This year we celebrate the 56th anniversary of USSR airborne magnetics and 53rd anniversary of its use for geological interpretations. There are three large periods in Russian aeromagnetics.

The Flying Laboratory (FL) based on the IL-76MD Aircraft (Figure 1) was built in 1988. The FL belongs to the Precision Instruments Scientific and Production Association, Moscow. It is managed and serviced by the M. M. Gromov Flight Research Institute, Zhukovsky, Moscow region.

I talk about a flying laboratory based on the IL18 aircraft. It has been carrying out research since 1985. I talk about two modifications to this laboratory: First, the aircraft, which belongs to Civil Aviation Ministry, was to be modified. Second, more advanced modifications were carried out upon the IL18 which belongs to the Leninetz Concern.

It is well known that the study of spatial and temporal characteristics of the GeoMagnetic Field (GMF) is very impor- tant. The GMF is used to study the nature of geomagnetism, investigate the deep structure of the Earth, dynamics and peculiarities of its development, forecast earthquakes, explore mineral resources, for the purposes of autonomous navigation and air traffic control, and solution of other problems.

Historically, the Russian airborne data logging systems start from the early 1950 1:200,000 general mapping of the former USSR. Until the middle 1980s, magnetic and punch tapes were practically the only media used on board. Unfortunately, we were not able to find the photographs illustrating the devices of early periods.

I am representing the flight test institute named by Gromov. It is situated at the airfield to the south of Gromov Flight Testing Institute, Zhukovskij, where the flying laboratory IL76MD is stationed. We took off from this airfield to make our way to Denver. The crew of the Flight Test Institute was piloting the IL76MD. Dr. Dewhurst has visited our company, but until recently our institute was not well known here in the United States. I think that after the International Air Show, which took place at our Institute in August 12-16, 1992, the Institute will be better known in the United States. By the way, we are planning to to organize air shows like that on a regular basis. For the time being, we are planning to have one every two years. We hope that this will give us a background for future advantageous cooperation. At the air show which we had this year, a number of American companies took part.

The characteristics of the GOI Airborne LIDAR System are presented. The improvements provided by the high repetition frequency (16 kHz) of Cu⁺ laser and the narrow band (2 angstroms) of a holographic filter device on REOXAN material are discussed. The comparison of the system performance with that of known modern LIDAR systems in different modes of operation and external conditions (aircraft altitude, depth, sunlight intensity, sea-water parameters) on the base of Sakitt's criterion (D-index of discrimination) is presented.

In several LIDAR sounding experiments, certain anomalies in the registered pulse shape were observed, such as the time delay between maxima of pulse of sea-water response and surface- reflected pulse, and unexpectedly high level of signals from isolated sea-water layers. These peculiarities cannot be explained with the traditional theoretical treatment of the echo-signals. In this paper, a new explanation of the return signals shape anomalies is presented. Our approach is based on the accounting of the angular anisotropy of the scattering in the back hemisphere and the geometrical conditions of the typical LIDAR experiments. We present computational data and laboratory measurement results related to enhanced backscattering by large coated particles suggested to model the optical properties of some algal cell species (diatoms, and so forth). The model calculations of the LIDAR signal shape show that such particles may be responsible for an anomalously high level of LIDAR signals from isolated sea-water layers.

The paper is devoted to consideration of the main airborne and ship LIDAR systems developed in Russia in the last years for sea water analysis and bathymetry of near coastal regions. The comparative analysis of the systems and their analogies from other countries are given. The level achieved in elaboration of separate elements of LIDARS is also examined (lasers, receiving optical systems, spectral selectors, cooling devices, and so forth).

The St. Petersburg Filial (Division) of IZMIRAN has recently initiated a major new research project involving the Airborne Optic and Magnetic Observatory (ABOMO). ABOMO is designed specifically for studies of auroral, magnetic, ionospheric and atmospheric phenomena including ozone and other important atmospheric constituents. The observatory is constructed aboard a modified four-engine turboprop aircraft AN-12.

Data on the spectral transparency of the atmosphere and on the solar halo obtained in the region of the Norwegian and Greenland Seas are given and analyzed. The use of the procedure of the joint circulation of the spectral transparency of the atmosphere and brightness of the solar halo to the aerosol microstructure, as well as synchronous aerological observations, made it possible to check the aerosol microstructure variations depending on a vertical distribution of meteorological components.

A possible mechanism of the influence of solar and geomagnetic activity and of other cosmophysical factors on processes in the lower atmosphere, weather and climate is considered. The main feature of the proposed mechanism is the change of the atmosphere transparency under the influence of galactic and solar cosmic rays. This change of atmosphere transparency is connected with the change of the atmospheric species content, with the development of cycles of nitrogen and hydrogen physical-chemical reactions, including changes in the structure of the clouds. The main cause of the variations in intensity of cosmic rays is the variability of solar activity and of solar wind structure.

