34 results about "Satellite altimetry" patented technology

The invention discloses a method for extracting the lake and reservoir water level based on screened satellite altimetry data. The method includes the steps that satellite altimetry data is selected and downloaded, and basic editing processing is conducted on the satellite altimetry data; the lake and reservoir water level is preliminarily calculated with the satellite altimetry data and a water level altimetry formula; quality evaluation and quality grading are conducted on the satellite altimetry data according to the preliminarily calculated water level; abnormal data is screened out basedon the quality evaluation result, a high-quality data set is retained, and the altimetry mean water level is calculated to serve as the current lake and reservoir water level; finally, water level data of different periods is reduced to the same reference point, filtering processing is conducted in the whole time series, and gross errors are removed to obtain a relatively consistent lake and reservoir water level time series. The method can effectively eliminate interference caused by satellite altimetry data noise and improve the availability of satellite altimetry data and the precision of lake and reservoir water level monitoring.

The invention discloses a method for determining sea surface topographic structure based on barodynamics, which comprises the following steps: S1, performing the gross error detection on sea surface height data to obtain a gross error-free height data; S2, calculating a reference gravity field in satellite altimetry gravity field inversion; S3, based on the reference gravity field, deleting long-wave components in the sea surface topography from the gross error-free height data; S4, utilizing the gross error-free height data to separate the intermediate wave components in the sea surface topography; and S5, in the calculation of a geoid height by utilizing the reference gravity field, adding parameters which are acquired in the step of separating the intermediate wave components in the sea surface topography, and comparing the added result with a sea surface height acquired according to a satellite altimetry data so as to determine various frequency components in the sea surface height. By using the method, the reliable sea surface height data is acquired, thereby acquiring the accurate measured sea surface topographic structure data.

The invention discloses a method for improving the accuracy of a satellite altimetry cross point. The method comprises the following steps of: calculating the distance and the data density between adjacent data points on each track; selecting a track with the smallest data density in all the tracks as a reference track and the other tracks as tracks to be averaged; selecting the frequency of interpolation polynomial for each track to be averaged; fitting the tracks to be averaged by the polynomials; calculating the longitude, the latitude and the sea level height of a point, closest to each reference point, on each fitted curve; calculating the longitude, the latitude and the sea level height of a data point on an averaged track; circularly judging whether a cross point is generated and calculating the longitude, the latitude and the sea level height of the cross point; and converting the judgment of the cross point between two tracks into judgment on whether a connecting line section between two adjacent height measurement data points in any track forms an intersection point with a connecting line section between two adjacent data points in the rest tracks, wherein the intersection point is taken as the cross point. Compared with conventional methods, the method has the characteristics of high accuracy, easiness in calculation, wide application range, high operation efficiency and the like.

The invention relates to a large inland lake and wetland water level inversion method based on satellite altimetry data. The method comprises the steps that echo data is preprocessed, a dominant riseleading edge in an echo waveform obtained after preprocessing is extracted, and echo waveform resetting is performed; continuous echo data in multiple trajectories are arbitrarily selected in a research region, different thresholds are used to perform echo resetting, and improved values corresponding to reset echoes are calculated; the maximum improved value is found out, and the threshold corresponding to the maximum improved value is used as an optimal threshold; the optimal threshold is used to perform echo waveform resetting, and water levels are calculated; all the water levels in the research region are post-processed; and last, data verification is performed on time-sequence water levels, whether precision obtained after data verification is within an allowed range or not is judged,and if yes, the time-sequence water levels are output; or otherwise echo resetting is continued. The water level inversion method is simple in calculation, high in speed and high in precision.

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 discloses a satellite altimetry gravity data and ship borne gravity data fusion method of combining fractal interpolation and net function interpolation. The method includes the basic steps of: using net function interpolation for interpolation on satellite altimetry gravity data; calculating difference values of an interpolation result and the ship borne gravity data; carrying out clustering analysis on the difference values, and dividing a whole area into a plurality of sub-areas; carrying out fractal interpolation on the difference values on each longitudinal and horizontal grid edge of each sub-area, carrying out net function interpolation inside the sub-areas, and obtaining gravity data correction values; and using the gravity data correction values as centers, carryingout fusion calculation to obtain a data fusion product for each sub-area according to the satellite altimetry gravity values, and finally, obtaining a whole-area data fusion product. The method provided by the invention is scientific and reasonable, a realization process is simple and easy to understand, high-precision and high-resolution gravity data can be obtained after fusion on the ship bornegravity data and the satellite altimetry gravity data, and at the same time, similarity of local features and overall features of the multi-source gravity data is fully maintained.

