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38results about How to "Improve the accuracy of orbit determination" patented technology

Low orbit satellite multi-sensor fault tolerance autonomous navigation method based on federal UKF algorithm

The invention relates to a multi-sensor autonomous navigation method for the low-orbiting satellite with fault-tolerance function and based on federated UKF algorithm, belonging to satellite autonomous navigation method. The method comprises the following steps of: constructing an orbital dynamics equation of earth satellite in a rectangular coordinate system; constructing a subsystem measurement equation with the output values of a star sensor and an infrared earth sensor as measurement quantities; constructing a subsystem measurement equation with the output values of magnetometer and a radar altimeter as measurement quantities; constructing a subsystem measurement equation with the output value of an ultraviolet sensor as measurement quantity; selecting a Sigma sampling point; constructing a predictive equation and an update equation of discrete UKF algorithm; respectively and independently performing Sigma sampling point calculation of each subsystem, and performing predictive update and measurement update; determining whether the output of each sub-filter is valid according to the predicted filter residual, isolating in case of malfunction, otherwise, inputting the filter result to a main filter for information fusion; constructing a non-reset federated UKF filter equation based on the UKF algorithm; and outputting earth satellite state estimated value X and variance matrix P thereof according to the steps.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Space-based phased-array radar space multi-target orbit determination method

The invention discloses a space-based phased-array radar space multi-target orbit determination method, which mainly solves the problems that the space weak target cannot be evaluated effectively and the target orbit determination precision is low in the prior art. The method comprises the following steps of: processing target echo data by a zero-setting conformal algorithm, acquiring distance prior information by utilizing a distance pulse compression principle, and segmentally processing echo signals according to the distance prior information; segmenting the echo signals according to the number of the targets, wherein each segment of data is a target signal and an adjacent unit signal; performing multi-target two-dimensional angle evaluation on each segment of data by utilizing a sum-difference multi-beam angle-measuring principle; performing coordinate conversion based on a space target tracking result and detection satellite orbit information; and performing orbit determination on different space targets by a Laplace type iterative algorithm, and improving the orbit determination precision by a least square algorithm. According to the method, the influence of strong signals on weak targets can be reduced and the parameters of the weak targets can be evaluated accurately. The method can be applied in the actual application fields of space situation awareness, orbit resource management and the like.
Owner:XIDIAN UNIV

Spaceborne GPS orbit determination method based on adaptive measurement noise variance estimation

ActiveCN107367744AReducing the requirement for prior information on measurement noiseImprove the accuracy of orbit determinationSatellite radio beaconingVIT signalsNarrowband
The invention discloses a spaceborne GPS orbit determination method based on adaptive measurement noise variance estimation. The method comprises steps: (1) according to I and Q paths of signals in a spaceborne GPS receiver tracking loop, a narrowband broadband power ratio method is used to estimate a carrier noise ratio (C / N0) of the signals; (2) according to the C / N0 of a tracking loop in each channel, pseudo distance measurement errors between L1 and L2 dual-frequency signals are calculated; (3) L1 and L2 dual-frequency pseudo distance measurement values are combined to obtain a pseudo distance measurement value rhoIF with no ionosphere delay and the error sigmaIF; and (4) with the rhoIF as an observed quantity, an EKF algorithm is used to estimate the orbit information of the satellite. In the method, the measurement noise variance matrix is adaptively adjusted through monitoring changes of the C / N0 of signals in each channel of the spaceborne GPS receiver in real time, the noise statistical characteristics of the observed quantity can be reflected correctly, defects existing in insufficient priori information and dynamic environment of the traditional fixed design EKF algorithm are overcome, and a higher orbit determination precision can be acquired.
Owner:WENZHOU UNIVERSITY

Image-based remote sensing satellite multi-mode autonomous orbit determination method

