CN101713649A

CN101713649A - Disturbing gravity-based quasi-geoid land-sea seamless splicing method

Info

Publication number: CN101713649A
Application number: CN200910210687A
Authority: CN
Inventors: 张利明; 李斐; 章传银; 柯宝贵
Original assignee: Chinese Academy of Surveying and Mapping
Current assignee: Chinese Academy of Surveying and Mapping
Priority date: 2009-11-05
Filing date: 2009-11-05
Publication date: 2010-05-26
Anticipated expiration: 2029-11-05
Also published as: CN101713649B

Abstract

The invention discloses a geoid-like seamless splicing method of land and sea based on disturbed gravity. This method makes full use of the physical characteristics of disturbance gravity that is not limited by the local elevation datum, uses the unified earth reference ellipsoid as the coordinate reference frame, and uses the global navigation and positioning system (GNSS) with the unified land and sea datum and gravity data to calculate the unified disturbance of land and sea Gravity, which introduces the unified disturbance gravity of land and sea into the more rigorous algorithm proposed by the present invention, so as to realize the seamless splicing of land and sea similar to the geoid. Different from the existing fitting algorithm that uses gravity anomaly and Stokes formula to calculate land-sea elevation anomaly, this method is rigorous in theory and can effectively eliminate the result error caused by the singularity of kernel function.

Description

A geoid-like seamless stitching method of land and sea based on disturbed gravity

技术领域technical field

本发明是一种基于扰动重力的似大地水准面陆海无缝拼接方法，属于“大地测量与测量工程”学科中的“物理大地测量”技术领域。The invention relates to a geoid-like sea-sea seamless splicing method based on disturbed gravity, and belongs to the technical field of "physical geodesy" in the discipline of "geodesy and surveying engineering".

背景技术Background technique

陆海似大地水准面拼接是目前物理大地测量学科领域中的一个热点和难点。目前陆海似大地水准面拼接的主要方法有最小二乘频谱组合法、迭代FFT方法、最小二乘配置法等。近年来国内发展了一种“扩展法”，其基本原理是通过重力异常分别计算陆地、海岸线附近和海洋的似大地水准面，然后利用海岸线附近与陆地重合的似大地水准面反算拟合参数，最后利用所求的拟合参数进行海洋似大地水准面校正，从而形成陆海无缝拼接的似大地水准面。Land-sea quasi-geoid stitching is a hot and difficult point in the field of physical geodesy. At present, the main methods of land-sea quasi-geoid stitching include least squares spectrum combination method, iterative FFT method, least squares collocation method, etc. In recent years, an "extended method" has been developed in China, the basic principle of which is to calculate the quasi-geoid of the land, near the coastline, and the ocean through gravity anomalies, and then use the quasi-geoid near the coastline that coincides with the land to inversely calculate the fitting parameters , and finally use the obtained fitting parameters to correct the ocean quasi-geoid, so as to form a quasi-geoid seamlessly joined by land and sea.

事实上，现有陆海似大地水准面无缝拼接方法都是基于“重力异常”这个物理量。同时重力异常一般是基于局部高程基准确定，这样就形成基于多种局部高程基准下的“重力异常”，利用这种“重力异常”计算的陆海似大地水准面势必会出现基准不统一问题。仅利用数学上的拟合简单处理这些不统一问题显然没有物理理论支持。而直接利用“扰动重力”这个不受局部高程基准限制的物理量来实现似大地水准面陆海无缝拼接至今还无人涉足。As a matter of fact, the existing sea-land quasi-geoid seamless stitching methods are all based on the physical quantity of "gravity anomaly". At the same time, gravity anomalies are generally determined based on local elevation datums, thus forming “gravity anomalies” based on various local elevation datums, and using such “gravity anomalies” to calculate land-ocean quasi-geoids will inevitably have the problem of inconsistent datums. Simply using mathematical fitting to simply deal with these non-uniform problems obviously has no physical theory support. However, the direct use of "disturbed gravity", a physical quantity that is not limited by the local elevation datum, to realize the seamless stitching of land and sea on the quasi-geoid has not been set foot so far.

