|
|
Identification of potentially hazardous substances using active electromagnetic waves Invention relates to imaging systems and can be used to detect concealed objects. Electrical properties of concealed objects, for example permittivity, can be obtained from information on incident, reflected and transmitted electromagnetic waves in an imaging system. The imaging system comprises a transmitter for directing radiation into the inspected volume, a receiver for receiving scattered radiation from said volume, a reflecting array for focusing an incident radiation beam, a processor for processing scattered radiation for imaging in accordance with the amplitude and phase of the received radiation and a display. The difference in the amplitude and phase between the object and the reflecting space is used to estimate relative permittivity and therefore serves to classify objects using a relative permittivity database of substances. |
|
Machine inner space control system Machine (2) inner space control system (20) comprises radar (26) transmitting radar radiation (28) into inner space (6), radar receiver (34) to receive radar radiation reflected into said space (6) and outputting it as a received signal (36), control and processing unit (38) to define actual signature (40a) from received signal (36) and to compare it with stored preset signature (40b) of flawless machine (2) and unit (42) to output signal (46, 52a,b) of fault at departure of actual signature (40a) from preset signature (40b) by permissible tolerance (44). |
|
Target detection in sar-imaged sea area Method comprises steps of: calculating a first reference quantity which characterises a Poisson distribution assumed for characteristics that the pixels in the Synthetic Aperture Radar (SAR) image would have if the sea area were free of targets. The method further comprises steps of: selecting pixels in the Synthetic Aperture Radar (SAR) image, calculating a real quantity which characterises a real statistical distribution of characteristics of the selected pixels, and detecting a target in the sea area based on the calculated first reference and real quantities. The selected pixels are in the same sub-image of the Synthetic Aperture Radar (SAR) image, and detecting involves detecting a target in a sea sub-area of the sea area, the sea sub-area being represented by the sub-image. |
|
Apparatus for measuring effective scattering area of radar objects Apparatus has a transmitting and a receiving unit connected a recorder, a support-swivelling block on which is mounted a two-dimensional flat square equidistant array of identical and identically directed radar objects, placed at the nodes of a two-dimensional grid with square cells with spacing where λ is the wavelength, wherein one of the diagonals, the normal to the plane of the array, the normal to the plane of the front of the electromagnetic wave emitted by the transmitting unit and the normal to the plane of the front of the electromagnetic wave reflected from that array lie in a single plane. |
|
Radar device for classifying vibrating aircraft with flight path instabilities in surface layers Disclosed device has a synchroniser, a modulator, a microwave oscillator, an antenna switch, a receiver, a range measuring system, a resolver, an antenna, an antenna control system, a velocity measuring system, three analogue-to-digital converters, memory, a fast Fourier transformation computer, a classification unit, designed and connected to each other in a certain way. |
|
Method of measuring local effective reflective surfaces of objects in ultra wide frequency Proposed method of measuring local effective reflective surfaces of objects relates to radar-location. The method is based on irradiating radar-location objects in free space with a series of ultra-short pulses. The measured time dependence of the probe signal in the point of irradiation of the object at a distance R from antennae is approximated using a wavelet and numerical values of its parametres w and z are found. Through Fourier transform of the measured time dependence of the probe signal, the energy frequency spectrum (EFS) of the probing field is determined. The time signal reflected from the object is then recorded, and based on the found approximate wavelet energy wavelet-spectra of coefficients of wavelet-transformation of the reflected signal are calculated. On the wavelet spectrogram of the energy spectrum in coordinates of scale and shift parametres, the values of scale and shift parametres of the corresponding maximum reflected energy are calculated, arising from the j-th local scattering centre - "bright point". The local energy spectrum of coefficients of wavelet-transformation is calculated. Frequency is determined as the average wavelet frequency with parametres w and z and scale and shift parametres of the analysed "bright point". The frequency range of the analysed local energy frequency spectrum is determined and the local energy frequency spectrum of the j-th "bright point" is determined. From the measurements carried out, the local effective reflective surface of the analysed local scattering centre of the object is determined. |
|
Dual-threshold signal detector of panoramic receiver for sequential analysis Invention pertains to radio technology and can be used in panoramic receivers of jamming stations, radio direction-finders and similar devices for detecting ground based sources of radio frequency emission, functioning under conditions of interference of unknown intensity. The technical outcome is the reduction of the survey time of the analysed frequency band at a given certainty of opening a radio frequency environment. A dual-threshold scheme for decision taking is realised with automatic switching on the results of controlling the ratio of the power of the signal/noise in the resolution cell. The detector consists of a receiver antenna (1), linear receive path (2), quartz phase detectors (3.1,3.2), reference frequency generator (4), 90° phase shifting unit (5), integrators (6.1,6.2,6.3), quadratic detectors (7.1,7.2,7.3), adder (8), threshold device (17), unit for calculating coefficient K of increasing the analysis time of one resolution cell (14), unit for generating the first and second thresholds (16), switches (9.1,9.2,9.3), comparators (10.1,10.2), accumulators (11.1,11.2), OR elements (13.1,13.2), device for measuring the ratio of the power of signal/noise (12), subtracting unit (15). |
|
Device for identifying random signals Proposed device designed for identifying objects incorporating revolving components (helicopters, propeller-driven airplanes) by means of acquisition radars at relatively low repetition frequency of sounding pulses (about 2000 Hz) and low time of contact with target (tens of ms) in intensive interference environment functions to separate heterogeneous part in received signal that characterizes time of hitting window occupied by pulse burst being identified with main maximum of secondary radiation diagram of revolving components by adequate processing of pulse burst in frequency and time domains thereby enabling object identification. Device has analog-to-digital converter 1, digital computing units 2/1 - 2N, random-access memory 3, comparison unit 7, control unit 8, multiplexer 4, ranking unit 5, calculating unit 6, and inverter 9. Each digital computing unit has squarer 13, multiplier 10, adder 11, read-only memory 14, and shift register 12. Control unit has clock generator 15, pulse counters 16/1 - 16/3, and AND gate 17. |
Another patent 2528470.