RU2637048C1 - Asteroid motion parameters determining system - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: asteroid motion parameters determining system contains a transmitter, a duplexer, a transceiving antenna, receiving antennas, a reference oscillator, a pulse generator, an electronic switch, a local oscillator, a mixer, a difference frequency filter, high-frequency amplifiers, multipliers, bandpass filters, a delay line, phase detectors, a phase shifter for 90°, a registration unit, a low-pass filter, a phase meter, and a computational unit. The motion parameters are determined by using complex signals with phase manipulation, receiving antennas placed in the azimuth plane along the circumference, with the possibility of their electronic rotation around the transceiving antenna located in the center of the circumference and two receiving antennas placed in the elevation plane.

EFFECT: increasing the accuracy of determining the asteroid motion parameters.

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Description

The proposed system relates to systems used for the implementation of complexes to protect the Earth from flying objects of natural and artificial origin, approaching the Earth.

Known devices and systems for determining the parameters of motion of asteroids (RF patents Nos. 2.107.306, 2.175.139, 2.235.955, 2.250.470, 2.267.975, 2.273.034,2.374.597,2.392.639, 2.453.813,2.518 .108, 2.554.086, 2.568.628, 2.578003; US patents Nos. 5,920278, 6.683.558, 7.197.381, 7.463.181; EP patents Nos. 1,026.519, 1.651.978; Medvedev U. D. and others Asteroid-comet hazard. / Under the editorship of A.G. Sokolsky - St. Petersburg, Institute of Theoretical Astronomy RAS, 1996 and others).

Of the known devices and systems closest to the proposed one is the "Device for determining the parameters of the motion of an asteroid" (RF patent No. 2.568.628, B64G 3/00, 2014), which is selected as the base object.

The known device includes a ground-based radar system (radar) with four receiving and one transmitting antenna, with two phase detectors, four information display units, a shift recorder and an asteroid speed calculation unit. A transmitting antenna mounted in the center of the circle emits a continuous signal with initial modulation according to a one-sided ramp law. Signals reflected from the asteroid are received by four antennas located evenly along the circumference. The parameters of the asteroid’s motion are determined by the moments of detection and by the frequencies of the difference signals received and generated in the receiving antennas using the above radar tools.

A disadvantage of the known device is the low accuracy of determining the parameters of motion of the asteroid.

вокруг приемопередающей антенны, размещенной в центре окружности, и двух приемных антенн, размещенных в угломестной плоскости.An object of the invention is to increase the accuracy of determining the parameters of motion of an asteroid by using complex signals with phase shift keying, n received antennas placed in the azimuthal plane along a circle of radius d with the possibility of their electronic rotation with angular velocity

around a transceiver antenna located in the center of the circle, and two receiving antennas located in the elevation plane.

