Earth Gravity Field Models Research Articles

Comparison of global Earth’s gravity field models with the aerogravimetric data obtained during a transcontinental flight

Some methodological features of the airborne gravity surveys of Russia’s territory at the latitude of 60° from Arkhangelsk to Kamchatka are described. The results of these surveys are presented. The data obtained from gravimeters installed aboard an aircraft laboratory are compared with EGM2008 and EIGEN-6C3, the state-of-the-art global Earth gravity field models. It is shown that the present-day models have the highest errors near the coastal tectonic structures of the Kamchatka Peninsula.

Requirements Analysis for Future Satellite Gravity Mission Improved-GRACE

The Earth’s gravitational field from the Next-Generation Gravimetry Mission (NGGM) and the Improved-Gravity Recovery and Climate Experiment (Improved-GRACE) complete up to degree and order 120 is recovered by a closed-loop numerical simulation using different orbital altitudes of 325 and 300 km, different orbital inclinations of 96.78° and 89° and different inter-satellite ranges of 10 and 50 km. The preferred orbit parameters of the future twin Improved-GRACE satellites are proposed based on the results of the simulations in this study. The research results show: (1) In order to achieve the scientific objectives, which require that the accuracy of the next-generation Earth gravity field models is at least one order of magnitude better than that of the current gravity models, the orbit design at an altitude of 300 ± 50 km is recommended for the future Improved-GRACE mission. This altitude is determined by a trade-off analysis between the recovery accuracy of the gravity field and the operational lifetime of the satellite system. (2) Because the accuracy of the Earth’s gravitational field from NGGM with an orbital inclination of 96.78° will be decreased due to a lack of the observation data in the polar areas, we propose that a near-polar orbit (inclination of 89° ± 2°) is a preferable selection for the future twin Improved-GRACE satellites. (3) The future Improved-GRACE mission has to adopt an inter-satellite range of 50 ± 10 km, because the common signals of the Earth’s gravitational field between the twin NGGM satellites will be substantially eliminated with a shorter inter-satellite range of 10 km. With these orbit design parameters, the Earth’s gravitational field from the Improved-GRACE mission is precisely recovered complete up to degree and order 120 with a cumulative geoid height error of about 0.7 mm.

Physical analysis on improving the recovery accuracy of the Earth's gravity field by a combination of satellite observations in along-track and cross-track directions

The physical investigations on the accuracy improvement to the measurement of the Earth's gravity field recovery are carried out based on the next-generation Pendulum-A/B out-of-plane twin-satellite formation in this paper. Firstly, the Earth's gravity field complete up to degree and order 100 is, respectively, recovered by the collinear and pendulum satellite formations using the orbital parameters of the satellite and the matching accuracies of key payloads from the twin GRACE satellites. The research results show that the accuracy of the Earth's gravity field model from the Pendulum-A/B satellite formation is about two times higher than from the collinear satellite formation, and the further improvement of the determination accuracy of the Earth's gravity field model is feasible by the next-generation Pendulum-A/B out-of-plane twin-satellite formation. Secondly, the Earth's gravity field from Pendulum-A/B complete up to degree and order 100 is accurately recovered based on the orbital parameters of the satellite (e.g., an orbital altitude of 400 km, an intersatellite range of 100 km, an orbital inclination of 89° and an orbital eccentricity of 0.001), the matching accuracies of space-borne instruments (e.g. 10−6 m in the intersatellite range, 10−3 m in the orbital position, 10−6 m/s in orbital velocity, and 10−11 m/s2 in non-conservative force), an observation time of 30 days and a sampling interval of 10 s. The measurement accuracy of the Earth's gravity field from the next-generation Pendulum-A/B out-of-plane twin-satellite formation is full of promise for being improved by about 10 times compared with that from the current GRACE satellite formation. Finally, the physical requirements for the next-generation Pendulum-A/B out-of-plane twin-satellite formation are analyzed, and it is proposed that the satellite orbital altitude be preferably designed to be close to 400±50 km and the matching precision of key sensors from the Pendulum-A/B mission be about one order of magnitude higher than from the GRACE program.