发明内容Contents of the invention

针对技术背景中的问题，本发明提出利用扰动重力来实现似大地水准面的陆海无缝拼接方法，并提出了利用扰动重力计算似大地水准面的奇异点处理方法。Aiming at the problems in the technical background, the present invention proposes a method for realizing seamless stitching of land and sea with quasi-geoid by using disturbed gravity, and proposes a singular point processing method for calculating quasi-geoid by using disturbed gravity.

本发明的目的可以通过以下技术方案来实现：一种基于扰动重力的似大地水准面陆海无缝拼接方法，其特征在于，该方法包括以下步骤：The object of the present invention can be achieved through the following technical solutions: a method for seamless stitching of quasi-geoid land and sea based on disturbed gravity, characterized in that the method comprises the following steps:

(1)将陆海重力数据预处理为陆海扰动重力数据；(1) Preprocessing land and sea gravity data into land and sea disturbance gravity data;

(2)陆海统一的扰动重力数据格网化处理；(2) Unified grid processing of disturbance gravity data for land and sea;

(3)陆海统一的重力似大地水准面计算；(3) Unified gravity quasi-geoid calculation for land and sea;

(4)利用陆地及海岸线附近GPS水准数据提取陆海重力似大地水准面系统差；(4) Use the GPS leveling data near the land and coastline to extract the land-sea gravity-like geoid system difference;

(5)进行系统差拟合改正，实现一种基于扰动重力的似大地水准面的陆海无缝拼接。(5) Carry out system error fitting corrections to realize a seamless sea-land splicing based on a geoid-like sea level based on disturbed gravity.

所述步骤(1)中，其主要特征在于，包括以下内容：In the described step (1), its main feature is to include the following:

a.将海洋重力场数据处理为与陆地基准一致的海洋扰动重力数据，利用船测扰动重力数据检核海洋扰动重力数据是否有系统差，如果有，则进行系统差拟合改正；a. Process the ocean gravity field data into ocean disturbance gravity data that is consistent with the land reference, use the ship survey disturbance gravity data to check whether the ocean disturbance gravity data has systematic differences, and if so, perform system difference fitting correction;

b.基于现有高精度地球重力场模型对地面扰动重力与经a步骤修正过的海洋扰动重力数据进行系统差分析，并对海洋扰动重力进行系统差改正；b. Based on the existing high-precision earth gravity field model, the system difference analysis is performed on the ground disturbance gravity and the ocean disturbance gravity data corrected in step a, and the system difference correction is performed on the ocean disturbance gravity;

c.将海岸带扰动重力数据经同一重力场模型系统差改正后处理为与陆地基准一致海岸带扰动重力数据。c. The coastal zone disturbance gravity data is corrected by the same gravity field model system difference and processed into the coastal zone disturbance gravity data consistent with the land reference.

所述步骤(2)中，其主要特征在于，进行陆海统一的布格扰动重力格网化处理，并判断格网化布格扰动重力数据在接边处是否有跳变现象，如果陆海基准一致，那么经格网化处理的陆海统一的扰动重力数据在接边处应无跳变现象；如有跳变现象，则应根据陆地扰动重力数据为标准探测系统差大小，并进行相应的系统差改正。In the step (2), its main feature is to carry out the unified Bouguer disturbance gravity grid processing of land and sea, and judge whether there is a jump phenomenon in the gridded Bouguer disturbance gravity data at the edge, if the land and sea If the benchmarks are consistent, then the unified land-sea disturbance gravity data processed by the grid should have no jump phenomenon at the border; The system error correction.

