This paper briefly recounted the general situation, the main technological development and the application results of airborne geophysical survey in national land and resources survey since the beginning of the 21st century, and made an analysis and prognosis of the development trend of airborne geophysical exploration in China.

The development of the gravity gradiometer is described simply in this paper, and the measuring principle and development experience of the rotating accelerometer gravity gradiometer are emphatically discussed. On the basis of researches on the existing airborne gravity gradiometer, the prospects of the airborne gravity gradiometer are also presented.

The Altyn Tagh fault zone is an important strike-slip fault zone in northwestern China. The aeromagnetic data processed with methods of reduction to the pole and upward continuation offer plentiful information on faults and geological blocks. On such a basis, the geological-geophysical characteristics and displacement of main faults in the Altyn Tagh fault zone were analyzed. The detachment between its cap rock and basement was simulated by means of forward operation and inversion. Its formation time and tectonic evolution are discussed on the basis of geological data.

Located in the transitional position between Qinling Mountains and Sichuan Basin, the Daba Mountain nappe structure is composed of pull-apart basin, nappe zone, mobile belt, disturbed zone and main slide surface, with the mobile belt and the disturbed zone being favorable places for oil-gas accumulation. Based on computing and analyzing gravitational and magnetic data, the authors obtained the nappe distance of the nappe zone, and reached the conclusion that sedimentary strata of Sichuan basin may exist under the inferred nappe zone. The result is helpful to exploring oil-gas resources in Sichuan basin.

Using aeromagnetic data in combination with other geophysical information, the authors studied basic characteristics of the Tan-Lu fault belt in the Bohai Sea area, discussed detailed features of the tectonic line passing through the sea area, and investigated the control role of the fault belt over the Bohai Sea Basin as well as the relationship between this fault belt and the oil and gas fields. The Bohai Gulf area seems to the authors to be a favorable place in search for volcanic type oil and gas accumulation. It is also pointed out that new oil and gas fields might be found along the major fractural line of the Tan-Lu fault belt and its lateral areas.

This paper describes the present situation of applying aerogeophysical techniques to 1:250 000 regional geological mapping. It is believed that aerogeophysical techniques are important in identifying volcanic rocks, intrusive rocks, metamorphic rocks, fractures and volcanic structures, and that the application results are especially obvious in detecting underground information. Therefore, these techniques can make regional geological mapping more effective and scientific.

An analysis of the gravity and magnetic data shows that the boundary between the Yangtze platform and the Songpan-Ganzi orogenic belt should be the Songpan-Wenxian fault rather than the Longmenshan fault. This means that the whole Longmenshan area should belong to the Yangtze platform. Meanwhile, it is thought that the basement rock characteristics of the Songpan-Ganzi orogenic belt are different from those of the Yangtze platform.

In the past twenty years, more and more Pt1 and Ar geo-information was found in Southeast China, and the geo-information concentratedly obtained around the Wuyi uplift is called "Wuyi geo-information". The "Wuyi geo-information" manifested in different geophysical fields shows that there are several remaining continental nuclei in this area. Based on a synthetic analysis of some kinds of geophysical fields, the authors hold that there exist several remaining continental nuclei in Southeast China, and the Cathaysia was formed by the accretion of many remaining continental nuclei.

According to a preliminary study of the aeromagnetic data, a deep NS-trending fault was recently recognized which controls the western edge of continental shelf basins of the East China Sea. The authors have studied the formation period of the NS-trending fault, and also analyzed the geological significance of this fault in controlling igneous rocks and the strike of the tectonic line.

High resolution aerogeophysical survey was carried out in the Beishan area in recent years, which makes it possible to distinguish different lithologies on the basis of their geophysical fields. The results obtained can also provide new information for geological exploration. This paper describes briefly the mapping of acid intrusive rocks in eastern Beishan area.

A statistical analysis of magnetic characteristics of genetically different granites shows that different types of granites composed of different mantle source materials have different magnetic characteristics: the more the deep source materials in the granite, the stronger the magnetism. The judgment of the genetic type of the granite on the basis of the intensity of magnetism is of important geological significance in geological interpretation of the magnetic surveying data obtained from the southeast coastal area of China as well as in the related geological researches and ore-prospecting work.

Based on the newly-obtained 1:200 000 aeromagnetic survey data in combination with geological, geophysical and geochemical data available, the authors evaluated the ore-searching prospects in the area along the Yarlung Zangbo River and two other rivers of Tibet. 28 promising areas were detected which can be divided into three grades, and 21 ore targets were delineated within the 1st and 2nd grade areas. Fairly good aeromagnetic anomalies lie in these targets, and hence these targets deserve much attention in further ore-prospecting work.

Based on 1:200 000 high-precision aeromagnetic survey in Weixi-Ninglang area along the central part of the Sanjiang region and a comparison with the magnetic anomaly characteristics of the known intermediate-acid intrusive bodies, the authors have found that quite a few magnetic anomalies are consistent with the known intermediate-acid intrusive bodies. In combination with physical characters and geological, gravity and geochemical data, tens of shallow or concealed intermediate-acid intrusive bodies were delineated. An analysis of the relationship between these rock bodies and known ore resources reveals the close relationship between the intermediate-acid intrusive bodies and Au, Ag, Cu, Pb, Zn polymetallic ore resources. It is thus concluded that these intrusive bodies serve as favorable areas in search for these ore resources.

Airborne geophysical integrated station survey was carried out in Beishan area in 2005, which makes it possible for researchers to establish different criteria in search for some typical deposits, sets up a standard for ore prognosis in different geophysical fields and geologic settings, and will greatly help the ore-prospecting work in this area.

