Worldwide growth of space communications has caused a rapid increase in the number of satellites operating in geostationary orbits, causing overcrowded orbits. This practical resource is designed to help professionals overcome this problem. This timely book provides a solid understanding of the use of radio interferometers for tracking and monitoring satellites in overcrowded environments. Practitioners learn the fundamentals of radio interferometer hardware, including antennas, receiving equipment, signal processing and phase detection, and measurement accuracies. This in-depth volume describes the nature of the targets to be tracked by the interferometer, helping to clarify the movement of target satellites and what specific information has to be caught by the interferometer. Additionally, engineers find details on applications to practical cases of satellite tracking, covering different types of interferometers, recent technical developments, orbital monitoring and safety control.
Table Of Contents
Overview of Part I: Radio Interferometer ; Receiving Antenna - Receiving Points and the Baseline. Reference Point. Polarization. Sidelobe. Mechanical Stability. ; Receiving Equipment - Frequency Conversion. Receiving Routes. Phase Stability. Reference Correction. Cable Stability Condition. Reference Coupler. ; Phase Detection - Direct Phase Measurement. Separate Measurement. Fourier Transform. Problem of Image Spectrum. Signal Processing for Phase Measurement. Noise Reduction. Tracking Nonbeacon Signals. Appendix. ; Signal, Noise, and Precision - Required SNR. Signal Power and Noise Power. Beacon Downlink Budget. Tracking a Weak Signal. Estimates in PFD. ; Error Factors - Baseline Error. Phase Ambiguity. Atmospheric Refraction. Effect of Rainwater.; Design and Installation - System Layout. Reflecting Interferometer. ; Overview of Part II: Geostationary Satellite Orbit ; Kepler 's Laws - Kepler 's First Law. Kepler 's Second Law. Kepler 's Third Law. Physical Meanings. Significance of Kepler 's Laws. ; Near-Stationary Orbit - Geostationary and Near-Stationary Orbits. Orbit with Small Eccentricity. Motion Due to Small Eccentricity. Motion Due to Nonstationary Radius. Motions in an Orbital Plane. Motion Perpendicular to an Orbital Plane. Relative Position Coordinates. Appendix. ; Changing the Orbit - Orbital Energy. In-Plane Orbital Changes. In-Plane Orbital Maneuver. Inclination Maneuver. ; Orbital Perturbations - Perturbing Forces. Nonspherical Shape of the Earth. Patterns of Longitudinal Drift. Solar Radiation Pressure. Position of the Sun. Long-Term Effect. Gravity of the Sun. Tilting of the Orbital Plane. Gravity of the Moon. Sun-Moon Combined Effect. ; Station Keeping - EW Keeping for Drift-Rate Control. EW Keeping for Eccentricity Control. Combined EW Keeping. NS Keeping. Factors Depending on Satellites.; Overcrowding and Regulations - Orbital Regulations. Problem of Overcrowding. ; Overview of Part III: Interferometric Tracking ; Tracking and Orbit Estimation - General Concept. Styles of Orbit Estimation. Choice of Estimation Style. Software Units. Meaning of Orbit Estimation. Tracking Using an Interferometer. ; Azimuth-Elevation Tracking - Azimuth-Elevation Angles. Azimuth-Elevation Interferometer. Detection Unit Vector of a Baseline. Orbit Estimation. Accuracy Considerations. Nonhorizontal Baseline. Longitude Tracking - Satellite Longitudes. Longitude-Monitoring Interferometer. Orbit Estimation. Interferometer Setup. Monitoring Examples. ; Range-Azimuth Tracking - Combined Tracking for Orbit Estimation. Merit of Combined Tracking. Interferometer Hardware and Performance. Station Keeping with Safety Monitoring.; Differential Tracking - Differential Tracking Concept. Interferometer Hardware. Orbit Estimation. Possible Applications. ; Rotary-Baseline Interferometer - Rotary Baseline. Rotary Baseline with Mirrors. Rotary-Baseline Interferometer. Operation and Data Processing. Orbit Estimation. Long-Term Monitoring. Error Considerations. Error Calibration. Nongeometrical Error. ; Geolocation Interferometer - Geolocation: Principle and Problem. Weak-Signal Detection. Delay Limit and Delay Line. Correlation Processing. Time-Integration Effect. Problem of Satellite-Transponder Phase. Phase Measurement Accuracy. Locating the Earth Station. Transponder Frequency Errors. Orbital Information. Quick Orbit Estimation.;