The problem is solved in that the system for determining the parameters of the motion of an asteroid containing, in accordance with the closest analogue, a transmitter, four receiving antennas located on a circle at an equal distance from each other in a circle, a mixer and a filter of a difference frequency, the first and second phase detectors, differs from the closest analogue in that it is equipped with m receiving antennas located on a circle in the azimuthal plane, two receiving antennas placed in an elevation plane speed, transceiver antenna located in the center of the circle, duplexer, reference generator, pulse generator, electronic switch, four high-frequency amplifiers, six multipliers, four bandpass filters, delay line, 90 ° phase shifter, recording unit, third, fourth and fifth phase detectors, a low-pass filter, a phase meter and a computing unit, and a pulse generator, an electronic switch, n outputs are connected in series to the first output of the reference oscillator which is connected to n = 4 + m receiving antennas evenly spaced around a circle of radius d with the possibility of electronic rotation around a transceiving antenna located in the center of the circle, a second high-frequency amplifier, a first multiplier, the second input of which is connected to the output of a difference frequency filter, the first a bandpass filter, a delay line, a first phase detector, the second input of which is connected to the output of the first bandpass filter, a 90 ° phase shifter, a second phase detector, the second input of which is connected to the second output a reference oscillator and a registration unit, a duplexer is connected to the first output of the transmitter, the input-output of which is connected to the transceiver antenna, and the first high-frequency amplifier, the output of which is connected to the first input of the mixer, to the second input of which the local oscillator output is connected, to the output of the first bandpass a second multiplier, the second input of which is connected to the output of the local oscillator, the second bandpass filter and the third phase detector, the second input of which is connected to the third the reference oscillator, and the output is connected to the second input of the registration unit, a third multiplier is connected in series to the second output of the transmitter, the second input of which is connected to the output of the first high-frequency amplifier, a low-pass filter and a computing unit whose output is connected to the third input of the registration unit, to the first receiving antenna located in the elevation plane is connected in series with a third high-frequency amplifier, a fourth multiplier, the second input of which is connected to the output of the filter the remaining frequency, the third bandpass filter and the fourth phase detector, the second input of which is connected to the local oscillator output, and the output is connected to the fourth input of the registration unit and to the second input of the computing unit, the fourth high-frequency amplifier is connected in series to the second receiving antenna located in the elevation plane a fifth multiplier, the second input of which is connected to the output of the differential frequency filter, a fourth bandpass filter and a fifth phase detector, the second input of which is connected to the output of the local oscillator, and the output is connected to the fifth input of the registration unit and to the third input of the computing unit, the sixth multiplier is connected to the output of the third bandpass filter, the second input of which is connected to the output of the fourth bandpass filter, and the phase meter, the output of which is connected to the fourth input of the computing unit.

The structural diagram of the proposed system is presented in FIG. 1. The relative position of the transceiver antenna 3, the receiving antennas 4.i (i = 1, 2, ..., n), 25,26 and the asteroid are shown in FIG. 2.

вокруг приемопередающей антенны 3, размещенной в центре окружности, усилитель 12 высокой частоты, первый перемножитель 13, второй вход которого соединен с выходом фильтра 11 разностной частоты, первый полосовой фильтр 14, линия задержки 15, первый фазовый детектор 16, фазовращатель 17 на 90°, второй фазовый детектор 18, второй вход которого соединен с вторым выходом опорного генератора 5 и блок 22 регистрации. К выходу первого полосового фильтра 14 последовательно подключены второй перемножитель 19, второй вход которого соединен с выходом гетеродина 9, второй полосовой фильтр 20 и первый фазовый детектор 21, второй вход которого соединен с третьим выходом опорного генератора 5, а выход подключен к второму входу блока 22 регистрации. К второму выходу передатчика 1 последовательно подключены третий перемножитель 23, второй вход которого соединен с выходом первого усилителя 8 высокой частоты, фильтр 24 низких частот и вычислительный блок 37, выход которого подключен к третьему входу блока 22 регистрации. К выходу первой приемной антенны 25, размещенной в угломестной плоскости, последовательно подключены третий усилитель 27 высокой частоты, четвертый перемножитель 29, второй вход которого соединен с выходом фильтра 11 разностной частоты, третий полосовой фильтр 31 и четвертый фазовый детектор 33, второй вход которого соединен с выходом гетеродина 9, а выход подключен к четвертому входу блока 22 регистрации и к второму входу вычислительного блока 37. К выходу второй приемной антенны 26, размещенной в угломестной плоскости, последовательно подключены четвертый усилитель 28 высокой частоты, пятый перемножитель 30, второй вход которого соединен с выходом фильтра 11 разностной частоты, четвертый полосовой фильтр 32 и пятый фазовый детектор 34, второй вход которого соединен с выходом гетеродина 9, а выход подключен к пятому входу блока 22 регистрации и к третьему входу вычислительному блоку 37. К выходу третьего полосового фильтра 31 последовательно подключены шестой перемножитель 35, второй вход которого соединен с выходом четвертого полосового фильтра 32, и фазометр 36, выход которого соединен с четвертым входом вычислительного блока 37.The system for determining the parameters of the motion of an asteroid contains a series-connected transmitter 1, a duplexer 2, the input-output of which is connected to a transceiver antenna 3, a high-frequency amplifier 8, a mixer 10, the second input of which is connected to the output of the local oscillator 9, and a difference filter 11. A pulse generator 6, an electronic switch 7, n inputs of which are connected to the outputs of n receiving antennas 4.i (i = 1, 2, ..., n) arranged around a circle of radii d with the possibility of electronic rotation, are connected in series to the first output of the reference generator 5 with speed

