74 results about "Geoid" patented technology

The invention provides a method for constructing a geographic coordinate system with a laser tracker. A level of the laser tracker is aligned with the geoid, so that the horizontal of the place where the tracker is located is found, a high-precision theodolite is then utilized to find the direction of the true north, the adjusted theodolite is used for measuring the horizontal angles between fourtarget balls placed according to certain requirement, the tracker measures and projects the four target balls into a horizontal plane, so that the mutual positional relation among the four points in the horizontal plane is obtained, and by means of calculation, the horizontal included angle between the connecting line of the projected points of the corresponding target balls and the direction of the true north can be obtained. Finally, tracker software is used for establishing a coordinate system (the origin is given according to the requirement) with the direction of the connecting line of the projected points of the corresponding target balls and the direction of the normal vector of the horizontal plane as axes and rotating the coordinate system around the direction of the normal vector of the horizontal plane for the horizontal included angle, and thereby the needed geographic coordinate system is obtained. The method enables laser tracker to have the function of establishing the geographic coordinate system, and can also be applied to other cases needing the establishment of geographic coordinate systems.

The invention relates to a method for precisely measuring the earth gravitational field, in particular to a method for inverting the earth gravitational field by using a variance-covariance diagonal tensor principle. The method comprises the following steps of: establishing a cumulative geoidal surface error model on the basis of satellite gravity gradient variance-covariance diagonal tensor principle; accurately and rapidly inverting the earth gravitational field by using the satellite gravity gradient measurement data of a spaceborne gravity gradiometer; and developing requirement argumentation on a GOCE (Gravity Field and Steady-State Ocean Circulation Explorer)-II satellite gravity gradient system by using the satellite orbit altitude and the precision index of the satellite gravity gradiometer. The method disclosed by the invention is high in inversion precision of the earth gravitational field, high in inversion speed of the satellite gravity gradient, explicit in physical content of a satellite observation equation, capable of easily developing the requirement analysis of the satellite gravity gradient system and low in requirement on computer performances. Therefore, the method for inverting the earth gravitational field by using the variance-covariance diagonal tensor principle is an effective method for resolving the earth gravitational field with high precision and high spatial resolution.

The invention relates to a satellite gravity gradient inversion method based on power spectrum half analysis; builds an individual and a united analytical error models of accumulated geoid accuracy influenced by a gravity gradient tensor error of a satellite gravity gradient meter and an orbital position error of a global position system (GPS)/ global navigation satellite system (GLONASS) composite receiver; and simultaneously provides a method for verifying a satellite gravity gradient inversion half analysis error model, and a method for determining parameter requirements of a next generation GOCE Follow-On gravity gradient satellite according to effects of satellite gravity gradient measurement accuracy, satellite orbit position measurement accuracy and satellite orbit height on accumulated geoid based on the satellite gravity gradient inversion half analysis error model. The satellite gravity gradient inversion method is high in accuracy, high in speed of resolving the earth gravitational field, and explicit in physical meaning of a satellite observation equation, simplifies a computational process, and facilitates performing requirement analysis of a next generation gravity gradient satellite system.

The invention relates to an area quasi-geoid refining method based on an earth gravity model (EGM2008). The method comprises the following steps of: 1) determining an area range and distributing control points; 2) performing field measurement (data acquisition); 3) on the basis of the EGM2008, acquiring a gravity height anomaly of each control point; 4) fitting a quadratic polynomial; 5) measuring adjustment; 6) performing analog computation on a neural network; and 7) refining a model. By adoption of the method, the accuracy of an area height anomaly computation result is high, and the application range of a measurement result of a global positioning system (GPS) height is expanded. Compared with the conventional quadratic polynomial fitting method, the method provided by the invention has the advantages that by a great amount of engineering project application result analysis, the accuracy of a height anomaly computation result is improved by 20 to 50 percent; after the accuracy is improved, the GPS height can replace low-level leveling, so the workload of the conventional low-level leveling which is high in cost, high in difficulty and long in period is reduced to the greatest extent, and economic benefit is obvious; and the method is applicable to the technical field of geodesy.

The invention relates to a method and system for indirectly influencing tightness by spherical terrain niches in determination of a plumb line deviation. The method comprises the steps: calculating a modeled value of plumb line deviation of any point of the ground; calculating Helmert residual gravity anomaly: presenting a universal curvature term of spherical integral of a terrain effect, replacing a plane approximation term with the obtained universal curvature term of spherical integral of the terrain effect, carrying out tightness integration so as to obtain a tightness equation for gravitational potentials of ground points by terrain gravitational potential and Helmert terrain agglomerated layers, calculating indirect influence on a basic terrain and second indirect influence on gravity anomaly caused by a geoid, and eliminating direct influence and indirect influence caused by a spherical terrain, so as to calculate the Helmert residual gravity anomaly; calculating a residual plumb line deviation of any point of the ground; restoring a removed model plumb line deviation, thereby determining the plumb line deviation. According to the method and the system, the indirect influence caused by the spherical terrain niches can be more effectively removed, and a high-precision geoid is determined, so that the method and the system are very suitable for being applied to the field of geodetic surveying and surveying/mapping engineering.

