189 results about "Synchronous orbit" patented technology

A practical orbit raising method and system wherein a satellite quickly escapes the Van Allen radiation belts and payload mass and mission life are maximized. A satellite is launched that contains high thrust chemical propulsion thrusters, high specific impulse electric propulsion thrusters and a solar array. The satellite quickly escapes the Van Allen radiation belts by firing the high thrust chemical propulsion thrusters at apogees of intermediate orbits, starting from the transfer orbit initiated by a launch vehicle, to successively raise the perigees until the perigee clears the Van Allen radiation belts. The payload mass and mission life are maximized by firing high specific impulse electric propulsion thrusters to raise the satellite to near synchronous orbit, while steering the thrust vector and solar array to maintain the sun's illumination on the solar array. The chemical and/or electric propulsion thrusters are then fired to achieve geosynchronous orbit.

The invention belongs to the field of satellite communication technologies and particularly relates to a ground station system and a method for avoiding collinear interference with a geostationary satellite. The system comprises a ground station located at one position of the earth and a non-geostationary satellite constellation connected to the ground station, wherein the ground station traces one satellite in the non-geostationary satellite constellation through controlling antenna beam and establishes a communication link with the satellite; when a connecting line between the ground station and one non-geostationary satellite points at the geostationary satellite, the ground station adjusts the beam direction and selects another non-geostationary satellite in the different direction in view to communicate, so that the collinear interference with the geostationary satellite is avoided. According to the ground station system and the method, the restriction that shutdown of the non-geostationary satellite is needed or the transmitting power of the non-geostationary satellite is greatly reduced when the collinear interference occurs is avoided, and the satellite communication of the ground station keeps continuous, so that the availability and the message capacity of the non-geostationary satellite constellation are improved and the same frequency coexistence of the non-geostationary satellite and the geostationary satellite is realized.

Method of and system for on-board substantially autonomous control for transferring a spacecraft from an initial orbit to a final geosynchronous orbit, by a trajectory that minimizes remaining transfer time and orbit transfer fuel. The spacecraft determines its orbit using a GPS-based system to determine the spacecraft orbital elements. Based on the measured orbit error, corrected co-state parameters are calculated and used to generate an updated thrust trajectory. The corrections are calculated using an innovative numerical procedure, carried out repetitively at a fixed interval until the target geosynchronous orbit is achieved.

The invention discloses a circular synthetic aperture radar (CSAR) 3D microwave imaging method for an earth synchronous orbit. In the method, parameters of the earth synchronous orbit are designed to cause a synthetic aperture radar (SAR) satellite platform to make a flight with an annular track around a target zone and above the target zone, and an antenna beam is caused to irradiate the target zone all the time by a circular synthetic aperture radar mode, and a ground object target is subject to continuous large-area fixed point observation to acquire high-resolution 3D imaging information of the ground object target. A CSAR system of the earth synchronous orbit provided by the system can acquire high-resolution 3D images of the ground object, solves the problem that the existing space-borne SARs are hard to acquire the high-resolution 3D information of the ground object; and is applicable to areas with complex and steep terrains as elevation information does not interfere with phase ambiguity in the SAR. The CSAR system of the earth synchronous orbit can realize the fixed point continuous observation of large-area zones, and solve the problems that the existing space-borne SARs have small observation zones and long revisit period.

The invention discloses a time synchronization method and a time synchronization device based on small inclination synchronous orbit satellite communication system. The time synchronization device provided by the invention comprises a communication ground station and a user terminal, used for performing Doppler frequency compensation on received and transmitted signals, time synchronization on the whole network and pre-deviation on frequency of the transmitted signal. According to the method and device, the variation of a path and the Doppler frequency deviation of signals between the user terminal and the SIGSO satellite can be compensated based on the terminal; the communication ground station measures and compensates the path delay, Doppler frequency deviation and satellite transponder clock drifting between the communication ground station and the satellite; via time synchronization and pre-deviation on transmitting frequency, the communication ground station and the transmitter of the user terminal ensure that the time when the signal arrives the communication ground station or the terminal is just the begin of a communication time slot distributed by the system, which can greatly improve the capture speed of the communication signal, and thus the system capacity of the communication system is improved, and the unit communication cost is reduced.

A method, apparatus for providing at least near continuous broadcast services to one or more terrestrial receiver stations is disclosed. The system comprises a plurality of satellites, each satellite in an inclined, elliptical geosynchronous orbit, each satellite providing a portion of the at least near continuous broadcast service to the terrestrial receiver. In one embodiment, the system also comprises a receiver station having an legacy antenna modified so as to include a sensitivity pattern substantially matched to the track of the apparent position of the satellites actively broadcasting information to the receiver stations. The present invention is also embodied in a method for receiving at least near continuous broadcast service from at least one of a plurality of satellites at a time, each satellite in an inclined, elliptical, geosynchronous orbit.

