National Academy of Sciences of Ukraine National Space Agency of Ukraine Radar Techniques and Facilities for On-Line Remote Sensing of the Earth from Aerospace Carriers Edited by Academician of the NASU S.N. Konyukhov Corresponding Member of the NASU V.I. Dranovsky Dr. V.N. Tsymbal Translated by V.I.Soroka Kharkov 2010 The Monograph Radar Techniques and Facilities for On-Line Remote Sensing of the Earth from Aerospace Carriers The present book is a carefully arranged summary of engineering and scientific achievements resulting from the research efforts and practical applications associated with the development and testing of different radar systems for on-line remote sensing of the Earth's environment. These systems were installed both aboard the EOS "Cosmos-1500/Okean/Sich" and a number of aircrafts. A special emphasis was placed upon physicotechnical specificities and data acquisition potentialities of these systems, particularly, their calibration characteristics and data processing techniques. Scientific and methodical problems associated with a real-time retrieval of data on the state of the World Ocean surface, ice and land have been widely discussed. A number of specific examples of thematic interpretation and practical use of radar data are cited. The book is intended for these who are interested in exploring the natural resources from space, meteorology, environmental protection, geocryology radiophysics and electronics. It is also hoped that it will be of much benefit in terms of having appropriate qualifications for these particular businesses. Reviewers: Academician of the NASU L.N. Litvinenko, Director of the Radioastronomical Institute of the NASU Dr. O.P. Fedorov, Director of the Space Research Institute of the NASU and NSAU Corresponding Member of the NASU V.I. Lyalko, Director of the Scientific Centre for Aerospace Research of the Earth of the NASU Dr. V.K. Volosyuk, Prof. of the N.Ye. Shukovsky National Aerospace University (NAU) "Kharkov Aviation Institute". Autors A.G. Boyev (§1.1, §1.2); V.B. Yefimov (§1.3); V.N. Tsymbal, S.Ye. Yatsevich (§1.4); I.A. Kalmykov, V.N. Tsymbal (§2); A.S. Kurekin, O.L. Yemelyanov, S.S. Kavelin, Yu.D. Saltykov, O.Yu. Kulilovsky, A.M. Popel (§2.1); A.Ya. Matveyev, V.N. Tsymbal, A.P. Yevdokimov, V.V. Kryzhanovsky, D.M. Bychkov (§2.2); O.V. Sytnik (§2.3); A.Ya. Matveyev, S.Ye. Yatsevich (§2.4); A.S. Gavrilenko (§2.5); V.N. Tsymbal (§§3.1-3.6); V.B. Yefimov (§§4.1-4.3); V.B. Yefimov, I.A. Kalmykov (§4.4); V.N. Tsymbal, I.A. Kalmykov (§§4.6, 4.7); A.G. Boyev, A.Ya. Matveyev, V.N. Tsymbal (§5.1); A.Ya. Matveyev (§5.2); A.Ya. Matveyev, V.N. Tsymbal (§5.3) S.E. Yatsevich, I.A. Kalmykov (§6.1); V.N. Tsymbal (§§6.2, 6.3); V.N. Tsymbal, A.S. Kurekin, A.S. Gavrilenko, A.Ya. Matveyev, D.M. Bychkov (§7.1); V.N. Tsymbal, A.S. Kurekin, A.S. Gavrilenko (§7.2); S.Ye. Yatsevich (Appendix 1); A.P. Yevdokimov, V.V. Kryzhanovsky (Appendix 2). The authors who have readily consented to make valuable contributions to this book constitute an expert team of researchers and design engineers who are currently with the following institutions: Kalmykov Center for Radiophysical Sensing of the Earth of the NASU and NSAU, A.Ya. Usikov Institute for Radiophysics and Electronics of the NASU, Radioastronomical Institute of the NASU and the Design Office "Yuzhnoye". UDC 621.396.96'06 R13 Radar Techniques and Facilities for On-Line Remote Sensing of the Earth from Aerospace Carriers / A.G. Boyev, V.B. Yefimov, V.N. Tsymbal at al.; edited by S.N. Konyukhov, V.I. Dranovsky, V.N. Tsymbal. – Kharkov (Ukraine): Publishing house Sheynina O.V. – 2010. – 428 p. ISBN 978-966-1536-57-8 3 TABLE OF CONTENTS Page FOREWORD........................................................................ 5 CHAPTER 1. THEORETICAL FOUNDATIONS AND DISTINCTIVE FEATURES OF RADAR TECHNIQUES AND FACILITIES OF REMOTE SENSING OF THE EARTH……………………………….................................. 14 Introduction............................................................................................................ 14 § 1.1 Radio wave scattering by sea surface………............................................... 16 § 1.2 The influence of surface-active films on radio wave scattering by sea surface .......................................................................................................... 26 § 1.3 Microwave radio wave sea ice scattering …………………........................ 42 § 1.4 Features of land surface, vegetation and soil scattering at microwave band.................................................................................................... 58 CHAPTER 2. AEROSPACE RADARS OF ON-LINE REMOTE SENSING OF THE EARTH…………………………………………………..…………..... 86 §2.1 The basic operating features of the EOS "Cosmos-1500" SLR..................... 104 §2.2 Airborne radar complexes for remote sensing of the Earth........................... 110 §2.3 The criterion for informative characteristic properties offered by remote sensing radar systems........................................................................ 130 §2.4 Calibration features of air- and spaceborne SLR and SAR systems for on- line environmental monitoring of the Earth………..................................... 