所述步骤(3)中，其主要特征在于，提出了一种Hotine积分奇异点的处理方法，奇异点处理公式为In described step (3), its main feature is that, proposed a kind of processing method of Hotine integral singular point, singular point processing formula is

$δN δ N = = \frac{R R \cdot &Center Dot; \overset{&OverBar; &OverBar;}{δg δ g}}{22 γ γ} \{\begin{matrix} cos cos (({ψ ψ}_{00})) + + \frac{33 {cos cos}^{22} (({ψ ψ}_{00}))}{44} + + cos cos (({ψ ψ}_{00})) ln ln [[11 + + csc csc ((\frac{{ψ ψ}_{00}}{22}))]] \\ + + 22 ln ln [[cos cos ((\frac{{ψ ψ}_{00}}{44})) + + sin sin ((\frac{{ψ ψ}_{00}}{44}))]] + + ln ln [[sin sin ((\frac{{ψ ψ}_{00}}{22}))]] + + 22 sin sin ((\frac{{ψ ψ}_{00}}{22})) - - \frac{77}{44} \end{matrix}\}$

上式中，δN为奇异区域的高程异常影响，R为地球平均半径，δg为奇异区域的扰动重力平均值，γ为正常重力，ψ₀为小球冠球面角距。由小球冠与经纬差格网(Δλ为经度格网间距，

为纬度，Δ

为纬度格网间距)的等面积关系In the above formula, δN is the elevation anomaly effect in the singular area, R is the average radius of the earth, δg is the average value of the disturbance gravity in the singular area, γ is the normal gravity, and ψ ₀ is the angular distance of the small spherical cap. From the small spherical cap and the longitude-latitude difference grid (Δλ is the longitude grid spacing,

is the latitude, Δ

is the equal-area relationship of latitude grid spacing)

可得到ψ₀的计算公式，即The calculation formula of ψ ₀ can be obtained, namely

与现有方法相比，本发明基于扰动重力数据完成似大地水准面的陆海无缝拼接，理论上不存在现有利用重力异常数据的高程基准不统一的问题，同时本发明提出的奇异点处理方法较之原有方法具有更加严密的结果。Compared with the existing method, the present invention completes the geoid-like seamless splicing of land and sea based on the disturbed gravity data. Theoretically, there is no problem that the existing elevation reference using gravity anomaly data is not uniform. At the same time, the singular point proposed by the present invention The processing method has more rigorous results than the original method.

附图说明Description of drawings

图1为一种基于扰动重力的似大地水准面陆海无缝拼接实施方案流程。Fig. 1 is a process flow of an implementation scheme of quasi-geoid land-sea seamless splicing based on disturbed gravity.

具体实施方式Detailed ways

一、陆海重力数据预处理1. Preprocessing of land and sea gravity data

本文所指的陆海重力数据主要包括陆地重力数据、海岸线重力数据、海洋重力数据。理论上讲，如果这三种数据都是基于统一的框架(重力基准框架、三维椭球参考框架等)，那么这三种数据不存在系统差，即完全可以实现无缝拼接。事实上，由于重力基准偏差以及参考椭球不同等多种因素会导致三种不同数据存在拼接差，即使在一种类型数据中也存在系统偏差，例如我国早期重力数据与我国2000重力基准就存在最大达十几毫伽的系统偏差，在海洋部分的重力数据由于来源不同所导致的系统偏差亦有很大的不同。因此需要将不同的重力数据处理为统一基准。The land and sea gravity data referred to in this paper mainly include land gravity data, coastline gravity data, and ocean gravity data. Theoretically speaking, if these three data are based on a unified frame (gravity reference frame, three-dimensional ellipsoid reference frame, etc.), then there is no systematic difference in these three data, that is, seamless splicing can be achieved completely. In fact, due to various factors such as the deviation of the gravity datum and the difference in the reference ellipsoid, there will be differences in splicing of the three different data, and there will be systematic deviations even in one type of data, for example, the early gravity data of my country and the 2000 gravity datum of my country The maximum system deviation is more than ten milligal, and the gravity data in the ocean part is also very different due to different sources. Therefore, different gravity data need to be processed into a unified benchmark.

