Direction finder

 

(57) Abstract:

The invention relates to electrical engineering and can be used for detection, reception, direction finding and analysis phase-shift keyed (QPSK) signals against the background noise. Achievable technical result of the invention is to increase the sensitivity of the signal in the measurement of small phase shifts corresponding to the small bearings on the radiation source signals. Direction finder contains the receivers 1 and 2, the oscillators 3 and 4, the mixers 5, 6 and 7, amplifiers, 5.1 and 6.1 of the intermediate frequency band-pass filter 8, the amplitude detectors 9 and 10, the integrators 11 and 12, the threshold blocks 13, 14 and 23, block 15 matches, keys 16 and 24, the phase detectors 17 and 26, a multiplier 18 frequency by two, block 19 delay, multiplier 20, the amplifier 21 and 25, the phase shifter 27 90o, Quad 28, 30, 31 and 33, the scaling multiplier 29, myCitadel 32, the adder 34 and the Registrar. 2 Il.

The invention relates to electrical engineering and can be used for detection, reception, direction finding and analysis phase-shift keyed (QPSK) signals against the background noise.

Known devices for direction finding of signals against interference (ed. mon. The USSR 1555695; patents of the Russian Federation 2003131, 2006872, 2010258, 2012010 and others).

From izvestnyh as the nearest equivalent.

The specified direction finder provides reception, direction finding and analysis of QPSK signals against the background noise. At this frequency fG1and fT2local oscillators separated by twice the value of the intermediate frequency

fT2- fG1= 2fCR< / BR>
and are symmetric about the carrier frequency fcthe received QPSK signal

fc- fG1= fT2- fc= fCR.

An object of the invention is to increase the sensitivity of the signal in the measurement of small phase shifts corresponding to the small bearings on the radiation source signals.

The problem is solved in that in the signal, containing a series of the first receiver, the first mixer, a second input connected to the output of the first oscillator, the first intermediate amplifier, the first peak detector, the first integrator, the first threshold unit, the unit matches the first key and the first phase detector, cascaded second receiver, a second mixer, a second input connected to the output of the second local oscillator, a second intermediate frequency amplifier, the second amplitude detector, the second integrator and the second threshold unit, the output kotoroy mixer, a second input connected to the output of the second local oscillator, and a band-pass filter, the output of which is connected to a second input of the first key, sequentially connected to the output of the first intermediate frequency amplifier, a frequency multiplier is two, the second amplifier and the second phase detector, a second input connected to the output of the bandpass filter, and the output connected to the first local oscillator, connected in series to the output of the second amplifier intermediate frequency multiplier, a second input connected to the output of the first intermediate frequency amplifier, a lowpass filter, the third threshold unit and the second key, the second input is through the first amplifier is connected to the output of the multiplier, and the output connected to the second input of the first phase detector, put the Phaser on the 90ofour Quad, the scaling multiplier, myCitadel, the adder and the Registrar, and to the output of the first phase detector connected in series Phaser 90othe first squarer, the scaling multiplier, a second input through the second squarer coupled to the output of the first phase detector, myCitadel, the second input is through the third squarer connected to vihervaara Quad, and the Registrar.

The structural diagram of the direction finder shown in Fig.1. Frequency diagram illustrating the formation of the additional mirror and Raman) of the receiving channels is shown in Fig.2.