A satellite altimetry gravity data and shipborne measurement gravity data fusion method disclosed by the present invention comprises the basic steps of determining a fitting radius by taking a shipborne measurement gravity data point as the center; calculating the weights of the satellite altimetry gravity data points within the range of the fitting radius; calculating the interpolation results ofthe satellite altimetry gravity data points at the shipborne measurement gravity data point; calculating the difference values between the interpolation results and the shipborne measurement gravitydata; according to the difference values and the weights, calculating the correction values of the satellite altimetry gravity data points; fusing and calculating to obtain the gravity fusion data. The method provided by the present invention has the advantages of being scientific and reasonable, being easy to realize, being high in precision, etc., and enables the precision of a marine gravity data fusion product to be improved by the satellite altimetry gravity data and shipborne measurement gravity data fusion.

The invention discloses a local gravity anomaly extraction method based on satellite height measurement gravity data, which comprises the following basic steps of: processing satellite altimetry gravity data by using a sobel operator to obtain each gravity anomaly region; extracting a minimum enclosing rectangle of each gravity anomaly region according to the boundary line of each gravity anomalyregion; performing coordinate system rotation on the minimum enclosing rectangle of each gravity anomaly region to obtain a transformation rectangle, and obtaining a gravity anomaly value in each transformation rectangle region by utilizing an improved curved surface fitting method; performing interpolation processing on the gravity abnormal value of each transformation rectangle by utilizing a network function to obtain a regional abnormal gravity value of each gravity abnormal region; and finally obtaining a local gravity abnormal value of each gravity abnormal region. The method is scientific and reasonable and has high operability and practicability, and the satellite height measurement gravity data are processed through the network function interpolation method to obtain local gravityanomaly information.

The invention discloses a river virtual station water level time sequence reconstruction method and system. The method comprises the steps of: taking an average waveform of a central foot point and an adjacent point as a reference on the basis of improved adaptive wavelet analysis, extracting a plurality of pulse peak values meeting parameter conditions, enabling the pulse peak values to be paired with wavelets of an along-rail waveform, and forming a plurality of groups of latitudinal elevation profiles, and constructing a multi-target optimization function by using wave peak energy and elevation standard error, and determining a target water surface elevation observation group; and finally, optimizing a water level elevation time sequence through time sequence noise detection and elevation reselection. According to the method, on the basis of publicly obtained satellite altimetry data and auxiliary data, automatic river virtual site water level time sequence extraction can be achieved; and the method can automatically adapt to main wave peak detection under the conditions of high noise level and multi-peak distribution, improve the river water level extraction precision under the complex earth surface condition, and provide support for applications such as river water regimen monitoring, global change and water circulation monitoring.

The invention discloses a fusion method of satellite altimetry gravity data and ship survey gravity data. The basic steps are: determining the fitting radius with the ship survey gravity data point as the center; calculating the weight of the satellite altimetry gravity data points within the fitting radius range ; Calculate the interpolation result of the satellite altimetry gravity data point at the ship survey gravity data point; calculate the difference between the interpolation result and the ship survey gravity data; calculate the correction value of each satellite altimetry gravity data point according to the difference and weight; The fusion calculation obtains the gravity fusion data. The method provided by the invention has the advantages of being scientific and reasonable, easy to implement, and high in precision, and improves the accuracy of marine gravity data fusion products through fusion of satellite altimetry gravity data and ship survey gravity data.

The invention discloses a tide correction method based on satellite altimetry data, and relates to the technical field of satellite altimetry. Tide information is extracted through a sea level height time sequence measured by an altimetric measurement satellite, tide correction is performed on the satellite altimetry data according to the tide information, as a result, inadaptability, caused by usage of a global tide model, to tide correction of regional sea areas can be avoided, and the practicability and accuracy of the satellite altimetry data in monitoring and predicting regional sea level changes are improved.