首先需要将陆地重力数据、海岸带重力数据、海洋重力数据采用本领域公知的扰动重力定义公式计算为理论上基准一致的扰动重力；然后利用船测扰动重力点值数据检核卫星测高扰动重力数据的精度(船测扰动重力数据精度高于卫星测高扰动重力)，进行系统偏差提取，即计算船测扰动重力与卫星测高扰动重力数据的系统差，并对卫星测高扰动重力数据系统差改正(常数改正)，使之与船测扰动重力点值数据不存在系统差；陆地与海岸带扰动重力点值数据以及海洋扰动重力数据应基于某一高精度地球重力场模型(例如EGM2008)分别进行系统差分析与改正，即采用利用地球重力场模型导出的扰动重力数据与以上三种扰动重力数据相比较，则得到统计意义上的系统偏差值，并利用该值进行系统差改正(常数校正)；最后则形成陆地、海岸带与海洋扰动重力数据。Firstly, the land gravity data, coastal zone gravity data, and ocean gravity data need to be calculated by using the well-known disturbance gravity definition formula in the field to obtain a theoretically consistent disturbance gravity; The accuracy of the data (the accuracy of the ship survey disturbance gravity data is higher than the satellite altimetry disturbance gravity data), the system deviation extraction is performed, that is, the system difference between the ship survey disturbance gravity data and the satellite altimetry disturbance gravity data is calculated, and the satellite altimetry disturbance gravity data system Correction of difference (constant correction) so that there is no systematic difference with ship survey disturbance gravity point value data; land and coastal zone disturbance gravity point value data and ocean disturbance gravity data should be based on a high-precision earth gravity field model (such as EGM2008) Carry out systematic difference analysis and correction respectively, that is, use the disturbance gravity data derived from the earth's gravity field model to compare with the above three kinds of disturbance gravity data, then get the systematic deviation value in the statistical sense, and use this value to correct the system difference (constant Correction); Finally, the land, coastal zone and ocean disturbance gravity data are formed.

二、陆海统一的扰动重力数据格网化处理2. Unified grid processing of disturbance gravity data for land and sea

将第一步处理的陆地、海岸带以及海洋扰动重力点值数据(在此可以将海洋格网数据看成点值数据处理)经重力归算后分别得到点值布格扰动重力，对其进行粗差探测(可选用多种方法)并选择合适的拟合方法将点值布格扰动重力格网化处理，处理为等间距经纬格网数值模型，然后利用画图软件绘制等值线图，分析在陆海接边区域是否存在跳变现象(本发明所指的跳变类似于曲面函数在某一界面的不连续的现象)。如有，则利用部分陆海重合区域数据计算系统差(如果没有重合区域可以根据布格扰动重力等值线图走势适当外延到海洋分析系统差)并以陆地布格扰动重力数据为标准改正海洋重力数据(常数改正)。完成改正后则形成陆海一致的布格扰动重力格网数据，再通过恢复格网布格改正和地形改正从而形成所需要的陆海一致的扰动重力格网数据。The land, coastal zone and ocean disturbance gravity point value data processed in the first step (here the ocean grid data can be regarded as point value data processing) are respectively obtained after gravity reduction and the point value Bouguer disturbance gravity is obtained. Gross error detection (multiple methods can be selected) and appropriate fitting methods are used to process the point value Bouguer disturbance gravity grid into a numerical model of an equidistant latitude and longitude grid, and then use drawing software to draw contour maps for analysis. Whether there is a jump phenomenon in the land-sea boundary area (the jump referred to in the present invention is similar to the discontinuity phenomenon of a surface function at a certain interface). If there is, use the data of part of the land-ocean overlapping area to calculate the system difference (if there is no overlapping area, it can be properly extended to the ocean analysis system difference according to the trend of the Bouguer disturbance gravity contour map) and correct the ocean based on the land Bouguer disturbance gravity data. Gravity data (constant correction). After the correction is completed, the land-sea consistent Bouguer disturbance gravity grid data will be formed, and then the required land-sea consistent disturbance gravity grid data will be formed by restoring the grid Bouguer correction and terrain correction.

