Several types of navigation systems exist and are widely used, differing in operating principles and measurement accuracy. In the future, a fundamentally new system may come into operation, which calculates coordinates based on the features of the Earth's gravitational field (GPF). It is expected that this method of positioning will be particularly accurate - and at the same time highly complex.
Promising direction
The presence of a developed space constellation and the improvement of all basic technologies open up new opportunities for world science. In particular, the presence of high-precision instruments for measuring the physical fields of the planet and objects on its surface makes it possible to draw up detailed models of various kinds, suitable for use in various fields.
Over the past several years, research has been carried out in our country and abroad in the direction of the so-called. gravitational navigation systems. The necessary work is carried out and new data is collected, processed for further use. The basic principles of the new navigation system have already been determined, and the process of its creation continues.
Several organizations are working in this direction in Russia. In particular, the All-Russian Research Institute of Physical, Technical and Radio Engineering Measurements (VNIIFTRI) from Rosstandart is developing equipment for collecting data and processing incoming information about the gas processing plant in order to create new navigation aids.
Recent posts on the topic of gravity navigation appeared the other day. The weekly "Zvezda" with reference to the management of Rosstandart wrote about the continuation of work on a promising project and obtaining new results. They also recalled the advantages of new technologies and their areas of application.
Measurement and Calculation
The concept of gravitational navigation is based on the fact that the parameters of the GPZ at different points on the planet's surface (or above it) are slightly different. The earth is not a perfect ball or ellipsoid; its surface has the most complex relief, and the thickness of the earth's crust is composed of different materials. All this affects the parameters of gravity on and near the surface. Often, the actual values differ from the calculated ones for a given point, which is called a gravitational anomaly. In addition, due to a number of factors, different centrifugal forces are observed at different points.
The concept provides for the measurement of the parameters of the GPP and centrifugal force at different points with further processing. The resulting gravimetric map can be entered into the memory of navigation equipment and used in calculations. Based on the data on the GPZ, it is possible to correct the operation of inertial or satellite navigation systems. In this case, the total error of the entire complex is reduced to centimeters. In addition, an INS with correction based on GPZ data is distinguished by the highest noise immunity.
Observations show that the GPZ is a fairly reliable "benchmark" for navigation systems. The rate of change of the gravitational field is much lower than that of the magnetic field, and the data on the GPZ can be used for tens of years without a noticeable loss in the accuracy of calculations. However, earthquakes and other processes can change the state of the GPZ and require updating the maps.
Practical measures
According to reports in recent years, Russian scientists - like their foreign colleagues - have been collecting data, searching for gravitational anomalies and compiling gravity maps for several years. Special equipment on board aircraft and satellites measures field values at a huge number of points and transmits them to ground computing centers. The result of this work is a map capable of providing high navigation accuracy.
We are also developing navigation equipment capable of using new maps and interacting with other equipment. However, as far as is known, such projects have not yet led to the appearance of products suitable for real use.
The introduction of new principles of navigation may still be hampered by the lack of accurate maps of a significant part of the earth's surface. In fact, at the moment, navigation through the GPZ in practice does not provide any special advantages over INS or satellite systems. The situation can change only in the future, when all the necessary research and design work has been completed.
Applications
The new principles of navigation can find application in various fields where a particularly accurate determination of coordinates, independence from external signal sources, and other specific features are required. First of all, this is military affairs. The emergence of serviceable gravitational navigation systems will increase the combat effectiveness of a wide range of equipment and weapons.
The military may be interested in both the increased accuracy of calculating the coordinates, and the unique noise immunity. In fact, the only way to influence such systems is to artificially change the GPP - which requires colossal efforts or is completely impossible.
A high-precision guided missile, using a gravimetric map, will be able to more accurately follow a given route and hit a target with known coordinates with less deviation. Such principles can be used by both cruise and ballistic missiles. However, such an operation will require an accurate and up-to-date map of the GPZ on the route, which makes special demands on reconnaissance and organization of the strike.
New principles of navigation are of great interest to science. With their help, you can make a more accurate linkage, which is useful for various studies in a number of areas. The accuracy of data collection is improving, and this can form the basis for important new discoveries.
We should not forget about civil and commercial transport. Under normal circumstances, ships or aircraft have sufficient navigation aids, but in some situations more accurate systems may be required. It is quite possible that the emergence of full-fledged operational means of navigation through the gas processing plant will be of interest to aircraft and shipbuilders, as well as commercial carriers.
Waiting for success
According to the latest reports, VNIIFTRI is now busy with compiling accurate gravimetric maps of different areas, suitable for further use in practice. The data on the parameters of the GPP and the observed forces are processed and converted into a convenient form for use. The development of navigation equipment for practical implementation is also underway.
Both of these components of the new direction are distinguished by high complexity, duration and labor costs. Unfortunately, even the approximate timing of the introduction of new technologies in practice remains unknown. In addition, the actual prospects of such developments in terms of application in various fields are unclear. Nevertheless, work is underway, and real results should be expected in the future. If new technologies come to use and meet expectations, a radical change will occur in a number of areas.