The Research of GPS Elevation Fitting Considering the Influence of Covariance Function

The common method to determine Quasi-Geoids is GPS leveling however the Quasi-Geoid of this method determined is a kind of trend surface which not take the physical property of geoid into consideration, and the fitting method is surface fitting which only consider the surveying error, lead to inaccurate fitting result. In allusion to these problems, Remove-restore method is used to remove the long wave information of earth gravity field model to get more smooth residual gravity height anomaly, then compared the influence of different covariance function to the fitting result of least square collocation which take surveying error and model error into account. The results show that Gaussian and resemble Gaussian function can achieve higher fitting precision to the large area with height anomaly value changes significance; the Remove-restore method can effectively improve the fitting precision to least square collocation method which depend on the covariance value of each points.

GOCE kinematic orbit adjustment for EGM validation and accelerometer calibration

The main principle and mathematical model of GOCE kinematic orbit adjustment for Earth gravity field model (EGM) validation and accelerometer calibration are presented. Based on 60 days GOCE kinematic orbits with 1–2 cm accuracy and accelerometer data from 2009-11-02 to 2009-12-31, the RMS-of-fit (ROF) of them using EGM2008, EIGEN-5C, ITG-GRACE2010S and GOCO01S up to 120, 150 and 180 degree and order (d/o) are evaluated and compared. The scale factors and biases of GOCE accelerometer data are calibrated and the energy balance method (EBM) is performed to test the accuracy of accelerometer calibration. The results show that GOCE orbits are also sensitive to EGM from 120 to 150 d/o. The ROFs of EGMs with 150 and 180 d/o are obviously better than those of EGMs with 120 d/o. The ROFs of GOCO01S and ITG-GRACE2010S are almost the same up to 120 and 150 d/o, which are about 3.3 cm and 1.8 cm, respectively. They are far better than those of EGM2008 and EIGEN-5C with the same d/o. The ROF of GOCO01S with 180 d/o is about 1.6 cm, which is the best one among those EGMs. The accelerometer calibration accuracies (ACAs) of ITG-GRACE2010S and GOCO01S are obviously higher that those of EGM2008 and EIGEN-5C. The ACA of GOCO01S with 180 d/o is far higher than that of EGMs with 120 d/o, and a little higher than that of ITG-GRACE2010S with 150 d/o. It is suggested that the newest released EGM such as GOCO01S or GOCO02S till at least 150 d/o should be chosen in GOCE precise orbit determination (POD) and accelerometer calibration.

Precise Recovery of the Earth's Gravitational Field by Grace Follow‐On Satellite Gravity Gradiometry Method

AbstractBecause the twin GRACE Follow‐On satellites are equivalent to the one‐dimensional horizontal gravity gradiometer with a baseline length of the intersatellite range, the feasibility demonstrations on precisely and rapidly recovering the next‐generation Earth's gravitational field by the GRACE Follow‐On satellite gravity gradiometry method (GFO‐SGGM) are carried out in this study. The research results are as follows: Firstly, based on the GRACE Follow‐On satellite gravity gradiometry method, using the orbital parameters of the satellite (e.g. orbital altitude of 250 km, intersatellite range of 50 km, orbital inclination of 89° and orbital eccentricity of 0.001), the measurement precisions of key payloads (e.g. 10−6 m in intersatellite range, 10−7 m·s−1 in intersatellite range‐ rate and 10−10 m·s−2 in intersatellite range‐acceleration by the interferometric laser ranging system, 10−3 m in orbital position and 10−6 m·s−1 in orbital velocity by the GPS receiver, and 10−11 m·s−2 in non‐conservative force by the accelerometer), a 30‐day observation time and a sampling interval of 10 s, the Earth's gravitational field complete up to degree and order 120 is accurately recovered, and the cumulative geoid height error is 9.331×10−4 m at degree 120. Secondly, in 120 degrees, the accuracy of the gravity recovery from the future twin GRACE Follow‐On satellites is averagely improved by about 61 times than that from the current twin GRACE satellites. Therefore, the GRACE Follow‐On satellite gravity gradiometry method promisingly becomes a preferred approach for further improving the determination accuracy of the next‐generation Earth gravity field model. Finally, the advantages of the next‐generation GRACE Follow‐On mission as compared with the present GRACE mission principally consist of the lower orbital altitude of the satellite between 200 km and 300 km, the higher measurement accuracy of the space‐borne instruments between 10−7 m·s−1 and 10−9 m·s−1 and the shorter intersatellite range between 50 km and 100 km.

