Phase method for direction finding

FIELD: radio electronics, applicable for passive radio monitoring in multi-channel system designed for direction finding of several sources of radio emission simultaneously getting into the reception zone.

SUBSTANCE: expanded functional potentialities by way of direction finding in two planes of several sources of radio emission simultaneously getting into the reception zone.

EFFECT: expanded functional potentialities.

2 dwg

 

The proposed method relates to the field of radio electronics and can be used for passive monitoring in multi-channel systems for direction-finding multiple sources of radio emission, at the same time falling within the band of the reception.

Known methods of direction finding (patents of the Russian Federationâ„–2003131, 2006872, 2010258, 2012010, 2155352, 2207583, 2175770, Kinkelin IE and other Phase method for the determination of coordinates. M: Owls. radio, 1979; Space radio systems. Edited Shibukawa. - M.: Owls. radio, 1967, p.134-138, RIS,and others)

Known methods closest to the proposed is (Space radio systems. Edited Shibukawa. - M.: Owls. radio, 1967, p.134-138, RIS,and others), which is selected as a prototype.

This method provides a direction finding only one source of radio emission, and only in one plane.

An object of the invention is to enhance the functionality of the method by measurements in two planes several sources of radio emission, at the same time falling within the band of the reception.

The problem is solved in that phase according to the method of direction finding, based on the reception of signals at two spaced antennas, the gain and limiting the amplitude of signals received in the first and second receivers, use isout third receiving antenna and the third receiver, in which the received signals are also amplify and limit the amplitude, while the receiving antenna is placed at the geometric form of a right angle, the top of which is placed a third receiving antenna common to the other two receiving antennas located in the azimuthal and elevation planes, signals received by the first and second receivers, passed through n-idler delay line, forming in each plane n of the correlation processing channels, with each channel processing delayed signal Peremohy with the third signal receiver, emit low-frequency voltage, compare it with a threshold voltage and in case of exceeding the threshold voltage register is the excess and decide on the number and the channel number processing, which exceeded the threshold voltage, the number of emitters, and their elevation angles.

The structural scheme of the device that implements the proposed phase method of direction finding, presented in figure 1. The mutual arrangement of the receiving antennas is shown in figure 2. The device contains three receiving channel, each of which consists of sequentially includes: receiving antenna 1 (2, 3), the receiver 4 (5, 6). To the output of the receiver 4(5) serially connected n-breather delay line 7.i (8.i), the multiplier 9.i (10.i), a second input connected to in the course of the receiver 6, filter 11.i (12.i) lower frequencies, the threshold block 13.i (14.i), blocks 15.i (16.i) registration (i=1, 2,...,n).

The proposed phase method of direction finding implemented as follows.

Signals to multiple emitters simultaneously detectable by a reception antenna 1, 2, 3, amplified and limited in amplitude in receivers 4, 5, 6, respectively. While receiving antennas 1, 2, 3 are in the form of geometric straight angle, the top of which is placed the third receiving antenna 3 common to the other two receiving antennas 1 and 2, located in the elevation and azimuth planes. Then the signals received by the first 4 and second 5 receivers, passed through n-idler delay line 7.i and 8i (i=1, 2,...,n), respectively.

It should be noted that according to the phase method of direction finding phase difference Δϕ1and Δϕ2the signals received by the antennas 1 and 2, 1 and 3 are determined by the expressions:

where d is the distance between the spaced antenna (measurement basis);

λ wavelength;

β, α - the elevation and azimuth of the source.

However, the phase method of direction finding inherent contradiction between the requirements of accuracy and uniqueness of reference angles β and α. Indeed, according to these expressions, the phase system the feeling is atelinae to change angles β and αthe longer the relative size of the measuring base. But with the growthdecrease the values of the angular coordinates β and αin which the phase difference Δϕ1and Δϕ2exceed the value of 2πi.e. comes the ambiguity of reference.

To eliminate the ambiguity of the phase method of direction finding sources of radio emission are two classical methods: the use of antennas with a sharp directivity and the use of multiple measurement bases (multi-channel) in each plane.

