I. V. Popov

Autodyne millimeter-wave FMCW radar

The results of investigations of 8-mm band FMCW autodyne radar are given in this work. The radar intended for speed and range measurement of objects. Self-detection autodyne transmitter is made on base of Gann diode with varactor tuning. Digital methods of radiating signal forming and spectral signal processing and digital filtering of difference frequency signal are realized in the radar. Autodyne radar potential is not less 85 dB having output power of about 25 mW. Resolution on distance at the tuning band of 500 MHz is 0.6 m and range measurement accuracy 0.3 m. Dimensions of the radar are 92times92times166 mm. Mass is 0.35 Kg.

Diagnostics of refraction coefficient on results of meteorological parameters measurement in arbitrary points of area

It is known the operating efficiency of radio technical systems of different function (navigation, radar, communication), to a great extent depend on condition of propagation of radio-waves is conditioned on atmosphere refraction state. It for ones turn is conditioned on spatial-temporal distribution of refraction coefficient n . And variation of mean refraction and numerous cases of so called anomalous propagation of radio-waves could lead to considerable increasing of signal level over the horizon or signal fading in the radio-optical line of distance and influence on accuracy of radar and navigation measurements. At present for location the systems of global navigation is in wide application. The completely deployed GPS system of USA exists today. Russia realizes intense work on unwrapping of complete constellation of GLONAS satellites. In the Europe the development of Galileo system is finishes. To the utmost the troposphere influences on results of coordinate measurements. Ignoring of this fact leads to error of measuring of pseudo-range from 2,5 m. (in zenith) to 25 m. (while satellite elevation about 5 degrees). The possible way to decreasing of location error is taking into account troposphere influence while processing of information in the Ukrainian system of cosmic navigation provision (USCNP) [1, 2]. There are two main modes of correction: real-time and post session. For real-time processing we propose to use the data of meteorological stations are in the set of controlling-correcting stations (CCS) USCNP. At that have to be provided accuracies of coordinates determination not worth of some meters. While post session processing corrections are forming on the base of phase observations by stations of USCNP net. The obtained errors of measurement are about some centimeters. Troposphere delays in the real-time the meteorological parameters are obtained in series of points of space are used for approximation. The meteorological parameters of functions approximating dependence of temperature, pressure and humidity on latitude and longitude in the range of Ukraine are forming and giving for users on the base of these delays. Besides the parameters of functions approximating dependence of zenith troposphere delay on latitude and longitude in the range of Ukraine are forming and giving for users. Both these approaches are on the base of troposphere delays calculation using data of meteorological stations to the sea level. Truncation error of estimation is about 2.5%. The analyses is carried out [2] and shows the order of approximating model practically not influences on error of troposphere delay measurement and so we conclude about possibility of usage of zero order model, i.e. the mean data for Ukraine. We seem the bases for such conclusion is small accuracies of measurement of meteorological parameters.

Polarization-Spectrum Signatures of Above-Water and Surface Targets

The results of experimental study of backscatter spectral -polarization features from above-water and surface objects are presented. Investigations were carried out with coherent systems both with the pulse and CW modes of millimeter and centimeter wave bands (from 10 sm to 2 mm). The informative features are concerned with modulation both the amplitude and Doppler translation are condition on modulation of scattered signal at the stroke rate for the oared boat and the frequency modulation concerned with hands and lags move of moving man as well are ascertained. For the scattering from the object body the small level of depolarization factor of the scattered signal is typical. Ascertained that for the coincident by frequency spectral components of the signal scattered from the objects on orthogonal polarizations the high values of cross correlation factor is typical.

Informative characters in spectral-polarization images of backscattering from surface objects

The frequency, spectral and polarization features of the signals scattered by transportation (wheeled, caterpillar) and biological objects (person, animals, birds) are studied with coherent radar in pulse and CW modes in wave bands 10 cm, 3cm, 8 mm, 4mm and 2mm. Its showed that Doppler spectrum of signals scattered by person contains dominant line which corresponds to velocity of target and pedestal (below the line at -10÷ -15 db ) caused by secondary phase modulation due to fine structure of target movement. In the case of transportation the pedestal is of ruled structure due to vibrations of the target. The characteristics of signals scattered that presented in the paper are of interest for target detection and recognition

Millimeter Wave Radar for Study of Polarization-Spectrum Features of Signals Scattered by Hydrometeors

The experimental study of spectrum-polarization features of backscatter from hydrometeors and their influence on backscatter from rough sea surface are presented. The coherent radar in pulse and CW modes were used in wide frequency range (¿ = 0,2 ÷ 10 cm). The information signs based on correlation of orthogonal polarization components and synchronism of fluctuations of Doppler frequency due to wind pulsation were studied. It was showed a high cross-correlation for orthogonal polarization components at the same frequencies for backscatter from different objects

Description of nonstationary non-Gaussian processes using finite atomic functions

The possibility of using finite atomic functions of Kravchenko-Rvachev for description of the laws of distribution of the refractive index of the troposphere, the intensity of the scattering from the sea, seasonal behavior unit RCS of land areas with vegetation covering, as well as the spectrum of electromagnetic spikes of lithospheric origin is considered.

Signatures of acousto-electromagnetic portraits of aerodynamic and terrestrial mechanical objects

The possibility of creating a dictionary of signs for the radar recognition of the aerodynamic and terrestrial mechanical objects through the use of data about as dimensions of the objects, and the acoustic noise is analyzed. RCS of aerodynamic objects at resonant and short wavelengths as well as their speeds of revolution are estimated.

Estimation of complex permittivity of the medium on frequency and steepness of autogenerator electronic tuning

The methods of determination of complex permittivity of the substance filling the resonator on changing the frequency and steepness of adjustment of generator is stabilized by them is considered. Calculated ratios and the results of their experimental check are presented.

Nonequidistant two-dimensional antenna arrays are based on magic squares

The method of two-dimensional not equidistant antenna arrays design is based on magic squares is proposed. The properties of antenna arrays (directivity pattern, side lobe level, frequency overlap) are studied. An algorithm for providing full frequency coverage of synthesized arrays using magic squares and a method for obtaining arrays of large size using compound squares is proposed.

Optimal reception of signals propagating in media with absorption and dispersion

The features of optimal reception of signals propagating in media with the absorption and dispersion are considered. It is shown that in this case bandwidth of emission-reception should be adapted to the desired range of distances, as well as to compensate the phase distortion is introduced by medium of propagation. It is proposed using of the modified correlation functions for signal analysis in such cases.