Device for measuring angles designated low-altitude targets
(57) Abstract:Usage: in the low-altitude radar detection for measuring angles. The inventive contains three symmetrical horizontally directed spaced along the height of the receiving antennas 1, 2, 3, three receivers 4, 5, 6, a transmitter 7 elevation low-level circuit that allows for measurement of elevation angles low-level circuits in the selector low elevation angles above the ground. 1-4-7, 2-5-7, 3-6-7. 2 Il. The invention relates to radar systems and can be used in low-altitude radar detection for measuring angles designated low-altitude air targets in the sector of small elevation angles above the ground.The aim of the invention is the ability to measure angles designated low-altitude targets in the sector of small elevation angles above the ground.In Fig. 1 presents a simplified block diagram of the device, conventionally a diagram of the above ground antennas and their radiation pattern.The structure of the device includes the following elements: three symmetrical horizontally directed spaced along the height of the receiving antennas 1, 2, 3, the receivers 4, 5, 6 and the transmitter angle designated low-altitude targets.Elevation work with the beam width in the vertical plane already.The complex voltage amplitude of the echo signal at the output of one of the receiving channels is represented in the following form:
e-jkz[F()ejkhsin+F(-)e-jkhsin] (1) where the elevation angle of the target;
r the slant range from the location of the antennas on the earth's surface to the target;
- the complex gain of the receiving channel;
h height of the antenna above the ground;
2 / wave number;
F( ) is the normalized antenna pattern in the vertical plane in free space;
complex coefficient depending on the characteristics of the transmission system radar and target are the same for both antennas;
the complex coefficient of reflection of radio waves from an earth surface at a vertical or horizontal polarization.Let us assume that the shape of the pattern F( ) is symmetric in the vertical plane, then F( ) F (). It is known that at small slip angles of the complex coefficient of reflection of radio waves from earth -1 for any polarization of radio waves and any real characteristics of the earth's surface. With this in mind, the formula (1) can be simplified and written in the following form:
e-jkr[F()2ej/2th height above the ground. The lower and upper antenna and the receivers are the same. From the formula (2) shows that in the sector of small elevation angles, the phase shift of the echo signals at the output of the receiving channels of the upper and lower antennas is almost independent of the angle of designated goals and the voltage error at the output of the phase detector is close to zero. Therefore, the similar can't measure the angles designated low-altitude targets, and to accompany such targets in the sector of small elevation angles above the ground.This goal is achieved thanks to the joint solution of a system of two transcendental equations with one unknown on the interval elevation of the working sector of the device
0, where Gm1, Gm2, Gm3the maximum gain of the lower, middle and upper antennas, respectively;
TO1TO2TO3the gains of the receivers associated with the respective antennas;
F1( ), F2( ), F3( )- normalized pattern of the respective antennas in the vertical plane in free space;
h1h2h3the height of the respective antennas above the ground;
U1U2U3the amplitude of the stress echo with whom her expression for the complex amplitudes of the voltages U1U2U3the echo signals at the outputs of the receivers of the lower, middle and upper antenna.Un= j2 Ke-jkrFn()sin sin, (4) where n 1, 2, 3. Finding from the formula (4) the relationship of the amplitudes of the voltages U3/U2and U2/U1the echo signals at the outputs of receivers top, middle and bottom antennas, we get the system of transcendental equations (3) to determine the elevation angle of the target .Elevation working sectors of each of the equations of this system has many roots. From this set, choose the root that is the same for the first and second equations of system (3).However, there may be these private building antenna system, when among the many roots of the first and second equations of system (3) elevation operating sector will be more of the same. In such cases, the solution of system (3) is ambiguous and suggested the device will not function. Therefore, you should take special measures when building the antenna system, so that such ambiguity was not elevation desktop sector.Ambiguity will not, if the height above ground of the top of the antenna h3is not a multiple of the height of rise h2h1the other two antennas is to the other antenna and covers only a relatively small (not more than 5-7) number of interference lobes of the lower antenna, occur due to the influence of radio waves reflected from the earth's surface.In Fig. 2 shows the calculated dependence relations voltage signal and the argument of h1sin for a) proper construction of the antenna system (a) and (b) incorrect construction of the antenna system (b). For a given direction of the goal, which is marked by the arrow on these graphs crosses marked the roots of the first and second equations of system (3), and crosses in circles roots, the same for the first and second equations. In both cases the height of the antennas above the ground were chosen so that h22h1and h3Uh1. In addition, the bottom 1 and medium 2 antennas of the same, all the receivers are the same, i.e., TO1TO2= K3. In the case of (a) the pattern of the upper antenna 3 in the vertical plane was four times narrower than the antennas 1, 2 and covered about 5 interference lobes of the lower antenna, and in case (b) all three antennas were the same with the bottom antenna. As can be seen from the graphs (see Fig. 2), if built properly, the antenna system may unambiguous determination of the angle designated purpose, and at the wrong equation system 3 have many of the same roots and unambiguous the device is performed as follows.As the antennas 1, 2, 3 can be used horizontally symmetric directional antennas (e.g., mirror or horn). The receivers 4, 5, 6 made by conventional superheterodyne circuit. Limitation of the signal amplitude in the path of the receivers is unacceptable. The identity of the amplitude and phase characteristics of these receivers are not required. Special calculator 7 is made in digital form and is a specialized computer for joint solution of a system of two transcendental equations (3) with one unknown and a broad selection of roots of these equations one is the same for both equations.The dynamics of the operation of the proposed device is as follows.Receiving antennas 1, 2, 3 receive echo signals low-level goals that come to the antenna as a direct radio wave and radio wave reflected from the ground. The receivers 4, 5, 6 amplify the echo signals, and convert, to an intermediate frequency and detects. The output voltage U1U2U3receivers on videocassete come to the transmitter 7, where they are converted into digital form. The computer 7 determines the angle designated low-altitude targets by the joint solution of equations (3) on the interval for the PURPOSES containing three symmetrical horizontal directed, spaced along the height of the receiving antenna, each of which is connected with the corresponding receivers, characterized in that the evaluator angle designated low-altitude targets, the first, second and third inputs connected to the outputs of the respective receivers, and the output is an output device, and calculating the angle q is produced by the following formulas:
< / BR>< / BR>where U1U2U3the amplitude of the voltage of the echo signals at the outputs of the receivers of the lower, middle and upper antennas, respectively,
the maximum gain of the lower, middle and upper antennas, respectively;
K1, K2, K3the gains of the receivers;
F1(), F2(), F3(a) normalized radiation pattern of the respective antennas in the vertical plane in free space;
h1h2h3the height of the respective antennas above the ground.
FIELD: detection of emergency radio buoys.
SUBSTANCE: system has two emergency radio buoys, satellite and information receipt station. Satellite has four antennae, three receipt devices, two memory devices and transmitter with antenna. information receipt station has antenna, receiver, two information processing devices, device for connecting to communication networks, control device and communication device of special rescue organizations. Third receipt device of satellite has five receipt antennae, seven mixers, six amplifiers of first intermediate frequency, two heterodynes, second intermediate frequency amplifier, block for detecting phase-manipulated signal, phase doubling block, two means for measuring spectrum width, comparison block, threshold block, delay line, two keys, phase-manipulated signal demodulator, ten multipliers, five narrow-band filters, lower frequency filter, four phase detector, five adders, four band filters, three phase inverters, two phase rotators for 90° and amplitude detector.
EFFECT: higher precision, higher interference resistance.
FIELD: radio communications.
SUBSTANCE: method includes, prior for each receipt station, which received radio signal with preset quality, on basis of calculated minimal normal values of total errors of phase difference of all couples of emitters in all hypothetical directions in range from 0 to 360° bearings to radio radiation source are calculated, then average value of coordinates of position of radio radiation is calculated from all points of intersection of bearing lines, after which procedure calculated coordinates are calculated using search iteration procedure of fastest descent.
EFFECT: higher precision.
3 cl, 10 dwg
FIELD: radio communications.
SUBSTANCE: at preparatory stage method includes processes for determining amount of elementary snap zones, calculation for central and R peripheral bearing points with known coordinates of values of standard primary space-information parameters relatively to coordinates of position of centers of each elementary snap zone. At operation stage method includes processes of receipt of radio emission sources signals by group of R > 1 interconnected peripheral and central bearing points, measuring primary space-information parameters at outputs of antenna elements, while primary space-information parameters, measured by peripheral bearing points are sent to central bearing point, calculations for each elementary snap zone of difference between standard and measured primary space-information parameters, selection from produced values of minimal value, and coordinates of position of center of elementary snap zone are taken as coordinates of position of detected radio emission source. As primary space-information parameters values of differences of signals phases of all possible pairs of combinations of antenna elements within effect of each bearing point. Device at central bearing point additionally has adder, memory device, decision taking block and R + 1 analysis track.
EFFECT: higher precision.