System measurements with beam antennas have a large range and high resolution in the direction. However, they require search emitters before the start of measurement and automatic tracking in the direction of the antenna beam in the measurement process, as well as deprive phase method of direction finding one of its advantages is the possibility to use directional (isotropic) antenna systems.

Parallelism is usually achieved by using multiple measurement bases. While a smaller base forms a rough, but unambiguous scale reference fragile, and large base - accurate but ambiguous scale of reference.

In the proposed phase method of direction finding contradiction m is waiting for the requirements to the accuracy and uniqueness of reference angles β and α permitted due to the correlation processing of the received signals.

The phase difference of the high-frequency oscillations received by antennas 1 and 2, 1 and 3, defined by the ratio of (1). On the other hand, the phase difference is determined as follows:

wherethe time lag of the signal arriving at the antenna 1, with respect to the signal arriving at the antenna 3;

the time lag of the signal arriving at antenna 2 relative to the signal arriving at the antenna 3;

Therefore, by equating the above relation, we obtain:

By measuring the amount of delay τ1and τ2and knowing measuring database d, we can uniquely determine the true elevation angle and the azimuth of emitters:

The distance traversed by the signals from the radiation source to the receivers 4, 5 and 6 are not the same, and therefore, different phases of the received signals. Delay one of the signals depends on the position of the source of radiation and the measuring base d.

Since the signal into three channels receive the same, and the noise and interference in the independent channels, each channel will be present variations:

where,,- input vibrations in the first, second and third receiving channels, which is an additive mixture signal uc(t) and noise uR1(t), um2(t), us(t) in each receive channel.

In the correlators signals are multiplied together, and the mutually interfering signals are suppressed. The implementation of the cross-correlation function of signals from one source of radio emission in two independent channels takes the maximum value in the case of a compensation delay time of the signal on one channel due to the inclusion of the delay line. The number of correlators, is equal to n, is determined by the ease of application of n delay lines with a fixed time delay τi(i=1, 2,...,n). The number of correlators is determined by the required accuracy of the elevation angle and azimuth to the source of radio emission.

In General, you must ensure that the total delay of the signal in the range from -Δτ to Δτ using n delay lines. The time interval Δτ is determined from the expression:

where C is the speed of propagation of radio waves.

The presence simultaneously at the outputs of several correlators of local maxima of the cross correlation function corresponds to a situation of Bogdana the turn there are several sources of radio emission. On this basis the estimated number of emitters in the controlled area.

The mutual correlation function of the signal from one source of the radio waves received two identical channels, and formed by the correlator, is nothing like the autocorrelation function, but with different signal delay times.

The first and second receiving channels include multi-tap delay line 7.i and 8.i (i=1, 2,...,n) and the same number of correlators, consisting of a multiplier products 9.i (10.i) and filters 11.i (12.i) lower frequencies. The output voltage of the correlators are compared with the threshold voltage Uthenin threshold units 13.i and 14.i. The threshold voltage Uthenexceeded only at the maximum value of the voltage output of the correlator. In the case of multiple sources of radio emission can be observed maxima at the outputs of multiple correlators. In case of exceeding the threshold voltage Uthenthis excess is recorded corresponding blocks 15.i and 16.i registration. The number and the channel number processing, which exceeded the threshold voltage Uthen, the decision about the number of emitters, their azimuths and elevation angles.

Thus, the proposed method is compared with the prototype provides a direction finding in two planes n is how many emitters, at the same time falling within the band of the reception.

In addition, the proposed method allows to solve the contradiction between the requirements of accuracy and uniqueness of reference elevation angles and azimuths on the radiation sources of radio emission. This is achieved by correlation processing of the received signals.

Thus, the functionality of the method is expanded.

