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1.
依据物理大地测量学的广义带限水平边值问题理论,本文提出了基于带限航空矢量重力水平分量确定大地水准面的两步积分法。首先,依据广义带限水平边值问题解将带限航空矢量重力水平分量转化为飞行高度面上的带限扰动位;然后,利用带限Dirichlet边值问题解将飞行高度面上的带限扰动位向下延拓到海平面(海拔高程起算面,也称平均海面)上的带限扰动位;最后,依据Bruns公式将海平面上的扰动位转化为大地水准面高度。利用EGM2008重力位模型开展数值仿真计算试验,结果表明,广义带限水平边值问题解具有较好的低通滤波特性,能有效抑制观测高频噪声的影响;当带限航空矢量重力水平分量观测误差取3×10^(-5)m/s 2、测量飞行高度取6 km时,基于带限Dirichlet边值问题解的带限大地水准面计算精度优于3 cm,初步验证了两步积分法的计算稳定性和有效性。 相似文献
2.
基于数学和分析力学角度分别推导了航空矢量重力测量的数学模型,得到了一致的模型公式;给出了矢量模型的3个分量形式,其中垂直方向的分量就是标量重力测量的数学模型;简要介绍了我国研制成功的航空标量重力测量系统CHAGS的数据处理的过程,分析了标量重力测量中测线交叉点和重复测线的重力异常的精度;根据实测数据计算的结果表明:测线交叉点重力异常不符值的标准差约为5×10-5ms-2左右,重复测线的内符合精度优于5×10-5ms-2,达到了预期的要求。 相似文献
3.
航空重力测量数学模型及其测量精度分析 总被引：1，自引：0，他引：1
基于数学和分析力学角度分别推导了航空矢量重力测量的数学模型,得到了一致的模型公式;给出了矢量模型的3个分量形式,其中垂直方向的分量就是标量重力测量的数学模型;简要介绍了我国研制成功的航空标量重力测量系统CHAGS的数据处理的过程,分析了标量重力测量中测线交叉点和重复测线的重力异常的精度;根据实测数据计算的结果表明:测线交叉点重力异常不符值的标准差约为5×10-5ms-2左右,重复测线的内符合精度优于5×10-5ms-2,达到了预期的要求. 相似文献
4.
正航空重力测量技术是以飞机为载体,快速测定近地空中重力加速度的重力测量方法。经过数十年的沉淀与发展,航空重力测量技术已成为高效测定中高频地球重力场信息的主要手段。航空矢量重力测量技术相较于航空标量重力测量技术,不仅能获取重力扰动矢量的垂直分量,而且也能获取重力扰动矢量的水平分量(即垂线偏差)。 相似文献
5.
航空矢量重力测量误差模型的建立及初步分析 总被引：1，自引：0，他引：1
航空矢量重力测量的目的是确定沿飞行轨迹的整个重力扰动矢量。基于ＩＮＳ／ＧＰＳ的矢量重力测量,重力扰动矢量确定精度直接受ＩＮＳ测量误差和ＧＰＳ观测误差的影响。ＩＮＳ测量误差主要包括姿态测量误差和加速度计误差。影响ＧＰＳ导出加速度精度的主要误差是多路径效应和测量噪声。本文建立了航空矢量重力测量的基本误差模型,据此,对上述各项误差的成因,性质及消除措施作了初步探讨,其中重点分析了ＧＰＳ确定加速度的误差模 相似文献
6.
《武汉大学学报(信息科学版)》2016,(4)
目前的航空标量重力测量系统主要是在当地坐标系下求解重力垂向分量,该方法涉及厄特弗斯改正,却没有考虑垂线偏差的影响。改进方法在准惯性坐标系下求解重力观测量,给出了一个计算重力值的改进公式,避免了经典方法中的近似处理,从理论上完善了航空重力测量数据处理方法。实例验证了改进方法的正确性,并显示经典方法中的近似处理在实验区域内产生了亚mGal级的误差,这个误差在利用1/60s以下的截断频率进行低通滤波后基本可以忽略。除了理论上对经典方法的改进,改进方法还提供了确定扰动重力水平分量的公式,经过细致的数据处理后其精度可达mGal级。 相似文献
7.
联合使用位模型和地形信息的陆区航空重力向下延拓方法 总被引：1，自引：0，他引：1
为了规避传统逆Poisson积分向下延拓解算过程的不适定性问题,借鉴导航定位中的"差分"概念,利用超高阶位模型直接计算海域航空重力测量向下延拓改正数的方法。本文在此基础上提出联合使用重力位模型和地形高数据,计算陆部航空重力向下延拓总改正数的改进方案,以飞行高度面与地面对应点的位模型差分信息表征总改正数的中长波分量,以相对应的局部地形改正差分修正量表征总改正数的中高频成分,从而实现航空重力数据点对点向地面的全频段延拓。在地形变化不同区域,联合使用EGM2008位模型、地面实测重力和高分辨率高程数据进行了实际数值计算和精度评估,验证了该方法的有效性。 相似文献
8.