三、陆海统一的重力似大地水准面计算3. Unified gravity quasi-geoid calculation for land and sea

在计算中我们采用本领域熟知的顾及一阶项的Hotine积分公式和移去-恢复技术，顾及一阶项的Hotine积分公式为：In the calculation, we adopt the Hotine integral formula and the removal-restoration technique well known in the art considering the first-order term, and the Hotine integral formula considering the first-order term is:

$ζ ζ = = \frac{R R}{44 πγ πγ} {&Integral; &Integral;}_{σ σ} ((δg δg + + {δg δ g}_{11})) H h ((ψ ψ)) dσ dσ$

其中ψ为计算点与流动点之间的角距；where ψ is the angular distance between the calculation point and the flow point;

H(ψ)为的Hotine核；H(ψ) is the Hotine kernel;

R为地球平均半径R is the mean radius of the earth

σ为单位球面σ is the unit sphere

γ为正常重力γ is normal gravity

而δg₁的表达式为And the expression of δg ₁ is

${δg δg}_{11} = = \frac{{R R}^{22}}{22 π π} {&Integral; &Integral;}_{σ σ} \frac{h h - - {h h}_{p p}}{{l l}_{00}^{33}} [[δg δg - - \frac{11}{88 π π} {&Integral; &Integral;}_{σ σ} δgH δgH ((ψ ψ)) dσ dσ]] dσ dσ$

式中，h与h_P为流动点与计算点的大地高。In the formula, h and h _P are the geodetic heights of flow point and calculation point.

但本发明所采用的奇异积分处理方法有所不同。现有的奇异积分处理公式为However, the singular integral processing method adopted by the present invention is different. The existing singular integral processing formula is

与之不同的是，在此我们提出了严密的奇异积分公式，其推导过程如下：The difference is that here we propose a strict singular integral formula, and its derivation process is as follows:

我们知道，δN的严密积分公式为We know that the strict integral formula of δN is

$δN δ N = = \frac{R R}{44 πγ πγ} {&Integral; &Integral;}_{α α = = 00}^{22 π π} {&Integral; &Integral;}_{ψ ψ = = 00}^{{ψ ψ}_{00}} δgH δgH ((ψ ψ)) sin sin ((ψ ψ)) dψdα dψdα - - - - - - ((22))$

式中，α表示方位角，ψ表示球面角距，H(ψ)为Hotine核函数，其表达式可以在许多教科书中查到，这里不在给出。当ψ→0时，Hotine核函数出现奇异，即出现分母为0的现象，无法直接得到δN。理论上，从公式看扰动δg应该连续分布，但实际的测量中，我们只能测量离散的重力点值，不可能使重力点值连续分布，这就意味着在小球冠区域内我们可以平均扰动重力δg代替理论上应连续分布的点值，即在小球冠内，可以认为扰动重力为一常数。那么式(2)就可以表示为In the formula, α represents the azimuth angle, ψ represents the spherical angular distance, H(ψ) is the Hotine kernel function, and its expression can be found in many textbooks, so it will not be given here. When ψ→0, the Hotine kernel function is singular, that is, the denominator is 0, and δN cannot be obtained directly. Theoretically, the disturbance δg should be distributed continuously from the formula, but in actual measurement, we can only measure the discrete gravity point value, and it is impossible to make the gravity point value continuously distributed, which means that in the small spherical cap area we can average The disturbance gravity δg replaces the point value that should be distributed continuously in theory, that is, in the small spherical cap, the disturbance gravity can be considered as a constant. Then formula (2) can be expressed as

$δN δ N = = \frac{R R \overset{&OverBar; &OverBar;}{δg δg}}{44 πγ πγ} {&Integral; &Integral;}_{α α = = 00}^{22 π π} {&Integral; &Integral;}_{ψ ψ = = 00}^{{ψ ψ}_{00}} H h ((ψ ψ)) sin sin ((ψ ψ)) dψdα dψdα - - - - - - ((33))$