137 §2.5 The distinctive features of on–line data processing aboard the satellite - based SLR of the “Cosmos-1500” type and airborne multifrequency radar 152 complex “MARS”…………………………………………………............. CHAPTER 3. ON-LINE RADAR REMOTELY SENSED AEROSPACE MONITORING OF THE WORLD OCEAN…………………………................. 179 §3.1 Monitoring of the hazardous processes in the ocean-air system…………… 179 §3.2 Determination of the near-sea surface wind field parameters from radar images of the ocean surface…..……………………………........................ 197 §3.3 Tropical cyclones, hurricanes, typhoons….................................................... 206 §3.4 Comparison between remotely sensed radar data and in-situ measurements. Estimation of validity of definition of the near-sea surface wind field parameters from radar data………….......................................... 215 §3.5 Widespread effects of hazardous atmospheric processes in coastal areas and inland seas …………………………………......................................... 219 §3.6 Use of multifrequency radar data for monitoring of the aroused sea surface state............................................................................................................... 226 CHAPTER 4. ON-LINE RADAR SEA ICE MONITORING. ENSURING THE NAVIGATION SAFETY IN ICE CONDITIONS............................................... 228 § 4.1 Experimental investigations into the signatures of microwave sea ice backscattering …………….………………................................................. 228 § 4.2 The linkage between the characteristics of microwave radio signals scattered by sea ice and its physical-chemical and electrophysical properties…………………………………………………………………. 240 § 4.3 Methodical features of thematic processing of the spaceborne SLR information on the ice sheets…………..………………………………...... 246 § 4.4 Remote sea ice diagnostics using spaceborne SLR facilities…..…….......... 248 § 4.5 Particular features of ice cover remote sensing by multifrequency radar techniques…………………………………………………………............. 260 § 4.6 Rescue operations aimed at salving the cargo vessel fleet using the data from the EOS "Cosmos-1500" SLR............................................................. 265 4 § 4.7 On the arrangements that were made to salvage the research/expedition vessel "Mikhail Somov" perilously jammed in the Antarctic ice…............ 269 CHAPTER 5. ON-LINE DETECTION OF MANIFEST SIGNATURES OF SURFACE AND INTERNAL SEA PROCESSES USING RADAR TECHNIQUES....................................................................................................... 272 § 5.1 Investigation into the inhomogeneities caused by oil product spills............ 273 § 5.2 Studies of inhomogeneities arising in sea currents ……………………...... 288 § 5.3 Studies into manifestation of internal and seismic waves on the sea surface …………………………………………………………………….. 296 CHAPTER 6. ON-LINE RADAR MONITORING OF LAND............................ 298 §6.1. Determination of agrometeorological properties and soil moisture from space radar images at the autumn-winter season…………………………. 298 §6.2 The study of the manifest indications of geological formations and mineral deposits using multifrequency remote sensing radars.................................. 316 §6.3 Description of subsurface formation detection procedures using multifrequency sensing tools........................................................................ 320 CHAPTER 7. ON THE ADVANCES IN THE DESIGN AND DEVELOPMENT OF RADAR SYSTEM FOR ON-LINE MONITORING OF THE EARTH'S ENVIRONMENT........................................................................ 327 §7.1 Description of the initial results achieved in the operation of the airborne remote sensing complex, otherwise referred to as the "ARSC-30".............. 327 §7.2 The prospects for further development of spaceborne radar facilities for on- line remote sensing of the Earth in Ukraine. In lieu of the conclusion………….. 338 References….......................................................................................................... 341 APPENDIX 1. INTEGRATION OF DATA ON AEROSPACE RADAR SENSING AND IN-SITU MEASUREMENTS INDUCTED IN NATURAL TESTING AREAS……………………………………………………………… 356 References to the Appendix 1 .......……................................................................ 391 APPENDIX 2. FEATURES OF THE ANTENNA SYSTEMS OF EOS PERSPECTIVE SPACE RADARS....................................................................... 393 §1. The high resolution antenna system of the space SAR with the on-line beam control............................................................................................................. 393 §2. The multipurpose antenna system of multimode space side looking radar................................................................................................................ 412 References to the Appendix 2............................................................................... 