The invention discloses a three-dimensional coordinate conversion method. The three-dimensional coordinate conversion method comprises the steps of receiving an original three-dimensional coordinate sent by a client; making a half line by using a position point of an original plane coordinate in an original plan area as a starting point, calculating the number of intersections of the half line and boundary lines of all coordinate conversion areas one by one, and using conversion parameters corresponding to the coordinate conversion areas of which the number of intersections is odd as conversion parameters of the original plane coordinate; converting the original plane coordinate into a target plane coordinate according to the conversion parameters of the original plane coordinate; converting an original elevation into a target elevation according to the target plane coordinate and a pre-established pseudo-geoid model; feeding the target plane coordinate and the target elevation back to the client. Correspondingly, the invention further discloses a three-dimensional coordinate conversion device. By adopting an embodiment of the three-dimensional coordinate conversion method, the original three-dimensional coordinate can be automatically converted, and the conversion efficiency and accuracy are increased.

The invention discloses a method for improving ocean gravity field interpolation precision based on a submarine topography three-dimensional optimization principle. The method comprises steps of submarine topography data and a global gravity field model being acquired; constructing a three-dimensional ocean gravity anomaly model according to the acquired submarine topographic data and the global gravity field model; performing interpolation calculation on the three-dimensional ocean gravity anomaly model to obtain a geoid three-dimensional correction model; and according to the geoid three-dimensional correction model, determining a gravity anomaly value at an unknown point in the prediction area to obtain a high-precision and high-spatial-resolution marine gravity anomaly map. According to the method, the submarine topography is introduced into a common two-dimensional Kriging formula, a novel submarine topography three-dimensional optimization method is constructed, the precision loss is minimized while the spatial resolution of the global marine gravity anomaly map is improved, the interpolation precision is high, the calculation speed is high, and an effective basis is providedfor improving the submarine gravity matching navigation precision.

The invention discloses a method of measuring a level elevation difference based on a geoid model. The method comprises the steps: calculating a height anomaly difference of two adjacent control points by adopting the geoid model, so as to obtain a geodetic height difference of the two adjacent control points by virtue of the measurement of a GNSS (Global Navigation Satellite System), carrying out subtraction on the height anomaly difference and the geodetic height difference to be converted to the level elevation difference, and calculating an elevation of each control point. The method can be applied to multiple terrains including plains, hills, mountain areas and the like. With the adoption of the method, an interval between every two adjacent control points can reach 5-8km, the working efficiency can be improved by 6-10 times, and the third class or fourth class leveling accuracy can be realized; in addition, as the only heights of the two control points at the head and tail ends are needed, and the geometrical leveling is not needed, the method has the characteristics of low working intensity and high efficiency.

The invention discloses a method for carrying out quasigeoid refining on a superlarge region on the basis of a seamless partitioning technology, which comprises the following steps of: a step 1 of acquiring data; a step 2 of carrying out grid dividing on the whole region; a step 3 of sequentially calculating a height anomaly xi of each grid point in a grid model; a step 4 of establishing the grid model; and a step 5 of interpolating a grid. After the method disclosed by the invention is adopted, manual partitioning does not need to be carried out and the problem of edge connection of the region does not exit. When the model is applied, the grid interpolation can be directly carried out. As shown in Figure 2, the height anomaly of any one point in a certain grid in the region can be calculated by interpolation through adopting a bilinear interpolating method.

The invention discloses a method and a system for elevation precision control and correction of island remote sensing mapping, and relates to the technical field of geodetic surveying engineering. The method comprises the steps of S1, extracting shorelines from island remote sensing images; S2, obtaining a first average sea surface height and a second average sea surface height, and performing datum conversion on the second average sea surface height; S3, calculating geoidal surface; S4, carrying out harmonic analysis to obtain a tidal harmonic constant; S5, calculating elevation of mean high-water springs; S6, calculating and removing systematic errors of the shorelines in the island remote sensing images; and S7, fitting the shorelines in the island remote sensing images with the systematic errors removed and the shorelines on the mean high-water springs. Correction of the shorelines in the island remote sensing images is realized by fitting the fitting the shorelines in the island remote sensing images with the systematic errors removed and the shorelines on the mean high-water springs, thereby increasing the elevation precision obtained by the island remote sensing mapping.