本文首先给出了航空矢量重力测量的数学模型，并依此得出了扰动重力矢量的误差模型。重点研究了平台式和捷联式两种情况下姿态误差对扰动重力矢量的影响，并得到了一致的姿态指标。水平姿态误差应小于0．2″，垂直姿态误差应小于10″，对航空矢量重力测量的发展具有一定的指导意义。 相似文献
9.
给出了由地面重力数据计算外空扰动重力矢量的公式,并根据Wong and Gore截断理论给出了外区重力异常对计算点影响的公式.根据外空扰动重力与地面数据分辨率及其覆盖范围之间的关系,将重力异常分成不同频段、不同分辨率,分别计算了截断误差.利用全球重力位模型,计算出不同频段的截断误差,并给出了各频段相应的积分半径.对于模拟和检验航空矢量重力数据有一定的参考价值. 相似文献
10.
利用航空重力测量方法可以获得测区的格网平均重力异常，由此，用范宁梅尼兹公式即可计算得到垂线偏差。本文基于大同航空重力测量数据，分析了这种方法的精度。结果表明，垂线偏差的子午和卯酉分量在空中的比较精度分别为0．46”和0．32”；在地面的比较精度分别为0．52”和0．38”。 相似文献
11.
M. S. Senobari 《Journal of Geodesy》2010,84(5):277-291
A method for airborne vector gravimetry has been developed. The method is based on developing the error dynamics equations
of the INS in the inertial frame where the INS system errors are estimated in a wave estimator using inertial GPS position
as update. Then using the error-corrected INS acceleration and the GPS acceleration in the inertial frame, the gravity disturbance
vector is extracted. In the paper, the focus is on the improvement of accuracy for the horizontal components of the airborne
gravity vector. This is achieved by using a decoupled model in the wave estimator and decorrelating the gravity disturbance
from the INS system errors through the estimation process. The results of this method on the real strapdown INS/DGPS data
are promising. The internal accuracy of the horizontal components of the estimated gravity disturbance for repeated airborne
lines is comparable with the accuracy of the down component and is about 4–8 mGal. Better accuracy (2–4 mGal) is achieved
after applying a wave-number correlation filter (WCF) to the parallel lines of the estimated airborne gravity disturbances. 相似文献
12.
SHIPan SUNZhongmiao XIAOYun 《地球空间信息科学学报》2004,7(3):204-209
On the basis of a sinusoidal model of the disturbed horizontal acceleration, the spectrum characteristics of misaligned angle and horizontal acceleration correction are analyzed. In an airborne gravimetry test,the misaligned angle of platform and horizontal acceleration correction are calculated. They are 5‘ and 3 mGal,respectively, when the flight is stable. 相似文献
13.
On the basis of a sinusoidal model of the disturbed horizontal acceleration, the spectrum characteristics of misaligned angle and horizontal acceleration correction are analyzed. In an airborne gravimetry test, the misaligned angle of platform and horizontal acceleration correction are calculated. They are 5′ and 3 mGal, respectively, when the flight is stable. 相似文献
14.
Topographic–isostatic masses represent an important source of gravity field information, especially in the high-frequency
band, even if the detailed mass-density distribution inside the topographic masses is unknown. If this information is used
within a remove-restore procedure, then the instability problems in downward continuation of gravity observations from aircraft
or satellite altitudes can be reduced. In this article, integral formulae are derived for determination of gravitational effects
of topographic–isostatic masses on the first- and second-order derivatives of the gravitational potential for three topographic–isostatic
models. The application of these formulas is useful for airborne gravimetry/gradiometry and satellite gravity gradiometry.
The formulas are presented in spherical approximation by separating the 3D integration in an analytical integration in the
radial direction and 2D integration over the mean sphere. Therefore, spherical volume elements can be considered as being
approximated by mass-lines located at the centre of the discretization compartments (the mass of the tesseroid is condensed
mathematically along its vertical axis). The errors of this approximation are investigated for the second-order derivatives
of the topographic–isostatic gravitational potential in the vicinity of the Earth’s surface. The formulas are then applied
to various scenarios of airborne gravimetry/gradiometry and satellite gradiometry. The components of the gravitational vector
at aircraft altitudes of 4 and 10 km have been determined, as well as the gravitational tensor components at a satellite altitude
of 250 km envisaged for the forthcoming GOCE (gravity field and steady-state ocean-circulation explorer) mission. The numerical
computations are based on digital elevation models with a 5-arc-minute resolution for satellite gravity gradiometry and 1-arc-minute
resolution for airborne gravity/gradiometry. 相似文献
15.