around the transceiver antenna 3 located in the center of the circle, a high-frequency amplifier 12, a first multiplier 13, the second input of which is connected to the output of the differential frequency filter 11, a first band-pass filter 14, a delay line 15, a first phase detector 16, a phase shifter 17 90 °, a second phase detector 18, the second input of which is connected to the second output of the reference generator 5 and the registration unit 22. The second multiplier 19, the second input of which is connected to the output of the local oscillator 9, the second pass filter 20 and the first phase detector 21, the second input of which is connected to the third output of the reference oscillator 5, and the output is connected to the second input of the block 22, are connected in series to the output of the first bandpass filter 14 registration. A third multiplier 23, the second input of which is connected to the output of the first high-frequency amplifier 8, a low-pass filter 24 and a computing unit 37, the output of which is connected to the third input of the registration unit 22, is connected in series to the second output of the transmitter 1. To the output of the first receiving antenna 25 located in the elevation plane, a third high-frequency amplifier 27, a fourth multiplier 29, the second input of which is connected to the output of the difference frequency filter 11, the third band-pass filter 31 and the fourth phase detector 33, the second input of which is connected to the output of the local oscillator 9, and the output is connected to the fourth input of the registration unit 22 and to the second input of the computing unit 37. To the output of the second receiving antenna 26 located in the elevation plane, sequentially connect We have a fourth high-frequency amplifier 28, a fifth multiplier 30, the second input of which is connected to the output of the differential frequency filter 11, a fourth band-pass filter 32 and a fifth phase detector 34, the second input of which is connected to the output of the local oscillator 9, and the output is connected to the fifth input of the registration unit 22 and to the third input of the computing unit 37. The sixth multiplier 35, the second input of which is connected to the output of the fourth band-pass filter 32, and the phase meter 36, the output of which is connected to the fourth input of the computing unit 37.

The proposed system works as follows.

The transmitter 1 generates a complex signal with phase shift keying (PSK)

u _c (t) = U _c ⋅cos [ω _c t + ϕ _k (t) + ϕ _s ], 0≤t≤T _c ,

where u_c, ω_c, ϕ_c, T_c - amplitude, carrier frequency, initial phase and signal duration;

ϕ _k = {0, π} is the manipulated component of the phase, which reflects the law of phase manipulation in accordance with the modulating code M (t), and ϕ _k (t) = const for kτ _E <t <(k + 1) τ _E and can vary abruptly at t = kτ _Oe , i.e. at the borders between elementary premises (k = 1, 2, ..., N-1);

τ _E , N - the duration and number of chips that make up a signal of duration T _c (T _c = Nτ _E ),

which through the duplexer 2 enters the transceiver antenna 3 and is radiated by it towards the asteroid approaching the Earth with a speed of V = 30 km / s.

Complex QPS signals reflected from the asteroid:

u ₁ (t) = U ₁ cos [(ω _c ± Δω) t + ϕ _k (t) + ϕ ₁ ],

u ₃ (t) = U ₃ cos [(ω _c ± Δω) t + ϕ _k (t) + ϕ ₂ ),

u ₄ (t) = U ₄ cos [(ω _c ± Δω) t + ϕ _k (t) + ϕ ₃ ), 0≤t≤T _c

where ± Δω is the instability of the carrier frequency of the signals due to various destabilizing factors, including the Doppler effect

d is the radius of the circle on which the receiving antennas 4i are located (i = 1, 2, ..., n, n = 4 + m) (measuring base)

