Precise positioning of the Chang’E-3 lunar lander using a kinematic statistical method

A kinematic statistical method is proposed to determine the position for Chang’E-3(CE-3) lunar lander.This method uses both ranging and VLBI measurements to the lander for a continuous arc,combing with precise knowledge about the motion of the moon as provided by planetary ephemeris,to estimate the lander’s position on the lunar surface with high accuracy.Accuracy analyses are carried out with simulation data using the software developed at Shanghai Astronomical Observatory in this study to show that measurement errors will dominate the position accuracy.Application of lunar digital elevation model(DEM) as constraints in the lander positioning is also analyzed.Simulations show that combing range/doppler and VLBI data,single epoch positioning accuracy is at several hundred meters level,but with ten minutes data accumulation positioning accuracy is able to be achieved with several meters.Analysis also shows that the information given by DEM can provide constraints in positioning,when DEM data reduce a 3-dimensional positioning problem to 2-dimensional.Considering the Sinus Iridum,CE-3 lander’s planned landing area,has been observed with dedicated details during the CE-1 and CE-2 missions,and its regional DEM model accuracy may be higher than global models,which will certainly support CE-3’s lander positioning.     

Orbit determination of Chang＇E-3 and positioning of the lander and the rover

Chang＇E-3 landed on the east of Sinus Iridum area on December 14, 2013, performing China＇s first successful soft landing on the lunar surface. We present the results on precision orbit determination and positioning of the lander and the rover. We and methods used to achieve period December 2-21, 2014. describe the data, modeling, position knowledge over the In addition to the radiometric X-band range and Doppler tracking data, delta differential one-way ranging data are also used in the calculation, which show that they strongly improve the accuracy of the orbit reconstruction. Total position overlap differences are about 20 and 30m for the 100km × 100km and 100 kmx 15 km lunar orbit, respectively, increased by ,- 50 % with respect to CE-2 and at the same level as other lunar spacecrafts of recent era such as SELENE and lunar reconnaissance orbiter （LRO）. The position error of the soft landing trajectory is less than 100 m. A kinematic statistical method is applied to determine the position of the lander and relative position of the rover with respect to the lander. The position difference of the lander is better than 50 m compared to LRO photograph result. Compared with the delta very long baseline interferometry （VLBI） group delay between the lander and the rover, the delta VLBI phase delay can improve the relative position of the rover from ～ 1,000 to ～1 m.     

Preliminary results of TiO<Subscript>2</Subscript> mapping using Imaging Interferometer data from Chang’E-1

The distribution of titanium abundance on the lunar surface is important knowledge for lunar geologic studies and future resource utilization.In this paper,we develop a preliminary model based on"ground truths"from Apollo and Luna sample-return sites to produce a titanium abundance map from Chang’E-1 Imaging Interferometer(IIM) images.The derived TiO2 abundances are validated with Clementine UVVIS results in several regions,including lunar highlands neighboring the Apollo 16 landing site,and high-Ti and low-Ti maria near the standard site of Mare Serenitatis(MS2) .The validation results show that TiO2 abundances modeled with Chang’E-1 IIM data are overestimated for highlands(～0.7 wt.%) and low-Ti maria(～1.5 wt.%) and underestimated for high-Ti maria(～0.8 wt.%).     

Preliminary results of FeO mapping using Imaging Interferometer data from Chang'E-1

Information about the variability,and spatial distribution of iron abundance is important to understand lunar geological history and for future resource utilization. In this paper we present a preliminary model to produce an iron abundance map using images taken by an Imaging Interferometer on board the satellite Chang’E-1. Compared with the Clementine UVVIS images,the images from the Chang’E-1 satellite also allowed for the extraction of FeO abundance distributions on the Moon. However,the prelimi-nary model results suggest an underestimation of ～2 wt.% for the FeO content of the mare region and an overestimation of ～3 wt.% for the highland region.     