Evaluation of the third- and fourth-generation GOCE Earth gravity field models with Australian terrestrial gravity data in spherical harmonics

In March 2013, the fourth generation of European Space Agency’s (ESA) global gravity field models, DIR4 (Bruinsma et al. in Proceedings of the ESA living planet symposium, 28 June–2 July, Bergen, ESA, Publication SP-686, 2010b) and TIM4 (Migliaccio et al. in Proceedings of the ESA living planet symposium, 28 June–2 July, Bergen, ESA, Publication SP-686, 2010), generated from the Gravity field and steady-state Ocean Circulation Explorer (GOCE) gravity observation satellite was released. We evaluate the models using an independent ground truth data set of gravity anomalies over Australia. Combined with Gravity Recovery and Climate Experiment (GRACE) satellite gravity, a new gravity model is obtained that is used to perform comparisons with GOCE models in spherical harmonics. Over Australia, the new gravity model proves to have significantly higher accuracy in the degrees below 120 as compared to EGM2008 and seems to be at least comparable to the accuracy of this model between degree 150 and degree 260. Comparisons in terms of residual quasi-geoid heights, gravity disturbances, and radial gravity gradients evaluated on the ellipsoid and at approximate GOCE mean satellite altitude ( $$h=250$$ km) show both fourth generation models to improve significantly w.r.t. their predecessors. Relatively, we find a root-mean-square improvement of 39 % for the DIR4 and 23 % for TIM4 over the respective third release models at a spatial scale of 100 km (degree 200). In terms of absolute errors, TIM4 is found to perform slightly better in the bands from degree 120 up to degree 160 and DIR4 is found to perform slightly better than TIM4 from degree 170 up to degree 250. Our analyses cannot confirm the DIR4 formal error of 1 cm geoid height (0.35 mGal in terms of gravity) at degree 200. The formal errors of TIM4, with 3.2 cm geoid height (0.9 mGal in terms of gravity) at degree 200, seem to be realistic. Due to combination with GRACE and SLR data, the DIR models, at satellite altitude, clearly show lower RMS values compared to TIM models in the long wavelength part of the spectrum (below degree and order 120). Our study shows different spectral sensitivity of different functionals at ground level and at GOCE satellite altitude and establishes the link among these findings and the Meissl scheme (Rummel and van Gelderen in Manusrcipta Geodaetica 20:379–385, 1995).

Precise and Rapid Recovery of the Earth's Gravitational Field by the Next‐Generation Four‐Satellite Cartwheel Formation System

AbstractFirstly, the orbital stability design of the next‐generation gravity satellite formation is very important for precisely developing the Earth gravity field model with high spatial resolution. Therefore, for the sake of guaranteeing the stability of the next‐generation Four‐Satellite Cartwheel Formation (FSCF), the optimal design of the orbital elements is proposed as follows: (1) the semimajor axis a, orbital eccentricity e, orbital inclination i and longitude of ascending node Ω keep invariant; (2) the argument of perigee ω and mean anomaly M need to have a discrepancy of 180°, respectively; (3) the initial argument of perigee ω should be set at the equator, and the initial mean anomaly must be designed at the poles; (4) the ratio between semimajor and semiminor axes from the elliptical orbit of the satellite formation system is 2:1. Secondly, the Earth's gravitational field from the next‐generation FSCF complete up to degree and order 120 is accurately and rapid recovered based on the intersatellite range‐rate interpolation method using the correlation coefficients (0.85 in intersatellite range‐rate of the interferometric laser ranging system, 0.95 in orbital position and velocity of the GPS receiver, and 0.90 in non‐conservative force of the accelerometer), an observation time of 30 days and a sampling interval of 10 s, and cumulative geoid height error is 1.162×10−4 m at degree 120, which is at least one order of magnitude higher than the accuracy of the Earth's gravitational field from GRACE. Finally, the advantages of the next‐generation FSCF are the lower orbital altitude, the higher observation accuracy, the full‐tensor observations, the weak aliasing effects, and the strong time‐varying signals.

