millimetric and centimetric radio waves
N.S. Akinshin, R.P. Bystrov, A.A. Potapov
An analysis of domestic and foreign publications, currently is held numerous theoretical and experimental research aimed at accelerating the development of radar technology. Moreover, for the successful implementation of radar systems, detection and identification of ground objects require study the energy and spectral characteristics of reflection and scattering of centimeter and millimeter radio waves by terrestrial objects on a background of different types of underlying surfaces and local items that are the basis for evaluating the EPR facilities and specific EPR interfering backgrounds.
The article highlights selected results of many years of theoretical and experimental studies of the above questions. In dealing with recognition of classes of mobile and fixed, as well as selection of slowly moving objects associated with the evaluation of the ESR on a background of interfering reflections, a modeling of the earth's surface reflection was performed, object model vehicles (cars, armored vehicles, etc.), as well as rights. Calculated on the basis of the proposed models integral distribution functions show that the limits of changes of mean-square width of the spectra of signals reflected from different classes have significant differences.
One of biggest challenges in radar is the detection of slowly moving objects (at a rate less than 4-5 km/h). The paper analyzes and experiments with two methods of selection of slowly moving objects: the method of time-averaged reflected coherent signals and method of using the secondary emission properties in the direction of propagation of electromagnetic waves.
It is shown that at millimeter wavelengths in comparison with long-wavelength range (8 mm and 3 cm) appears an excellent opportunity to detect non-moving objects with the engine running. To study the detection of non-moving objects with the running engine developed a model of fixed oscillating object. It is shown that the radar, having a transmitting system with a generator that provides high stability within 10-9 ... 10-10, can be successfully used to detect a slow-moving or stationary with the engine facilities.
On the basis of special experimental studies and analysis of information data on the radar characteristics of typical objects (tracked and wheeled armored vehicle) are shown results of the study reflect the properties of ground objects.
The features of the characteristics of the EPR at multiposition radar are described. These studies show that the obtained mathematical relationships for multiposition radar systems are the logical consistency with existing concepts, defining the characteristics of the object.
The practical usefulness of the proposed work features multi-position ESR is that it allows in a matrix form to calculate the signal level at the input multi-position system, describe the model inputs (in matrix representation) and to form a radar picture of the object for further recognition.
There is no doubt that the introduction of multiposition radar, requires further development of the theory of multiposition radar and extensive experimental studies.