Terrestrial surface images obtained by airborne or spaceborne remote sensing in various spectral ranges are widely used in many applications, including geophysics and ecological monitoring. A broad class of problems arising in the analysis of such imagery can be formulated in terms of object identification. Here are just a few examples.

The problem of digital image recognition can be regarded both as a problem of testing multiple hypotheses and as a position measurement problem. In the first case, a criterion of algorithm efficiency can be the probability of a correct decision, while in the second one it should be the measurement accuracy [1]. Automatic image recognition can result in so-called anomalous errors when the maximum of the algorithm response (which we shall call the decision function, or DF) appears at a location entirely different from the true position. Usually, the response field has a peak at approximately the correct place and a number of other, smaller peaks located at random. Under strong image distortions, one of these false peaks can become larger than the main peak, leading to an anomalous error. On the other hand, the maximum of the main peak may be somewhat shifted from the correct match position. This deviation, usually small, will be referred to as a normal error.

In the systems that use imaging radars for aircraft navigation, one of the main problems is the estimation of aircraft attitude based on the Doppler spectrum of the received signal. This information is required not only for purely navigational purposes: without knowing the precise orientation of SAR antenna beam, it is practically impossible to correctly build a uniform radar image within the antenna pattern because of signal modulation (or weakening) by the antenna beam in the azimuth direction. The methodology of such measurements has been developed in a number of our works using a statistical approach to pattern recognition, including the issues of suboptimal algorithm construction and accuracy evaluation [1,2].

A geomagnetic field is a vectorial quantity. However, the single method of conducting magnetic surveys is the measurement of the modulus (absolute value) of the magnetic field intensity T. This is caused by the constructive simplicity of the T-magnetometer and by the possibility of measurements on a moving carrier and by insufficiently strict, often qualitative, geological interpretation of magnetic anomalies. For measurement of the vectorial geomagnetic field components H and Z, there are necessarily more complex measuring arrangements, caused by stringent requirements for disposition of magnetic sensors and platform stabilization on a moving carrier.

This work deals with a principally new method of definition of the components of a magnetic induction vector of a geomagnetic field on board a moving carrier which has an intrinsic magnetic field. The basic physical principles of the suggested method, which is called the method of definition of the angular components (MDAC), are investigated in simple examples (MOUK). They allow us to explain methods of exception of the influence of the intrinsic magnetic field of the carrier on measurement results.

Modern equipment and techniques of airborne surveys (ABS) enable us to carry out measurements with an error less than 2 - 5 nT. These surveys permit us to map anomalies having an intensity equal 2 - 15 nT, that is, the so-called `thin structure' of the magnetic field. Raising the accuracy of the measurement of a geomagnetic field expands the range or scope of the objectives to be recorded. That poses the problem of the special nontraditional manner of the technique of the survey, the acquisition and the mapping. Of very great importance is detecting and calculating the variations which at high latitudes change very rapidly in space and time. Under these conditions, the direct method of accounting for the variations, requiring the creation of a dense net of variation stations on coast and aquatory, appears to be non- effective and sometimes impossible. Then it is necessary to use the indirect method which is based on a special technique of the survey and its acquisitions.

Compiling a geomagnetic map is the final stage of magnetic surveys. The connection between the technique of the survey, its accuracy and the map quality is clear. The map quality is determined by the accuracy of the information taken from it. The accuracy of the map characterizes by its rms (rE); summarizing from the rms of the initial information and from the errors of mapping:

The following types of magnetic observations and surveys were made by the geophysicists of the former USSR on its territory and on the territories of other countries and aquatories: . observations from the observatories S observations from the 1 76 repeat stations . land magnetic surveys . airborne surveys . hydromagnetic surveys . surveys from satellites . the standard magnetic measurements carried out at the observatories with standard apparatus by a standard program At the repeat stations, the modulus of total force (F), the horizontal component (H) and the magnetic declination (D) are measured with proton magnetometer (MMP-203), the quartz QHM-magnetometer and the astronomical theodolite. The errors of the measurement of F, H and D are equal to 12nT, 35nT, *12' accordingly. The observations are execute once in five years.

This report is devoted to the achievements of the consortium called Leninetz in terms of magnetometers and the development of these kinds of devices. The report is in two parts, the first one is devoted to the highly precise calibration system for magnetometers. The second part is devoted to a description of various types of magnetometers developed and manufactured by our company. The technical principles which are presented in this report are embedded in the development of this calibration system, which has been tested. There is technical documentation for this system and it is ready for mass production.

The summary geomagnetic field on the reference field for the regional anomalies is surface of the Earth consists of the follow- the sum of the main geomagnetic field and ing components: the intermediate anomalies. Since the components mentioned above have the F0 = Fm + Fim + Fr + F1 + F (1) different space-spectral characteristics, different methods are used for the analytiwhere cal descriptions. The main geomagnetic field, being the global reference field, is approximated by F0 - the observed geomagnetic field the optimal way as a spherical harmonic Fm - the main geomagnetic field series [1]: Fim - the field of the intermediate anoma- n lies Fr - the field of the regional anomalies X = (g cosm\ + n=i m=O F1 - the field of the local anomalies, - the external geomagnetic field.