A signal-strength model for gravity-field spectrum components in a local space

In the Earth gravity-field model, potential coefficients are projections of the Earth gravitational potential on the corresponding spherical harmonics by degree and order. These coefficients reflect the spectral composition of the Earth gravitational potential in the whole space, but they cannot reflect the spectral composition in a local area. In this study, the Earth gravitational potential was projected on spherical harmonics in a local area using a window function introduced to facilitate the mathematical expressions. Then a model for the spectral structure of the Earth gravitational potential in the local area was established. The model can reflect the signal strength of any gravity-field spectrum component in the local area, which adds information for the description of the gravity field of the Earth, and which has great significance for Earth-sciences research and satellite gravity measurements. Taking the third-degree coefficients, for example, the signal-strength distributions of potential coefficients were computed. The data show that the signal-strength distributions of third-degree coefficients on the sphere surface are independent of the longitude. Among the third-degree coefficients, the zero-order, first-order and second-order coefficients are stronger near the two poles of the Earth, while the third-order coefficient is stronger near the equator.

Improved Geoid Determination Based on the Shallow-Layer Method: A Case Study Using EGM08 and CRUST2.0 in the Xinjiang and Tibetan Regions

In this paper we present the concepts and realization of the shallow-layer Shen geoid determination method, which is quite different from the classical geoid modeling methods (Stokes' method, Molodenskii's method, etc.), for determining the global or regional geoids. This method takes full advantage of the precise Earth gravity field model EGM2008, digital topographic model DTM2006.0 and global crust model CRUST2.0 of a shallow layer, a layer from the Earth's surface to a depth. As a case study this method is applied to the determination of a 5' × 5' geoid over the Xinjiang and Tibetan regions, which ranges from latitude 25 to 50°N and longitude 70 to 100°E. The modeled 5' × 5' regional geoid is compared with the EGM2008 geoid model in the same study area and validated by 21 GPS/leveling benchmarks (GPSBMs) distributed sparsely in the Xinjiang area. The results show that the regional geoid reaches an accuracy of ~18 cm and agrees with the GPSBMs better than the EGM2008 geoid in the Xinjiang region.

A contrastive study on the influences of radial and three-dimensional satellite gravity gradiometry on the accuracy of the Earth's gravitational field recovery

The accuracy of the Earth's gravitational field measured from the gravity field and steady-state ocean circulation explorer (GOCE), up to 250 degrees, influenced by the radial gravity gradient Vzz and three-dimensional gravity gradient Vij from the satellite gravity gradiometry (SGG) are contrastively demonstrated based on the analytical error model and numerical simulation, respectively. Firstly, the new analytical error model of the cumulative geoid height, influenced by the radial gravity gradient Vzz and three-dimensional gravity gradient Vij are established, respectively. In 250 degrees, the GOCE cumulative geoid height error measured by the radial gravity gradient Vzz is about 2½ times higher than that measured by the three-dimensional gravity gradient Vij. Secondly, the Earth's gravitational field from GOCE completely up to 250 degrees is recovered using the radial gravity gradient Vzz and three-dimensional gravity gradient Vij by numerical simulation, respectively. The study results show that when the measurement error of the gravity gradient is 3 × 10−12/s2, the cumulative geoid height errors using the radial gravity gradient Vzz and three-dimensional gravity gradient Vij are 12.319 cm and 9.295 cm at 250 degrees, respectively. The accuracy of the cumulative geoid height using the three-dimensional gravity gradient Vij is improved by 30%–40% on average compared with that using the radial gravity gradient Vzz in 250 degrees. Finally, by mutual verification of the analytical error model and numerical simulation, the orders of magnitude from the accuracies of the Earth's gravitational field recovery make no substantial differences based on the radial and three-dimensional gravity gradients, respectively. Therefore, it is feasible to develop in advance a radial cold-atom interferometric gradiometer with a measurement accuracy of 10−13/s2−10−15/s2 for precisely producing the next-generation GOCE Follow-On Earth gravity field model with a high spatial resolution.

Research and Application of the Refining Method of Region Quasi-Geoid

GPS technology has penetrated into all fields of surveying and mapping disciplines,and has been widely used in leveling measurement .By studying the feasibility of the refining of region quasi-geoid based on the existing quasi-geoid,this paper shows a new method which is a combination of the Earth's gravity field model and the GPS leveling fitting method to determine the region quasi-geoid and provide the specific ideas and calculation steps and do analysis and discussion about the feasibility and superiority of this method using actual data.This new method makes full use of the advantages of the high resolution of the gravity geoid and the high-precision of the GPS geoid to realize the complementary strengths.