经过严密推导，可以得到After rigorous derivation, it can be obtained

${&Integral; &Integral;}_{ψ ψ = = 00}^{{ψ ψ}_{00}} H h ((ψ ψ)) sin sin ((ψ ψ)) dψ dψ = = {|\begin{matrix} cos cos ((ψ ψ)) + + \frac{33 co co {s the s}^{22} ((ψ ψ))}{44} + + cos cos ((ψ ψ)) ln ln [[11 + + csc csc ((\frac{ψ ψ}{22}))]] \\ + + 22 ln ln [[cos cos ((\frac{ψ ψ}{44})) + + sin sin ((\frac{ψ ψ}{44}))]] + + ln ln [[sin sin ((\frac{ψ ψ}{22}))]] + + 22 sin sin ((\frac{ψ ψ}{22})) \end{matrix}|}_{ψ ψ = = 00}^{ψ ψ = = {ψ ψ}_{00}} - - - - - - ((44))$

当ψ＝0时，上式右边式子是奇异的，但表现出弱奇异特征，并且其极限值为常数，即When ψ=0, the formula on the right side of the above formula is singular, but shows weak singularity, and its limit value is constant, that is

$\underset{ψ ψ &RightArrow; &Right Arrow; 00}{limit limit} \{\begin{matrix} cos cos ((ψ ψ)) + + \frac{33 {cos cos}^{22} ((ψ ψ))}{44} + + cos cos ((ψ ψ)) ln ln [[11 + + csc csc ((\frac{ψ ψ}{22}))]] \\ + + 22 ln ln [[cos cos ((\frac{ψ ψ}{44})) + + sin sin ((\frac{ψ ψ}{44}))]] + + ln ln [[sin sin ((\frac{ψ ψ}{22}))]] + + 22 sin sin ((\frac{ψ ψ}{22})) \end{matrix}\} = = \frac{77}{44} - - - - - - ((55))$

将上式代入式(3)，则得到Substituting the above formula into formula (3), we get

$δN δ N = = \frac{R R \cdot &Center Dot; \overset{&OverBar; &OverBar;}{δg δg}}{22 γ γ} \{\begin{matrix} cos cos (({ψ ψ}_{00})) + + \frac{33 {cos cos}^{22} (({ψ ψ}_{00}))}{44} + + cos cos (({ψ ψ}_{00})) ln ln [[11 + + csc csc ((\frac{{ψ ψ}_{00}}{22}))]] \\ + + 22 ln ln [[cos cos ((\frac{{ψ ψ}_{00}}{44})) + + sin sin ((\frac{{ψ ψ}_{00}}{44}))]] + + ln ln [[sin sin ((\frac{{ψ ψ}_{00}}{22}))]] + + 22 sin sin ((\frac{{ψ ψ}_{00}}{22})) - - \frac{77}{44} \end{matrix}\} - - - - - - ((66))$

由小球冠与经纬差格网(经度格网间距Δλ与纬度格网间距

)的等面积关系

可得到ψ₀的计算公式，即From the small spherical cap and the latitude and longitude difference grid (longitude grid spacing Δλ and latitude grid spacing

) equal-area relationship

The calculation formula of ψ ₀ can be obtained, namely

两者不同之处在于我们的公式相比以往公式理论上是严密的，但形式稍显复杂。The difference between the two is that our formula is theoretically rigorous compared to previous formulas, but the form is slightly more complicated.

四、利用陆地及海岸线附近GPS水准数据提取陆海重力似大地水准面系统差4. Using the GPS level data near the land and coastline to extract the land-sea gravity quasi-geoid system difference

利用重力似大地水准面内插GPS水准点上的高程异常值，与利用GPS水准数据计算的高精度高程异常值相比较，可以得到高程异常差值的标准差与平均值等统计信息。判断标准差大小是否满足设计精度要求。Using the gravity quasi-geoid to interpolate the elevation anomalies on GPS leveling points, and comparing them with the high-precision elevation anomalies calculated by using GPS leveling data, statistical information such as the standard deviation and average value of elevation anomalies can be obtained. Determine whether the standard deviation meets the design accuracy requirements.

