399results about "Navigation by astronomical means" patented technology

The present invention relates to a solar azimuth estimation method and system based on multi-channel feature enhancement and region-aware attention, belonging to the technical field of intelligent navigation for low-altitude economy unmanned systems. Aiming at the problem of decreased accuracy in solar azimuth estimation based on polarization images under complex cloud cover conditions, the present invention proposes a deep learning framework integrating multi-channel features and direction-aware attention. First, based on polarization light field information acquired by a division-of-focal-plane polarization camera, a three-channel composite input feature composed of a polarization intensity map, an adaptive threshold gradient map, and high-frequency residual edge information is constructed. Second, a ResNet backbone network embedded with a squeeze-and-excitation mechanism is adopted, and a direction-aware polarization attention module is introduced to achieve adaptive fusion of multi-scale features through luminance guidance, deep feature enhancement, and a gradient edge branch.

The invention relates to a sun meridian detection and course angle real-time calculation method based on polarized light field vector characteristics, and aims to solve the problems that a traditional sun meridian detection method is easily interfered in low signal-to-noise ratio scenes such as haze and cloud layer shielding, lens distortion causes polarization angle errors, the false detection rate is high, and the calculation accuracy is high. In order to solve the problems that the real-time performance and robustness of course calculation are affected due to the fact that single polarization angle information is difficult to fully reflect the sun direction, polarization parameter calculation is carried out by utilizing a multi-channel polarization image, and the sun meridian is detected by adopting Hough transform through fisheye lens correction, bilateral filtering and candidate region screening, so that the real-time performance and robustness of course calculation are improved. And a multi-point inversion method is combined to accurately obtain a sun vector and a zenith angle and an azimuth angle thereof, and finally a course angle is calculated in real time. The problems of imaging distortion and insufficient real-time processing in the traditional sun positioning technology can be effectively solved, and a powerful navigation positioning technical guarantee is provided for the fields of unmanned aerial vehicles, autonomous navigation, polarized light navigation and the like.

The present invention relates to a real-time heading angle calculation method based on the vector characteristics of the polarized light field. Aiming at the problems of traditional solar meridian detection methods, such as being easily disturbed in low signal-to-noise ratio scenarios like haze and cloud cover, the occurrence of polarization angle errors and high false detection rates caused by lens distortion, and the difficulty of using single polarization angle information to fully reflect the solar direction, which affects the real-time performance and robustness of heading calculation. This method calculates polarization parameters by using multi-channel polarization images.

Methods and systems are provided for determining navigational information for an entity such as a vehicle using celestial measurements. One method involves determining a Kalman gain based at least in part on inertial measurement data at or before a current point in time associated with the celestial measurement data, determining a celestial measurement error based at least in part on a relationship between the celestial measurement data and a prior estimate for the celestial measurement data, determining a current estimated error associated with the location of the entity based at least in part on a prior estimated error associated with the location, the Kalman gain and the celestial measurement error, and determining an updated estimate of the location of the entity based at least in part on the current estimated error and a prior estimate of the location of the entity.

The invention provides an integrated navigation method combining starlight refraction positioning with inertial navigation in a near space, and belongs to the technical field of starlight refraction navigation positioning. The method comprises the following steps: firstly, determining a state model of starlight refraction positioning in a near space by taking an error equation of an inertial navigation system of a near space aircraft as a state equation; designing a near space starlight refraction positioning algorithm, identifying a refraction star by using a star sensor on the aircraft, acquiring a refraction angle as a measurement, and establishing a measurement model of starlight refraction positioning in a near space; and obtaining the optimal estimation value of the system state variable by using an extended Kalman filter (EKF) method. The method has the advantages of being suitable for near space, high in reliability, high in autonomy and the like, and can be finally used for pure astronomical positioning and astronomical / inertial integrated navigation.