425 5 Dedicated to the memory of Anatoly Ivanovich Kalmykov, the eminent scientist FOREWORD Dear reader, The book you are now holding in your hands is dedicated to radar techniques and facilities for on-line remote sensing of the Earth. We would like to give some brief explanations to those who are actually getting interested in this aspect of human endeavor, which is of certain value and captivates one’s imagination. Remote sensing is a sort of technology. To be more specific, it is a combination of methods and ways of extracting information on a great variety of man-made and natural objects phenomena and processes occurring at a certain distance when there is no immediate contact with them. At present some useful information on remote sensing applications can be gained from distinctive features of different-in-length electromagnetic (EM) waves reflection both from objects to be studied and from those of intrinsic radiation of EM waves by these particular objects. The remote sensing systems based upon artificial radiation and reception of EM waves reflected from the objects being explored that are referred to as “active”. They include, above all, radar, lidar (optical wave bands, in most cases, with adjacent UV and IR regions) and sonar (or sound) wave bands. The systems that are exclusively based upon receiving EM waves radiated (or re-reflected upon irradiation by some natural illumination source like, say, the Sun) by the objects under study are called “passive”. Among those are the photographic systems intended for registering the reflected solar radiation as well as the various types of radiometers having different wavelengths. The spectrum of EM waves in remote sensing applications is rather wide. It varies from the shortest X-ray wavelengths of 10-12 m and UV optical-range waves to ultrasound and acoustic wavelengths of more than 104 m. Some general concept of EM radiation bands used in remote sensing is depicted by Fig.1 [1], in which EM wave spectra are shown to be radiated by a black body at its different temperatures and by the Sun as well. Here a comparison is made between the spectral characteristics of EM radiation transmitted by the Earth atmosphere and the EM wave bands utilized by different remote sensing systems. 6 Fig.1.1. EM wave spectra radiated by a black body at its different temperatures and by the Sun; spectral characteristics of EM radiation transmitted by the Earth atmosphere and the EM wave bands utilized by different remote sensing systems It is clearly seen that one could hardly find all portions of EM wave spectrum to be equally suitable for remote sensing applications. We will give the information relevant to the above Figure in subsequent sections. Needless to bring home to anyone living at this modern age the paramount importance of remote sensing technology, to those who think it normal to see for themselves the tangible results it yields every day, especially when televised weather forecasts are presented. This is most convincingly evidenced by the wide-ranging applications of remote sensing in every areas of human endeavor, by the efforts and resources put into it by highly developed and developing countries round the world. Most of the resources and allocations are mainly focused on air-and spaceborne remote sensing systems And no wonder that it is exactly the aerospace facilities for remote sensing of the Earth (RSE) that are basically intended to resolve the issues of global monitoring of the processes occurring on the Earth and which are in fact challenging to get them under control using ground-based facilities only. A wide variety of problems that have to be addressed by the present-day aerospace remote sensing facilities ranges from military reconnaissance operations to prevention of natural, technogenic and environmental catastrophes, rescue of personnel, mineral prospecting in any parts of the Earth, to name but a few. An incomparable role is played by the remote sensing facilities while observing the hard-to-reach and outlying areas of the globe, i.e. deserts, vast oceanic expanses, Arctic and Antarctic regions. This diversity of problems to be tackled requires that remote sensing air- and spaceborne facilities be dedicated to serving specific purposes. In other words, priorities should be given to selecting the types and physical principles of their operation, their parameters (in particular, swaths, spatial resolution, the data processing period and presentation of data, the mode of delivering the retrieved data to users, etc.) in strict 7 compliance with specific features of issues being solved. In fact, it does not seem to be difficult to make sure that various problems are optimally handled by selecting totally different sets of remote sensing facilities. As an example, consider one of the gravest issues like natural catastrophes. The most calamitous natural phenomena are the so-called tropical cyclones or, in other words, typhoons and hurricanes. They possess a formidable breakout force. The wind speed in their epicenter may at times be over 150 km/h. They are bound to cause horrifying ocean waves and are attended by torrential rains, thereby leaving flooded areas, landslides, etc. in their trail. They sweep over the areas for a distance of hundreds of kilometers and are capable of traveling along complicated trajectories at high speeds that often reach 100 km/h. A huge number of innocent people are often victimized by tropical cyclones, thousands