Direction finder contains the first 1 and second 2 receivers, the first 3 and second 4 oscillators, the first 5 second 6 and third 7 mixers, 5.1 first and second 6.1 intermediate frequency amplifiers, band-pass filter 8, the first 9 and second 10 amplitude detectors, the first 11 and second 12 integrators, the first 13 and second 14 threshold units, unit 15 matches the first key 16, the first phase detector 17, the multiplier 18 frequency by two, block 19 delay, multiplier 20, the first amplifier 21, the filter 22 of the lower frequencies, the third threshold unit 23, the second key 24, the second amplifier 25, the second phase detector 26, the phase shifter 27 90othe first 28, second 30, third 31 and 33 fourth Quad, the scaling multiplier 29, myCitadel 32, the adder 34 and 35 Registrar. And to the output of receiver 1 (2) connected in series mixer 5 (6), a second input connected to the output of the local oscillator 3 (4), amplifier, 5.1 (6.1) intermediate frequency, amplitude detector 9 (10), the integrator 11 (12), the threshold unit 13 (14), the unit 15 matches the key 16 and the phase detectionin 4, and band-pass filter 8, the output of which is connected to a second input key 16. To the output of the intermediate frequency amplifier 6.1 serially connected unit 19 delay, multiplier 20, a second input connected to the output of the amplifier intermediate frequency 5.5, the filter 22 of the lower frequencies, the threshold unit 23 and the key 24, the second input is via the amplifier 21 is connected to the output of the multiplier 20, and the output connected to the second input of the phase detector 17. The output of the amplifier 5.1 intermediate frequency connected in series multiplier 18 frequency by two, the amplifier 25 and the phase detector 26, a second input connected to the output of the bandpass filter 8, and the output is connected to the local oscillator 3. To the output of the phase detector 17 connected in series Phaser 27 90o, Quad splitter 28, the scaling multiplier 29, the second input is through a squarer 30 is connected to the output of the phase detector 17, myCitadel 32, the second input is through a squarer 31 is connected to the output of the Quad 30, the adder 34, the second input is through a squarer 33 is connected to a second output Quad 28, and the Registrar is 35.

Direction finder works as follows.

The first inputs of the mixers 5 and 6 from the outputs of the receivers 1 and 2 do fct+ak(t)+a2], 0tTc,

where VcfcTc,1,2- amplitude, carrier frequency, duration, and initial phase signals;

k(t) = {0,} - manipulated component phases, reflecting the law of phase manipulation, and

k(t) = const for Kand<t<(K+1)and< / BR>
and may change abruptly at t = Kandthat is on the border between elementary parcels (K=1, 2,...,N-1);

andN - the length and number of basic assumptions which form the signal duration Tc(Tc= Nand).

On the second inputs of the mixers 5 and 6 from the outputs of the oscillators 3 and 4 are served voltage, respectively:

UG1(t) = VG1cos(2fG1t+aG1)

UT2(t) = VT2cos(2fT2t+aT2)

where VG1VT2fG1fT2,G1,T2- amplitude, frequency and initial phase voltages of the oscillators.

Moreover, the frequency fG1and fT2local oscillators 3 and 4 are separated by twice the value of the intermediate frequency

fT2- fG1= 2fCR< / BR>
and selected symmetric about the carrier frequency fcaccept QPSK signals

fc- fG1= fT2- fc= fPR
UPR1(t) = VPR1cos[2fCRt+ak(t)+aPR1],

UAC2(t) = VAC2cos[2fCRtk(t)AC2],

0tc,

where VPR1= 1/2K1VwithVG1;

VAC2= 1/2K1VwithVT2;

K1- gain mixers;

fCR= fc- fG1= fT2- fc- intermediate frequency;

PR1=1-T2;AC2=2-T2;

These voltage detected in the amplitude detectors 9 and 10 are accumulated in the integrators 11 and 12 and compared with the threshold level Vporin threshold units 13 and 14. Moreover, the threshold level Vporis chosen so that the threshold blocks 13 and 14 are not triggered by random noise.

If you receive a QPSK signal in the main channel at a frequency ofc(Fig.2) voltage are formed simultaneously at the outputs of threshold units 13 and 14. These stresses act on the block 15 matches, which is triggered and its output voltage opens the key 16. The keys 16 and 24 in the initial state are always closed.

Voltage UG1(t) and UT2(t) from the outputs of the oscillators 3 and 4 arrive at the mixer 7, the output of which produces a voltage

The
s

U6(t) = Vgcos(4fCRt+ag)

where 2fCR= fT2- fG1;g=T2-G1;

which through public key 16 is supplied to the first input of the phase detector 17.

The voltage UPR1(t) from the output of the amplifier 5.1 intermediate frequency is supplied to the first input of the multiplier products 20, to the second input of which a voltage UAC2(t) from the output of the amplifier 6.1 intermediate frequency that has passed through the block 19 delay

< / BR>
0twith,

where the time delay unit 19 delay.

The output of multiplier 20 is formed of the voltage sum and difference frequencies. Bandpass amplifier 21 is allocated the total voltage frequency

U(t) = Vcos(4fCRt-2fCR+g+)

0tc,

where V= 1/2K2VPR1VAC2;

TO2- transfer coefficient multiplier;

=2-1= 2d/sino- phase shift determines the direction of the radiation source;

d - the distance between the receiving antennas a and b (test database);

- wave length;

otrue bearing.