The modeling analysis of microwave emission from stratified media of non-uniform lunar cratered terrain surface for Chinese Chang-E 1 observation

In China’s first lunar exploration project,Chang-E 1,the multi-channel (3.0,7.8,19.35,37 GHz) microwave radiometers were aboard the satellite,with the purpose of measuring microwave brightness temperature from lunar surface and surveying the global distribution of lunar regolith layer thickness,and global evaluation of 3He content.To analyze the modeling of microwave radiative transfer from three-layered media of lunar surface,some factors,such as the cratered lunar surface roughness,scattering of regolith particulate medium with temperature profile,are discussed.Based on the statistics of the lunar cratered terrain and using Monte Carlo (MC) method,the cratered lunar surfaces are numerically generated.The triangulated network is utilized to divide the undulated lunar surface into discrete triangle meshes with the size 10 m as a digital surface topography.The reflectivities of each plane mesh are calculated,and the average reflectivity for all MC-realized lunar surfaces is obtained.It is found that under the spatial resolution of 30 km×30 km of Chang-E 1 radiometer observation,the lunar surface can be well modeled as a flat surface.It makes the predominance of the parameters,such as the regolith layer thickness and stratified structures,to be studied.Using the radiative transfer equation of stratified media with dense scatterers,the scattering coefficient of the regolith particulate medium is found negligible,and the emission is mainly governed by the absorptive property of the medium.Brightness temperature of multi-layered media,i.e.lunar soil,regolith layer with temperature profile and underlying rock media,are derived and calculated,and relevant main factors to affect the modeling and emission simulation are analyzed.     

China''s Lunar Exploration Program——The Third Milestone for China''s Space Industry

1PrefaceThe moon is the only natural satellite of theEarth.It has a tranquil,bright and clearappearance in the eyes of people on the Earth.Because of its thin brilliance that brings loverswith quiet warmthinthe night,it is likened to ajade plate or a lovely and graceful woman.In the late1950s and early1960s of the lastcentury,the former Soviet Union and the UnitedStateslaunched spacecraft to explore the moon insuccession.Particularly,the U.S.performedthefirst manned landing in the Apollo11…     

Improving the accuracy of GRACE Earth’s gravitational field using the combination of different inclinations

In this paper, the GRACE Earth’s gravitational field complete up to degree and order 120 is recovered based on the combination of different inclinations using the energy conservation principle. The results show that because different inclinations of satellite are sensitive to the geopotential coefficients with different degrees l and orders m, the design of GRACE exploiting 89o inclination can improve effectively the accuracy of geopotential zonal harmonic coefficients. However, it is less sensitive to the geopotential tesseral harmonic coefficients. Accordingly, the second group of GRACE exploiting lower inclination is required to determine high-accurately the geopotential tesseral harmonic coefficients and cover the shortage of the single group of GRACE exploiting 89o inclination. Two groups of GRACE individually exploiting 89o+(82o－84o) inclinations are the optimal combination of the Earth’s gravitational field recovery complete up to degree and order 120. In the degree 120, the joint accuracy of cumulative geoid height based on two groups of GRACE individually exploiting 89o and 83o inclinations is averagely 2 times higher than the accuracy of a group of GRACE exploiting 89o inclination.     

Improving the accuracy of GRACE Earth’s gravitational field using the combination of different inclinations

In this paper, the GRACE Earth’s gravitational field complete up to degree and order 120 is recovered based on the combination of different inclinations using the energy conservation principle. The results show that because different inclinations of satellite are sensitive to the geopotential coefficients with different degrees l and orders m, the design of GRACE exploiting 89o inclination can improve effectively the accuracy of geopotential zonal harmonic coefficients. However, it is less sensitive to the geopotential tesseral harmonic coefficients. Accordingly, the second group of GRACE exploiting lower inclination is required to determine high-accurately the geopotential tesseral harmonic coefficients and cover the shortage of the single group of GRACE exploiting 89o inclination. Two groups of GRACE individually exploiting 89o+(82o－84o) inclinations are the optimal combination of the Earth’s gravitational field recovery complete up to degree and order 120. In the degree 120, the joint accuracy of cumulative geoid height based on two groups of GRACE individually exploiting 89o and 83o inclinations is averagely 2 times higher than the accuracy of a group of GRACE exploiting 89o inclination.     

Metallogenic epoch and genesis of the gold deposits in Jiaodong Peninsula, Eastern China: a regional review

Gold deposits are characterized by multi-sources, superimposition, large scale and temporal-spatial concentration in Jiaodong Peninsula, Eastern China. In this paper, we review the history and the development of the study on metallogenic chronology and genesis of gold deposits, summarize the main features of superimposed metallogenesis, provide evidence of the Mesozoic complex metallogenic system, and point out some problems for further research of Jiaodong gold deposit cluster from a regional view. Although gold deposits are different in genetic types, ore-forming materials and geological settings, our research indicates that the accumulation and emplacement of the ore-forming materials are temporally-spatially concentrated on a large scale, and the main metallogenic epoch of Jiaodong gold deposits was concentrated in Mesozoic. Metallogenic chronology and geological-geochemical data indicate that there are two periods of gold mineralizations occurred in 130?110 Ma and 90?80 Ma respectively in Jiaodong ore cluster. The gold deposit cluster results from the superimposition of the polygenetic mineralization, and further study is needed to investigate the formation and evolution of the Mesozoic complex metallogenic system.     