of vessels find themselves sunken and heavy material damages are inflicted. In spite of the great engineering potential of today all these hazardous events cannot but pose a colossal threat to numerous countries around the world. It is quite evident that the measures taken to minimize the aftermaths of tropical hurricanes may well be effective provided one should take care of their timely detection using the reliable data on their imminent danger, their direction and the speed with which they travel. Of course, these data are to be made available in good time and on a 24-hour basis and keep one informed about the atmospheric processes over the vast oceanic expanses stretching for tens of millions of square kilometers, where these hurricanes tend to originate. This problem can hardly be tackled without having to fall back upon the wide–swath spaceborne global remote sensing systems which are supposed to operate continually, round-the-clock, because the movement of hurricanes is never discontinued night and day. The data thus obtained should be promptly dispatched to a large number of users ranging from the special state-run emergency services that organize and coordinate rescue and evacuation operations in the hardest-hit areas to the captains of ships and numerous owners of small-size motor boats and yachts which might to get caught in hurricane- affected zones. The rate at which the radar data are delivered to those who may fall victims to those elemental events is very essential in terms of salvaging dwellings and properties. Therefore the best solution would be to process the remote sensing data on a real-time basis, directly onboard the man-made satellites of the Earth. Apart from the onboard radio channels being utilized to give operational warnings of emergency situations in the open sea, the data retrieved could be transferred, say, through the APT standard channels. The receiving stations of these channels are of significant current use. Thousands of these stations are being run all over the world. Thus, even if some features of tropical cyclones, typhoons and hurricanes are given a cursory glance, one is practically able to specify the basic requirements for spaceborne systems which are intended for their operational monitoring, i.e. for their prompt detection, diagnosis of their parameters, monitoring of their development and movement. Basically this implies the global surveying of the ocean surface, the capability of daily (regardless of light conditions) detection of the most active processes in the air-sea system in their early stages of development with a subsequent monitoring of their dynamics and diagnosis of parameters. This also highlights the capability of processing remote sensing data directly onboard a spacecraft on a real-time basis and a swift transfer of data to a great number of users. Meanwhile, when analyzing other environmentally related processes such as degradation of fertile soils, desertification or the causes behind deforestation in many parts of the world, one has to come up with totally different remote sensing facilities. Although these processes are of global nature, they tend to develop gradually, their time range running into decades. 8 In others words, the areas susceptible to these hazardous events can be surveyed at a slow rate, stepwise, and no operational mode is then needed. These particular processes reveal themselves in a great diversity (for instance, in changing the color index of forest tree foliage, the growth of frees, their structure, the composition and color of soil covers, compactness of grassed soils, etc.). Therefore, different remote sensing facilities are needed to monitor their dynamics and there is no point in hastily selecting optimal surveying conditions to be applied to each of these facilities. The raw data retrieved from this type of sensing can be transferred to a limited number of research centers for subsequent integrated processing of data to be utilized after a little while. The disastrous events also differ in the scopes of their manifest effects produced by elemental processes, in the rate at which they gather their momentum, etc. For instance, the oil spilled across the sea surface is initially spreading fast in response to the surface tension forces and the due to the displacement of sea currents and wind velocities. Therefore the spaceborne remote sensing facilities taken alone, on frequent occasion, appear to be rather insufficient to provide effective monitoring of the above technogenic catastrophes. It is then indispensable to make use of airborne remote sensing systems capable of updating the information on how the hazardous events develop within a short span of time by means of repeated observations. It stands to reason that it is impossible to give meticulous attention to a great diversity of remote sensing systems and techniques in a single book. Here we will consider the specific features of on-line remote sensing facilities involving the use of aerospace carriers, and a special emphasis will be placed exclusively upon satellite-based radar systems. The reasons why the afore-mentioned radar systems are worthy of note are as follows. First, they offer the