RU2134429C1 - Phase direction finding method - Google Patents

Abstract

FIELD: radiolocation and radio navigation. SUBSTANCE: complex signals are received by five antennas positioned in the form of geometric right angle in which vertex antenna of measurement channel is placed, signals are frequency converted and voltages of first intermediate frequency are isolated to form by this one measurement and four direction finding channels. Phase difference between harmonic oscillations on frequency of second heterodyne and voltage of second heterodyne is measured in measurement channel and is used to evaluate values of azimuth and angle of elevation of signal radiation source. Phase difference between harmonic voltage on frequency of first heterodyne and voltage of first heterodyne is measured, carrier frequency of received signal is measured as well as angle of sight of radiation source of complex signal and difference of phase differences between first direction finding and measurement channels, between second and first direction finding channels in azimuthal plane. Their values are used to determine range to signal radiation source. EFFECT: expanded functional capabilities of method by location of radiation source of complex signals. 2 cl, 4 dwg

Description

 The proposed method relates to radar, radio navigation and can be used to determine the location of the radiation sources of complex signals.

где d - расстояние между антеннами (измерительная база);
λ - длина волны;
α - угол прихода радиоволн,
фазовый способ тем чувствительнее к изменению угла α, чем больше относительный размер базы

Но с ростом

уменьшается значение угловой координаты α, при котором разность фаз Δφ превосходит значение 2π, т.е. наступает неоднозначность отсчета. Разрешение отмеченного противоречия в данном способе достигается применением нескольких измерительных баз (многошкальность).As the basic method, the phase direction finding method was chosen (Cosmic trajectory measurements. Under the general editorship of P. A. Agadzhanov and others. M .: Sov. Radio, 1969, p. 244-245). The specified method is characterized by a contradiction between the requirements of measurement accuracy and the uniqueness of the angle reading. Indeed, according to the formula

where d is the distance between the antennas (measuring base);
λ is the wavelength;
α is the angle of arrival of radio waves,
the phase method is the more sensitive to the change in the angle α, the larger the relative size of the base

But with growth

the value of the angular coordinate α decreases, at which the phase difference Δφ exceeds the value 2π, i.e. ambiguity of counting occurs. The resolution of the noted contradiction in this method is achieved by the use of several measuring bases (multiscale).

 However, the basic direction finding method does not provide the ability to measure the distance to the radiation source of complex signals, i.e. does not allow to determine the location of the radiation source of complex signals.

 The aim of the invention is to expand the functionality of the method by determining the location of the radiation source of complex signals.

 This goal is achieved by the fact that in a method based on the reception of signals to three antennas located in the azimuthal plane on one line, converting them in frequency and isolating the voltages of the first intermediate frequency, two additional antennas are placed on the elevated plane on another line perpendicular to the first, receive signals from them, transform the latter in frequency and isolate the voltages of the first intermediate frequency, thereby forming one measuring and four direction finding channels, two for each plane Then, in the measuring channel, the voltage of the first intermediate frequency is converted a second time in frequency, the voltage of the second intermediate frequency is isolated, it is multiplied with the voltages of the first intermediate frequency of the direction finding channels, harmonic oscillations at the frequency of the second local oscillator are retained from the obtained voltages while maintaining phase relationships, the phase differences between harmonic oscillations and the voltage of the second local oscillator and from them evaluate the azimuth and elevation angle of the signal radiation source, multiplying t is the received signal of the second direction-finding channel with the voltage of the first intermediate frequency of the first direction-finding channel in the azimuthal plane, harmonic oscillation at the frequency of the first local oscillator is preserved from the received voltage while maintaining phase relationships, the phase difference between the harmonic oscillation and the voltage of the first local oscillator is measured, the carrier frequency of the received signal is measured, angle of sight of the signal radiation source and the phase difference between the first direction finding and measuring channels And between the second and first direction finding channels in the azimuthal plane and their distance estimate value signal to the radiation source, the measured values of the azimuth, elevation and range determine the location of the radiation source.

где λ - длина волны.Receiving antennas 1-5 are placed in the form of a geometric right angle, at the top of which the antenna 1 of the measuring channel is placed, thereby forming two measuring bases d and 2d in each plane, between which the inequality

where λ is the wavelength.