Adjustable block 19 delay, multiplier 20 and the filter 22 of the lower frequencies form the correlator. Get the
where t1, t2- time of the signals of the distance from the radiation source to the first and second antennas;

R is the difference between the distances from the radiation source to the first and second antennas;

C is the speed of propagation of radio waves.

When this threshold level Vporin the threshold block 23 is exceeded only when the maximum value of the correlation function R(o) and does not exceed the lateral lobes of the correlation function R().

If the threshold level Vporin the threshold block 23 is formed by a DC voltage is supplied to the control input key 23 and opens it. While useful voltage U(t) from the output of bandpass amplifier 21 through a public key 24 is supplied to the second input of phase detector 17, the output of which is formed of a low-frequency voltage

Un() = Vncos(2fCRo-o)

where Vn= 1/2K3VVg;

TO3- gain of the phase detector, is proportional to the measured phase shift.

To ensure the symmetry of the carrier frequency fcrelative frequency fG1and fT2local oscillators 3 and 4 is used, the system fatoua multiplier 18 frequency by two, bandpass amplifier 25 and the phase detector 26, a second input connected to the output of the bandpass filter 8, and the output connected to the control input of the local oscillator 3.

Converted by the frequency FMN signal UPR1(t) from the output of the amplifier 5.1 intermediate frequency simultaneously to the input of the multiplier 18 frequency by two, the output of which is formed by the following harmonic oscillation

Uh(t) = VPR1cos(4fCRt+2PR1), 0twith.

As specified in the oscillation phase shift keying already missing. Harmonic oscillation Uh(t) stands bandpass amplifier 25 and is supplied to the first input of phase detector 26, to the second input of which is applied the reference voltage Uo(t) from the output of the band pass filter 8. If these voltages differ from each other in frequency or phase, the output of phase detector 26 produces a control voltage. And the amplitude and polarity of this voltage depends on the degree and direction of deviation of the carrier frequencycthe received QPSK signal relative to the frequency fG1and fT2local oscillators 3 and 4. Control voltage affects the local oscillator 3, changing its frequency fG1so that kept theT2- fG1= 2fCR,

fc- fG1= fT2- fc= fCR.

The voltage Un() from the output of the phase detector 17 is fed to the input of the phase shifter 27 90o, the output of which produces a voltage

< / BR>
This voltage is fed to the input of the Quad 28, the output of which produces a voltage

U6() = V2nsin2(2fCRo-o)

Simultaneously, the voltage Un() from the output of the phase detector 17 is fed to the input of the Quad 30, the output of which produces a voltage

U7() = V2ncos2(2fCRo-o)

This voltage is fed to the input of the Quad 31, the output of which produces a voltage

U8() = V4ncos4(2fCRo-o)

The voltage U6() and U7() are fed to the two inputs of the scaling multiplier 29, the output of which produces a voltage

< / BR>
The voltage U8() and U9() are fed to the two inputs of vicites 32, the output of which is formed a voltage

< / BR>
The voltage U6() with the second output Quad 28 to the input of the Quad 33, the output of which produces a voltage

U
< / BR>
which is fixed by the Registrar 35.

The above-described operation of the direction finder corresponds to the case of reception of QPSK signals in the main channel at frequency fc.

If a false signal (interferer) is taken by the first image channel at frequency f1or on the second image channel at frequency f2or any Raman channel, after conversion by the frequency it is highlighted amplifier 5.1 or 6.1 intermediate frequency. The voltage will only be present at the output of the threshold block 13 or 14. Block 15 match fails, the key 16 is not opened, the reference voltage is applied to the phase detector 17 and a false signal (interferer) taken on the first f1or the second f2mirror TV, on the first fK1or the second fK2or other Raman channels is suppressed.

If the interfering signals (noise) are taken simultaneously on the first f1and the second f2image channel, the unit 15 matches fires and the key 16 is opened. When this reference voltage Uo(t) arrives at the first input of the phase detector 17. However, to the second input of the phase de who passed false signals (interference), taken at different mirror frequencies f1and f2. Between the channel voltages there is a weak correlation. The output voltage of the correlator does not exceed the threshold level Vporin the threshold unit 23, the key 24 is not opened and the interfering signals (noise) taken simultaneously in the mirror channels at frequencies f1and f2are suppressed.