λ is the wavelength;

- скорость электронного вращения приемных антенн 4.i(i=1, 2, …, n) вокруг приемопередающей антенны 3;

- the speed of the electronic rotation of the receiving antennas 4.i (i = 1, 2, ..., n) around the transceiver antenna 3;

α - bearing (azimuth) to the asteroid,

from the outputs of the transceiver and receiving antennas 3, 4.i (i = 1, 2, ..., n), 25 and 26 directly and through duplexer 2 and electronic switch 7, are fed to the inputs of high-frequency amplifiers 8, 12, 27 and 28, and then to the first inputs of the mixer 10, multipliers 13, 29 and 30, respectively. The second input of the mixer 10 from the output of the local oscillator 9 is supplied with voltage

u _g (t) = U _g cos (ω _g t + ϕ _g ).

At the output of the mixer 10, voltages of combination frequencies are generated. Filter 11 is allocated voltage differential (intermediate) frequency

u _ave (t) = U _prosp cos [(ω _{ave ± Δω) t + φ k (} t) + φ _etc.],

Where

ω _CR = ω _with -ω _g - difference (intermediate) frequency;

ϕ _ol = ϕ _g -ϕ _g ,

which is fed to the second inputs of the multipliers 13, 29 and 30. At the output of the multiplier 13 a phase-modulated (FM) oscillation is generated at the frequency ω _{g of the} local oscillator 9

Where

which is allocated by a band-pass filter and fed to the first inputs of the phase detector 16, delay line 15 and multiplier 19. The second input of the latter is supplied with the voltage u _g (t) of the local oscillator 9. A harmonic voltage is generated at the output of the multiplier 19

Where

which is allocated by the band-pass filter 20 and fed to the first input of the phase detector 21. At the second input of the phase detector 21 from the third output of the reference generator 5, the reference voltage

u ₀ (t) = U ₀ cosΩt.

The output of the phase detector 21 produces a low-frequency voltage

u _н1 (α) = U _н1 cosα,

Where

which is fixed by the registration unit 22. This forms the asteroid direction-finding scale in the azimuthal plane, which is an accurate but ambiguous scale.

называемая индексом фазовой модуляции, характеризует максимальное значение отклонения фазы от нулевого значения, происходящего при электронном вращении приемных антенн 4.i(i=1, 2, …, n) вокруг приемопередающей антенны 3.At the same time, the phase-modulated oscillation u ₅ (t) is subjected to autocorrelation processing using an autocorrelator consisting of a delay line 15 and a phase detector 16. In the phase-modulated voltage u ₅ (t), the quantity

called the phase modulation index, characterizes the maximum value of the phase deviation from the zero value that occurs during the electronic rotation of the receiving antennas 4.i (i = 1, 2, ..., n) around the transceiver antenna 3.

коммутируются с помощью электронного коммутатора 7, управляемого n-фазным генератором 6 импульсов. Управляющие импульсы формируются генератором 6 импульсов из гармонического напряжения, вырабатываемого опорным генератором 5Receiving antennas 4.i (i = 1, 2, ..., n) alternately with frequency

are switched using an electronic switch 7 controlled by an n-phase pulse generator 6. The control pulses are generated by the 6 pulse generator from the harmonic voltage generated by the reference generator 5

u _j (t) = U ₀ cosΩt.

наступает неоднозначность отсчета угла α. Устранение указанной неоднозначности путем уменьшения отношения

обычно себя не оправдывает, так как при этом теряется основное достоинство широкобазового пеленгатора. Кроме того, в диапазонах метровых и особенно дециметровых волн брать малые значения

частот не удается из-за конструктивных соображений.However, when

ambiguity of reading the angle α occurs. Resolving this ambiguity by reducing the ratio

usually doesn’t justify itself, since the main advantage of a broad-based direction finder is lost. In addition, in the ranges of meter and especially decimeter waves, take small values

frequencies fails due to design considerations.