Precise Recovery of the Earth's Gravitational Field With GRACE: Intersatellite Range-Rate Interpolation Approach

First, a new observation equation of a satellite from the intersatellite range-rate interpolation approach (IRRIA) is created by inserting the precise intersatellite range-rate measurements into the line-of-sight component of the orbital velocity difference vector. Second, by a comparison of the two-point, four-point, six-point, and eight-point interpolation formulas, the accuracy of the Earth's gravitational field is substantially improved using the six-point IRRIA formula due to an optimum signal-to-noise ratio. Third, a new Gravity Recovery and Climate Experiment (GRACE) satellite-only Earth gravity field model WHIGG-GEGM02S is produced by GRACE-Level-1B real data during the year 2009 using the IRRIA, and the cumulative geoid height error and cumulative gravity anomaly error are 1.140 ×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> m and 1.807 ×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> m/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at degree 120, respectively. Finally, the new WHIGG-GEGM02S model is much closer to the existing GGM02S model by a comparison of the root mean square of the geoid height differences between the global positioning system/leveling observations and the existing seven GRACE global gravity field models.

Overview of the LARES Mission: orbit, error analysis and technological aspects

LARES (LAser RElativity Satellite), is an Italian Space Agency (ASI) mission to be launched beginning of 2012 with the new European launch vehicle, VEGA; the launch opportunity was provided by the European Space Agency (ESA). LARES is a laser ranged satellite; it will be launched into a nearly circular orbit, with an altitude of 1450 km and an inclination of 69.5 degrees. The goal of the mission is the measurement of the Lense-Thirring effect with an uncertainty of few percent; such a small uncertainty will be achieved using LARES data together with data from the LAGEOS I (NASA) and LAGEOS II (NASA and ASI) satellites, and because GRACE mission (NASA-CSR and DLR-GFZ) is improving Earth's gravity field models. This paper describes LARES experiment along with the principal error sources affecting the measurement. Furthermore, some engineering aspects of the mission, in particular the structure and materials of the satellite (designed in order to minimize the non-gravitational perturbations), are described.

On simulation of precise orbit determination of HY-2 with centimeter precision based on satellite-borne GPS technique

The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so that the observations are not openly released. In order to study the precise orbit determination precision and procedure for HY-2 based on the satellite-borne GPS technique, the satellite-borne GPS data are simulated in this paper. The HY-2 satellite-borne GPS antenna can receive at least seven GPS satellites each epoch, which can validate the GPS receiver and antenna design. What’s more, the precise orbit determination processing flow is given and precise orbit determination experiments are conducted using the HY-2-borne GPS data with both the reduced-dynamic method and the kinematic geometry method. With the 1 and 3 mm phase data random errors, the radial orbit determination precision can achieve the centimeter level using these two methods and the kinematic orbit accuracy is slightly lower than that of the reduced-dynamic orbit. The earth gravity field model is an important factor which seriously affects the precise orbit determination of altimeter satellites. The reduced-dynamic orbit determination experiments are made with different earth gravity field models, such as EIGEN2, EGM96, TEG4, and GEMT3. Using a large number of high precision satellite-borne GPS data, the HY-2 precise orbit determination can reach the centimeter level with commonly used earth gravity field models up to above 50 degrees and orders.

Estimation of the zero-height geopotential level W o LVD in a local vertical datum from inversion of co-located GPS, leveling and geoid heights: a case study in the Hellenic islands

The estimation of the zero-height geopotential level of a local vertical datum (LVD) is a key task towards the connection of isolated physical height frames and their unification into a common vertical reference system. Such an estimate resolves, in principle, the ‘ambiguity’ of a traditional crust-fixed LVD by linking it with a particular equipotential surface of Earth’s gravity field under the presence of an external geopotential model. The aim of this paper is to study the estimation scheme that can be followed for solving the aforementioned problem based on the joint inversion of co-located GPS and leveling heights in conjunction with a fixed Earth gravity field model. Several case studies with real data are also presented that provide, for the first time, precise estimates of the LVD offsets for a number of Hellenic islands across the Aegean and Ionian Sea.