The invention discloses a space-based deep space relay communication satellite networking system. The system comprises a spacecraft and a ground station, wherein the spacecraft comprises a UNICON heliocentric constellation and a geosynchronous orbit constellation; the heliocentric constellation comprises six UNICON communication satellites which are arranged on a heliocentric orbit through constellation layout, and the geosynchronous orbit constellation comprises three GEO satellites which are located on a geosynchronous orbit; a user deep space detector transmits data to the UNICON heliocentric constellation and then sends the data to the ground station through the geosynchronous orbit constellation; two laser communication telescopes are arranged at the top of each UNICON communication satellite, each laser communication telescope can rotate by 180 degrees along the longitudinal axis, so that 360-degree scanning is realized, and laser communication can be carried out between every two communication satellites. The satellite system can provide high-speed uplink and downlink data access services for deep space exploration tasks of different data rates and different orbits.

The device is utilized for measuring the parameters in the procedure of trailing satellites between the synchronous orbit and the low orbit. The device is composed of the three parts: the optical assembly, the electromechanical system and the computer control system. The usage of the device includes testing the trailing parameters, validating performances and evaluation of the satellite laser communication system from earth based laboratory. Meanwhile, the device provides an experimental analysis of feasibility of new technical executive plan for developing satellite laser communication system. The invention features simple structure, high practicability and accuracy. The device can generate 2D motion track and small floor space etc.

The invention discloses a mixed orbit IGSO (inclined geosynchronous satellite orbit) constellation capable of covering a target area and the global scale. The constellation comprises at least five IGSO satellites which are positioned on an earth synchronous orbit and are divided into two groups, wherein each group of IGSO satellites contains at least three IGSO satellites; the two groups of IGSO satellites share one IGSO satellite; the at least three IGSO satellites in the first group share one orbit surface, the right ascensions of ascending nodes are same, each mean anomaly is 120 degrees, the three IGSO satellites have the same orbit inclination angle, and the three IGSO satellites are connected by fixed inter-satellite links in a communication way; the at least three IGSO satellites in the second group have the same sub-satellite point across-equator longitude, each mean anomaly is 120 degrees, wherein the at least two IGSO satellites not shared by the first group have the same orbit inclination angle and the same ground track, inter-satellite links are not established among the three IGSO satellites in the second group, and the three IGSO satellites are always observed by a position-limited and signal-closing station by adjusting the orbit inclination angle. According to the mixed orbit IGSO constellation, the target area can be covered in a multiple way only in the way that the position-limited and signal-closing station lands, and meanwhile, the global scale is also covered by the mixed orbit IGSO constellation.

The invention discloses a geosynchronous orbit synthetic aperture radar velocity spatial variability compensating method. According to the method, the velocity spatial variability is compensated through self-adaptive phase compensation processing, so that a core problem, i.e. a velocity spatial variability compensation problem, of geosynchronous orbit synthetic aperture radar (GEO SAR) large-scale scene imaging is solved, the GEO SAR large-scale scene imaging focusing processing of arbitrary position is realized, and a good effect is obtained.

The invention discloses an LTE maritime emergency communication system based on an unmanned ship base station network. The system comprises the unmanned ship base station network, a short LTE base station and a synchronous orbit communication satellite. The unmanned ship base station network comprises a parent node unmanned ship and an unmanned ship subset. The parent node unmanned ship is the relay station between the communication satellite and the unmanned ship subset and furthermore performs real-time monitoring and controlling on the chain state and stationary point position of the unmanned ship subset. According to the emergency communication system, a centralized deposition manner is utilized. Namely the parent node unmanned ship performs global configuration on the whole unmanned ship base station network, thereby constructing a sea environment oriented rescuing emergency communication system, and settling a problem of depositing the maritime emergency communication system by means of a satellite communication resource and an ad hoc network which is loaded by the unmanned ships.

The invention relates to a system with wide geographical coverage for monitoring positions in real time, comprising position monitoring terminals, a communication satellite and a position monitoring central station, wherein the position monitoring terminals comprise a GNSS (global navigation satellite system) positioning module, a satellite communication module, a control module and a power supply module respectively; the communication satellite is a synchronous orbit communication satellite; the position monitoring central station comprises a heavy caliber parabolic antenna, a satellite communication receiver and a data processing computer; and the position monitoring terminals are used for passing positioning information acquired by the positioning modules back to the monitoring central station by a satellite link, so that the central station can monitor the positions of the position monitoring terminals in real time. In the monitoring system, bandwidth resources of one satellite transponder are utilized, and an FDMA (frequency division multiple access) way, a CDMA (code division multiple access) way and a TDMA (time division multiple access) way are adopted to monitor the positions of the multiple position monitoring terminals in real time. The system is applied to regions with satellite signal coverage only without ground communication network coverage particularly. The system has the characteristics of instantaneity, multiple users and wide geographical coverage.

The present disclosure is directed to an inclined geosynchronous orbit satellite system that can efficiently provide continuous communication to multiple geographic regions across the world using satellites in inclined geosynchronous orbital paths having an equatorial crossing and enabling the reuse of frequencies assigned within GSO orbital locations. The inclined orbit satellite system can include multiple inclined orbit satellites that are capable of co-existing with geostationary satellites to provide continuous uninterrupted service.