The invention discloses a sea level change prediction method based on satellite altimetry data, and relates to the technical field of satellite altimetry data application. The sea surface height datainterpolation result at the grid center point is calculated by searching the interpolation weight of each sea surface height data within the radius with the determined grid center point as the circlecenter by using the sea surface height long-time series data measured by the satellite altimeter. Then the parameters of seasonal difference autoregressive moving average prediction model are determined at the center of each grid by using the interpolation results of sea surface height data. Finally, the predicted sea surface height at the center of each grid in the study area is calculated basedon the predicted model. By combining the satellite altimetry data with the seasonal difference autoregressive moving average model, the invention can predict the large-scale sea level change.

The invention discloses a water vapor correction precision analysis method under different sea conditions based on microwave radiation. Firstly, factors influencing determination of water vapor correction precision are deduced by a water vapor correction model, wherein the factors comprise sea conditions, brightness temperature measurement values of the frequency, brightness temperature values of other frequencies and brightness temperature measurement precision. Numerical simulation is carried out on brightness temperature measurement values through a brightness temperature determination theoretical model, and an error propagation coefficient is calculated by traversing a brightness temperature measurement value range; and finally calculating the water vapor correction precision under different sea conditions. Compared with a water vapor correction precision analysis method obtained by using test data in the prior art, the method considers more comprehensive and finer problems, the water vapor correction precision under different sea conditions is obtained, and a solution is provided for realizing fine determination of satellite altimetry precision under different sea conditions.

The invention relates to the technical field of water resource remote sensing monitoring, and provides a method for calculating and calibrating river and lake water levels based on satellite altimetry data, which comprises the following steps of: distinguishing a water body part from a non-water body part according to an optical satellite image, acquiring satellite transit orbit data and selecting a plurality of initial measuring points; according to a satellite height measurement principle, determining and rejecting the initial measurement points with abnormal imaging, then reserving the remaining measurement points as target measurement points, setting a rejecting judgment standard of the target measurement points, reserving the target measurement points meeting the standard as effective measurement points, calculating a satellite height measurement water level test value and an average value of the effective measurement points at the measurement time, and taking the average value as the satellite observation water level at the measurement time. A satellite observation water level time sequence and an actual measurement water level time sequence of multiple measurement times are obtained, the average deviation of the two time sequences serves as a calibration parameter, and calculation and calibration of the river and lake water level are achieved by optimizing the calibration parameter. The method can effectively solve the problem that the calculation and calibration precision of the discontinuous water area cannot be guaranteed.

The invention discloses a satellite altimetry data collinear processing method, and relates to the technical field of satellite altimetry data processing. The scheme of the invention is based on satellite altimetry data, and constructs a reference orbit by using a quadratic polynomial, so that discrete data can be more closely approximated; and then, the longitude and latitude of normal points onthe reference orbit are calculated by using the satellite sampling interval along the orbit, so that the data missing is reduced; and finally, the sea surface height of each normal point is determinedby using a weighted distance method, and thus a number of orbits that have the same number and are not closely repeated are fitted into a single orbit.

The invention provides a frequency domain method for inverting an ocean gravity gradient by using satellite altimetry data. The method comprises the steps of (1) calculating to obtain south-north vertical line deviation and east-west vertical line deviation according to altimetry satellite data; (2) obtaining radial disturbance gravity anomaly by means of the vertical line deviation derived from the altimetry satellite data, and calculating disturbance gravity anomaly in other directions by means of the south-north vertical line deviation and the east-west vertical line deviation; (3) carrying out Fourier transform calculation on the obtained disturbance gravity anomaly so as to obtain a Fourier transform calculation value of the disturbance gravity gradient in each direction under a spherical coordinate system; and (4) calculating the full-tensor gravity gradient through the Fourier transform calculation value of the disturbance gravity gradient. According to the invention, the full-tensor gravity gradient can be calculated according to the satellite altimetry data.

The invention discloses a method for determining sea surface topographic structure based on barodynamics, which comprises the following steps: S1, performing the gross error detection on sea surface height data to obtain a gross error-free height data; S2, calculating a reference gravity field in satellite altimetry gravity field inversion; S3, based on the reference gravity field, deleting long-wave components in the sea surface topography from the gross error-free height data; S4, utilizing the gross error-free height data to separate the intermediate wave components in the sea surface topography; and S5, in the calculation of a geoid height by utilizing the reference gravity field, adding parameters which are acquired in the step of separating the intermediate wave components in the sea surface topography, and comparing the added result with a sea surface height acquired according to a satellite altimetry data so as to determine various frequency components in the sea surface height. By using the method, the reliable sea surface height data is acquired, thereby acquiring the accurate measured sea surface topographic structure data.

