Sea surface height inspection equipment layout method based on interference imaging altimeter

Abstract

The invention discloses a sea surface height inspection equipment layout method based on an interference imaging altimeter, which belongs to the technical field of altimeter inspection, is used for sea surface height inspection equipment layout, and comprises the following steps: obtaining position data of a Glider buoy and temperature-salinity-depth data of a profile observed by the Glider buoy, putting the Glider buoy and a GNSS buoy in the same area at the same time before a satellite passes, and putting the GNSS buoy in the same area at the same time; the synchronous observation of the GNSS and the Glider buoy is realized; and carrying out position positioning when the Glider buoy descends and ascends to outcrop, carrying out matching with a grid position in a swath range observed by a satellite, and carrying out sea surface height inversion according to temperature-salinity-depth data of a section obtained through observation of the Glider buoy. The method adapts to data characteristics of different resolutions of the interference imaging altimeter, sea surface height synchronous observation of satellite data with different spatial resolutions under satellite transit is realized, and calibration inspection of the altimeter satellite is accurately completed.

Description

TECHNICAL FIELD

[0001] The application discloses a sea surface height inspection equipment layout method based on an interferometric imaging altimeter, and belongs to the technical field of altimeter inspection. BACKGROUND

[0002] The calibration inspection of the prior art for the altimeter is mainly carried out for a traditional altimeter, but the traditional altimeter only has an observation of a substar point, and meanwhile, the substar point footprint of the traditional altimeter is 3 km in range, which is relatively large in range scale. The inspection for the traditional altimeter is mainly carried out through a process of time exchange space or distance derivation, but for the interferometric imaging altimeter, a research should be conducted on a sea surface height inspection equipment layout method and system for the interferometric imaging altimeter according to the swath range and the resolution of data. At present, a feasibility research on the interferometric imaging altimeter inspection method based on the existing altimeter inspection method is carried out, a theoretical analysis on the interferometric imaging altimeter inspection method based on the specific volume height is carried out, and the basic conditions of the method under different meteorological conditions are analyzed, but how to use these elements to complete the sea surface height inspection equipment layout for the interferometric imaging altimeter is still not solved. SUMMARY

[0003] The application aims to provide a sea surface height inspection equipment layout method based on an interferometric imaging altimeter, so as to solve the problem that the swath range and the resolution of data are not combined in the sea surface height inspection of the interferometric imaging altimeter in the prior art.

[0004] A sea surface height inspection equipment layout method based on an interferometric imaging altimeter, comprising: S1. According to the prediction of the wind and the vortex in the observation area, a time period with small wind wave in the time period when the vortex passes is selected to carry out the sea surface height calibration inspection; S2. The instantaneous sea surface height to the height and spatial position information of the reference ellipsoid of the observation point is obtained by using the GNSS buoy observation, the position data of the Glider buoy and the temperature-salinity-depth data of the section observed by the Glider buoy are obtained; S3. Before the satellite passes, the Glider buoy and the GNSS buoy are simultaneously and regionally cast, and the synchronous observation of the GNSS buoy and the Glider buoy is realized; S4. The three-dimensional position relationship observation is carried out, and the observation data set is formed within the satellite passing time; S5. The position positioning is carried out when the Glider buoy descends and ascends the outcrop, the grid position in the swath range of the satellite observation is matched, and the sea surface height is inverted by using the temperature-salinity-depth data of the section observed by the Glider buoy; S6. For data in a 250m grid, a time-for-space approach is used, and the altitude and spatial location information from GNSS buoy observations are used for verification. For the 2km grid data, the sea surface height was retrieved by inverting the temperature, salinity, and depth profile data observed by the Glider buoy and verified using the spatial averaging method.