The invention discloses a star point coordinate extraction and star sensor attitude optimization method based on deep learning. The whole process of pseudo star map generation, star point coordinate extraction and attitude calculation is optimized. Multi-factor interference such as spacecraft jitter and optical distortion is simulated through dynamic star point modeling, and a high-fidelity pseudo star map is generated; a noise adaptive detection network is designed to fuse denoising and key point detection, and star point positioning precision in a low signal-to-noise ratio environment is improved; and optimizing attitude solution, constructing a loss function based on star point coordinates, and performing back propagation to optimize attitude parameters to realize an algorithm closed loop. According to the method, real data can be expanded to realize effective training of the model, and the positioning precision is improved; the star point coordinate positioning precision is improved to a sub-pixel level (RMSElt; 0.3 pixel); an end-to-end optimization framework reduces error accumulation in a traditional assembly line, and the robustness of the system is improved by 40%.

The invention relates to the technical field of image processing and sensors, in particular to a star point detection algorithm based on an event camera, and the algorithm comprises the following steps: S1, carrying out the preprocessing and noise filtering of an event stream; carrying out noise filtering on an original event stream of an event camera, and removing noise events which do not conform to space-time correlation through space-time density analysis and adaptive time window adjustment; s2, star point centroid extraction and trajectory analysis; and carrying out time slice interception and clustering processing on the event stream after noise reduction, calculating a weighted centroid of a star point event cluster, and fitting a motion trail of a star point. High precision of star point detection is ensured through calculation and dynamic adjustment, and noise is removed by setting a threshold according to camera parameters; the angular velocity is utilized to determine time slices, and the centroid is calculated and the trajectory is fitted through clustering and weighting, so that the detection precision is far higher than that of a traditional method, and star points can be accurately identified in a complex environment.

The invention relates to the technical field of space target detection, in particular to a dynamic space target detection method based on event information, and the method comprises the steps: reading a target event flow according to a certain time length, and obtaining an initial pseudo image frame; eliminating noise events based on the corresponding event density information by using a pre-established circular local sliding window, and judging whether a certain noise reduction condition is met or not; if not, eliminating noise events based on the corresponding event density information by using the self-adaptive filtering characteristic of a pre-established multi-neighborhood radius local sliding window, and calculating the centroid information of the detection space target; judging whether the centroid information meets a certain precision condition or not; and if not, correcting the motion track by using the data of the inertial measurement unit to obtain centroid information meeting a certain precision condition, and obtaining motion information of the detection space target. Therefore, the problems of low space target extraction precision, difficult tracking and the like in a high-dynamic maneuvering scene are solved.

The invention belongs to the technical field of attitude change detection, and particularly relates to a real-time monitoring system and method for attitude change of a front-rear view surveying and mapping camera. The method comprises the following steps: firstly carrying out ground calibration, then determining a reference moment as a moment when the real-time monitoring system starts to start, then constructing a monitoring link at the reference moment, measuring a corresponding matrix obtained at a working moment, finally confirming the monitoring link at the working moment, and deducing a transformation matrix of the front-view camera and the rear-view camera under a J2000 coordinate system. According to the method, the real-time performance of the measurement process and the comprehensiveness of system monitoring can be considered while the geometric accuracy of the surveying and mapping camera is ensured.

The invention discloses a near-earth space all-day star sensing system based on a sub-wavelength metal grating and a working method thereof, and belongs to the technical field of star sensors. In order to increase the number of fixed stars which can be detected by the near-earth space all-time star-sensitive system, the near-earth space all-time star-sensitive system comprises an optical system, an InGaAs detector, a spectrum optical filter, a micro-polaroid array, a memory, a processor, a control unit and a time unit, the InGaAs detector is respectively connected with the micro-polaroid array, the memory and the control unit; the micro-polaroid array is connected with the optical system, and the optical system is connected with the spectrum optical filter; the memory is respectively connected with the processor and the time unit; and the processor is connected with the control unit. According to the invention, the polarization filtering work of the sky background is realized, and the number of observable fixed stars is effectively increased on the basis of ensuring the miniaturization of a near-earth space all-day star-sensitive system.

