sight Subsystem Composition 1297.5.1.2 Coarse Aiming Control Subsystem Design 1327.5.2 Design of Precision Sighting Subsystem 1337.5.2.1 The Composition of the Precision Aiming Subsystem 1337.5.2.2 Design of Precision Aiming Control System 135References 1368 Inter-Satellite Laser Link Tracking Error 1398.1 Definition of Alignment Error 1398.2 Alignment Error Model and Factor Analysis 1408.2.1 Mathematical Modeling of Alignment Errors 1408.2.2 Factors Causing Alignment Errors 1438.2.3 Influence of Tracking Error on Beam Distribution at Receiver 1448.2.3.1 The Effect of Tracking Error on the Beam Intensity at the Receiving End 1458.2.3.2 Influence of Tracking Error on Beam Power at Receiver 1468.2.4 Influence of Tracking and Pointing Error on Communication Error Rate 1478.3 Analysis of Tracking and Pointing Error Sources of Inter-Satellite Laser Communication System 1498.3.1 Satellite Platform Vibration 1518.3.2 Detector Noise 1528.3.2.1 Characteristics and Types of Detector Noise 1528.3.2.2 Effect of Detector Noise on System Performance 1558.4 Satellite Platform Vibration Suppression Scheme 1578.4.1 Satellite Platform Vibration Suppression Scheme 1578.4.1.1 Passive Vibration Isolation 1578.4.1.2 Active Control 1588.4.2 Feedforward Vibration Suppression Algorithm 1598.4.2.1 Influence of Satellite Platform Vibration on Precision Aiming Control System 1598.4.2.2 Analysis of Feedforward Vibration Suppression Algorithm 161References 1659 Inter-Satellite Link Laser Modulation Mode 1679.1 Block Diagram of Inter-Satellite Link Optical Communication System 1679.2 Typical Incoherent Optical Modulation (IM/DD) 1689.2.1 On-Off Key Control 1699.2.2 Pulse Position Modulation 1699.2.3 Differential Pulse Position Modulation 1699.2.4 Digital Pulse Interval Modulation 1719.2.5 Double Head Pulse Interval Modulation 1719.3 Coherent Optical Communication Modulator and Modulation Principle 1729.3.1 Optical Modulator 1739.3.2 Coherent Optical Communication Modulation Format 1749.3.2.1 Binary Phase Shift Keying 1749.3.2.2 Quaternary Phase Shift Keying 1759.3.2.3 8psk 1769.3.2.4 8qam 1789.4 Comparison of Communication Performance of Laser Modulation Schemes 1799.4.1 Average Transmit Power 1799.4.1.1 OOK 1799.4.1.2 PPM 1799.4.1.3 DPPM 1799.4.1.4 DPIM 1809.4.1.5 DH-PIM 1809.4.1.6 Coherent PSK 1809.4.2 Transmission Bandwidth 1809.4.2.1 PPM 1809.4.2.2 DPPM 1819.4.2.3 DPIM 1819.4.2.4 DH-PIM 1819.4.2.5 Coherent PSK 1819.4.3 Bit Error Rate 1819.4.3.1 OOK 1829.4.3.2 PPM 1829.4.3.3 DPPM 1829.4.3.4 DPIM 1839.4.3.5 DH-PIM 1839.4.3.6 BPSK 1839.4.4 Summary 183References 184Index 187

Jianjun Zhang, PhD, is a Professor at Beijing Institute of Spacecraft System Engineering, China Academy of Space Technology. He has published more than 50 SCI/EI search papers in international journals and conferences, authorized more than 20 invention patents at home and abroad, and published 3 monographs. Jing Li, PhD, is an Associate Professor at the School of Automation, Beijing Institute of Technology. She has presided over more than 10 projects at leading institutions.