五、进行系统差改正，实现一种基于扰动重力的似大地水准面的陆海无缝拼接5. Carry out system difference correction to realize a seamless stitching of land and sea based on a geoid-like surface based on disturbed gravity

如果利用GPS水准数据检核的标准差满足设计精度要求，则直接进行常数系统差改正即可。如检核标准差未满足精度要求，则需要分析系统差分布规律，选择合适的拟合方法完成陆海似大地水准面改正，从而实现似大地水准面的陆海无缝拼接。而拟合方法可以选择常数或线性拟合、多项式拟合、球面函数拟合、神经网络拟合等多种数学模型或几种模型的组合。If the standard deviation checked by the GPS leveling data meets the design accuracy requirements, then the constant system deviation correction can be performed directly. If the verification standard deviation does not meet the accuracy requirements, it is necessary to analyze the distribution of system differences and select an appropriate fitting method to complete the land-sea quasi-geoid correction, so as to realize the seamless stitching of land-sea quasi-geoid. And the fitting method can choose a variety of mathematical models such as constant or linear fitting, polynomial fitting, spherical function fitting, neural network fitting, or a combination of several models.

Claims

1. A method based on the seamless stitching of the geoid land and sea based on the disturbance of gravity is characterized in that, utilizing the disturbance gravity data to carry out the seamless stitching of the quasi-geoid land and sea, the method may further comprise the steps:

(1) Preprocessing land and sea gravity data into land and sea disturbance gravity data;

(2) Unified grid processing of disturbance gravity data for land and sea;

(3) Unified gravity quasi-geoid calculation for land and sea;

(4) Use land and coastal zone GPS leveling data to extract the land-sea gravity-like geoid system difference;

(5) Carry out systematic difference correction to realize a seamless stitching of land and sea based on a geoid-like surface based on disturbed gravity.

2. the quasi-geoid land-sea seamless splicing method based on disturbed gravity according to claim 1, characterized in that, the step (1) includes the following:

a. Process the ocean gravity field data into the ocean disturbance gravity data consistent with the land reference, use the ship survey disturbance gravity data to check whether there is any systematic error in the ocean disturbance gravity data, and if so, perform systematic error correction.

b. Based on the existing high-precision earth gravity field model, perform systematic difference analysis on the ground disturbance gravity and the ocean disturbance gravity data corrected in step a, and perform systematic difference correction on the ocean disturbance gravity;

c. Process the disturbance gravity data of the coastal zone to the disturbance gravity data of the coastal zone consistent with the land reference after being corrected by the same gravity field model system difference.

3. the quasi-geoid land-sea seamless splicing method based on the disturbed gravity according to claim 1, characterized in that, in the step (2), carry out the unified Bouguer disturbed gravity grid processing of the land and sea, And judge whether the gridded Bouguer disturbance gravity data has a jump phenomenon at the border, if the land and sea datum are consistent, then the unified disturbance gravity data of the land and sea after the grid processing should have no jump phenomenon at the border; If there is a jump phenomenon, the size of the system difference should be detected according to the land disturbance gravity data as a standard, and the corresponding system difference correction should be carried out.

4. the quasi-geoid land-sea seamless splicing method based on the perturbed gravity according to claim 1 is characterized in that, in the described step (3), a kind of strict Hotine integral singular point processing method is adopted, and the singularity The point processing formula is

δN δN = = \frac{R R \cdot &Center Dot; \overset{&OverBar; &OverBar;}{δg δg}}{22 γ γ} \{\begin{matrix} cos cos (({ψ ψ}_{00})) + + \frac{33 {cos cos}^{22} (({ψ ψ}_{00}))}{44} + + cos cos (({ψ ψ}_{00})) ln ln [[11 + + csc csc ((\frac{{ψ ψ}_{00}}{22}))]] \\ + + 22 ln ln [[cos cos ((\frac{{ψ ψ}_{00}}{44})) + + sin sin ((\frac{{ψ ψ}_{00}}{44}))]] + + ln ln [[sin sin ((\frac{{ψ ψ}_{00}}{22}))]] + + 22 sin sin ((\frac{{ψ ψ}_{00}}{22})) - - \frac{77}{44} \end{matrix}\}