The invention discloses an image-based remote sensing satellite multi-mode autonomous orbit determination method. The remote sensing satellite multi-mode autonomous orbit determination method comprises the following steps of: step 1, preprocessing a remote sensing image; step 2, matching the preprocessed remote sensing image with a ground feature point library and a remote sensing image at a previous moment, and extracting orbit determination feature points; step 3, establishing a multi-mode orbit determination measurement equation based on monocular vision and multi-view geometric principles;step 4, establishing an orbit determination state equation based on an orbit dynamics model; step 5, and performing high-precision real-time optimal estimation on an orbit determination state quantity through adopting a filtering algorithm based on the orbit determination measurement equation and the orbit determination state equation. According to the remote sensing satellite multi-mode autonomous orbit determination method, the problems of poor orbital determination autonomy and low orbital determination precision of the remote sensing satellite are solved, and the multi-mode autonomous orbital determination observation model based on the image is constructed according to the monocular vision and multi-view geometric principle, so that the improvement of the precision and reliability ofautonomous orbital determination of the remote sensing satellite and the enhancement of the autonomy are realized.
Owner:SHANGHAI AEROSPACE CONTROL TECH INST

Atmospheric resistance perturbation modeling and calculating method for low earth orbit satellite

ActiveCN111238489ATo overcome the calculation error of atmospheric drag perturbation caused by the difficulty of accurately describing atmospheric changesImprove the accuracy of orbit determinationInstruments for comonautical navigationAdaptive controlLow earth orbitAtmospheric sciences
The invention discloses an atmospheric resistance perturbation modeling and calculating method for a low earth orbit satellite. The method is specifically implemented according to the following steps:1, establishing a Box-Wing model of a satellite; 2, establishing a piecewise linear atmospheric resistance perturbation model; 3, according to the Box-Wing model established in the step 1 and the piecewise linear atmospheric resistance perturbation model established in the step 2, calculating the folded atmospheric resistance perturbation acceleration at the moment t. By utilizing the method to calculate the atmospheric resistance perturbation of the satellite, atmospheric resistance perturbation calculation errors caused by the fact that a traditional single atmospheric resistance factor isdifficult to accurately describe atmospheric changes can be overcome, the orbit determination precision is effectively improved, and technical support is provided for precise orbit determination of alow-orbit satellite, especially precise orbit determination under special conditions such as magnetic storm.
Owner:CHINA XIAN SATELLITE CONTROL CENT

High-precision real-time absolute orbit determination method

InactiveCN110988941AImprove reliabilityMeet the needs of high-precision real-time orbit determinationSatellite radio beaconingCarrier signalOrbit prediction
The invention relates to a high-precision real-time absolute orbit determination method. Under the application background of high-precision real-time orbit determination of a satellite-borne receiver,with a pseudo-range and a carrier phase are used as the observed quantity of a filtering equation, state parameters such as satellite operation positions and speeds are stably output with high precision by using extended Kalman filtering and combining a highly nonlinear kinetic model. While the high-precision carrier phase observed quantity is fully utilized, various ways are adopted to improve the operation efficiency, the requirements of high-precision real-time orbit determination of medium and low orbits are met, the orbit determination and speed measurement precision is greatly improved.In addition, the method also has orbit prediction and extrapolation capabilities, so that the reliability of on-orbit output of the navigation equipment is improved to a great extent. The low-orbit satellite scene simulation real-time orbit determination test is carried out on the receiver platform, the technical indexes that the real-time absolute orbit determination position precision is superior to 0.5 m and the speed measurement precision is superior to 0.5 mm / s can be realized; and compared with a conventional pseudo-range real-time single-point positioning method, the provided method enables the orbit determination speed measurement precision to be greatly improved.
Owner:BEIJING RES INST OF TELEMETRY +2

Geometric method for determining space target initial orbit through optical telescope common-view observation and system

The invention belongs to the technical field of space target data processing, and discloses a geometric method for determining a space target initial orbit through optical telescope common-view observation and a system, which directly solve target position information through employing the geometric method in a triangle formed by a space target and two observation stations based on binocular telescope common-view observation data, and directly solve speed information of the target by using a difference method according to the continuity of an observed quantity. The geometric method specifically comprises the following steps of: synchronizing the time of two pieces of observation data through adopting an interpolation method; calculating the distance of the target in a triangle ABS by usinga geometric approach; and acquiring a position vector of the target through utilizing the azimuth and distance information. Compared with a vector method in the prior art, the geometric method has the advantages that two unknown numbers are solved by two equations in the geometric method, two unknown numbers are solved by three equations in the vector method, the geometric method is accurate, andthe solution is unique. The invention further provides a position difference method for solving the speed, and the whole solving process completely gets rid of a mechanical equation; and the positiondifference method has obvious advantages for an orbital transfer target.
Owner:中国科学院国家天文台长春人造卫星观测站