Chang＇E-1 orbiter discovers a lunar nearside volcano： YUTU Mountain

In the day time of the Moon surface, the strong illumination from high altitude and high albedo rate radical craters will introduce the illumination effect on observing the nearby low altitude, low albedo rate and shallow small slop rate area seriously, and even can ＂hide＂ the later area from the light. Based on the lunar global topography model obtained by Chang＇E-1 mission, and by comparing with the lunar gravity model, a volcano named ＂YUTU Mountain＂ has been identified. It is a volcano with diameter of -300 km and height of -2 km located at （14°N, 308°E） in Oceanus ProceUarum. Besides, the DEM of another volcano named ＂GUISHU Mountain＂ in the same area has been improved. This new discovery will benefit the study of lunar magmatism and volcanism evolution in the nearside of the Moon.     

Metallogenic epoch and genesis of the gold deposits in Jiaodong Peninsula, Eastern China: a regional review

Gold deposits are characterized by multi-sources, superimposition, large scale and temporal-spatial concentration in Jiaodong Peninsula, Eastern China. In this paper, we review the history and the development of the study on metallogenic chronology and genesis of gold deposits, summarize the main features of superimposed metallogenesis, provide evidence of the Mesozoic complex metallogenic system, and point out some problems for further research of Jiaodong gold deposit cluster from a regional view. Although gold deposits are different in genetic types, ore-forming materials and geological settings, our research indicates that the accumulation and emplacement of the ore-forming materials are temporally-spatially concentrated on a large scale, and the main metallogenic epoch of Jiaodong gold deposits was concentrated in Mesozoic. Metallogenic chronology and geological-geochemical data indicate that there are two periods of gold mineralizations occurred in 130-110 Ma and 90-80 Ma respectively in Jiaodong ore cluster. The gold deposit cluster results from the superimposition of the polygenetic mineralization, and further study is needed to investigate the formation and evolution of the Mesozoic complex metallogenic system.     

An FPGA Implementation of GF （p） Elliptic Curve Cryptographic Coprocessor

A GF (p) elliptic curve cryptographic coprocessor is proposed and implemented on Field Programmable Gate Array (FPGA). The focus of the coprocessor is on the most critical, complicated and time-consuming point multiplications. The technique of coordinates conversion and fast multiplication algorithm of two large integers are utilized to avoid frequent inversions and to accelerate the field multiplications used in point multiplications. The characteristic of hardware parallelism is considered in the implementation of point multiplications. The coprocessor implemented on XILINX XC2V3000 computes a point multiplication for an arbitrarypoint on a curve defined over GF(2^192-2^64-1) with the frequency of 10 MHz in 4.40 ms in the average case and 5.74ms in the worst case. At the same circumstance, the coprocessor implemented on XILINX XC2V4000 takes 2.2 ms in the average case and 2.88 ms in the worst case.     

Simulation and evaluation of the quality and availability of typical GLI ocean image

ADEOS-II satellite will be launched in the near future. It collocates many remote sensing instruments in the same platform. Among them, Global Image (GLI) is considered to be a main sensor which will play a key role. In order to understand the characteristics of future GLI ocean color images, a simulation and evaluation of the quality and availability of GLI typical ocean image has been done. In the paper, we first introduce the simulation models briefly, and simulate typical cases of radiance images at visible channels, in which the radiance distribution is based on geographic location, the satellite orbital parameters and sensor properties. A method, complex signal noise ratio (CSNR) to evaluate the image quality and availability, is developed according to the characteristics of image. Meanwhile, a series of CSNR images are generated from the simulated radiance components for different cases, which can be used to evaluate the quality and availability of GLI images before the ADEOS-II is placed in orbit. Finally, the quality and availability of GLI images are quantitatively analyzed by the simulated CSNR data. The results will be beneficial to the people who are in charge of GLI mission or plan to use the data from GLI.     

Unusual discrepancy between TOMS and ground-based measurements of the total ozone in 2002—2003

Monitoring the atmospheric ozone is one of the key projects in the atmospheric and environmental sciences, and the decrease of ozone in stratosphere has aroused the interests of governments and public in the world. Mainly two methods are used to measure the total atmospheric ozone in the globe: ground-based observation mainly including Dobson and Brewer ozone instruments, and satellite measurement. The popular satellite products are the Total Ozone Mapping Spectrometer (TOMS) data provided by the National Aeronautics and Space Administration (NASA) of the United States of America.     