[0005] S1 includes S1.1, which analyzes the root mean square error, error and correlation coefficient inside and outside the vortex using historical data or reanalysis model data for the observation area to be tested, and determines the location to carry out the calibration test by combining the calibration test accuracy under different vortex conditions in the observation area. S1.2. Using historical data or reanalysis model data, conduct calibration verification to analyze the relationship between sea surface height and specific volume height under different wind speed conditions at different locations, and determine the wind speed section for calibration verification. S1.3 Analyze the differences in sea surface height and specific volume height in the observation area during different seasons to determine the time for calibration testing.

[0006] S2 includes the specific volume height calculated by combining temperature, salinity, and depth data from Glider buoy observations. : ; ; In the formula, It is the gravitational constant. It's atmospheric pressure. It is the pressure at the bottom of the sea. It has a salinity of 35, a temperature of 0 degrees Celsius, and a pressure of [missing information]. The volume below, It is a high specific volume anomaly. It is the depth of the sea. It is a reference density. It's a density anomaly. It's about depth.

[0007] S3 includes S3.1, which combines the position and time of satellite overpass and deploys two devices simultaneously in the ocean before the time window arrives. The GNSS buoy is anchored in the center of the observation area, while the Glider buoy drifts to the bottom. After deployment, the staff immediately move away from the deployment area. S3.2 Conduct a GNSS buoy observation and Glider buoy profile observation in the same area, and locate the difference between sea surface height and specific volume height in the observation area based on the results of the profile observation inversion. S3.3 Before the satellite passes overhead, control the Glider buoy to rise to the sea surface and send a signal for positioning, and synchronize with the positioning position of the GNSS buoy. Use the Glider buoy's own power to deploy the two devices in the area within the swath range around the GNSS.

[0008] The location of the difference between sea level and specific volume height in the observation area includes: ; In the formula, It is the initial absolute value of sea surface height measured by GNSS buoys. It is the initial value of the specific volume height.

[0009] S4 includes S4.1, ensuring that the GNSS buoy anchoring position is within the swath space observed by the satellite; S4.2 At the moment of satellite transit, the GNSS buoy transmits a signal to obtain its three-dimensional spatial information. The horizontal position of the GNSS buoy is obtained through the latitude and longitude information of the three-dimensional spatial information. The horizontal position of the GNSS buoy is matched with the altimeter observation grid to obtain the matched horizontal position of the GNSS buoy. The elevation information is compared with the satellite observation data of the matched grid to obtain the average difference after multiple comparisons. The systematic error of the altimeter error is determined, and the altimeter verification is completed. The elevation information is the vertical position of the GNSS buoy to the reference ellipsoid.

[0010] S5 includes Glider buoys that drift on the ocean floor after being deployed and before satellites pass overhead; As the satellite approaches, the Glider buoy surfaces to determine its location in space and uses its own energy and power to propel itself to the area of ​​the swath space observed by the satellite. As the satellite passes overhead, the Glider buoy completes its descent and ascent, conducts two temperature, salinity, and depth (TDM) profile observations, obtains TDM data at different depths, calculates its specific volume height, and locates its position after ascent, thus obtaining spatial information about the Glider buoy's descent and ascent processes.

[0011] S6 includes assimilating the temperature, salinity, and depth profile data observed by the Glider buoy into the same profile, analyzing the spatial position information of the two contacts with the water surface during the dive and ascent, and if the two contacts are in the same grid, then the grid used for altimeter data calibration and verification by the Glider buoy is used as the grid for altimeter data verification; if the two contacts belong to different grids, then the grid where the center of the two spatial positions is located is used as the grid for altimeter data verification. The data observed by the Glider buoy is subjected to specific volume height calculation to obtain an initial value of specific volume height, which is converted into absolute sea level height required for the test, and the test is completed.