 In this case, smaller bases d form rough, but unambiguous scales of reference angles, and large bases 2d form accurate, but ambiguous scales of reference angles.

 Receiving antennas 1-5 can also be placed in the form of a symmetrical geometric cross, in the center of which is placed the antenna 1 of the measuring channel.

 The location of the radiation source of the complex signal according to the proposed method is carried out by performing the following sequence of operations.

где U_пр1=1/2K₁U₁U_г1; φ_пр1= φ₁-φ_г1;
где U_пр2=1/2K₁U₂U_г2; φ_пр2= φ₂-φ_г1;
где U_пр3=1/2K₁U₃U_г1; φ_пр3= φ₃-φ_г1;
где U_пр4=1/2K₁U₄U_г2; φ_пр4= φ₄-φ_г1;
где U_пр5=1/2K₁U₅U_г2; φ_пр5= φ₅-φ_г1;
K₁ - коэффициент передачи преобразователя частоты;
ω_пр1= ω_c-ω_г1 - первая промежуточная частота;
U_г1, ω_г1, φ_г1 - амплитуда, частота и начальная фаза напряжения первого гетеродина,
образуя тем самым один измерительный и четыре пеленгационных канала, по два на каждую плоскость.1. Receive complex signals, for example, with phase shift keying (QPSK) and an unstable carrier frequency for five antennas 1-5, located in the form of a geometric right angle, at the top of which the antenna 1 of the measuring channel is placed:
u ₁ (t) = U ₁ cos [(ω _c ± Δω) t + φ _k (t) + φ ₁ ],
u ₂ (t) = U ₂ cos [(ω _c ± Δω) t + φ _k (t) + φ ₂ ],
u ₃ (t) = U ₃ cos [(ω _c ± Δω) t + φ _k (t) + φ ₃ ],
u ₄ (t) = U ₄ cos [(ω _c ± Δω) t + φ _k (t) + φ ₄ ],
u ₅ (t) = U ₅ cos [(ω _c ± Δω) t + φ _k (t) + φ ₅ ], 0 ≤ t ≤ T _c ,
where U ₁ -U ₂ are the amplitudes of the signals;
ω _c , T _c , φ ₁ -φ ₅ - carrier frequency, duration and initial phase of the signals;
± Δω - carrier frequency instability caused by various destabilizing factors;
φ _k (t) = {0, π} is the manipulated component of the phase that displays the law of phase manipulation, and φ _k (t) = const for
kτ _and <t <(k + 1) τ _and u can change stepwise at t = kτ _and , i.e. at the boundaries between elementary premises (k = 1,2, ..., Nl);
τ _and , N is the duration and number of chips that make up the signal of duration T _c (T _c = Nτ _and ).
2. Convert them in frequency and isolate the voltage of the first intermediate frequency:
u _CR1 (t) = U _CR1 cos [(ω _CR1 ± Δω) t + φ _k (t) + φ _CR1 ],
u _CR2 (t) = U _CR2 cos [(ω _CR1 ± Δω) t + φ _k (t) + φ _CR2 ],
u _CR3 (t) = U _CR3 cos [(ω _CR1 ± Δω) t + φ _k (t) + φ _CR3 ],
u _CR4 (t) = U _CR4 cos [(ω _CR1 ± Δω) t + φ _k (t) + φ _CR4 ],

where U _CR1 = 1 / 2K ₁ U ₁ U _g1 ; φ _pr1 = φ ₁ -φ _g1 ;
where U _pr2 = 1 / 2K ₁ U ₂ U _g2 ; φ _pr2 = φ ₂ -φ _g1 ;
where U _pr3 = 1 / 2K ₁ U ₃ U _g1 ; φ _pr3 = φ ₃ -φ _g1 ;
where U _pr4 = 1 / 2K ₁ U ₄ U _g2 ; φ _pr4 = φ ₄ -φ _g1 ;
where U _pr5 = 1 / 2K ₁ U ₅ U _g2 ; φ _pr5 = φ ₅ -φ _g1 ;
K ₁ - gear ratio of the frequency converter;
ω _pr1 = ω _c -ω _g1 is the first intermediate frequency;
U _g1 , ω _g1 , φ _g1 - amplitude, frequency and initial phase of the voltage of the first local oscillator,
thereby forming one measuring and four direction finding channels, two on each plane.