2 cl, 35 dwg
FIELD: radio engineering.
SUBSTANCE: method can be used for detection and finding of on-ground radio-frequency radiation sources. Method is based upon receiving of radio-frequency radiation in N≥3 points being distant from each other is space, transmission of data to central point, determination of Rn(x,y) distance from any point of (x,y) space to any n=1,2,...Nth point of receiving of data, measurement of efficient values f voltage of received radio signals Un, transmission of the signals to central point where they are subject to transformation to spatial indeterminate function F(x,y). Availability of radiation and position of source are found from location and value of maximum of the function. Value and position of maximum of spatial indetermination are evaluated in neighborhood of point having coordinates to be equal to weighted average coordinates of reception points with weights being equal to measured efficient values of voltage of received radio signals raised to 4/p power. P parameter is determined while taking dependence of strength of source field into account on distance with standard value being equal to 1 or 2.
EFFECT: improved precision; increased efficiency; stabilization of false alarm level.
FIELD: radio engineering, in particular, radio bearing detection, possible use in systems for determining position of radio emission sources.
SUBSTANCE: in radio bearing indicator for determining two-dimensional bearing, containing ring-shaped equal-distanced antenna array with even N number of antennas, N-channel digital radio receiver, N-channel device for measuring complex amplitude, N-input buffer memorizing device, multiplier of complex numbers, clock generator, device for determining phases difference, multi-scale device for measuring phase influx and block for determining radio waves incoming angle, additionally included are pulses generator and controllable accumulating adder.
EFFECT: increased bearing detection speed.
FIELD: radio engineering, possible use for determining position of radio radiation sources in decametric range when using one receiving station.
SUBSTANCE: increased precision of position detection is achieved based on additional information, received as a result of division of beams of multi-beam field of received signal and modeling the process of radio-waves expansion in three-dimensional non-homogeneous ionosphere, thus making it possible to correct deviations of beam trajectories of signal by distance and by direction, considering inclinations of reflective layer of ionosphere, and also to remove ambiguousness of one-positional coordinates measuring by comparing trajectories of selected beams.
EFFECT: increased precision of one-positional determining of position of decametric transmitters.
FIELD: radio engineering, possible use for determining position of objects using radiations of their decametric transmitters with use of two or more receiving stations (range and direction finders).
SUBSTANCE: method is based on using additional information about rules of ionosphere distribution of decametric signals. This information is considered at each receiving station when determining assumed coordinates of objects by one-positional method with use of ionosphere model. In central calculator, connected to all stations, by comparing results of physically different methods of estimation of spatial coordinates (one-positional and multi-positional) indeterminacy of unification of measurement results is removed and position of objects is determined unambiguously with use of two or more stations.
EFFECT: increased precision of determining position of a set of one-typed decametric transmitters by wider class of signals, including complex signals with low spectral density of power.
FIELD: radio engineering, possible use in passive radio control systems for detecting and determining parameters of a set of transmitters with leap-like frequency alternation, simultaneously present in current receipt frequencies band.
SUBSTANCE: in accordance to method, additional signs are used for identification of signals with leap-like frequency autocorrelation function and selective functions of durations distribution and value of frequency leaps of elements of signal frequency-time matrix, preliminarily selected from input flow of signals with use of spatial mutual correlation connections between separate frequency-time signal components.
EFFECT: increased efficiency of detection of determining of parameters frequency-time matrix, describing rule of leap-like frequency alternation; average signal energy; most likely value of durations of separate radiations; speed of leap-like frequency alternation, azimuth and elevation of transmitter.
FIELD: passive radiolocation.
SUBSTANCE: in the known method for determining coordinates of source on basis of time difference of arrival of signals, signals are detected additionally, signal/noise ratio in which is maximal and large weight coefficients are assigned to them, to other signals appropriately lesser weight coefficients are assigned.
EFFECT: increased probability of detection and increased precision of determining object coordinates.
7 dwg, 1 program
FIELD: measuring equipment, possible use in acoustics and radio-engineering for reproducing images and determining, with increased resolution, azimuth and local angle directions towards sources of waves of various nature: resilient waves in different substances, in particular, sound waves, waves on surface of liquid and electromagnetic waves.
SUBSTANCE: method includes using nonlinear pseudo-request algorithm, providing optimization of operations of nonlinear processing of signals at each iteration of radio image restoration process (complex angular spectrum) without using normalization parameter.
EFFECT: increased direction-finding efficiency of closely located sources of radiation of coherent signals of waves of various natures.