Patent RU-2354994-C1 (RU)
Inventor: MEN SHIKH OLEG FEDOROVICH
IPC: G01S17/06
Filed: 2007-10-29
Granted: 2009-05-10
Abstract: FIELD: physics; measurement. 
     SUBSTANCE: present invention relates to measuring techniques and instrument making and can be used in laser Doppler location of stealth objects flying at low altitudes above water basins. The method of processing information in a coherent laser locator with a photodetector array is based on reception of laser radiation from glare of the sea surface, arising when probing radiation is scattered by the stealth object. The current location of an object and its velocity vector can be reconstructed through measurement of angle of arrival of radiation from the glare of the sea surface using a photosensitive reception matrix and through measurement of Doppler frequency shifts in a multi-channel unit for optimum filtration based on heterodyne reception methods using multi-channel dispersive delay lines using statistical averaging methods. Cutting on the number of information processing units is achieved due to creation of two- or three-dimensional groups of elements of a photodetector array, connected to information processing channels. In the processing channel, the signal is converted to a linear-frequency-modulated equivalent with subsequent amplification, spectro-time "compression" in the dispersive delay line, detection and minimum threshold cutting with a given threshold value, which allows for converting a signal with Doppler frequency shift to a short pulse, the time position of which, relative the strobe-pulse for the beginning of the measuring cycle, uniquely characterises the value of the given Doppler frequency shift. This time position of the pulse is coded in a digital code and stored in the corresponding buffer memory of a memory device, in the code of which there is also a code of the number of the measurement cycle and the code of the number of the channel, on which the signal from an element of the photodetector array was processed. From the set of such code records in the given measurement cycle, information is obtained on Doppler frequency shifts in signals of corresponding elements of the array and the position angle on the glare of the sea surface, detected by the locator in the given measuring cycle relative the optical axis of the receiving-transmitting objective of the locator, as well as scatter angles of the probing radiation of the stealth object, generating the said glares. If conditions are met for detecting an object and its bearing auto-tracking, where the inclined range line and the optical axis of the receiving-transmitting objective of the locator lie in the same plane, location of the object and measurement of its radial velocity is done through calculation, using a minimum of two different reflected radiation in a given measurement cycle, based on the method of overlapping circles. The radiation pattern of the locator is fan-shaped - wide on the position angle and extremely narrow on the azimuth. 
     EFFECT: simplification of the design of the device implementing the method, particularly the design of the information processing unit with dispersive delay lines, as well as possibility of locating stealth objects without reception of radiation directly from the located object in its probing direction. 
     7 cl, 11 dwg