. Это достигается автокорреляционной обработкой фазомодулированного напряжения u₅(t) с помощью линии задержки 15 и фазового детектора 16. Причем время задержки τ линии задержки 15 выбирается таким, чтобы уменьшить индекс фазовой модуляции до величиныIn connection with the stated reason, the problem arises of decreasing the phase modulation index without decreasing the relative size of the measuring base

. This is achieved by autocorrelation processing of the phase-modulated voltage u ₅ (t) using the delay line 15 and the phase detector 16. Moreover, the delay time τ of the delay line 15 is chosen so as to reduce the phase modulation index to a value

where d ₂ <d,

обеспечивающее однозначную пеленгацию астероида в азимутальной плоскости. На выходе фазового детектора 16 образуется гармоническое напряжениеwhere the inequality holds

providing unambiguous direction finding of an asteroid in the azimuthal plane. The output of the phase detector 16 produces a harmonic voltage

u ₇ (t) = U ₇ cos (Ωt-α), 0≤t≤T _s ,

Where

which through the phase shifter 17 through 90 ° enters the first input of the phase detector 18, the second input of which from the second output of the reference generator 5 is supplied with a reference voltage u ₆ (t). The output of the phase detector 18 produces a low-frequency voltage

u _p2 (t) = U _н2 sinα,

Where

which is fixed by the registration unit 22. Thus, a rough but unambiguous scale of direction finding of an asteroid in the azimuthal plane is formed.

The second input of the multipliers 29 and 30 from the output of the filter 11 of the differential frequency voltage is supplied voltage u _p (t). At the output of the multipliers 29 and 30, harmonic voltages are generated at the frequency ω _{g of the} local oscillator 9, respectively.

u ₈ (t) = U ₈ cos (ω _g t + ϕ _g + Δϕ ₁ ),

u ₉ (t) = U ₉ cos (ω _g t + ϕ _g + Δϕ ₂ }, 0≤t≤T _c ,

Where

d ₁ - the distance between the receiving antennas 3 and 25 (measuring base);

2d ₁ - the distance between the receiving antennas 3 and 26 (measuring base),

which are allocated by bandpass filters 31 and 32 and fed to the first input of the phase detectors 33 and 34, respectively, the second input of which is supplied with the voltage u _g (t) of the local oscillator 9. At the output of the phase detectors 33 and 34, low-frequency voltages are generated, respectively:

u _n3 (t) = U _n3 cosΔϕ ₁ ,

u _n4 (t) = U _n4 cosΔϕ ₂ ,

Where

which is fixed by the registration unit 22.

Thus, a rough but unequivocal direction finding scale, an accurate but ambiguous asteroid direction finding scale are formed in the elevation plane. Moreover, between the measuring bases d ₁ and 2d ₁ establish the following inequality:

In this case, the antennas 25 and 26 are installed on a special mast. The voltages u ₈ (t) and u ₉ (t) from the outputs of the bandpass filters 31 and 32 are simultaneously fed to two inputs of the multiplier 35, the output of which produces a voltage proportional to the difference of the phase differences

u ₁₀ (t) = U ₁₀ cos (Δϕ ₁ -Δϕ ₂ ),

Where

This voltage is fed to the input of the phasemeter 36. The latter measures the difference of the phase differences

Δ (Δϕ) = Δϕ ₁ -Δϕ ₂ ,

which goes to the input of the computing unit 37, which determines the distance to the asteroid

and the height of the asteroid’s flight above the horizon

h = D⋅sinβ.

Voltages u _c (t) and u ₁ (t) are supplied to two inputs of the multiplier 23, at the output of which a low-frequency voltage is formed

u _n (t) = U _n cos (± Δωt + ϕ _n ), 0≤t≤T _s ,

Where

ϕ _n = ϕ _with -ϕ ₁ ,

proportional to the Doppler shift ± Δω. In this case, the magnitude and sign of the Doppler shift determine the magnitude and direction of the radial velocity of the asteroid.