optimum performance in terms of meeting the requirements for a speedy acquisition of data irrespective of light conditions, the time of day, cloud canopy, etc. Second, they allow one not only to keep track of how different natural and technogenic catastrophes manifest themselves, but also to promptly evaluate most essential parameters relevant to those phenomena and events which are most likely to be responsible for the dreadful consequences they entail. Take, for example, the near-sea surface wind velocity, the torrential rains brought about by tropical cyclones, age gradations and respective thickness’ of sea ice, the oil film thickness on the sea surface, etc. To put it in a nutshell, basically it is difficult to overestimate the importance of the operational capabilities of remote sensing radar facilities. We will dwell upon them in subsequent sections. Third, the remote sensing experts of Ukraine have a backlog of expertise associated with efficient developments of low-cost but high-performance aerospace remote sensing systems and are widely experienced in their applications. In the light of what was stated above we think it unfair to leave the foregoing description of the possibilities offered by remote sensing radar facilities totally unfounded. Therefore we would like to cite just one illustrative example so as to convince our readers of the excellent benefits derived from remote sensing applications. Imagine the following situation: October 1983, the northern coast of the Chukot region, the polar, dark nights with severe frosts and blizzards fall upon this snowy desolate area. Also as well as every year a convoy of 22 vessels ploughs its way through the Arctic ice to the port of Pevek when following the well-trodden route. Normally the vessels are loaded with provisions, fuel and other supplies the Chukot inhabitants need so badly. The polar explorers, geologists, builders and their families will never endure the rigours of a dreadful arctic winter if they run dramatically short of life-support supplies at the most critical, hardest period of time. If one wishes to sound ironical, the convoy was “a bit” late. 9 It was held up for about a month because of some typical hitches in preparatory operations. Everybody hoped for the best. But, helas, the outcome turned out to be deplorable. All of a sudden the heavy masses of multiyear near-polar ice floes started moving southward, and the convoy got hipped in the Longa strait to the south of the Wrangel Island. And soon the most powerful atomic ice-breakers were seen to be heading for the distressed vessels. But the multiyear ice, whose thickness was 5 meters and up, was a really “hard nut to crack”. In the long run everything ended up in a tragedy. One vessel was mercilessly crushed by the ice and sank and the other was badly damaged. The icebreakers were strenuously attempting to get through; even the propeller screws have broken down but to no avail. A menace hanging over that area with a population numbering hundreds of thousands might become a grim reality. The high-ranking officials of the Former Soviet Union (FSU) felt gravely concerned about the fate of the convoy in question. The top executives who were responsible for the safe and effective navigation in the Arctic region were closely watching the developments. The loss of the ships whose cargoes were estimated at over 8 billion $ dollar might be thought of as an enormous tragedy and, should it happen, new challenging problems would come cropping up and that would incur additional expenses. In particular, thousands of people would have to be airlifted from those far-flung areas of Chukot, since they were on the verge of being abandoned with no provisions and fuel supplies so necessary to keep the region infrastructure going under those unbearably severe conditions. The data provided by the airborne ice reconnaissance were far from encouraging. It seemed like the ice wilderness was never-ending with huge floes stretching far beyond the horizon, which was in fact impossible to cut through. Just at that time the leading experts of the FSU State Committee for Hydrometeorology (“Goskomgidromet”) of the USSR), the “Yuzhnoye Design Office and the Institute of Radiophysics and Electronics (Kharkov) of the Academy of Sciences of Ukraine were actively involved in preparations for the planned orbital testing of the remote sensing radiophysical equipment installed onboard the “Cosmos-1500” satellite that was launched in September, 28, 1983. This experimental complex was designed and developed by the Ukrainian researchers and experts of the IRE (NASU); Special Design Office of the IRE NASU and the Special Design Office Marine Hidrophysical Institute (NASU) under the supervision of Prof. A.I. Kalmykov. The key component of the entire remote sensing system was the side-looking radar (SLR), which played a dominant role. Here it would be worthwhile to touch upon the background of development and launching of the “Cosmos-1500” satellite carrying the first-ever homemade spaceborne remote sensing SLR. The whole story appears to be exciting and leaves one greatly amazed. There was a lot of controversy and arguments over this project, which occasionally