Navigation satellite orbit determination and improvement non-singular point technology under nonconservative force effects

The invention relates to a navigation satellite orbit determination and improvement non-singular point technology under nonconservative force effects. The technology is characterized by comprising obtaining a theoretical expression of a nonconservative force perturbation through a Gauss equation, forming a theoretical expression of a disturbed orbit without singular points according to a Gauss-Xu equation, and performing theoretical fitting according to observation to as to determine a navigational satellite orbit or improve the orbit. Since the orbits of beidou navigation satellites are all near-circular or near equator, and the singular points exist in all classic orbit theories, orbit determination or orbit improvement fails. The technology provided by the invention can be applied to the orbit determination or improvement of the beidou navigation satellite orbits, and no singular points exist. Besides, the technology is simple, computational complexity is reduced, and the technology is suitable for satellite automatic orbit determination. Since a satellite perturbative force comprises two kinds, i.e., a potential force and a nonconservative force, the invention, together with the invention with an invention right registry number 201310545077.2, i.e., a navigation satellite orbit determination and improvement non-singular point technology under the potential force, forms a complete non-singular point orbit determination and improvement technology through combination application.
Owner:威海五洲卫星导航科技股份有限公司

Method for overcoming deviation of precise orbit determination system of beidou second-generation GEO (geostationary orbit) satellite

The invention provides a method for overcoming deviation of a precise orbit determination system of a beidou second-generation GEO (geostationary orbit) satellite. According to the method, a fuzzy degree fixation process is used and strict judgment criteria are adopted in the beidou fuzzy degree fixation process to guarantee the success rate of the fuzzy degree fixation process; a space relation between a Y-axis direction of a solar panel and a sunlight incidence direction in a zero-offset state is analyzed; corresponding parameters are set for estimating and absorbing a reflection force in a light pressure model, and a reasonable prior information and experience model is built from posterior long-term observation data, so that an effective background constraint to light pressure parameters in a GEO orbit determination process is formed, the influence due to insufficient geometrical observation conditions and other model errors is avoided, and the orbit determination precision is improved; a clock offset model is built within a time allowed by the frequency stability, a relation between epochs is established, a model constraint is built by adopting an inter-satellite single difference method when a satellite clock of a GEO is modeled, the influence of a receiver clock offset of an observation station is eliminated, the purpose of reducing the correlation is reached, and the resolving and forecast accuracy of the beidou GEO is improved finally.
Owner:WUHAN UNIV

A dual-mode integrated space-based space debris detection system with full airspace coverage

ActiveCN103675938BAchieve full airspace coverageMake up for defects limited by lighting conditionsOptical detectionDual modeDetector array
Disclosed is a full-airspace-coverage dual-mode integrated space-based space debris detection system which comprises an optical system, a light splitting element, a detector array and refrigerating systems. The detector array comprises a visible light detector array and an infrared detector array, and the optical system and the infrared detector array are provided with the refrigerating systems respectively. Visible light reflected by space debris targets and infrared light radiated by the space debris targets are collected by the optical system, and the light splitting element divides the visible light and the infrared light into two independent branches which reach the visible detector array and the infrared detector array respectively. The refrigerating systems refrigerate the optical system and the infrared detector array respectively. When the detection system detects a space debris layer outside an earth shadow area, the visible light detector array performs imaging; when the detection system detects a space debris layer covered by the earth shadow area, the infrared detector array performs imaging. The visible light detector array and the infrared detector array works in a time-sharing manner, so that full airspace coverage of space debris detection is realized.
Owner:BEIJING RES INST OF SPATIAL MECHANICAL & ELECTRICAL TECH

Singular-point-free technology for determining and improving navigation satellite orbit under action of potential force