The phase method of direction finding, based on the reception of signals at two spaced antennas, the gain and limiting the amplitude of signals received in the first and second receivers, wherein using the third receiving antenna and the third receiver in which the received signals are also amplify and limit the amplitude, while the receiving antenna is placed at the geometric form of a right angle, the top of which is placed a third receiving antenna common to the other two receiving antennas located in the azimuthal and elevation planes, signals received by the first and second receivers, pass through a - n-idler delay line forming in each plane n of the correlation processing channels, with each channel processing delayed signal Peremohy with the third signal receiver, emit low-frequency voltage, compare it with a threshold voltage and in case of excess of Pirogovo the voltage register is the excess and make a decision on the number and the channel number processing, which exceeded the threshold voltage, the number of emitters, their azimuths and elevation angles.



 

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The phase signal, // 2206901

The invention relates to electrical engineering and can be used in multi-channel RDF, radar, sonar and other systems, passive and active location, using the receiving antenna arrays and methods for multi-channel spatial-temporal signal processing, and systems spatially dispersed and polarization-diversity reception

Direction finder // 2190235
The invention relates to electrical engineering and can be used for detection, reception, direction finding and analysis phase-shift keyed (QPSK) signals against interference

FIELD: finding of azimuth of radio emission source (RES) in wide-base direction finding systems.

SUBSTANCE: angle of azimuth of RES is measured with high degree of precision due to elimination of methodical errors in direction finding caused by linearization of model electromagnet wave propagation wave front. As surface of RES location the plane is used which has RES line of location which has to be crossing of two hyperbolic surfaces of location corresponding to difference-time measurement. Method of RES direction finding is based upon receiving its signal by three aerials disposed randomly, measuring of two time differences of RES signal receiving by aerials which form measuring bases and subsequent processing of results of measurement to calculate values of RES angles of azimuth and coordinates of point through which the RES axis of sight passes. The data received are represented in suitable form. Device for realization of the method has three aerials disposed at vertexes of random triangle, two units for measuring time difference of signal receiving, computing unit and indication unit. Output of common aerial of measuring bases is connected with second inputs of time difference meters which receive signals from outputs of the rest aerials. Measured values of time differences enter inputs of computing unit which calculates values of RES angle of azimuth and coordinates of point through which the RES axis of sight passes. Data received from output of computing analyzing unit enter indication unit intended for those data representation.

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FIELD: radio engineering, applicable for location of posthorizon objects by radiations of their radars, for example, of naval formations of battle ships with operating navigational radars with the aid of coastal stationary or mobile passive radars.

SUBSTANCE: the method consists in detection of radiations and measurement of the bearings (azimuths) with the use of minimum two spaced apart passive radars, and calculation of the coordinates of the sources of r.f. radiations by the triangulation method, determination of location is performed in three stages, in the first stage the posthorizon objects are searched and detected by the radiation of their radars at each passive radar, the radio engineering and time parameters of radar radiations are measured, the detected radars with posthorizon objects are identified by the radio engineering parameters of radiations and bearing, and continuous tracking of these objects is proceeded, the information on the objects located within the radio horizon obtained from each passive radar is eliminated, the working sector of angles is specified for guidance and tracking of the selected posthorizon object, in the second stage continuous tracking of one posthorizon object is performed at least by two passive radars, and the time of reception of each radar pulse of this object is fixed, in the third stage the period of scanning of this radar, the difference of the angles of radiation by the main radar beam of each passive radar and the range to the posthorizon object with due account made for the difference of the angles of radiation are determined by the bearings (azimuths) measured by the passive radar and the times of reception of each pulse of the tracked radar. The method is realized with the aid at least of two spaced apart passive radars, each of them has aerials of the channel of compensation of side and phone lobes, a narrow-band reflector-type aerial, series-connected noiseless radio-frequency amplifier, multichannel receiving device, device of primary information processing and measurement of carrier frequency, amplitude and time of reception of signals of the detected radar, device of static processing of information and measurement of the bearing, repetition period, duration of the train and repetition of the pulse trains and a device for calculation of the difference of the angle of radiation of the aerials of the passive radars by the detected radar.