The invention relates to the technical field of digital twinning, and particularly discloses a space debris collision detection digital twinning method and system, and the method comprises the steps: carrying out the grid processing of space debris through a space grid between the earth and the moon; performing space debris collision detection on the space debris by using a grid collision screening algorithm; and according to a space debris collision detection result, screening out space debris which may be collided, and sending out an early warning. According to the method, the space grid collision screening algorithm based on the space grid between the earth and the moon is adopted to carry out collision screening and secondary screening on the space debris, a large number of space debris which cannot be collided can be efficiently rejected, and therefore resources are concentrated to carry out more accurate analysis on high-risk collision.

The invention relates to an attitude prediction type star tracking method, and relates to the technical field of star sensors. The method comprises the following steps: obtaining historical angular velocity data; predicting the angular velocity of the next frame; predicting the attitude quaternion of the next frame; projecting a sky area fixed star to an image surface; performing window matching on the projection star and the observation star of the next frame; calculating the accurate attitude quaternion of the next frame; the target with the window matched successfully is used for attitude calculation, and the accurate attitude of the next frame is obtained; and repeating the steps to realize autonomous star tracking. According to the attitude prediction type star tracking method disclosed by the invention, the angular velocity of the next frame can be quickly and accurately predicted through polynomial fitting of historical angular velocity data, and the real-time performance and the accuracy are remarkably improved; the method can well adapt to high-angular-speed maneuver, and the tracking capability of the star sensor in a complex dynamic environment is enhanced; the method reduces the dependence on an external sensor, improves the independence and anti-interference capability of the system, simplifies the calculation process, and improves the overall calculation efficiency.

The invention provides an inertial navigation aided navigation positioning method and system, and the method comprises the steps: calculating the coordinate of each navigation satellite in an ECEF coordinate system according to the satellite ephemeris of a satellite navigation system; according to the navigation satellite coordinate and the inertial navigation system positioning result, the azimuth angle and the pitch angle of the navigation satellite relative to the optical detection equipment under the ENU coordinate system are solved, and the navigation satellite is tracked; acquiring star maps collected by the optical detection equipment, matching the star maps through a star map recognition algorithm, resolving a coordinate transformation matrix between two continuous frames of star maps, and recognizing fixed stars and satellites in the star maps based on the transformation matrix; converting the identified fixed star in the field of view into an ECEF coordinate system, calculating an observation angular distance between the fixed star and the satellite, and calculating a satellite observation vector in the ECEF coordinate system according to the observation angular distance; and performing error correction on the positioning result of the inertial navigation system based on the satellite observation vector. Through the scheme, the positioning precision of the inertial navigation system can be improved, and the influence of interference deception signals is reduced.

The invention discloses a star sensor fixed star detection capability analysis method based on a polarization degree image, and belongs to the technical field of star sensor detection. In order to solve the problems of few detection means and low utilization rate of sky light radiation information during star observation of a near-earth space all-time star sensor, the method comprises the following steps: constructing a star sensor integrated with a focal plane micro-polarizer array, and acquiring four gray star maps through short exposure by using the star sensor integrated with the focal plane micro-polarizer array; a star sky Stokes vector diagram is calculated; calculating star sky polarization degree distribution to obtain a polarization degree star map; constructing a fixed star polarization signal-to-noise ratio calculation formula in the polarization degree star map by utilizing a physical process of converting radiation energy into polarization degree; the calculation formula calculates the polarization signal-to-noise ratio of the fixed star in the field of view; and comparing the polarization signal-to-noise ratio of the fixed star with a signal-to-noise ratio threshold value detected by the near-earth space all-time star sensor, and judging the detectable capability of the fixed star in the polarization degree star map. According to the method, the robustness of the near-earth space all-day star-sensitive technology to a complex environment is improved.