The invention relates to a singular-point-free technology for determining and improving the navigation satellite orbit under the action of a potential force. The technical features are that a theoretical expression of potential force perturbation is acquired through a Lagrange fundamental equation, then a singular-point-free theoretical expression of a satellite disturbed orbit is formed, the theoretical expression is fitted according to observation for a navigation satellite, thereby determining the orbit of the navigation satellite or carrying out improvement on the navigation satellite orbit. Because orbits of all Beidou navigation satellites are near-circular orbits or equatorial orbits, a singular-point problem exists in all classic orbital theories, so that orbit determination or orbit improvement are failed. The technical method provided by the invention can provide theoretical orbit determination and orbit improvement for the orbits of the Beidou navigation satellites without a problem of singular points. In addition, the technical calculation method adopted by the singular-point-free technology is simple, thereby being capable of effectively reducing the calculation amount, and applicable to satellite automatic orbit determination. Because perturbative forces of the satellites are divided into two types which are potential forces and non-conservative forces, so that the singular-point-free technology provided by the invention is applicable to orbit determination of potential force perturbation. The perturbation of the non-conservative forces is explained in another invention, and the overall singular-point-free orbit determination technology is formed by combining the two aspects.
Owner:威海五洲卫星导航科技股份有限公司

Precise orbit determination method of navigation satellite for assisting clock error between stations

InactiveCN101702030BImprove errorImproved geometry factorSatellite radio beaconingArea networkCarrier signal
The invention relates to a precise orbit determination method of a navigation satellite for assisting a clock error between stations, which is characterized by comprising the following steps: configuring an atomic clock and a nanosecond stage time synchronization system at each station of an area network, receiving a distance measurement signal of a navigation satellite by each station of the area network to obtain the carrier phase data of each station, detecting the periodic trip generation moment of the carrier phase data by a Blewitt method and carrying out time synchronization between the stations by a two-way satellite time frequency transmission method TWSTFT to obtain a clock error between the stations; resolving a differential equation under an inertial coordinate system to obtain an orbit of the navigation satellite. Before orbit determination data are processed, the method firstly realizes the time synchronization between the stations with high accuracy (i.e.: obtaining theclock error between the stations). During the processing of the orbit determination data, an improved non-error method is adopted, only the orbit needs to be resolved, and the clock error between thestations does not need to be resolved, which not only can improve geometrical factors but also is beneficial to separating a system error (the clock error between the stations). Thus, the orbit determination accuracy can be enhanced.
Owner:NAT TIME SERVICE CENT CHINESE ACAD OF SCI

Cooperative Orbit Determination Method Based on Optical Observation of Space Objects by Constellation

The invention discloses a coordinated orbit determination method for space targets based on the optical observation of constellations, belonging to the aerospace field. The implementation method of the present invention is as follows: during the flight process of the spacecraft around the central celestial body, the orbital dynamics model of the spacecraft relative to the central celestial body is established, and the state model of the constellation optical observation coordination system is constructed; based on the relative line of sight of the constellation to the target spacecraft Vector direction measurement, combining the observation information of multiple observation stars on the target star, and establishing the observation model of the orbit determination system; combined with the established state model of the constellation optical observation orbit determination system, and the established observation model of the constellation optical observation orbit determination system, The nonlinear navigation filter algorithm is used to estimate the position of the target star, and the orbit parameters of n observation stars are corrected at the same time, that is, the cooperative orbit determination of the space target based on the optical observation of the star group is realized. The invention can improve the optical orbit determination accuracy of the space target, and provide technical reference for future space target observation and tracking.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Relative Orbit Determination Method for Formation Satellites Ease of On-orbit Real-time Processing

The invention discloses a method for relative orbit determination of formation satellites, which is easy to be processed on-orbit and in real time, and belongs to the field of satellite formation relative navigation. The method uses GPS / BDS broadcast ephemeris and a simplified relative dynamics model to determine formation satellite GPS / The BDS dual-frequency observation data is processed in real-time on-orbit. Considering the limited computing resources of the on-board processor, the operation mode of dynamic orbit prediction and orbit interpolation is designed, and the core complex data processing process is realized by time-sharing and multi-step to reduce the single The calculation of the epoch is time-consuming, and the high-precision absolute and relative orbit results of the formation satellites with adjustable frequency can be output. The present invention is not only suitable for inter-satellite formations with a relatively large inter-satellite distance range, but also can continuously output relatively smooth navigation results that meet certain precision requirements when GPS / BDS signals are interrupted, and has high orbit determination accuracy, good stability and It has low requirements on the performance of the on-board processor and is easy to implement in engineering.
Owner:WUHAN UNIV

A Geosynchronous Orbit Constellation Orbit Determination Method Based on Ground Station/Inter-Satellite Link/GNSS Joint Measurement