16.
Downward continuation and geoid determination based on band-limited airborne gravity data 总被引：4，自引：3，他引：4
The downward continuation of the harmonic disturbing gravity potential, derived at flight level from discrete observations
of airborne gravity by the spherical Hotine integral, to the geoid is discussed. The initial-boundary-value approach, based
on both the direct and inverse solution to Dirichlet's problem of potential theory, is used. Evaluation of the discretized
Fredholm integral equation of the first kind and its inverse is numerically tested using synthetic airborne gravity data.
Characteristics of the synthetic gravity data correspond to typical airborne data used for geoid determination today and in
the foreseeable future: discrete gravity observations at a mean flight height of 2 to 6 km above mean sea level with minimum
spatial resolution of 2.5 arcmin and a noise level of 1.5 mGal. Numerical results for both approaches are presented and discussed.
The direct approach can successfully be used for the downward continuation of airborne potential without any numerical instabilities
associated with the inverse approach. In addition to these two-step approaches, a one-step procedure is also discussed. This
procedure is based on a direct relationship between gravity disturbances at flight level and the disturbing gravity potential
at sea level. This procedure provided the best results in terms of accuracy, stability and numerical efficiency. As a general
result, numerically stable downward continuation of airborne gravity data can be seen as another advantage of airborne gravimetry
in the field of geoid determination.
Received: 6 June 2001 / Accepted: 3 January 2002 相似文献
17.
航空重力测量的滤波处理及最佳波长分辨率的探讨 总被引：1，自引：0，他引：1
根据航空重力测量的数据性质，对其滤波处理中最佳滤长分辨率的确定，提出了一种采用静态飞行数据进行检测的方法－即利用静态飞行数据处理后的重力异常误差平方和最小的原则。并对其在航空重力测量中的必要性做了检验和说明。 相似文献
18.
19.
利用空中平均重力异常确定区域大地水准面 总被引：3，自引：0，他引：3
提出了直接利用空中平均重力异常计算区域大地水准面的方法。模拟计算的结果表明, 该方法与传统的利用地面平均空间重力异常确定的大地水准面精度相当, 但其显著优点是勿需空中重力异常的向下解析延拓, 从而可以避免延拓误差对大地水准面精化的影响。 相似文献
20.
Flight test results from a strapdown airborne gravity system 总被引：3，自引：0，他引：3
In June 1995, a flight test was carried out over the Rocky Mountains to assess the accuracy of airborne gravity for geoid
determination. The gravity system consisted of a strapdown inertial navigation system (INS), two GPS receivers with zero baseline
on the airplane and multiple GPS master stations on the ground, and a data logging system. To the best of our knowledge, this
was the first time that a strapdown INS has been used for airborne gravimetry. The test was designed to assess repeatability
as well as accuracy of airborne gravimetry in a highly variable gravity field. An east-west profile of 250 km across the Rocky
Mountains was chosen and four flights over the same ground track were made. The flying altitude was about 5.5km, i.e., between
2.5 and 5.0km above ground, and the average flying speed was about 430km/h. This corresponds to a spatial resolution (half
wavelength of cutoff frequency) of 5.07.0km when using filter lengths between 90 and 120s. This resolution is sufficient for
geoid determination, but may not satisfy other applications of airborne gravimetry. The evaluation of the internal and external
accuracy is based on repeated flights and comparison with upward continued ground gravity using a detailed terrain model.
Gravity results from repeated flight lines show that the standard deviation between flights is about 2mGal for a single profile
and a filter length of 120s, and about 3mGal for a filter length of 90s. The standard deviation of the difference between
airborne gravity upward continued ground gravity is about 3mGal for both filter lengths. A critical discussion of these results
and how they relate to the different transfer functions applied, is given in the paper. Two different mathematical approaches
to airborne scalar gravimetry are applied and compared, namely strapdown inertial scalar gravimetry (SISG) and rotation invariant
scalar gravimetry (RISG). Results show a significantly better performance of the SISG approach for a strapdown INS of this
accuracy class. Because of major differences in the error model of the two approaches, the RISG method can be used as an effective
reliability check of the SISG method. A spectral analysis of the residual errors of the flight profiles indicates that a relative
geoid accuracy of 23cm over distances of 200km (0.1 ppm) can be achieved by this method. Since these results present a first
data analysis, it is expected that further improvements are possible as more refined modelling is applied.
Received: 19 August 1996 / Accepted: 12 May 1997 相似文献