[0012] Compared with the prior art, the application has the following beneficial effects: the application is suitable for the data characteristics of different resolutions of the interferometric altimeter, realizes the synchronous observation of the sea level height under the satellite transit of the satellite data of different spatial resolutions, and accurately completes the calibration test of the altimeter satellite. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is the difference between the sea level height and the specific volume height under different wind speeds in the test area; Figure 2 is the difference between the sea level height and the specific volume height under the U direction wind speed in the test area; Figure 3 is the difference between the sea level height and the specific volume height under the V direction wind speed in the test area; Figure 4 is the difference between the root mean square errors of the sea level height and the specific volume height in different months in the vortex inside and outside the test area; Figure 5 is the difference between the errors of the sea level height and the specific volume height in different months in the vortex inside and outside the test area; Figure 6 is the difference between the correlation coefficients of the sea level height and the specific volume height in different months in the vortex inside and outside the test area; Figure 7 is the difference between the correlation coefficients of the sea level height and the specific volume height under different wind speeds in the test area; Figure 8 is the difference between the correlation coefficients of the sea level height and the specific volume height under the U direction wind speed in the test area; Figure 9 is the difference between the correlation coefficients of the sea level height and the specific volume height under the V direction wind speed in the test area; Figure 10 is the relationship between the sea level height and the specific volume height; Figure 11 is the deployment scheme of the GNSS buoy and the Glider when the satellite transits. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and advantages of the application more clear, the technical scheme in the application is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0015] A sea surface height verification device arrangement method based on an interferometric altimeter, comprising: S1. According to the predicted situation of the wind and vortex in the observation area, a time period with small wind wave in the time period when the vortex passes is selected to carry out sea surface height calibration verification; S2, using the GNSS buoy observation to obtain the instantaneous sea surface height to the height and spatial position information of the reference ellipsoid of the observation point, obtaining the position data of the Glider buoy and the temperature-salinity-depth data of the section observed by the Glider buoy; S3, before the satellite passes, the Glider buoy and the GNSS buoy are simultaneously and regionally launched to realize the synchronous observation of the GNSS buoy and the Glider buoy; S4, three-dimensional position relationship observation is carried out, and an observation data set is formed within the satellite passing time; S5, when the Glider buoy descends and ascends the outcrop, position positioning is carried out, and the grid position in the cutting range observed by the satellite is matched, the temperature-salinity-depth data of the section observed by the Glider buoy is used to carry out sea surface height inversion; S6, for the data of 250m grid, the method of time for space is adopted, and the height and spatial position information observed by the GNSS buoy is used for verification; For the data of 2km grid, the temperature-salinity-depth profile data observed by the Glider buoy is used, and the sea surface height is inverted by the method of spatial averaging for verification.

[0016] S1 includes S1.1, for the observation area to be verified, the root mean square error, error and correlation coefficient of the vortex inside and outside are analyzed by using historical data or reanalysis mode data, and the position of the calibration verification is determined according to the calibration verification accuracy under different vortex conditions in the observation area; S1.2, the relationship between sea surface height and specific volume height under different wind speed conditions in the position where the calibration verification is carried out is analyzed by using historical data or reanalysis mode data, and the wind speed section where the calibration verification is carried out is determined; S1.3, the difference of sea surface height and specific volume height in different seasons in the observation area is analyzed, and the time when the calibration verification is carried out is determined.

[0017] S2 includes calculating the specific volume height by combining the temperature-salinity-depth data of the section observed by the Glider buoy : ; ; In the formula, is the gravitational constant, is the atmospheric pressure, is the sea water bottom pressure, It has a salinity of 35, a temperature of 0 degrees Celsius, and a pressure of [missing information]. The volume below, It is a high specific volume anomaly. It is the depth of the sea. It is a reference density. It's a density anomaly. It's about depth.

[0018] S3 includes S3.1, which combines the position and time of satellite overpass and deploys two devices simultaneously in the ocean before the time window arrives. The GNSS buoy is anchored in the center of the observation area, while the Glider buoy drifts to the bottom. After deployment, the staff immediately move away from the deployment area. S3.2 Conduct a GNSS buoy observation and Glider buoy profile observation in the same area, and locate the difference between sea surface height and specific volume height in the observation area based on the results of the profile observation inversion. S3.3 Before the satellite passes overhead, control the Glider buoy to rise to the sea surface and send a signal for positioning, and synchronize with the positioning position of the GNSS buoy. Use the Glider buoy's own power to deploy the two devices in the area within the swath range around the GNSS.