The invention discloses a star point motion parameter estimation method for a high-dynamic star sensor. The method specifically comprises the following steps: (1) acquiring a star map under a dynamic condition through a fixed star sensor; (2) carrying out filtering preprocessing on the fixed star sensor image obtained in the step (1); (3) carrying out threshold segmentation on the image processed in the step (2) and carrying out connected domain extraction to obtain rough star points; (4) selecting the brightest star point in the star points obtained in the step (3); (5) obtaining a sub-pixel star point track by using the brightest star point adjacent area obtained in the step (4) and adopting a Zernike moment sub-pixel edge extraction method; and (6) utilizing the sub-pixel star point trajectory obtained in the step (5), and adopting least square fitting to obtain star point motion parameters. The method has the beneficial effects that the precision of star point trailing length and angle estimation is improved, so that the extraction precision of star points in a dynamic environment is improved, and the precision of a fixed star sensor is improved.

The invention discloses a fixed star detection capability improving method fusing energy and polarization information, and belongs to the technical field of star sensor detection. In order to solve the problem that a near-earth space all-day star sensor is insufficient in fixed star detection capability in a strong atmospheric background stray light interference environment, the method comprises the following steps: exposing the sky once by using a star sensor integrated with a focal plane micro-polarizer array to obtain four gray star maps; calculating a polarization degree calculation value to obtain a polarization degree star map, and determining the sky background polarization degree; setting a polarization degree segmentation threshold value; performing threshold segmentation on the polarization degree star map to obtain a polarization degree star map segmentation result; determining a weight coefficient according to the radiation energy ratio of the fixed star to the sky background; and comparing the sky background polarization degrees, and performing weighting processing on the gray star map or the accumulated star map with the highest signal-to-noise ratio based on different conditions to obtain a final processed high-signal-to-noise-ratio star map. According to the invention, the fixed star detection capability is effectively improved.

The invention relates to a GNSS (Global Navigation Satellite System) auxiliary measurement-based autonomous navigation method for a lunar satellite formation release process, which comprises the following steps of: establishing a kinetic model of a primary satellite and a secondary satellite under a lunar center inertial coordinate system J2000; establishing and fusing an inter-satellite measurement model and a distance measurement model of a main satellite fused GNSS signal to obtain a collaborative observation model; and acquiring orbit prediction information based on the kinetic model, acquiring collaborative theory observation information based on the collaborative observation model, performing fusion processing on the orbit prediction information and the collaborative theory observation information by adopting an extended Kalman filtering algorithm, and estimating orbit states of the primary satellite and the secondary satellites. According to the autonomous navigation method, full-autonomous orbit determination can be realized in orbit without depending on the support of a ground station.

A polarization orientation method based on sky region prior and morphological template matching of transform domain, which reduces an interference of reflected light through the sky region prior and solves sun blur through the morphological template matching of transform domain (MTMTD); a region division standard is given through prior knowledge of a sky region, and the sky region is identified by clustering darkest pixel images in 15-channel polarization images; meanwhile, the MTMTD strategy provided carries out a transform domain treatment on an image of the angle of polarization by an imaging method, and solves the problem of sun blur under a single Rayleigh scattering model without relying on an additional sensor.

The invention relates to a passive and wireless simulation sun sensor system, comprising: an NFC wireless receiving module configured to provide energy for an NFC simulation sun sensor patch and receive digital information of a solar ray angle sent by the NFC simulation sun sensor patch; the NFC simulation sun sensor patch comprises a four-quadrant battery piece which is configured to generate photo-generated current; the I / V conversion circuit is connected with the four-quadrant battery piece and is configured to convert photo-generated current into analog voltage; the microprocessor is connected with the I / V conversion circuit and the NFC antenna and is configured to process analog voltage to generate digital information of a solar ray angle; the NFC chip is connected with an NFC antenna and the microprocessor; and the NFC antenna is configured to send digital information of a solar ray angle to the NFC wireless receiving module, acquire energy from the NFC wireless receiving module and supply the energy to the NFC chip, the I / V conversion circuit and the microprocessor.