3. In the measuring channel, the voltage U _pr1 (t) of the first intermediate frequency is converted for the second time in frequency and the voltage of the second intermediate frequency is isolated.

u _CR6 (t) = U _CR6 cos [(ω _CR2 ± Δω) t + φ _CR6 ], 0 ≤ t ≤ T _c ,
where U _CR1 = 1 / 2K ₁ U ₁ U _g1 ;
_np2 ω = ω _z2 -ω _pr1 - second intermediate frequency;
φ = φ _{pr6 pr1} -φ _r2;
U _g2 , ω _g2 , φ _g2 - amplitude, frequency and initial phase of the voltage of the second local oscillator.

4. Multiply the voltage of the second intermediate frequency u _CR6 (t) with voltages u _CR2 (t) - u _CR5 (t) of the first intermediate frequency direction finding channels.

d, 2d - измерительные базы;
α, β - угловые координаты в азимутальной и угломестной плоскостях
6. Измеряют разности фаз Δφ₁÷ Δφ₄ между гармоническими колебаниями u₆(t)- u₉(t) и напряжением второго гетеродина:
u_г2(t) = U_г2cos(ω_г2t+φ_г2)
и по ним оценивают значения азимута α и угла мест β источника излучения сигнала.5. From the obtained stresses, harmonic oscillations in frequency ω _{g2 of the} second local oscillator are distinguished with the phase relation being preserved:
u ₆ (t) = U ₆ cos (ω _g2 t + φ _g2 + Δφ ₁ ),
u ₇ (t) = U ₇ cos (ω _g2 t + φ _g2 + Δφ ₂ ),
u ₈ (t) = U ₈ cos (ω _g2 t + φ _g2 + Δφ ₃ ),
u ₉ (t) = U ₉ cos (ω _g2 t + φ _g2 + Δφ ₄ ), 0 ≤ t ≤ T _c ,
where U ₆ = 1 / 2K ₂ U _pr2 U _pr6 ;
U ₇ = 1 / 2K ₂ U _pr3 U _pr6 ;
U ₈ = 1 / 2K ₂ U _pr4 U _pr6 ;
U ₉ = 1 / 2K ₂ U _pr5 U _pr6 ;
K ₂ - transmission coefficient of the multipliers;

d, 2d - measuring bases;
α, β - angular coordinates in the azimuthal and elevation planes
6. Measure the phase difference Δφ ₁ ÷ Δφ ₄ between harmonic oscillations u ₆ (t) - u ₉ (t) and the voltage of the second local oscillator:
u _g2 (t) = U _g2 cos (ω _g2 t + φ _g2 )
and they estimate the azimuth α and elevation angle β of the signal source.

7. Multiply the received signal u ₂ (t) of the first direction-finding channel with a voltage of u _pr3 (t) of the first intermediate frequency of the second direction-finding channel in the azimuth plane.

9. Измеряют разность фаз Δφ₅ между гармоническим колебанием u₁₀(t) и напряжением первого гетеродина
u_г1(t) = U_г1cos(ω_г1t+φ_г1).
10. Измеряют несущую частоту ω_c принимаемого сигнала и разность разностей фаз (фиг. 4)

Выразив sinα₁ и sinα₃ через стороны прямоугольных треугольников 11'И, 22'И и 33'И, получим

где D - дальность до источника излучения сложных сигналов. Вышеприведенные выражения можно записать в приближенном виде:

Значение разности фаз в приближенном виде выглядит следующим образом:

11. Искомую дальность D до источника излучения сложных сигналов оценивают по следующей формуле:

12. По измеренным значениям азимута α, угла места β и дальности D определяют местонахождение источника излучения сложных сигналов.8. From the obtained voltage, harmonic oscillation is isolated at a frequency ω _{g1 of the} first local oscillator while maintaining phase relationships
u ₁₀ (t) = U ₁₀ cos (ω _g1 t + φ _g1 + Δφ ₅ ), 0 ≤ t ≤ T _c ,
where U ₁₀ = 1 / 2K ₁ U ₃ U _pr2 ;

