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

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.

A satellite autonomous orbit determination method based on satellite-borne GNSS multiple antennas. According to the method, a Kalman filter is extended; multiple GNSS antennas measured pseudorange observation values are made full use of to carry out real-time filtering correction of an orbit prediction value using a high precision mechanical model; and high precision satellite orbit information is obtained. According to the invention, the problems of the high precision orbit determination in a complex posture maneuver can be solved. In the invention, the orbit determination result is high in precision, good in stability, and highly real-time, can meet the orbit determination demand of the low orbit satellite and high precision satellite, can be widely applied to the high precision orbit determination of the space station, high resolution earth observation satellite and other space missions, and has a wide promotion and application prospect.

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.

The invention discloses an autonomous orbit determination method of a Lagrange navigation satellite. The method comprises the following steps: acquiring three groups of inter-satellite ranging information by virtue of a navigation constellation containing at least four satellites; updating a neural network weight by utilizing the inter-satellite ranging information; estimating a nonlinear perturbing term according to the neural network weight; and structuring a neural network state observer by utilizing the obtained nonlinear perturbing term, and estimating orbit information of the Lagrange satellite. Based on elliptic restrictive three-body problems, the perturbing force suffered by the Lagrange navigation satellite is precisely estimated by virtue of the neural network, so that the model precision of the determined orbit is improved; and the state observer is used for precisely estimating the state of the Lagrange navigation satellite, so that no limitation is made for the system noise and the observation noise, and the universality is better.

The embodiments of the invention disclose an orbit determination method, device and system of a low-orbit satellite. Firstly, broadcast ephemeris sent by a navigation satellite is received, and the orbit and clock difference of the navigation satellite are calculated and obtained according to the broadcast ephemeris. Then, the correction information of the positioning information sent by a groundsystem is received to correct the positioning information, and the corrected positioning information is obtained. Then the revised positioning information and observation data are used for determiningthe orbit of the low-orbit satellite. That is, the embodiments of the invention introduce the correction information of the positioning information, and the accurate corrected positioning informationis used for determining the orbit the low-orbit satellite, so that the orbit determination accuracy of the low-orbit satellite is improved.

The invention relates to a satellite passive orbit measurement method and system, and relates to satellite technology. The satellite passive orbit measurement method of the present invention is to passively receive the radio signal broadcast by the satellite through the ground station, so as to realize the position measurement and orbit measurement of space objects such as satellites. The specific method is to set up 2 to 4 antennas in each measurement station, and use carrier signal waveform correlation to obtain the range difference D between the two antennas when receiving satellite signals. The rendezvous measurement model obtains the position and orbit of the satellite in space. While completing the above-mentioned rough orbit determination, 10-100 satellite position accuracy monitoring reference stations shall be established within the coverage area of ​​satellite signals. The vector correction number of the satellite position is obtained, so as to achieve the second high-precision orbit determination of the satellite.

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.

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.

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.

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.

A satellite autonomous orbit determination method based on satellite-borne GNSS multiple antennas. According to the method, a Kalman filter is extended; multiple GNSS antennas measured pseudorange observation values are made full use of to carry out real-time filtering correction of an orbit prediction value using a high precision mechanical model; and high precision satellite orbit information is obtained. According to the invention, the problems of the high precision orbit determination in a complex posture maneuver can be solved. In the invention, the orbit determination result is high in precision, good in stability, and highly real-time, can meet the orbit determination demand of the low orbit satellite and high precision satellite, can be widely applied to the high precision orbit determination of the space station, high resolution earth observation satellite and other space missions, and has a wide promotion and application prospect.

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.

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.

The invention discloses a mirror surface projection method for precisely determining an orbit of a geostationary orbit satellite and relates to the accurate orbit determination of the geostationary orbit satellite by a regional observation station. The mirror surface projection method comprises the critical steps of selection of a projection surface, establishment of a virtual observation station and selection of observation value of the virtual observation station. Due to the establishment of the virtual observation station, observation data is doubled, and the precision of a parameter is improved, wherein the parameter is evaluated by an orbit parameter evaluation observation equation set which is acquired based on the fact that the observation data is doubled. As is shown by a figure, the difference between the result evaluated by the mirror surface projection method and a truth value is obviously less than that between the result not evaluated by the mirror surface projection method and the truth value.

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.

The invention discloses a system and method suitable for combined orbit determination of networking low-orbit satellites. The system comprises an LE0 constellation ground centralized orbit determination module and an LEO constellation distributed orbit determination module. The LE0 constellation ground centralized orbit determination module is used for acquiring observation data and measurement data, and acquiring predicted orbit information of each LE0 constellation satellite according to the observation data and the measurement data; and the LEO constellation distributed orbit determination module is used for acquiring the orbit information of the LEO constellation satellite according to the measurement data and the predicted orbit information. The invention aims to provide a system and a method suitable for combined orbit determination of networking low-orbit satellites, and solves the problem that autonomous, real-time and high-precision orbit determination of LEO constellation satellites cannot be met under the condition that only a part of areas have LEO satellite ground tracking stations.

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.

The invention provides a spacecraft orbit determination method, device and system and a medium, and the method comprises the steps: firstly taking historical external measurement information of a plurality of spacecrafts as the input of an orbit determination method, taking orbit element information determined by a historical precise orbit as an output label, and then mapping the historical external measurement information into distribution information; and finally, solving the problem of inner product calculation between distributions by using a kernel technique, thereby establishing a mapping relation from the distribution information to the orbital elements, and providing the possibility of rapid determination for determining the spacecraft orbital through new observation information. According to the method, the influence of noise is fully considered during implementation, and under the condition that different random noise and system noise are added, the orbit determination result has high robustness.

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.

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.

The invention discloses an onboard GNSS-assisted Beidou navigation satellite orbit determination method, and relates to the technical field of earth observation and navigation. The method, by research of key technologies such as high-precision onboard GNSS tracking station epoch-by-epoch dynamic positioning, onboard GNSS Beidou satellite ambiguity determination, onboard GNSS-assisted Beidou satellite orbit determination, makes full use of the onboard (such as cargo ships and cruise ships in the oceans) GNSS data, optimizes tracking station configuration in BDS orbit determination, and assists precise Beidou navigation satellite orbit determination. The BDS precise orbit determination configuration is greatly enriched and BDS precision orbit system error is weakened because cargo ship onboard device air routes are everywhere in the oceans. Since there are many cruise ship routes, a dynamic location fills in the blank area of the tracking station, provides richer raw data for BDS precision orbit determination, improves the BDS precision orbit accuracy, and provides users with a more accurate track product.

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.

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.

The embodiment of the present application discloses a method and device for determining the orbit of a low-orbit satellite. Firstly, the broadcast ephemeris sent by the navigation satellite is received, and the orbit and clock error of the navigation satellite are calculated according to the broadcast ephemeris. Then, the correction information of the positioning information sent by the ground system is received, so as to correct the positioning information, and obtain the corrected positioning information. Then use the corrected positioning information and observation data to determine the orbit of the low-orbit satellite. That is, the embodiment of the present application introduces the correction information of the positioning information, and uses the accurate corrected positioning information to determine the orbit of the low-orbit satellite, thereby improving the accuracy of the orbit determination of the low-orbit satellite.