The invention discloses a satellite radar altimetry waveform resetting method based on the waveform derivative, which comprises the following steps: deriving the first-order derivative and the second-order derivative of the echo waveform based on the theoretical echo model; using the maximum value of the slope of the leading edge of the waveform, That is, when the second-order derivative is equal to zero, the calculation formula of the midpoint of the leading edge is obtained; the unknown parameters in the calculation formula of the midpoint of the leading edge are solved by fitting, and the position of the midpoint of the leading edge is determined; the resetting distance correction value is determined according to the preset tracking gate ;Further, according to the correction value of the resetting distance and the correction value of the height measurement error, calculate the sea surface height after the resetting method. The invention can improve the quality of satellite altimetry data, the high precision of the rescheduled sea surface is better than that of the conventional rescheduled method, and the correlation between the rescheduled sea surface height and the geoid height is obviously improved.

The invention discloses a satellite altimetry data collinear processing method, and relates to the technical field of satellite altimetry data processing. The scheme of the invention is based on satellite altimetry data, and constructs a reference orbit by using a quadratic polynomial, so that discrete data can be more closely approximated; and then, the longitude and latitude of normal points onthe reference orbit are calculated by using the satellite sampling interval along the orbit, so that the data missing is reduced; and finally, the sea surface height of each normal point is determinedby using a weighted distance method, and thus a number of orbits that have the same number and are not closely repeated are fitted into a single orbit.

The invention discloses a method for extracting the lake and reservoir water level based on screened satellite altimetry data. The method includes the steps that satellite altimetry data is selected and downloaded, and basic editing processing is conducted on the satellite altimetry data; the lake and reservoir water level is preliminarily calculated with the satellite altimetry data and a water level altimetry formula; quality evaluation and quality grading are conducted on the satellite altimetry data according to the preliminarily calculated water level; abnormal data is screened out basedon the quality evaluation result, a high-quality data set is retained, and the altimetry mean water level is calculated to serve as the current lake and reservoir water level; finally, water level data of different periods is reduced to the same reference point, filtering processing is conducted in the whole time series, and gross errors are removed to obtain a relatively consistent lake and reservoir water level time series. The method can effectively eliminate interference caused by satellite altimetry data noise and improve the availability of satellite altimetry data and the precision of lake and reservoir water level monitoring.

The invention provides a method and system for estimating sea ice thickness distribution based on least squares adjustment, which processes satellite altimetry data and extracts related parameters, including latitude and longitude, elevation, average sea surface height, orbit number, pulse peak value and pulse Accumulated standard deviation; sea ice freeboard height extraction, including interglacial channel identification based on satellite echo signal-related characteristic parameters, to obtain sea ice freeboard height; sea ice thickness estimation, based on conversion from sea ice freeboard to sea ice thickness relationship, establish a function model in the grid unit, establish an observation equation, and use the least squares adjustment to solve the corresponding sea ice thickness results; perform resampling and filling to obtain the final sea ice thickness distribution map. The present invention gets rid of the traditional method of using empirical values, avoids the uncertainty brought by conditions such as snow thickness and snow density under the special geographical location and climatic conditions of the sea ice area, thereby improving the estimation of sea ice thickness. measured reliability.

The invention relates to the technical field of satellite altimetry data processing, in particular to a self-adaptive waveform re-tracking algorithm based on a main wave crest, which is called AMWRT algorithm for short, and comprises the steps of extracting the main wave crest, performing waveform re-tracking on the main wave crest, judging the priority of an IMP value and the like. According to the algorithm, the complete waveform of the main wave crest is extracted, and then waveform re-tracking is performed on the main wave crest by using four different algorithms, so that the accurate waveform rising front edge midpoint position under the corresponding algorithm is obtained, and the difficulty that the front edge midpoint position of the complex waveform of the inland water body is difficult to accurately find in the previous waveform re-tracking algorithm is effectively solved; and finally, IMP values under four different threshold levels are calculated by using the front edge position, and the four IMP values are compared to determine the maximum IMP value as the result of the AMWRT algorithm. Compared with an existing waveform re-tracking algorithm, the algorithm has the advantages of higher satellite altimetry data processing precision, wider application range in inland waters and the like.