Magnetometric data traditionally were widely used in applied and geological- geophysical tasks. Primarily in such cases, the area of interest is divided by magnetic field characteristics. This procedure is to be done either qualitatively or quantitatively by using correlation analysis of data [1]. Qualitative methods have no quantitative criteria of field estimation and because of that they are subjective. The correlation analysis has digit characteristics, but in a non-ordinary field, the following difficulties could be met: • in anomalous field spectrums, as usual, several components are present and for division the components of anomalous field a priori knowledge of transformation optimal parameters is necessary; • some components of anomalous field are piece-stationary.

Geomagnetic pulsations are generated at great distances from the Earth's surface due to a plasmic instabilities of different kinds and a resonance processes in the solar wind and in the magnetospheric- ionospheric plasma. After complex pro- cesses of transformation and propagation along force lines of the magnetic field to the Earth's surface, they induce telluric currents in the conducting earth's crust. Geomagnetic pulsations observed on the earth's surface carry information about both the physical parameters of interplane- tary medium, magnetosphere and iono- sphere, and geoelectric features of the Earth's crust. At the same time geomagne- tic pulsations are natural hindrances that should be taken into account during the performance of precise magnetic surveys including surveys on marine and aircraft bearers. The research on the frequency of geomagnetic pulsation appearance and on the spatial-temporal distribution on their parameters can present highly useful and valuable material that can be considered in a wide context depending on the direction of investigations.

One of the major directions in geomagnetic studies is the study of regional and large regional anomalies (RA and LRA). V.1. Pochtarev (Pochtarev et al., 1965) was the first one who singled out this class of anomalies and developed a schematic map of LRA for the territory of the USSR. The size of the anomalies varies from 200 to 1000 km and, in the amplitude spectrum, RA are located in its main minimum.

The present report concerns applied aspects of employment of aerogeophysical methods to create a geophysical basis for geomapping and searching purposes. Adoption of high-accuracy equipment with digital measurement recording in practice of aerogeophysical surveying made it possible to set a task of investigation of the geological-geophysical structure of ore- promising provinces on a new qualitative level.

In 1991 it was 55 years since the application of airborne magnetic surveys on USSR territory, and 52 years since its practical usage at geological institutes. It is possible to outline three periods of such a survey. (1) 1936-55. In this period the magnetic field vertical component was measured with the use of an induction magnetometer developed by A.A. Logachev. The main features of this simple instrument is a half-ring collector, a type of suspension, a compensation mode of measuring with a semi-automatic analog recording, and so forth, and a special system of tuning enabling one to receive a root mean square error of the survey in the range of 50-200 nT. With the use of this magnetometer, the territory of 2,000,000 km2 was surveyed, a number of deposits were discovered ( Krasnokamensk iron-ore deposit in South Siberia in 1943 included), geological maps were refined, and in the period of 1948-49 the first survey in the Arctic (for geological zonation) was conducted.

A thorough system of interpretation programs and methods consists of a concordance of program system service and substance functional content, a wealthy range of techniques, wide scale of programs, which introduces original, apt, and luckily found calculation devices. The whole package and its method is supplied with author know-how, tending to put into practice, in full measure, the possibilities of such a splendid tool as the package. Processing of the material is performed with diverse algorithms, selected according to assigned requirements; it adequately reflects the situation, available geology reality and information security; and rationally and thriftily utilizes calculation means.

The characteristic of the ULF magnetic field emissions measured at two magnetic observatories in the Republic of Georgia prior to and after the M equals 6.9 earthquake that occurred near Spitak, Armenia on December 7, 1988 are compared with the apparently similar emissions associated with the M equals 7.1 earthquake that occurred near Loma Prieta, California on October 19, 1989.

At present, a complex of technical equipment and special technologies for the measurement of gravity fields in areas of water and difficult-to-access land locations (taiga, mountains, marshes, and so forth) has been created to solve geological and forecast-searching problems of oil, gas, and other minerals. The complex includes the shipboard gravimeter for non-stop measuring on a moving ship, the air-gravimeter for measuring from aircraft, and an on-land gravimeter with a remote control system for discrete measuring on the sea-floor and surface, on an outward suspension bracket of a helicopter, or on shipboard. Discrete distant measuring from helicopters and ships is held for surveys of high accuracy, as well as for supporting insurance of shipboard and air-gravimetric work.

Beginning from the seventies, the Central Scientific Research Institute Elektropribor (St. Petersburg) has developed automated gravity systems for oceanographic ships. The first automated system CHETA-AGG was delivered to the Navy Oceanographic Service in 1983. Today, more than 10 systems are used on ships. Their high accuracy and reliability is confirmed in the process of exploitation.