The invention relates to the technical field of satellite orbit determination, in particular to a low-orbit giant constellation autonomous orbit determination method based on a star sensor and inter-satellite angle measurement. The method comprises the following steps: step 1, determining a constellation configuration by using inter-satellite quantity measurement: expressing each satellite state quantity in a constellation by using six elements, constructing a partial derivative matrix of inter-satellite quantity measurement relative to state information, constructing a linear equation set according to the state quantity, the quantity measurement and the partial derivative matrix, and determining a constellation configuration; and solving the satellite state quantity describing the constellation configuration through an improved least square method. Step 2, correcting constellation drift by using a star sensor and a camera quantity measurement and combining the constellation configuration in the step 1: acquiring a true value of an included angle between an adjacent satellite direction vector and a certain fixed star direction vector by using the star sensor and the camera, then calculating an estimated value of the included angle between the adjacent satellite direction vector and the certain fixed star direction vector, and correcting the constellation drift; and the difference between the real value and the estimated value of the included angle is minimized to realize constellation correction. By adopting the scheme, orbit determination can be realized without relying on a ground observation station, and data is easy to manage.

The invention provides an astronomical positioning navigation method based on optical observation, which comprises the following steps: screening and sorting observation targets to be observed according to initial conditions of a platform and ephemeris of the observation targets to serve as an observation task list; driving the optical telescope to steer and collect observation images according to the observation task list; matching astronomical images in the observation image with a fixed star catalogue so as to calculate observed celestial coordinates of each astronomical image; extracting a moving target as an observation target through star change of the multiple frames of observation images, and obtaining a motion track of the observation target; and carrying out platform position calculation. According to the astronomical positioning and navigation method disclosed by the invention, the attitude and position calculation of the platform is completed by integrating optical observation data of a fixed star and an observation target, and the autonomous navigation and positioning of the platform under the condition of no GNSS signal are realized.

This paper discloses a polarization fusion orientation method for occluded environments. First, a polarization camera is used to capture a polarized image of the sky. The heading angle output by the E-vector polarization orientation method is used as the state variable, and the heading angle output by the fitted symmetry axis polarization orientation method is used as the observation variable. The heading angle fusion is achieved using a multi-frequency variational Bayesian strong tracking volumetric Kalman filter (MF-VBSTCKF). Different methods are selected to update the optimal heading angle at the sampling point and during the sampling interval. This method solves the problem that polarized light cannot achieve high-precision and high-robust heading angle measurement in occluded environments. It can improve the accuracy and robustness of polarization light orientation methods in occluded environments while ensuring high-frequency output of heading angles.

The application discloses a kind of combined navigation system online calibration method, system, storage medium and terminal, comprising: establishing the state space model of combined navigation system online calibration, the state space model includes the space installation error of auxiliary sensor, the constant drift of gyroscope, scale factor error and the bias error of accelerometer, while introducing the reference information provided by multiple auxiliary sensors;Error correction is carried out to the calibration parameter and navigation parameter of the online calibration model;The output information of different navigation sensors is information fusion;The state space model is carried out observability analysis and design maneuver trajectory.The present application can solve the problem that part of calibration parameter cannot be estimated and the observability of IMU scale factor error is weak in the existing combined navigation system online calibration method, while improving the calibration efficiency and precision of combined navigation system.

The invention provides an integrated calibration method, device and equipment for photoelectric non-uniformity of an optical star measurement sensor, and relates to the technical field of spacecraft celestial navigation. The method comprises the following steps: constructing lattice structure light to form array image spots on a star sensor, resampling to establish an actual PSF model, and realizing optical system aberration calibration of a corresponding area; sequentially displacing the array image spots, and calibrating the electrical response non-uniformity of each pixel by using the mapping relation between imaging data and PSF; and performing precise positioning on the image spot array after pixel response correction to obtain an image spot high-precision positioning result, and calibrating optical distortion of each pixel according to the high-precision positioning result. Therefore, the problems of photoelectric non-uniform coupling and limited calibration precision in calibration of the star measurement sensor are effectively solved, and high-precision and integrated calibration of optical aberration, distortion and electrical response of the star measurement sensor is realized.