[0019] The location of the difference between sea level and specific volume height in the observation area includes: ; In the formula, It is the initial absolute value of sea surface height measured by GNSS buoys. It is the initial value of the specific volume height.

[0020] S4 includes S4.1, ensuring that the GNSS buoy anchoring position is within the swath space observed by the satellite; S4.2 At the moment of satellite transit, the GNSS buoy transmits a signal to obtain its three-dimensional spatial information. The horizontal position of the GNSS buoy is obtained through the latitude and longitude information of the three-dimensional spatial information. The horizontal position of the GNSS buoy is matched with the altimeter observation grid to obtain the matched horizontal position of the GNSS buoy. The elevation information is compared with the satellite observation data of the matched grid to obtain the average difference after multiple comparisons. The systematic error of the altimeter error is determined, and the altimeter verification is completed. The elevation information is the vertical position of the GNSS buoy to the reference ellipsoid.

[0021] S5 includes Glider buoys that drift on the ocean floor after being deployed and before satellites pass overhead; As the satellite approaches, the Glider buoy surfaces to determine its location in space and uses its own energy and power to propel itself to the area of ​​the swath space observed by the satellite. When the satellite passes, the Glider buoy completes the diving and rising process, carries out two temperature and salinity profile observations, obtains temperature and salinity data at different depths, completes the calculation of the specific volume height, and carries out position positioning after the rising is completed, so as to obtain the spatial information of the diving and rising process of the Glider buoy.

[0022] S6 comprises: assimilating the temperature and salinity profile data observed by the Glider buoy into the same profile, analyzing the spatial position information of the two times of contacting the water surface through diving and rising, if both times are in the same grid, using the grid of the Glider buoy for realizing the altimeter data calibration and verification as the grid for carrying out the altimeter data verification, if the two times belong to different grids, using the grid where the centers of the two times of spatial positions are located as the grid for carrying out the altimeter data verification; The data observed by the Glider buoy is subjected to specific volume height calculation, so as to obtain the initial value of the specific volume height, convert into the absolute sea surface height required for verification, and complete the verification.

[0023] In the embodiment of the application, the relationship analysis between the sea surface height and the specific volume height in the vortex inner region and the vortex outer region is carried out, as shown in Table 1.

[0024] Table 1, relationship between sea surface height and specific volume height in vortex inner region and vortex outer region ; By comparing the results in the vortex inner region and the results in the vortex outer region in Table 1, it can be found that the results in the vortex inner region are obviously improved, and in this case, the interferometric synthetic aperture radar altimeter verification is better carried out in the vortex inner region. However, because the spatial position of the vortex is not fixed, a station can be set at a fixed position, and the time of the common passage of the vortex and the satellite is waited for to carry out the verification.

[0025] The historical data or reanalysis mode data is used to carry out the relationship research between the sea surface height and the specific volume height under different wind speed conditions in the verification development region, the wind speed section more suitable for carrying out the verification in the experimental region is determined, and the difference conditions of the sea surface height and the specific volume height under different wind speeds in the experimental region are obtained as shown in Figure 1 , the difference conditions of the sea surface height and the specific volume height under the V direction wind speed in the experimental region are as shown in Figure 2 , and the difference conditions of the sea surface height and the specific volume height under the V direction wind speed in the experimental region are as shown in Figure 3 In the experimental region, the frequency distribution of the difference between the sea surface height and the specific volume height under different wind speeds and the U and V direction wind speeds is carried out, and when the V direction wind speed is about 9 m / s, part of the abnormal data appears, and at this time, the U direction wind speed is about 10 m / s. In most cases in the experimental region, the U direction wind speed is concentrated around-2 m / s, and the V direction wind speed is concentrated around 0 m / s.