• Author Biography xiPreface xiii1 Introduction 11.1 Connotation of Inter-Satellite Link 11.2 Types of Inter-Satellite Links 51.3 Band Selection of Inter-Satellite Link 71.3.1 Selection of Link Band 71.3.2 Selection of Working Frequency 81.4 Microwave Inter-Satellite Link 101.4.1 Frequency Selection 101.4.2 Microwave Inter-Satellite Link Data Transmission System 121.5 Laser Inter-Satellite Link 141.5.1 Technical Characteristics of Laser Inter-Satellite Link 141.5.2 Future Requirements for Laser Inter-Satellite Links 151.5.3 Development Trend of Laser Inter-Satellite Links 161.5.3.1 The Development of Laser Communication Technology from Technical Verification to Engineering Application Stage 161.5.3.2 The Communication Rate Develops from Low Code Rate to High Code Rate 161.5.3.3 Deep Space Will Become an Important Place for Laser Communication Applications 171.5.3.4 Combined Use of Laser Communication and Laser Ranging 181.5.3.5 Integration and Miniaturization of Laser Communication Terminals 181.5.3.6 Networking of Laser Inter-Satellite Links 19References 192 Development History of Laser Inter-Satellite Link 212.1 Development Stage of Laser Inter-Satellite Link 212.2 Development Status of Laser Inter-Satellite Link Technology in Various Countries 222.2.1 United States 222.2.1.1 Lunar Laser Communication Demonstration 262.2.1.2 Relay Laser Communication Demonstration (LCRD) (GEO-Ground) 272.2.1.3 Integrated Laser Communication Terminal (ILLUMA-T) 302.2.1.4 Deep Space Optical Communication (DSOC) Project Terminal Reaches Level 6 Technology Maturity 302.2.1.5 Ultra-Light and Small Communication Terminal (OSCD) 332.2.2 Europe 332.2.2.1 Semiconductor Laser Inter-Satellite Link Experiment 332.2.2.2 European Data Relay Satellite System Project (EDRS) 342.2.2.3 Micro Laser Communication Terminal (OPTEL-μ) 352.2.3 Japan 362.2.3.1 Japanese Data Relay Satellite 372.2.3.2 High-Speed Communication of Advanced Laser Instruments 382.2.3.3 Miniaturized Laser Communication Terminal (SOTA) 392.3 Experience and Inspiration 392.3.1 Strengthen the Research on New Laser Inter-Satellite Links and Enhance the Innovation of Technology Research and Development 402.3.2 Strengthen the On-Orbit Verification of New Technologies and Improve the Engineering Level of New Technologies 402.3.3 Simplify the Product Spectrum and Promote the Construction of Product Pipelines 402.3.4 Respond to Commercial Product Demand and Reduce Product Cost 412.3.5 The Key Development Direction of Low-Orbit Laser Inter-Satellite Link Engineering Demonstration Work 41References 413 Spacecraft Orbits and Application 453.1 Overview 453.2 Kepler’s Laws 463.2.1 Kepler’s First Law 463.2.2 Kepler’s Second Law 473.2.3 Kepler’s Third Law 473.3 Two-Body Motion and Orbital Parameters 473.3.1 Two-Body Movement 473.3.2 Track Parameters 493.4 Near-Earth Space Orbits and Applications 533.4.1 Track Type 543.4.2 Sub-Satellite Point Trajectory 543.4.3 Several Commonly Used Tracks 553.4.3.1 Sun-Synchronous Orbit 553.4.3.2 Return to the Track 563.4.3.3 Geosynchronous Orbit 573.4.3.4 Freeze the Track 583.4.4 Overlay 593.4.4.1 Coverage Area 593.4.4.2 Minimum Observation Angle 60References 614 Basic Model of Constellation Inter-Satellite Link Networking 634.1 Application Requirements of Satellite Navigation Inter-Satellite Links 634.1.1 Constellation Precise Orbit Determination and Time Synchronization 644.1.2 Data Communication 644.1.3 Autonomous Operation 654.1.4 Extended Service 654.2 Basic Requirement Model of Inter-Satellite Link Network Application 664.2.1 Basic Configuration of Constellations 664.2.2 Inter-Satellite Transmission Network Based on STDMA 674.2.3 Antenna Solution 714.2.4 Inter-Satellite Link Application Mode 724.3 Inter-Satellite Link Network Chain Topology Model 744.3.1 Analysis of Topological Attribute of Inter-Satellite Links 744.3.2 Inter-Satellite Visibility Analysis 744.3.3 Inter-Satellite Link Topology Cost 774.3.3.1 Path Loss 784.3.3.2 Transmission Loss 794.3.3.3 Protocol Overhead 824.4 Inter-Satellite Link Network Protocol Model 834.4.1 Inter-Satellite Network Protocol Model 834.4.2 Transport Layer Protocol 84References 855 Principles of Laser Inter-Satellite Ranging 875.1 Principle of Inter-Satellite Ranging 875.2 Inter-Satellite Ranging Accuracy 885.3 Principle of Microwave Inter-Satellite Ranging 895.3.1 