A method for determining the position of the intersection of altimetry satellite tracks based on the minimum distance method, comprising the following steps: ① import satellite altimetry data; ② use the minimum latitude point to separate ascending orbit data and descending orbit data, and adjust the longitude of the arc to ‑180° ‑360°; ③ preliminarily judge whether the intersection point exists; ④ use the minimum distance method to obtain the two points with the closest distance between the ascending orbit and the descending orbit, and take 5 data points before and after these two points to obtain two binary ⑤ The first and last two points of the two arrays are connected to obtain a straight line, and four data points near the intersection of the two-day straight line are obtained; ⑥ The latitude and longitude coordinates and elevation of the exact intersection point are obtained by linear interpolation. This method can accurately determine the position of the ground intersection of altimetry satellite orbits, ensure the stability of calculating the elevation change of the polar ice sheet, and is suitable for studying the exact position of the intersection of multi-generation satellites and high latitude regions.

The invention discloses a method for making satellite altimetry data average sea surface height products based on network function interpolation. The specific steps include: data preprocessing, grid size and center point determination, grid interpolation, and fine interpolation. The invention is convenient for the computer to automatically divide the grid, has obvious statistical characteristics, and can reflect the spatial distribution law of the ocean gravity field in terms of physical characteristics, and the ocean gravity field is positively correlated with the average sea surface height, fully considering the physical characteristics of the sea level, and can Improved accuracy and spatial resolution of mean sea height products.

The invention discloses a method for improving the accuracy of a satellite altimetry cross point. The method comprises the following steps of: calculating the distance and the data density between adjacent data points on each track; selecting a track with the smallest data density in all the tracks as a reference track and the other tracks as tracks to be averaged; selecting the frequency of interpolation polynomial for each track to be averaged; fitting the tracks to be averaged by the polynomials; calculating the longitude, the latitude and the sea level height of a point, closest to each reference point, on each fitted curve; calculating the longitude, the latitude and the sea level height of a data point on an averaged track; circularly judging whether a cross point is generated and calculating the longitude, the latitude and the sea level height of the cross point; and converting the judgment of the cross point between two tracks into judgment on whether a connecting line section between two adjacent height measurement data points in any track forms an intersection point with a connecting line section between two adjacent data points in the rest tracks, wherein the intersection point is taken as the cross point. Compared with conventional methods, the method has the characteristics of high accuracy, easiness in calculation, wide application range, high operation efficiency and the like.

The present invention provides a sea area gravity anomaly inversion method and system based on satellite altimetry data. The method includes: calculating the sea surface height gradient of the sub-satellite point according to the sea surface height data collected by the satellite altimeter at the sub-satellite point in the preset sea area, According to the position of the sub-satellite point, the model vertical deviation gradient of the sub-satellite point is calculated, and the sea surface height gradient of the sub-satellite point is subtracted from the model vertical line deviation gradient to obtain the remaining gradient of the sub-satellite point; The remaining gradient of the next point is converted into a vertical deviation grid to obtain the remaining vertical deviation of the grid; the residual gravity anomaly of the grid is calculated according to the remaining vertical deviation of the grid, and the model gravity anomaly of the grid is calculated based on the gravity field model. Add the model gravity anomaly of the grid to the remaining gravity anomaly to obtain the gravity anomaly of the sea area of ​​the grid. The present invention realizes obtaining accurate sea area gravity anomalies through rigorous theoretical derivation.

The invention discloses a nonlinear method for inverting high-resolution submarine topography from local sea area disturbing gravity data. The method comprises the following steps: 1, acquiring ocean disturbing gravity data and water depth data of a south-north measuring line and an east-west measuring line of a local sea area; 2, establishing a local sea area south-north survey line and east-west survey line observation equation set; 3, solving a nonlinear correlation coefficient in the observation equation set of the south-north survey line and the east-west survey line of the local sea area by adopting a least square fitting method; 4, nonlinear correlation parameters between the local sea area disturbance gravity and the submarine topography are obtained; and 5, inverting grid sea depth data corresponding to the local sea area. According to the method, two mutually perpendicular gravity and water depth sequence measuring lines are obtained by carrying out south-north and east-west ship load water depth measurement in a local area, and the two measuring lines are used for fitting to obtain south-north and east-west nonlinear correlation function parameters; and then the parameters are combined with satellite altimetry gravity data to invert the submarine topography of the corresponding area.

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.