Based on the data of 1:50 000 helicopter electromagnetic and magnetic comprehensive survey in Longmen, Guangdong Province in 2005, in combination with the geological and mineral sources data, the authors analyzed and studied the relationship between the mineral resources and the aeromagnetic or aeroelectromagnetic anomaly characteristics in Longmen area. The local aeroelectromagnetic anomalies were classified by using the classification method for electromagnetic anomaly characteristics, and the anomalies resulting from electromagnetic interference were identified. Based on field inspection of three optimized local anomalies, the authors found that the air and ground anomalies are well consistent with each other. In addition, some significant good underground conductors were detected.

Based on the data obtained from the 1:5 000 helicopter electromagnetic and magnetic comprehensive survey in 2004, in combination with ground coal geology as well as geophysical prospecting and remote sensing information, the authors studied the relationship between the aeroelectromagnetic or aeromagnetic characteristics and the distribution of underground coal fire in Wuda area, Inner Mongolia. Through a comprehensive analysis, the dividing indexes for underground coal fire of this area were built, and the distribution and burning situation of underground coal fire in this area were analyzed.

According to the high temperature characteristics of the burning coal seam and the diffusion regularity of radon gas, this paper proposed a new calculation method for the burial depth of the burning coal seam based on radon gas measurement. This method was used in the Wuda working area of Inner Mongolia, and the result is quite consistent with that obtained by the magnetic method, suggesting that this method is reliable. The new method can provide a useful means for extracting more information about the coal fire from the radon measurement.

The power spectrum method has been extensively and successfully used by geophysicists both in China and abroad to estimate the buried depth of magnetic bodies. However, the estimated results only statistically reflect the average buried depth of the magnetic bodies under the calculation window, and the estimating precision is thus affected as a result of equal window size and equal sliding step in calculation. In this paper, the authors have developed a visualized and high precision program that can select window size and site and sliding step voluntarily. Its application to a coal fire area demonstrates the practicability of the program.

This paper has briefly discussed working principles of the electromagnetic system, the digital transmitter and the multi-frequency digital transmitting technology, and also dealt with the application of digital transmission to the electromagnetic system. The technical performance and survey capability of the electromanetic system have been greatly improved by introducing the up-to-date digital transmitting technology, which reduces the weight of the system, increases the flexibility and lowers the system drift and noise level.

Using FIR (Finite Impulse Response) lowpass digital filters based on window functions, the authors conducted experimental researches on the filtering of airborne gravity data, and obtained some useful results. By selecting proper window shape, window length and filter parameters, the window functions FIR lowpass digital filters can attain a good filtering effect on airborne gravity data.

The manual computer interaction aeromagnetic tangent method system is designed according to the flowchart of the manual tangent method. It combines manual experience and wisdom with strong computer power in calculating, consulting tables and processing graphs. It has many useful functions. Single profiles or multiple profiles can be displayed, zoomed and moved; characteristic lines and points can be protracted automatically and amended by manual computer interaction; depth, width and magnetization of magnetic body can be calculated automatically; results can be saved and displayed; visualization and work efficiency are improved considerably. Therefore, a great deal of work can be reduced. It also provides different means for effective interpretation of aeromagnetic anomaly. This system is developed with the VC + + development tool and is object-oriented. It can be applied on the win32 system.

Due to remarkable errors caused by the limited data-processing capacity and the low precision of curved surface data, the processing and transform methods for the curved surface potential field have seldom been used in practical work. In this paper,a frequency domain dipole layer method for the processing of aeromagnetic data of curved surface,together with the reducing noise means, is put forward. This method was used in the aeromagnetic area of Huangshi,Hubei Province. A comparison of the calculated data with the surveyed data shows that the result is satisfactory and the magnetic field is in accord with the magnetic body. It is obvious that the frequency domain dipole layer method has good practicality,and can hence be used to process the aeromagnetic data of curved surface.

There exist large quantities of aerogeophysical survey data, and the sampling rate of the coordinate data is not the same as that of the field data. Therefore, the efficient storage of the data seems to be the key technical problem in designing aerogeophysical database structure. The speed of storing and picking up data by the routine storage methods is slow. The storage method of BLOB can not only solve the problem that the sampling rate of the coordinate data is not the same as that of the field data but also reduce the record number and speed up storing and picking up data.

With the aerogeophysical collection data as an example and on the basis of Geodatabase data model and CaseTools and UML, this paper implements the construction of the Aero Geophysical Data Model.

Data constitute the foundation of a system. Correct data can give true information, whereas wrong data can misdirect the customer, resulting in heavy losses. When a system is built, we must first guarantee the correctness of the data. This paper deals with the means for data quality inspection in the aerogeophysical database system. Based on analyzing data characteristics and system requirement, the authors designed a different check means. With this means, the data are neither redundant nor insufficient, and thus the data integrity and validity can be ensured.

The aerogeophysical survey performed in some area of south China discovered that the natural radioactive radiation level is rather high in that area. The authors detected the geological factors responsible for such high radioactive radiation and the distribution of the radiation, evaluated the average effective dosage received by the inhabitants in the high natural radioactive radiation area, and discussed the harmful results of human activities leading to the transportation and diffusion of radioactive rock materials. The utilization of airborne geophysical data constitutes an important basis for the environmental protection planning.

The shallow water resources of Zhuhai-Shenzhen area in southern Guangdong Province have been polluted heavily due to different causes. The shortage of freshwater resources has resulted in the tightness of the civil water and industrial water supply and restricted the development of industry. In order to solve the problem, the aerogeophysical survey techniques (aeromagnetic survey, airborne electromagnetic survey and airborne gamma ray survey) were applied in this area in recent year. On such a basis, the distribution of the transgression and the freshwater was detected, and the shallow water quality and the ground hot water resource potential were evaluated. The results obtained prove to be very useful in the scientific evaluation of the shallow water resource environment.