INVESTIGATING THE ACCURACY OF GRAVITY FIELD MODELS USING SATELLITE LASER RANGING DATA

Continuous tracking of geodetic satellites using the Satellite Laser Ranging technique has provided unprecedented opportunity in long- to medium-wavelength gravity field modelling. Numerous gravity field models have been derived from such observations and have been made freely available to the science community for research purpose. The accuracy of most of the latest gravity field models in terms of precise orbit determination is currently at cm level. Improvement in the Earth gravity field modelling is anticipated as quantitative and qualitative data (in particular from low earth orbit satellites) become available in the future. Such expectations require that the accuracy and precision of existing gravity field models be assessed. The validation of gravity field models in terms of satellite orbit determination is often based on the difference between the observed and computed range. The resulting range residuals are considered an important index when determining the accuracy of the gravity models and hence the satellite orbits. In this contribution we investigate the general improvement in gravity field modelling over a period of 15 years. The orbit accuracy of twelve gravity field models (both satellite-only and combined models) were assessed by analysing seven months of data from LAGEOS 1 and 2 using HartRAO analysis software. Results show that the gravity field models developed over the years have improved by at least a factor of 2 since 1990, considering improvement in O-C residuals.

The ice sheet height changes and mass variations in Antarctica by using ICESat and GRACE data

The Gravity Recovery and Climate Experiment (GRACE) satellite mission has provided the monthly earth's gravity field models since August 2002, from which the mass variations in Antarctica can be estimated. Because of the very low-degree spherical harmonic coefficients, especially the degree-2 zonal term J2 are not well determined by GRACE, more attention should be paid on the effects of J2 when the earth's mass variations are derived from spherical harmonic coefficients. To see the differences more clearly, wavelet transformation is applied to the J2 time series derived from GRACE measurements by different agencies, such as Centre National d’Études Spatiales/Groupe de Recher de Deodesie Spatiale, GeoForschungsZentrum Potsdam, University of Texas Center for Space Research and that from satellite laser ranging observations. Periodic signals can be seen from the wavelet spectra. A Gaussian smoothing with a radius of 300 km is used in the gravity model-based mass rate estimation. Meanwhile, NASA's Ice, Cloud, and land Elevation Satellite (ICESat) has provided repeated laser altimeter data, and the ice sheet height changes are estimated by using crossover analysis. The mass rates estimated from GRACE are compared to the ice sheet height changes from ICESat. The mass rate in Amundsen Sea Embayment is estimated up to −8 cm/yr from GRACE, while the ice sheet height changes observed from ICESat is up to −32 cm over more than 3 years, this shows the comparable results in this region.

Orbit Determination and Sea Level Rise: How Astrodynamics Informs Us About the Climate

Advancements in satellite tracking systems, Earth-gravity field models, and the definition of the terrestrial reference frame have led to significant improvements in the orbit determination for low Earth orbit satellites over the last few decades. These improvements have allowed climate-driven variations in the hydrosphere to be detected for the first time. The monitoring of global mean sea level variations was not originally a goal of satellite altimeter missions such as TOPEX/Poseidon, but now they are measured with an accuracy of ∼4 mm every 10 days because of improvements in the orbit determination (radial component ∼1 cm) and other advances. Similarly, satellite gravity missions such as GRACE have allowed time-variable gravity to become a major scientific objective, with monthly estimates of changes in global ocean mass with an accuracy of 2 mm. Taking advantage of these measurements for climate change studies will require multidecadal time-series using multiple satellite missions that may be tracked by different techniques and methods as technology evolves. For this reason, maintenance and improvement of the terrestrial reference frame is a critical component of an overall plan to monitor the Earth’s water reservoirs from space.

Earth's Gravity Field Derived from Grace Satellite Tracking Data

An Earth's gravity field model IGGGRACE01S has been derived from 141 days of GRACE tracking data, including K-band, accelerometer, and satellite orbit data. The model resolves the geoid with an accuracy of about 0.012m at a resolution of 500m half-wavelengths, it improves the accuracy of the gravity field model in the long- to medium-wavelength part (< 80 degree) in comparison with the pre-CHAMP model. Comparing the coefficients of IGGGRACE01S, EIGEN-GRACE02S, EIGEN-CHAMP03S and EGM96 models, the result shows that the coefficients of IGGGRACE01S are much closer to those of EIGEN-GRACE02S, and very different to those of the other two models. Comparing the geoid undulations and gravity anomalies derived from IGGGRACE01S, EIGEN-GRACE02S and EGM96 models, the results indicate that the IGGGRACE01S solution is much closer to EIGENGRACE02S solution, and there exist large differences between IGGGRACE01S and EGM96 in Antarctica region. Comparing the gravity anomalies derived from IGGGRACE01S (72 degree) with NIMA gravity anomalies data (2.5° × 2.5°), the standard deviation is 4.8 mGal in China mainland region.