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EFFECT: enhanced accuracy of direction finding and excepted its dependence of the attitude of the object of direction-finding.

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FIELD: radio engineering.

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EFFECT: wide range of functional applications.

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FIELD: the proposed mode and arrangement refer to the field of radio electronics and may be used for definition of position of sources of emitting complex signals.

SUBSTANCE: the phase direction finder realizing the proposed phase mode of direction finding, has receiving aerials, receivers and a supporting generator, an impulse generator, an electronic commutator, a phase changer on 90, a phase detector and an indicator, a heterodyne, a mixer, an amplifier of an intermediate frequency, multipliers and band filters and a line of delay.

EFFECT: elimination of antagonism between requirements to accuracy of measuring and unique angle reading at phase mode of direction finding of sources of emitting of complex signals.

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FIELD: the invention refers to the field of radio technique and may be used in range-difference systems of definition of the position of the sources of radio emissions.

SUBSTANCE: the mode is based on measuring of two differences of distances Δr12 and Δr13 to two pairs of mobile supporting points {O1,O2}and {O1,O3 , } the coordinates ,j= 1,2,3 supporting points Oj in the moment of time of measuring of distances, then the vector of measured values is transformed into the vector of the coordinates of the three points F1,F2 and M belonging to a hyperbolina: the vector is stored and transmitted along the channels of transmitting information into the center of processing information for using it in quality of initial data at solution a range-difference navigational task; at that the points F1 and F2 defines the focuses of the hyperbolina if it is a hyperbola or an ellipse or a focus and its projection on a directrix if it is a parabola and the third point belongs to the hyperbolina in such a manner that the position of its project on the direct F1F2 defines the form of the curve of the second order.

EFFECT: decreases volume of stored and transmitted data.

5 dwg

FIELD: radio electronics, applicable for passive radio monitoring in multi-channel system designed for direction finding of several sources of radio emission simultaneously getting into the reception zone.

SUBSTANCE: expanded functional potentialities by way of direction finding in two planes of several sources of radio emission simultaneously getting into the reception zone.

EFFECT: expanded functional potentialities.

2 dwg

FIELD: finding coordinates of radio source.

SUBSTANCE: as planes of position of radio source the planes are used, which have line of position of radio source, which has to be crossing of two hyperbolic surfaces pf position corresponding to time-difference measurements. Method is based upon reception of signal of radio source by four aerials, on measurement of three differences in time of reception of radio source signal by aerials, which aerials form measuring bases, upon subsequent processing of results of measurements for calculation of values of parameters of position of radio source and for calculating coordinate of radio source as crossing point of three planes of position. Device for realization of the method has four aerials which aerials form three pairs of measuring bases, which bases are disposed in non-coincident planes, three calculators for calculating parameters of position of radio source, calculator of radio source coordinates made in form of unit for solving system of linear equations and indication unit.

EFFECT: precise measurement of linear coordinates of object.

2 cl, 8 dwg

FIELD: radio detection and ranging, radio navigation, applicable for determining the angular co-ordinates of the signal radiation source.

SUBSTANCE: the claimed method is realized with the aid of a device having three receiving derails, three receivers, two phase-meters, computer, adder and a recording unit connected in a definite way.

EFFECT: enhanced range of one-valued measurement of angles at a small length of the rough measuring base.

3 dwg

FIELD: proposed invention refers to radiolocation and may be used for definition of position and movement of sources of radiation of complex signals.

SUBSTANCE: achieved technical result of invention is increase of trustworthiness of reception of useful signals with a priori known carrier frequency and removal of ambiguity of direction finding by suppression false signals (interference) not interesting for radio control and coming from other directions. At that proposed arrangement has receiving antenna with circle diagram of radiation pattern , receiving antenna with cardioidic diagram of radiation pattern, block for control over diagram of radiation pattern, first and second receiving sets, division block, threshold block, former of control pulse, first and second keys, meter of frequency, memory block, block for comparison of codes, motor and register block.

EFFECT: increases trustworthiness of direction finding.

4 dwg

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