stirred up strong feelings, sparked off heated discussions to such an extent that the whole thing looked very much like a “Whodunit”. We will take up that story and give it a careful consideration later on. Setting aside all the arguments, all sorts of statements and reasoning that were prevalent at that time, the main thing remained extremely essential: the SLR “Cosmos- 1500” had been engineered using the physical principles of radio wave scattering by the aroused sea surface and, more importantly, these effects were revealed and studied by the Ukrainian radio physicists and the entire remote sensing arrangement was primarily developed by the Ukrainian experts only, and it is this particular contribution of the home team of engineers and researchers that caused a great deal of displeasure on the part of some opponents. And it is precisely at that crucial spell of a trying time when the cargo ships bound for the Chukotski Peninsular (Chukot) were in distress and on the point of sinking, 10 and everybody nerved themselves to stand physical and emotional strains that the SLR long-term testing was to start as planned. The trial procedure envisaged the radar surveying of the same, specially chosen, sea surface area near the African coast under the most diverse conditions, involving the ground-controlled facilities. In these circumstances Prof. A. I. Kalmykov who was given an unqualified support by the “Yuzhnoye“ Design Office Managerial group did his best so as to immediately suspend the scheduled orbital testing of the SLR facility and to allow it to "zero-in mission" a routine surveying of the ice-bound ships in the Longa strait. In those years it was next to impossible to act that way because of the strict rules and regulations existing in the FSU. Those who were well aware of them knew it was almost inconceivable to reverse the decisions made by the top space executives). Indeed, the first radar images of this area could effectively show the way to rescue the ice-bound convoy. If one takes a closer look at these images shown in this book he is bound to see it for himself. At the same time it just dawned upon the physicists in Kharkov: the disaster area did seem to be "besieged” by heavy ice near the Northern coast of Chukot. Meanwhile, at a distance of 100 km to the north of the Wrangel Island there was a vast zone covered with thin ice (The so-called “polynia, i.e. an unfrozen patch of water in the midst of an ice- bound sea), which could open the clear way to the long-suffering convoy. The radar images that had been previously acquired helped to discern the fissures and patches of ice-free water in heavy multiyear ice oriented southward. These fissures ran along the “polynia” near the Wrangel Island. After these unique data had been collected it took several days to make desperate moves in an effort to get the top managing executives responsible for the Navigation in the Arctic region (“Sevmorput”) to call their attention to those gruesome developments. And it was until after the threat to lodge a complaint with the Central Committee of the Communist Part of the USSR (now FSU) had become a tangible reality, those appeals did take effect. To be on the safe side, a decision was made to make sure that the SLR space- borne data were adequate. The aircraft involved in visual ice reconnaissance, which had hitherto been flying in the vicinity of the convoy and along the Chukot coastline were searching out the slightest fissures in ice floes, along the traditional route have been directed northward (to the area spotted by the SLR), right up to the Wrangel Island. To the greatest surprise of the ice reconnaissance experts who were committed to provide pilotage operations, the SLR data were ultimately confirmed. As a matter of fact, in the area detected by the SLR a zone of young ice could be easily seen. True, within several days that had elapsed since the “polynia” was detected from space, the ice inside it got somewhat solidified, but fortunately it kept quite suitable for free passage of the convoy. The patches of ice-free water stretching out as far as that zone were found in the hummocked ice fields. The convoy promptly altered its course and headed northward. As the fleet of cargo ships followed the ice-breakers, it soon succeeded in getting closer to the young ice zone and sailing further on it safely arrived at the port of Pevek in a few days’ time. Thus, the cargoes being worth 8 $ billion were salvaged and the population of Chukot could well go on living through the climatic whims of that outlying land. It was convincingly demonstrated that the spaceborne SLR on the “Cosmos-1500” satellite was extremely practicable in securing the high-latitude navigation safety. It should be noted that this assertion is far from groundless. The point is that most of the leading remote sensing experts in the FSU were vigorously opposed to the novel development such as the SLR of the “Cosmos-1500” system, since they believed it to be totally unpromising and frequently insisted that this project be abandoned for good and all. But those who were seriously anxious to go ahead with the work on creating and launching the advanced system were on the winning side.