Principle of Pseudo-Range Two-Way Ranging 895.3.2 Analysis of Error Sources in Microwave Ranging 915.3.2.1 Antenna Phase Center Error 915.3.2.2 Device Circuit Delay Error 935.3.2.3 Multipath Effect Error 935.3.2.4 Ionospheric Delay Error 935.3.2.5 Relativistic Effect Error 945.4 Principle of Laser Inter-Satellite Ranging 955.4.1 Principle of Laser Pulse Ranging 955.4.2 Analysis of Error Sources in Laser Ranging 96References 976 Composition of Laser Inter-Satellite Link 996.1 Basic Structure of Laser Inter-Satellite Link 996.1.1 Optical Transmitting Subsystem 996.1.2 Light Receiving Subsystem 1006.1.3 Align, Capture, Track Subsystem (PAT) 1016.2 Workflow of Laser Inter-Satellite Link 1016.3 Constraints 1036.3.1 Satellite Orbit 1036.3.2 Satellite Attitude 1046.3.3 Uncertain Angle of Pre-Cover 1056.3.4 Satellite Vibration Problem 1066.3.5 Dynamic Coupling Problem 1076.3.6 Influence of Background Stray Light 1076.4 Transmitter Design 1106.4.1 Choice of Laser 1106.4.2 Wavelength Selection 1116.4.3 Selection of the Diameter of the Transmitting Antenna 1126.4.4 Calculation of Transmitting Antenna Gain 1126.5 Receiver Design 1136.5.1 Selection of Receiver Detector 1136.5.2 Selection of Receiving Antenna Aperture 1146.5.3 Calculation of Receiving Antenna Gain 1146.5.4 Calculation of Received Power 115References 1157 Inter-Satellite Laser Capture, Aiming, and Tracking System 1177.1 Introduction 1177.2 Acquisition 1197.2.1 Capture Scheme 1207.2.1.1 Stare-Scan 1207.2.1.2 Scan-Scan 1217.2.2 Capture Path 1227.3 Pointing 1237.4 Tracking 1247.4.1 Analysis of Tracking System Beacon Beam Divergence 1247.4.2 The Role of the Tracking System in the APT System 1267.5 APT System Terminal Structure 1287.5.1 Coarse Sight Subsystem Design 1297.5.1.1 Coarse Sight Subsystem Composition 1297.5.1.2 Coarse Aiming Control Subsystem Design 1327.5.2 Design of Precision Sighting Subsystem 1337.5.2.1 The Composition of the Precision Aiming Subsystem 1337.5.2.2 Design of Precision Aiming Control System 135References 1368 Inter-Satellite Laser Link Tracking Error 1398.1 Definition of Alignment Error 1398.2 Alignment Error Model and Factor Analysis 1408.2.1 Mathematical Modeling of Alignment Errors 1408.2.2 Factors Causing Alignment Errors 1438.2.3 Influence of Tracking Error on Beam Distribution at Receiver 1448.2.3.1 The Effect of Tracking Error on the Beam Intensity at the Receiving End 1458.2.3.2 Influence of Tracking Error on Beam Power at Receiver 1468.2.4 Influence of Tracking and Pointing Error on Communication Error Rate 1478.3 Analysis of Tracking and Pointing Error Sources of Inter-Satellite Laser Communication System 1498.3.1 Satellite Platform Vibration 1518.3.2 Detector Noise 1528.3.2.1 Characteristics and Types of Detector Noise 1528.3.2.2 Effect of Detector Noise on System Performance 1558.4 Satellite Platform Vibration Suppression Scheme 1578.4.1 Satellite Platform Vibration Suppression Scheme 1578.4.1.1 Passive Vibration Isolation 1578.4.1.2 Active Control 1588.4.2 Feedforward Vibration Suppression Algorithm 1598.4.2.1 Influence of Satellite Platform Vibration on Precision Aiming Control System 1598.4.2.2 Analysis of Feedforward Vibration Suppression Algorithm 161References 1659 Inter-Satellite Link Laser Modulation Mode 1679.1 Block Diagram of Inter-Satellite Link Optical Communication System 1679.2 Typical Incoherent Optical Modulation (IM/DD) 1689.2.1 On-Off Key Control 1699.2.2 Pulse Position Modulation 1699.2.3 Differential Pulse Position Modulation 1699.2.4 Digital Pulse Interval Modulation 1719.2.5 Double Head Pulse Interval Modulation 1719.3 Coherent Optical Communication Modulator and Modulation Principle 1729.3.1 Optical Modulator 1739.3.2 Coherent Optical Communication Modulation Format 1749.3.2.1 Binary Phase Shift Keying 1749.3.2.2 Quaternary Phase Shift Keying 1759.3.2.3 8psk 1769.3.2.4 8qam 1789.4 Comparison of Communication Performance of Laser Modulation Schemes 1799.4.1 Average Transmit Power 1799.4.1.1 OOK 1799.4.1.2 PPM 1799.4.1.3 DPPM 1799.4.1.4 DPIM 1809.4.1.5 DH-PIM 1809.4.1.6 Coherent PSK 1809.4.2 Transmission Bandwidth 1809.4.2.1 PPM 1809.4.2.2 DPPM 1819.4.2.3 DPIM 1819.4.2.4 DH-PIM 1819.4.2.5 Coherent PSK 1819.4.3 Bit Error Rate 1819.4.3.1 OOK 1829.4.3.2 PPM 1829.4.3.3 DPPM 1829.4.3.4 DPIM 1839.4.3.5 DH-PIM 1839.4.3.6 BPSK 1839.4.4 Summary 183References 184Index 187