An Experimental Biotelemetric Study Based on Satellite Tracking During Post—nesting Migrations of Green Turtles

A biotelemetry experiment is conducted to study the migrant behavior of green turtles(Chelonia mydas)in South China Sea and acquire the physical environment data.The method in use is to track the post-nesting migrant routes of green turtles through the satellite linked transmitters attached on the back of turtles and the global satellite signal transmitting system of Argos.We obtained the positions of the post-nesting migrant routes of three green turtles and environment data,which are important in conservation of green turtles and the research of physical oceanography.Based on the test,the concept,principle and method of biotelemetry are also introduced in this paper with a discussion of the further development of this technique and its applying prospection in future.     

Seismic tomography of the Moon

We attempted to determine the first three-dimensional P and S wave velocity and Poisson＇s ratio structures of the lunar crust and mantle down to 1000 km depth under the near-side of the Moon by applying seismic tomography to the moonquake arrival-time data recorded by the Apollo seismic network operated during 1969 to 1977. Our results show that significant lateral heterogeneities may exist in the lunar interior. Because there is no plate tectonics in the Moon, the lateral heterogeneities may be produced at the early stage of the Moon formation and evolution, and they have been preserved till today. There seems to be a correlation between the distribution of deep moonquakes and lateral velocity variations in the lunar lower mantle, suggesting that the occurrence of deep moonquakes may be affected by the lunar structural heterogeneity in addition to the tidal stresses. Although this is an experimental work and the result is still preliminary, it indicates that tomographic imaging of the lunar interior is feasible.     

The trajectory parameters analysis of saltating sand grains driven by wind

The study of trajectory parameters of saltating sand grains is of great importance to forming the kinematic theory of wind-sand current. By establishing the simplified theoretical pattern and probing into the relationship between lift-off angle (α) and landing angle (β), relationship between the ratio of saltation length ( L) to maximum height (H) and lift-off angle as well as the angular variation laws of any point on the trajectory, it has been demonstrated that the relations among these parameters are nonlinear. Meanwhile, it has also been proved that the theoretical analysis is basically reliable in accordance with the wind tunnel experiments using high-speed multiflash photography. Generally, the trajectory shapes of saltating sand grains are controlled precisely and the theoretical analysis is closely combined with the experimental results.     

Application of Uncertainty Reasoning Theory to satellite Fault Detection and Diagnosis

Reasoning theories are divided into certainty reasoning theories and uncertainty reasoning theories.Now,only certainty reason-ing theories use to deitcs are used to detect and diagnose satellite faults.However,in practice,it is difficult to detect and diagnose some faults of the satellite autiomatically only by use of ccrtainty.Fortunately.uncerlainty Reasoning theories are applied to detect and diagnose satellite faults.Uncertainty reasoning theories include several kinds of theories,such as inclusion degree theory,rough set theory,evidence reasoning theory,probabilisticresoning theory,fuzzy,fuzzy reasoningteory,and so on.Inclusion degree theory.rough set theory and evidence reasoning theory are three advanced ones,Based on these three theories respectively.the audhor introduces three new methods to detect and diagnose satellite faults in this paper.It is shown that the methods,suitable for detecting and diagnosing satellite faults,especially uncertainty faults,can remedy the defects of the current methods.     

Distributed Satellite Cluster Network: a Survey

The ability of the monolithic satellite,satellite orbit(especially GEO),and radio resource are very limited,so the development of distributed satellite cluster network(DSCN) receives more and more worldwide attention.In this paper,DSCN is surveyed and the study status of DSCN architecture design is summarized.The formation flying of spacecrafts,reconfiguration,networking,and applied research on distributed satellite spacecraft are described in detail.The DSCN will provide a great technology innovation for space information network,satellite communications,satellite navigation,deep space exploration,and space remote sensing.In addition,this paper points out future trends of the DSCN development.     

Determination of cloud-top height from stereoscopic observation

A new and accurate method is presented based on the cloud movement (height and position), the spherical and plane triangular relationships of the spacecraft, the center of the earth, the projected-cloud and the true-cloud for determination of cloud-top height and position. Synthetic stereo images that have spatial resolution of 1.25 km from a single satellite are used to test this method. It is demonstrated that the cloud-top structure can be determined from the stereoscopic measurements of geo-synchronous satellite with vertical accuracy of approximately 500 m. The vertical accuracy can be better with lower orbiters.