[0026] The difference of the sea level height and the specific volume height in different seasons in the region is analyzed, the time when the calibration test should be carried out is determined, and the difference of the root mean square error of the sea level height and the specific volume height in different months in the test area is shown in Figure 4 The difference of the error of the sea level height and the specific volume height in different months in the test area is shown in Figure 5 The difference of the correlation coefficient of the sea level height and the specific volume height in different months in the test area is shown in Figure 6 For the vortex area, the vortex area and the vortex area, the change rule of different indicators with time is basically the same, and for the test, the selection of different areas is more important, but in time, March is not suitable for test, and the effect of August-November is better. The difference of the correlation coefficient of the sea level height and the specific volume height in different months in the test area is shown in Figure 7 The difference of the correlation coefficient of the sea level height and the specific volume height in different months in the test area is shown in Figure 8 The difference of the correlation coefficient of the sea level height and the specific volume height in different months in the test area is shown in Figure 9 The solid line in the figure is the correlation, and the dotted line is the wind speed, and it can be seen that there is a negative correlation between the two, so that the correlation is found to be poor with the increase of the wind speed, but only the overall trend.

[0027] The relationship between the sea level height and the specific volume height is shown in Figure 10 The deployment scheme of GNSS buoy and glider when the satellite passes is shown in Figure 11 The sea level height in the satellite data is obtained by subtracting the satellite positioning height from the satellite observation height, which is the distance from the instantaneous sea level to the satellite positioning reference surface-reference ellipsoid at the moment of satellite observation. And the specific volume height is the height change caused by the change of density in the observation reference surface, so it is not an absolute height, but only a height change. The sea level height test based on the specific volume height is carried out by analyzing the difference between the sea level height and the specific volume height in different pixels of the interferometric altimeter.

[0028] The minimum observation unit of the application is one GNSS and one glider, but any device can be used for extension network observation, and each observation device can be further expanded, as long as the running safety distance between devices is guaranteed, and the absolute height difference of the glider observation data can be realized by using GNSS.

[0029] The above examples are only used for illustrating the technical solutions of the present application, and are not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing examples can be modified, or some or all of the technical features can be replaced by equivalent replacements, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for deploying sea surface height measurement equipment based on an interferometric imaging altimeter, characterized in that, include: S1. Based on the wind and vortex prediction in the observation area, select a period of time with small winds and waves during the time the vortex passes through to carry out sea surface height calibration verification. S2. Use GNSS buoys to observe and obtain the instantaneous sea surface height to the height and spatial location information of the reference ellipsoid at the observation point, and obtain the position data of the Glider buoy and the temperature, salinity and depth data of the profile obtained by the Glider buoy observation; S3. Before the satellite passes overhead, Glider buoys and GNSS buoys will be deployed simultaneously in the same area to achieve synchronous observation between GNSS buoys and Glider buoys; S4. Conduct three-dimensional positional relationship observations and generate an observation dataset during the satellite's transit time; The S5 and Glider buoys are positioned when they descend and rise, and their positions are matched with the grid positions within the swath area observed by satellite. The sea surface height is then retrieved using the temperature, salinity, and depth data of the profile obtained from the Glider buoy observations. S6. For data in a 250m grid, a time-for-space approach is used, and the altitude and spatial location information from GNSS buoy observations are used for verification. For the 2km grid data, the sea surface height was retrieved by inverting the temperature, salinity, and depth profile data observed by the Glider buoy and verified using the spatial averaging method.

2. The method for deploying a sea surface height measurement device based on an interferometric imaging altimeter according to claim 1, characterized in that, S1 includes S1.1, which analyzes the root mean square error, error and correlation coefficient inside and outside the vortex using historical data or reanalysis model data for the observation area to be tested, and determines the location to carry out the calibration test by combining the calibration test accuracy under different vortex conditions in the observation area. S1.

2. Using historical data or reanalysis model data, conduct calibration verification to analyze the relationship between sea surface height and specific volume height under different wind speed conditions at different locations, and determine the wind speed section for calibration verification. S1.3 Analyze the differences in sea surface height and specific volume height in the observation area during different seasons to determine the time for calibration testing.