9. The phase difference Δφ ₅ between the harmonic oscillation u ₁₀ (t) and the voltage of the first local oscillator is measured
u _g1 (t) = U _g1 cos (ω _g1 t + φ _g1 ).
10. Measure the carrier frequency ω _{c of the} received signal and the phase difference (Fig. 4)

Expressing sinα ₁ and sinα ₃ through the sides of right triangles 11'I, 22'I and 33'I, we get

where D is the distance to the radiation source of complex signals. The above expressions can be written in approximate form:

The approximate value of the phase difference is as follows:

11. The desired range D to the radiation source of complex signals is estimated by the following formula:

12. From the measured values of the azimuth α, elevation angle β and range D determine the location of the radiation source of complex signals.

 The proposed phase direction finding method can be implemented by a device whose structural diagram is shown in FIG. 1. The relative position of the receiving antennas is shown in FIG. 2, 3, and 4.

 The device contains receiving antennas 1-5, high-frequency amplifiers 6-10, first local oscillator 11, mixers 12-16, 23, first-frequency amplifiers 17-21, second local oscillator 22, second intermediate frequency amplifier 24, multipliers 25-28, 29 , narrow-band filters 30 - 34, phase meters 35-40, frequency counter 41, computing unit 42 and registration unit 43.

 The measuring channel consists of a series-connected antenna 1, high-frequency amplifier 6, mixer 12, the second input of which is connected to the output of the local oscillator II, amplifier 17 of the first intermediate frequency, mixer 23, the second input of which is connected to the output of the local oscillator 22, amplifier 24 of the second intermediate frequency and frequency counter 41.

 Each direction finding channel consists of series-connected antennas 2 (3, 4, 5), a high-frequency amplifier 7 (8, 9, 10), a mixer 13 (14, 15, 16), the second input of which is connected to the output of the local oscillator 11, amplifier 18 (19, 20, 21) of the first intermediate frequency, multiplier 25 (26, 27, 28), the second input of which is connected to the output of the amplifier 24 of the second intermediate frequency, narrow-band filter 30 (31, 32, 33) and phase meter 35 (36, 37 , 38), the second input of which is connected to the output of the local oscillator 22. To the output of the high-frequency amplifier 7, a multiplier 29 is connected in series, the second input which is connected to the output of the amplifier 19 of the first intermediate frequency, a narrow-band filter 34, a phase meter 39, the second input of which is connected to the output of the local oscillator 11, a phase meter 40, the second input of which is connected to the output of the phase meter 35, the computing unit 42, the second input of which is connected to the output of the phase meter 39, and the third input is connected to the output of the frequency meter 41, and the registration unit 43, the second, third, fourth and fifth inputs of which are connected to the outputs of the phase meters 35-38, respectively.

 The device operates as follows.

Received complex signals, for example, with phase shift keying (QPSK) and an unstable carrier frequency U _g1 (t) -U _g5 (t), from the outputs of antennas 1-5 through high-frequency amplifiers _6-10 enter the first inputs of the mixers 12-16, respectively the second inputs of which the voltage of the first local oscillator 11
u _g1 (t) = U _g1 cos (ω _g1 t + φ _g1 ).
At the outputs of the mixers 12-16 are formed the voltage of the Raman frequencies. Amplifiers 17-21 are allocated voltage u _CR1 (t) -u _CR5 (t) only the first intermediate frequency. The voltage u _pr1 (t) from the output of the amplifier 17 of the first intermediate frequency is supplied to the first input of the mixer 23, the second input of which is the voltage of the local oscillator 22
u _g2 (t) = U _g2 cos (ω _g2 t + φ _g2 ).
At the output of the mixer 23, voltages of combination frequencies are generated. The amplifier 24 selects a voltage u _pr6 (t) of only the second intermediate frequency, which is fed to the second inputs of the multipliers 25-28, the first inputs of which receive voltage u _pr2 (t) -u _pr5 (t) of the first intermediate frequency. From the obtained voltages, narrow-band filters 30-33 distinguish harmonic oscillations u ₆ (t) -u ₉ (t), which are fed to the first inputs of the phase meters 35-38, the second inputs of which are supplied with the voltage u _r2 (t) of the local oscillator 22. The measured phase shifts Δφ ₁ , Δφ ₂ , Δφ ₃ and Δφ ₄ are registered in the registration unit 42.