A near infrared (NIR) wideband reflector coating designed to start reflecting solar energy wavelengths from at least 1.2 microns in a typical geosynchronous earth orbit or medium earth orbit satellite and from at least 1.3 microns in a typical low earth orbit satellite. Also, the (NIR) wideband reflector coating reflects solar energy wavelengths below 0.35 microns in all three applications. This invention works on triple junction (TJ) solar cells. The performance of at least 1.2-microns is on solar panels with near-normal incident solar angle, typical of Geosynchronous Earth Orbit (GEO) and Medium Earth Orbit (MEO) satellites. The performance of at least 1.3-microns is on solar panels with wide range of incident solar angles, a design requirement for Low Earth Orbit (LEO) satellites.

The invention provides a satellite temperature control method allowing rapid responding and multi-orbit adaption, wherein by adopting a heat pipe network, reinforcing contact thermal conduction, and spraying a high-emissivity thermal control coating inside a satellite to reinforce in-cabin thermal conduction and radiation heat exchange, a temperature field is distributed uniformly in a cabin; a whole satellite temperature level is adjusted by a compensative electric heater; a nightside of a side plate of the satellite is taken as a major heat dissipation face, the outer surface of the nightside is sprayed with a white paint, and all the other outer surfaces of the satellite body, except for the major heat dissipation face, are covered by multiple layers of thermal insulation assemblies; and components outside the satellite are sprayed with a white paint thermal control coating. A propelling cabin has independent design, wherein the entire outside of the cabin is covered by the multiple layers of the thermal insulation assemblies, a baseplate inside the cabin is covered by the multiple layers of the thermal insulation assemblies, and the propelling cabin is finally integrated with a platform cabin. By integral design of machinery, heat and electricity, the satellite temperature control method allowing the rapid responding and the multi-orbit adaption provided by the invention realizes thermal control requirements of the whole satellite under conditions of a sun-synchronous orbit and an inclined track by the temperature control method.

The invention relates to a synchronous orbit electric propulsion position maintenance and angular momentum unloading joint control method comprising the steps that a position maintenance cycle Ts, a control cycle Tc and orbit measurement time Tm are determined; the control cycle Tc is total time including completion of one time of the ignition process of all thrusters respectively; the orbit measurement time Tm is obtained in a way that time required by orbit measurement is rounded up to an integer of integer orbit cycles; one position maintenance cycle Ts includes one orbit measurement process Tm and multiple control cycles Tc: orbit element control variables, including inclination angle control variable vectors (deltaix, deltaiy), eccentricity control variable vectors (deltaex, deltaey) and a flat longitude drift rate control variable deltaD, of each control cycle are calculated before starting of each position maintenance cycle Ts; the electric thruster ignition parameters of each control cycle are determined, and the ignition parameters include ignition duration and an ignition position; and an electric thruster rotating angle is determined according to the electric thruster ignition parameters and angular momentum unloading quantity before starting of each control cycle Tc.

The invention discloses a geosynchronous orbit determination and parameter determination method based on differential algebra. A kinetic model described based on geosynchronous satellite orbit elements is selected and used, use of a relatively greater integration step in a numerical integration process is avoided and appearance of singular points is avoided for the kinetic model, moreover, a perturbative force item is added in the kinetic model, polynomial form integration is executed, thus, obit statuses and spacecraft parameters are obtained, high-order prediction is executed for the obtained parameters, and meanwhile, high-order prediction of observed quantity is executed; by means of nonlinear information of the kinetic model and an observation model, estimation accuracy is improved; in combination with actual observed values of a spacecraft, high-order prediction values of the obit status and the spacecraft parameters are updated and high-order estimated values as initial values are obtained; and by repeating the implementation process above, geosynchronous orbit determination and parameter determination can be completed. The method provided by the invention not only can improve accuracy of obit estimation and realize high-precision estimation of the parameters, but also can greatly reduce calculation cost.

The invention discloses a synchronous orbit satellite relative dip angle remote correcting method based on line-of-sight measurement. The method comprises the following steps: at first, carrying out remote orbit control on a synchronous orbit satellite through absolute navigation information provided by a ground measurement and control system, and directing the synchronous orbit satellite to a remote mooring point in the rear of a task object; then, through relative navigation information of an optical sensor and the absolute navigation information provided by the ground measurement and control system, and in combination with typical motion features of the relative orbit of a spacecraft, adopting the Least Squares method to fit and forecast variation of a line-of-sight azimuth angle; further, forecasting the periodic relative motion outside an orbital plane between the satellite and task object in combination with the nominal distance at the mooring point; and finally, carrying out velocity pulse control outside of the orbital plane on the operating satellite at the mooring point to eliminate relative position error outside of the orbital plane caused by the relative dip angle to avoid the situation that the task object is lost because the task object is beyond the field of view of the optical sensor, so that the satellite can rapidly and accurately approach the task object.