Geographic identification systems and methods of displaying geographic locations on maps and providing related location based services in accordance with embodiments of the invention are disclosed. One embodiment includes a GEOID server configured to communicate with a database containing GEOIDs, where each GEOID comprises a label and geographic information. In addition, the GEOID server is configured to communicate with a mapping server via a network, the GEOID server is configured to communicate with a plurality of user devices via the network, the GEOID server is configured to store GEOIDs in the database in response to information received from user devices via the network, the GEOID server is configured to retrieve geographic information in response to GEOID labels received from user devices via the Internet, and the GEOID server is configured to cause the display of a map provided by a mapping server on a user device, where the map indicates at least one location associated with the geographic information retrieved by the GEOID server in response to the GEOID label received from the user device.

The invention relates to an absolute calibration method for a satellite radar altimeter without a special calibration field and belongs to the technical field of calibration of satellite altimeters. According to the method, an absolute deviation of the satellite radar altimeter can be determined through processing tidal observation data and satellite altimetry data of a satisfactory oceanographic station, adding essential correction entries such as a geoid model, carrying out height datum unification, altimetry data space position interpolation and tidal observation data time interpolation, and finally, carrying out difference comparison on sea surface height of tidal observation and sea surface height of the satellite radar altimeter. Compared with the prior art, the method has the advantages that the special calibration field is not required, the existing oceanographic stations can have calibration capability by using existing business observation data of oceanographic stations of coasts or oceanic islands of our country and a regional accurate geoid, and thus, absolute measured deviations of the satellite altimeters at home and abroad can be acquired.

The invention relates to a geoid detection method and device, belongs to the field of geographical mapping, and particularly relates to a quasigeoid detection method and device. According to the method and device, detection point elevations adopt elevation starting points not lower than national second-class leveling points, detection is implemented according to second-class leveling accuracy, observation is performed by the aid of a digital level or a precise triangle elevation, altitude differences between two detection points can be compared for the area with high abnormal variation of the elevations and without leveling starting points, leveling elevations of the detection points and elevations acquired through quasigeoid refinement can be compared, the errors in the elevations of the detection points are counted, the quality of the quasigeoid refinement can be objectively and really evaluated, and reliability and accuracy of quasigeoid refinement results are mastered.

The invention relates to a precision measurement method of an earth gravitational field, in particular to an earth gravitational field recovery method based on a distance-among-star error model. The method is based on the influence of the distance-among-star error model, accumulates the relation of geoidal surface precision, and establishes a distance-among-star error model, and further precisely and fast recovers a current GRACE earth gravitational field and a next generation GRACE-II earth gravitational field based on the distance-among-star error model. The method is high in recovery precision to the earth gravitational field, greatly improves resolving speed, and is prone to carrying out high order gravitational field error analysis, physical meanings of satellite observation equation are clear, and the requirement of computer performance is low. Therefore, the method of the distance-among-star error model is an effective method for recovering the high precision and high spatial resolution earth gravitational field.

The present invention discloses a method for generating a two-dimensional layout diagram of a three-dimensional bridge model by using CATIA software. The method comprises the following steps: receiving data for designing a road in the CATIA software, establishing a three-dimensional model of the bridge, and storing all key design information in a parameter form and a design list form in the CATIAsoftware into the three-dimensional model space; making a two-dimensional graphic template by using the user-defined feature UDF in the CATIA software; in the three-dimensional model space where the overall bridge model is located, generating a vertical unfolding surface corresponding to the vertical hook surface where the center line of the road is located, a horizontal unfolding surface parallelto the geoidal surface, and a plurality of vertical surfaces passing through the sub-line; and projecting the corresponding information respectively to generate a layout diagram of each surface of the bridge in the traditional two-dimensional drawing. According to the method provided by the present invention, information in the three-dimensional graph can be effectively transmitted to the two-dimensional graph, and data synchronization and model linkage can be realized.

The invention relates to a method and a device for simultaneously determining three-dimensional geometry position and gravity potential, in particular to a method and a device for simultaneously determining the three-dimensional geometry position and the gravity potential by utilizing a global position system (GPS) signal. In the technical scheme, a novel method for determining the gravity potential (including elevation height) by utilizing the GPS signal is added on the basis of the traditional GPS positioning method, an observation equation between the GPS signal and the gravity potential is established, and the gravity potential is solved on the basis of a principle of least square by utilizing multiple observation data. The invention has the advantages that: heavy water level measurement and gravity measurement are not needed, and the geoidal surface is not needed to be pre-determined to determine the elevation height by utilizing the GPS positioning method, so that numerous laborpower and financial resources are saved, and the restriction on measurement caused by mountains and cross oceans is avoided.