The invention discloses a geosynchronous orbit constellation orbit determination method based on ground station / satellite link / GNSS combined measurement. The method comprises the steps of (1) establishing the state equation of a GSO constellation orbit determination system in a centralized structure, (2) establishing the measurement equation of the GSO constellation orbit determination system in a centralized structure, (3) carrying out combined optimization of a ground station for orbit determination and GNSS measurement combination, (4) determining the filtering method for realizing orbit parameter estimation according to the above established GSO constellation combined orbit determination system model based on ground station / satellite link / GNSS, and (5) carrying out the concrete realization of a GSO constellation orbit determination method based on ground station / satellite link / GNSS in the centralized structure. According to the method, the combined distribution optimization strategy of ground station and GNSS measurement is established based on a precision factor, and the calculation amount is reduced while the orbit determination precision is ensured.
Owner:BEIHANG UNIV +1

Low orbit satellite multi-sensor fault tolerance autonomous navigation method based on federal UKF algorithm

The invention relates to a multi-sensor autonomous navigation method for the low-orbiting satellite with fault-tolerance function and based on federated UKF algorithm, belonging to satellite autonomous navigation method. The method comprises the following steps of: constructing an orbital dynamics equation of earth satellite in a rectangular coordinate system; constructing a subsystem measurement equation with the output values of a star sensor and an infrared earth sensor as measurement quantities; constructing a subsystem measurement equation with the output values of magnetometer and a radar altimeter as measurement quantities; constructing a subsystem measurement equation with the output value of an ultraviolet sensor as measurement quantity; selecting a Sigma sampling point; constructing a predictive equation and an update equation of discrete UKF algorithm; respectively and independently performing Sigma sampling point calculation of each subsystem, and performing predictive update and measurement update; determining whether the output of each sub-filter is valid according to the predicted filter residual, isolating in case of malfunction, otherwise, inputting the filter result to a main filter for information fusion; constructing a non-reset federated UKF filter equation based on the UKF algorithm; and outputting earth satellite state estimated value X and variance matrix P thereof according to the steps.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Non-navigation GEO satellite forwarding type orbit determination method based on low orbit satellite assistance

According to the non-navigation GEO satellite forwarding type orbit determination method based on low orbit satellite assistance provided by the invention, the time delay of a downlink signal forwarded by a GEO satellite to a ground station and the low orbit satellite is measured by carrying a forwarding type receiver on the low orbit satellite, a ground forwarding type orbit determination network is assisted to carry out precise orbit determination on the GEO satellite, and the orbit determination precision is improved. Compared with the prior art, an uplink signal of the ground station is forwarded by the repeater carried by the GEO satellite, one path is received by the ground station, the other path is received by the low-orbit satellite serving as the motion observation station, and the GEO satellite does not need to carry an atomic clock; according to the method, the relative motion of the GEO satellite and the motion observation station can be artificially created, the orbit measurement geometric factors of the GEO are improved, the motion observation station assists the ground forwarding type orbit measurement network to carry out combined orbit determination, and the orbit determination precision is improved.
Owner:NAT TIME SERVICE CENT CHINESE ACAD OF SCI

Beidou Navigation Satellite Regional Orbit Determination Method Based on Multiple Co-located Receivers

The invention provides a multiple parallel address receiver-based Beidou navigation satellite region orbit determination method. The method comprises the steps of aiming at tracking stations of a China regional network, selecting data of multiple receivers at each station, and generating a medium long reference line and an ultrashort reference line according to the principle of the maximal common view observed quantities; based on single difference data of the medium long reference line and the ultrashort reference line, generating dual difference data to perform primary satellite precise orbit determination, and obtaining an ambiguity floating point solution and an estimation parameter; tracking station coordinates, and adopting different methods to calculate carrier phase ambiguity for reference lines of different lengths; using the generated carrier phase ambiguity to re-perform parameter estimation to calculate a satellite orbit. The Beidou navigation satellite region orbit determination is carried out by using multiple receivers placed in a parallel-address mode, the calculation successful rate of the carrier phase ambiguity can be improved, the value of a carrier phase observation value in the Beidou navigation satellite region orbit determination is improved and the Beidou navigation satellite orbit determination precision is finally improved.
Owner:NAT TIME SERVICE CENT CHINESE ACAD OF SCI
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