Phase 39 measures the phase shift Δφ ₅ . The phase difference difference Δ (Δφ) = Δ (Δφ ₁ -Δφ ₅ ) is measured by a phase meter 40 and enters the computing unit 42, where the distance D to the radiation source of the complex signal is determined indirectly, and then recorded in the registration unit 43. The latter determines the location of the radiation source of the complex signal.

Таким образом, предполагаемый способ по сравнению с базовым обеспечивает определение дальности до источника излучения сигнала и измерение угла места, т. е. обеспечивает определение местонахождения источника излучения сигнала. При уменьшении угла визирования (азимута α) точность определения дальности увеличивается. Причем определение дальности производится практически мгновенно.Maximum range error D

Thus, the proposed method in comparison with the basic one provides a determination of the distance to the signal source of the signal and a measurement of the elevation angle, i.e., it provides the determination of the location of the signal radiation source. With a decrease in the viewing angle (azimuth α), the accuracy of determining the range increases. Moreover, the determination of range is made almost instantly.

При этом меньшая база d образует грубую, но однозначную шкалу отсчета угла, а большая база 2d образует точную, но неоднозначную шкалу отсчета угла. Указанные базы формируют пятью антеннами, которые располагают в виде прямого геометрического угла, в вершине которого помещают антенну 1 измерительного канала, или в виде симметричного геометрического креста, в центре которого помещают антенну 1 измерительного канала.To eliminate the contradiction between the accuracy and uniqueness of direction finding of the radiation source of complex signals in each plane, two measuring bases d and 2d are used, between which the following inequality holds:

In this case, the smaller base d forms a rough but unambiguous angle reference scale, and the larger base 2d forms an accurate, but ambiguous angle reference scale. These bases are formed by five antennas, which are placed in the form of a right geometric angle, at the top of which the antenna 1 of the measuring channel is placed, or in the form of a symmetrical geometric cross, in the center of which the antenna 1 of the measuring channel is placed.

 In addition, the proposed method of direction finding is invariant to instability of the carrier frequency and the type of modulation of the received complex signals.

 Thereby, the functionality of the basic direction finding method is expanded.

Claims (3)

 1. Phase direction finding method based on the reception of signals on three antennas located in the azimuthal plane on one line, converting them in frequency and isolating the voltages of the first intermediate frequency, characterized in that two additional antennas are placed in the elevation plane on another line perpendicular to the first receive signals on them, transform the latter in frequency and isolate the voltages of the first intermediate frequency, thereby forming one measuring and four direction finding channels, two for each plane b) in the measuring channel, the voltage of the first intermediate frequency is converted a second time in frequency, the voltage of the second intermediate frequency is isolated, it is multiplied with the voltages of the first intermediate frequency of the direction finding channels, harmonic oscillations at the frequency of the second local oscillator are extracted from the obtained voltages while maintaining phase relationships, the phase differences between harmonic oscillations and the voltage of the second local oscillator and from them evaluate the azimuth and elevation angle of the signal radiation source, multiplying the received signal of the first direction-finding channel with the voltage of the first intermediate frequency of the second direction-finding channel in the azimuthal plane is extracted, the harmonic oscillation at the frequency of the first local oscillator is preserved from the received voltage while maintaining phase relations, the phase difference between the harmonic oscillation and the voltage of the first local oscillator is measured, the carrier frequency of the received signal is measured, angle of sight of the signal radiation source and the phase difference difference between the first direction finding and measuring channels and as well as between the second and the first direction finding channels in the azimuthal plane and their distance estimate value signal to the radiation source, the measured values of the azimuth, elevation and range determine the location of the radiation source. 2. The method according to claim 1, characterized in that the receiving antennas are placed in the form of a geometric right angle, at the top of which the antenna of the measuring channel is placed, thereby forming two measuring bases d and 2d in each plane, between which the inequality is established

where λ is the wavelength;
in this case, smaller bases d form coarse, but unambiguous scales of reference angles, and large bases 2d form accurate, but ambiguous scales of reference angles.  3. The method according to claim 1, characterized in that the receiving antennas are placed in the form of a symmetrical geometric cross, in the center of which is placed the antenna of the measuring channel.

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