The invention discloses a method for establishing engineering area level ellipsoids. The method comprises following steps: an engineering area level ellipsoid function composed of undetermined parameters is established on the basis of a standard ellipsoid function; by means of abnormal data of control point elevation, on the basis of a testing zone average elevation plane, the control point elevation is converted to the testing zone average geoid corresponding to the testing zone average elevation plane to obtain a testing zone ellipsoid surface point spatial rectangular coordinate under a source ellipsoid; translation parameters and long and short axis parameters are obtained under the coordinate; a new engineering level ellipsoid E1 is established through translating and adjusting the long axis and the short axis, and the spatial coordinate under a target ellipsoid is obtained; geodetic coordinate transformation, where the ellipsoid long axis and short axis are changeable, is performed on the converted coordinate under the engineering level ellipsoid E1 and further the coordinate is converted to an engineering plane coordinate for further accurate reduction. The level ellipsoid plane established by the method can be well matched with the geoid corresponding to the engineering testing zone average elevation plane, which facilitate data accurate deduction.

The invention provides a height anomaly fitting interpolation calculation method based on a mobile neural network. The method comprises the following steps of: constructing a BP (Back Propagation) neural network model, wherein the BP neural network module comprises an input layer, a hidden layer with nerve cells and an output layer, and each element of the input layer is connected with the corresponding nerve cell through a weight matrix; using a discrete GPS (Global Positioning System) point position as a center, and selecting the height anomaly and the earth coordinates of grid nodes in a quasigeoid grid number model, wherein the earth longitude difference and the earth latitude difference of the grid nodes are smaller than a space of a preset number of grid nodes; using the height anomaly and the earth coordinates of the preset number of grid nodes for forming a study set sample, training the neural network, and generating a network weight matrix when a network performance index reaches a preset extreme value; and inputting the earth coordinates of the discrete GPS point position, and calculating the height anomaly in the point through calculation. The method provided by the embodiment of the invention has the advantage of high precision of height anomaly fitting interpolation calculation.

The invention provides an inertial navigation method based on real-time gravity compensation. The inertial navigation method based on real-time gravity compensation comprises the steps that a navigation request is received; the accelerated speed of a moving carrier corresponding to a moving carrier identification in an inertial reference system is measured and obtained according to the navigation request, and a geographical coordinate of the position the moving carrier is located at the current moment is obtained; a projection point of the geographical coordinate of the position the moving carrier is located on the ground level plane is obtained and is used as a point to be interpolated; N interpolating points are selected from the ground level plane according to the point to be interpolated; the gravitational acceleration of the point to be interpolated is interpolated according to the gravitational accelerations corresponding to the N interpolating points; the gravitational acceleration of the position the moving carrier is located is obtained according to the gravitational acceleration of the point to be interpolated, the measured and obtained acceleration of the moving carrier is compensated, and corresponding navigation processing is performed according to the compensated acceleration. The navigation accuracy of the inertial reference system is improved by means of the inertial navigation method.

The invention discloses a real-time network RTK (Real-Time Kinematic) positioning method compatible with a quasi-geoid model. First, the approximate position of a user mobile station is obtained according to the longitude, latitude and geodetic height provided by GGA, and the elevation anomaly and normal elevation of the approximate position of the user are calculated by using the quasi-geoid griddata and an elevation anomaly interpolation function in a data processing center according to the geodetic coordinates B and L of the approximate position of the user. Then, the coordinate differencecaused by elevation anomaly correction is subtracted from the coordinates of a virtual reference station and the result is sent to the user mobile station, and the user mobile station carries out RTKrelative positioning to obtain geodetic coordinates including the normal elevation. By making full use of a CORS system and a high-precision quasi-geoid model, the user mobile station can obtain high-precision geodetic coordinates including the normal elevation in real time, the engineering efficiency is improved, and the workload is reduced.

The invention relates to a radio frequency receiver of an eight-frequency-point multi-mode satellite navigation system. The radio frequency receiver mainly comprises a radio frequency signal receiving link and a local oscillator signal generation circuit, wherein the radio frequency signal receiving link comprises a low noise amplifier, a power splitter, a crystal oscillator, a frequency mixer and a local oscillator sound generator, as well as a corresponding band-pass filter and an analog-digital converter. By adopting the radio frequency receiver of the eight-frequency-point multi-mode satellite navigation system, the sensitivity of the radio frequency receiver is improved, the number of circuits is reduced, the area of a chip is reduced, the power consumption and the cost of the circuits are lowered, and the radio frequency receiver is easy in chip integration and can be widely applied to precise application fields such as geodetic surveying, engineering surveying, precise deformation monitoring, geodynamics study, geoidal surface refining, earthquake prediction and the like.