For a similar reason suppressed and false signals (interference), taken at the same time on other channels.

If useful QPSK signal in the main channel at frequency fcthe block 15 matches is triggered, the key 16 is opened and the reference voltage Uo(t) arrives at the first input of the phase detector 17. In this case, the channel voltage UPR1(t) and UAC2(t) are formed by one and the same signal and between them there is a strong correlation. The output voltage of the correlator exceeds the threshold level Vporin the threshold unit 23, the key 24 is opened and useful FMN-signal at the signal input of the phase detector 17.

Thus, the proposed direction finder provides a precise and unambiguous definition of bearingoon the source and direction finding and unambiguous reference angular coordinateso. Indeed, according to the formula

= 2d/sino,

signal, the more sensitive to changes in bearing othe more the relative size of the database d/. But with increasing d/ decreases the value of the angular coordinateoat which the phase difference exceeds the value , then there comes the ambiguity of reference. In the proposed direction finder improving the accuracy of measurements is ensured by the increase of the relative size of the measurement base, and the resulting ambiguity of reference eliminates the correlation processing of the received QPSK signal.

Correlation processing of the received QPSK signal is provided and increase noise immunity by suppressing spurious signals (noise) taken on additional channels.

The proposed direction finder also provides a significant increase in the sensitivity in the measurement of small phase shifts. This is accomplished by implementing the following algorithm:

cos4-6cos2cos2+sin4= cos4,

which allows a 4-fold increase in the measured phase shift as compared with the initial phase shift.

In addition, the proposed direction finder provides the opportunity for ismultiline included the first receiver, the first mixer, a second input connected to the output of the first oscillator, the first intermediate frequency amplifier, the first peak detector, the first integrator, the first threshold unit, the unit matches the first key and the first phase detector, cascaded second receiver, a second mixer, a second input connected to the output of the second local oscillator, a second intermediate frequency amplifier, the second amplitude detector, the second integrator and the second threshold unit, the output of which is connected to a second input of block matching, sequentially connected to the output of the first local oscillator of the third mixer, a second input connected to the output of the second local oscillator, and band-pass filter, the output of which is connected to a second input of the first key, sequentially connected to the output of the first amplifier intermediate frequency multiplier frequency by two, the second amplifier and the second phase detector, a second input connected to the output of the bandpass filter, and the output connected to the first local oscillator, connected in series to the output of the second amplifier intermediate frequency the delay unit, a multiplier, a second input connected to the output of the first intermediate frequency amplifier, the EN with the output of the multiplier, and the output is connected to the second input of the first phase detector, characterized in that it introduced Phaser 90ofour Quad, the scaling multiplier, myCitadel, the adder and the Registrar, and to the output of the first phase detector connected in series Phaser 90othe first squarer, the scaling multiplier, a second input through the second squarer coupled to the output of the first phase detector, myCitadel, the second input is through the third squarer coupled to the output of the second Quad, the adder, the second input is through fourth squarer connected to the second output of the first Quad, and the Registrar.

 

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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.

EFFECT: widened operational capabilities of direction finder.

2 cl, 7 dwg

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.

EFFECT: reduced error of measurement of the coordinates of posthorizon sources of radio-frequency radiations.

3 cl, 5 dwg

FIELD: radio engineering, applicable in electromagnetic reconnaissance, radio navigation and radio detection and ranging for determination of the direction to the source of radiation or reflection of radio waves.

SUBSTANCE: the phase direction finder has two antennas, two receiving paths, three phase shifters, two phase detectors, two limiters, three adders, two modulus computation devices, subtracting device, amplifier, comparator, gate circuit and an oscillator.

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

2 cl, 10 dwg

FIELD: radio engineering.

SUBSTANCE: device has the first, the second and the third receiving antennas, the first, the second and the third high frequency amplifiers, the first and the second heterodynes, the first, the second and the third mixers, the first, the second and the third multipliers, the first, the second, the third and the fourth narrowband filters, the first, the second and the third intermediate frequency amplifiers, frequency multiplier by two, the first, the second and the third phase detectors, the first and the second correlator units, the first, the second, the third and the fourth threshold units, the first, the second, the third and the fourth keys and unit for recording.

EFFECT: wide range of functional applications.

3 dwg

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.

2 cl, 2 dwg

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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