The embodiment of the invention provides a data processing method and device and electronic equipment, and relates to the technical field of satellites.The method comprises the steps that star sensor data obtained by collecting spacecraft attitude information through a star sensor and gyroscope data obtained by collecting spacecraft attitude information through a gyroscope are obtained and comprise data from the k-n moment to the k moment; carrying out fusion and linear interference filtering processing on the data of the star sensor and the gyroscope at each moment by using Kalman filtering to obtain preliminary prediction data of attitude information, and calculating a first residual value of the data of the star sensor; the star sensor data, the gyroscope data and the first residual value from the k-n moment to the k moment are input into the trained LSTM network, a second residual value of the preliminary prediction data at the k moment is predicted, and the second residual value represents an error of nonlinear interference; and compensating the second residual value to the preliminary prediction data to obtain attitude information of the spacecraft at the moment k. According to the embodiment of the invention, the error of spacecraft attitude information acquisition is reduced.

A navigation method of a vehicle equipped with a star tracking device, a first inertial measurement device and a satellite positioning device, the star tracking device and the first inertial measurement device being connected to a single support. The method includes controlling movements of the support; simultaneously with these movements, calculating, in a horizontal plane, first positions of the vehicle, and second positions of the vehicle; calculating first deviations between the first positions and the second positions corresponding to each tracking heading and depicting them in a polar reference frame as a function of the corresponding heading and the values of the first deviations; carrying out a circular regression on said first deviations to determine, in this polar reference frame, a first circle; and determining a radius of the circle and a second deviation between a centre of the first circle and an origin of the polar reference frame.

The embodiment of the invention provides an interactive multi-model factor graph integrated navigation method based on tight coupling attitude constraint. In a specific embodiment, the method comprises the following steps: constructing an integrated navigation system; constructing an inertial measurement unit factor pre-integrated by the inertial navigation system; constructing a direct celestial navigation factor and a refraction celestial navigation factor which are respectively and tightly coupled with an inertial measurement unit factor based on the star sensor observation condition of the celestial navigation system; constructing a horizontal radio navigation factor and a vertical radio navigation factor based on the position information of the land-based radio navigation system; acquiring height measurement data of the barometric altimeter to construct barometric altimeter factors; dynamically adjusting the weight ratio of the height measurement data of the vertical radio navigation factor to the height measurement data of the barometric altimeter factor through an interactive multi-model algorithm; and carrying out global state estimation of the integrated navigation system on a factor graph framework formed by the factors.

The present invention discloses a low-cost commercial remote sensing satellite attitude determination information fusion method. On a commercial remote sensing satellite, two star sensors, two gyroscopes, two sun sensors, and one magnetometer are used to measure the satellite attitude. According to the data availability of each sensor, conditional judgment is performed, and quaternions and gyroscope angular velocity are used to perform attitude determination, and finally satellite attitude determination information is obtained. The information fusion method of the present invention is simple, does not rely on complex algorithms and expert experience, occupies less on-board resources, is easy to maintain, and reserves an interface for ground-based forced intervention in the on-board information fusion method, thereby improving the reliability and practicality of the fusion algorithm.

A kind of star sensor star detection capability analysis method based on polarization degree image belongs to star sensor detection technical field.For solving the problem that less detection means and low utilization rate of sky light radiation information when near-earth space all-time star sensor observes star, the present application includes the star sensor of integrated focal plane micro-polaroid array is built, four gray star maps are collected by short exposure using the star sensor of integrated focal plane micro-polaroid array;Calculate the sky Stokes vector diagram;Calculate the polarization degree distribution of starry sky to obtain the polarization degree star map;Utilize the physical process of radiation energy to polarization degree conversion to construct the polarization signal-to-noise ratio calculation formula of star in polarization degree star map;The polarization signal-to-noise ratio of star in field of view is calculated;The polarization signal-to-noise ratio of star is compared with the signal-to-noise ratio threshold value of near-earth space all-time star sensor detection, and the detectable ability of star in polarization degree star map is judged.The present application improves the robustness of near-earth space all-time star sensor technology to complex environment.