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 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.

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 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 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 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 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.