3. The method for deploying a sea surface height measurement device based on an interferometric imaging altimeter according to claim 2, characterized in that, S2 includes the specific volume height calculated by combining temperature, salinity, and depth data from Glider buoy observations. : ； ； In the formula, It is the gravitational constant. It's atmospheric pressure. It is the pressure at the bottom of the sea. It has a salinity of 35, a temperature of 0 degrees Celsius, and a pressure of [missing information]. The volume below, It is a high specific volume anomaly. It is the depth of the sea. It is a reference density. It's a density anomaly. It's about depth.

4. The method for deploying a sea surface height measurement device based on an interferometric imaging altimeter according to claim 3, characterized in that, S3 includes S3.1, which combines the position and time of satellite overpass and deploys two devices simultaneously in the ocean before the time window arrives. The GNSS buoy is anchored in the center of the observation area, while the Glider buoy drifts to the bottom. After deployment, the staff immediately move away from the deployment area. S3.2 Conduct a GNSS buoy observation and Glider buoy profile observation in the same area, and locate the difference between sea surface height and specific volume height in the observation area based on the results of the profile observation inversion. S3.3 Before the satellite passes overhead, control the Glider buoy to rise to the sea surface and send a signal for positioning, and synchronize with the positioning position of the GNSS buoy. Use the Glider buoy's own power to deploy the two devices in the area within the swath range around the GNSS.

5. The method for deploying a sea surface height measurement device based on an interferometric imaging altimeter according to claim 4, characterized in that, The location of the difference between sea level and specific volume height in the observation area includes: ； In the formula, It is the initial absolute value of sea surface height measured by GNSS buoys. It is the initial value of the specific volume height.

6. The method for deploying a sea surface height measurement device based on an interferometric imaging altimeter according to claim 5, characterized in that, S4 includes S4.1, ensuring that the GNSS buoy anchoring position is within the swath space observed by the satellite; S4.2 At the moment of satellite transit, the GNSS buoy transmits a signal to obtain its three-dimensional spatial information. The horizontal position of the GNSS buoy is obtained through the latitude and longitude information of the three-dimensional spatial information. The horizontal position of the GNSS buoy is matched with the altimeter observation grid to obtain the matched horizontal position of the GNSS buoy. The elevation information is compared with the satellite observation data of the matched grid to obtain the average difference after multiple comparisons. The systematic error of the altimeter error is determined, and the altimeter verification is completed. The elevation information is the vertical position of the GNSS buoy to the reference ellipsoid.

7. The method for deploying a sea surface height measurement device based on an interferometric imaging altimeter according to claim 6, characterized in that, S5 includes Glider buoys that drift on the ocean floor after being deployed and before satellites pass overhead; As the satellite approaches, the Glider buoy surfaces to determine its location in space and uses its own energy and power to propel itself to the area of ​​the swath space observed by the satellite. As the satellite passes overhead, the Glider buoy completes its descent and ascent, conducts two temperature, salinity, and depth (TDM) profile observations, obtains TDM data at different depths, calculates its specific volume height, and locates its position after ascent, thus obtaining spatial information about the Glider buoy's descent and ascent processes.

8. The method for deploying a sea surface height measurement device based on an interferometric imaging altimeter according to claim 7, characterized in that, S6 includes assimilating the temperature, salinity, and depth profile data observed by the Glider buoy into the same profile, analyzing the spatial position information of the two contacts with the water surface during the dive and ascent, and if the two contacts are in the same grid, then the grid used for altimeter data calibration and verification by the Glider buoy is used as the grid for altimeter data verification; if the two contacts belong to different grids, then the grid where the center of the two spatial positions is located is used as the grid for altimeter data verification. The specific volume height was calculated from the data observed by the Glider buoy, and the initial value of the specific volume height was obtained. This value was then converted into the absolute sea level height required for the test, thus completing the test.

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