The measured values of D, h and radial velocity are recorded by the registration unit 22.

вокруг приемопередающей антенны, размещенной в центре окружности, и двух приемных антенн, размещенных в угломестной плоскости.Thus, the proposed system in comparison with the base object and other technical solutions of a similar purpose provides increased accuracy in determining the parameters of the motion of the asteroid. This is achieved by using complex signals with phase shift keying, receiving antennas placed in the azimuthal plane along a circle of radius d with the possibility of their electronic rotation with angular velocity

around a transceiver antenna located in the center of the circle, and two receiving antennas located in the elevation plane.

Complex phase-shift signals have high energy and structural secrecy.

The energy secrecy of these signals is due to their high compressibility in time and spectrum with optimal processing, which reduces the instantaneous radiated power. As a result, the PSK signal at the receiving point may be masked by noise and interference. Moreover, the energy of a complex PSK signal is not small, it is simply distributed over the time-frequency domain so that at each point in this region the signal power is less than the power of noise and interference.

The structural secrecy of complex PSK signals is due to the diversity of their shapes and significant ranges of parameter changes, which makes it difficult to optimize or at least quasi-optimal processing of complex PSK signals of an a priori unknown structure in order to increase the sensitivity of the receiver.

Information sources

1. Asteroid-comet hazard: yesterday, today, tomorrow / Ed. B.M. Shustova, L.V. Rykhlova. - M .: FIZMATLIT. 2010 - 384 p.

2. RF patent №2.059.280. A method for determining the geometric characteristics of an object of a multi-aperture optical system / Bakut P.Α., Plotnikov I.P., Rozhkov I.A., Ryakhin A.D., Sviridov K.N. Publ. 04/27/1996

3. RF patent No. 2.175.139. The radar method of passive space objects. / Atanashev A.B., Zemlyanov A.B., Atanashev D.A., Boykov K.B., Dokukin V.F. Publ. 10/20/2001.

Claims (1)

A system for determining the parameters of the motion of an asteroid containing a transmitter, four receiving antennas located on a circle at an equal distance from each other, sequentially connected mixer and a filter of a difference frequency, the first and second phase detectors, characterized in that it is equipped with m receiving antennas, placed around the circumference in the azimuthal plane, two receiving antennas placed in the elevation plane, a transceiver antenna located in the center of the circle, a duplexer, a reference generator an oscillator, a pulse generator, an electronic switch, four high-frequency amplifiers, six multipliers, four band-pass filters, a delay line, a 90 ° phase shifter, a recording unit, a third, fourth and fifth phase detectors, a low-pass filter, a phase meter and a computing unit, and the first output of the reference generator is connected in series to a pulse generator, an electronic switch, n inputs of which are connected to n = 4 + m receiving antennas uniformly spaced around a circle of radius d with their electronic rotation around a transceiving antenna located in the center of the circle, a second high-frequency amplifier, a first multiplier, the second input of which is connected to the output of the difference frequency filter, the first bandpass filter, delay lines, the first phase detector, the second input of which is connected to the output of the first bandpass filter, phase shifter 90 °, the second phase detector, the second input of which is connected to the second output of the reference generator, and the registration unit, to the first output of the transmitter in series The duplexer is connected, the input-output of which is connected to the transceiver antenna, and the first high-frequency amplifier, the output of which is connected to the first input of the mixer, the local oscillator output is connected to the second input, the second multiplier is connected to the output of the first bandpass filter, the second input of which is connected to the output a local oscillator, a second bandpass filter and a third phase detector, the second input of which is connected to the third output of the reference generator, and the output is connected to the second input of the registration unit, to the second input the transmitter is connected in series with a third multiplier, the second input of which is connected to the output of the first high-frequency amplifier, a low-pass filter and a computational unit whose output is connected to the third input of the registration unit, a third high-frequency amplifier is connected in series to the first receiving antenna, the fourth multiplier, the second input of which is connected to the output of the differential frequency filter, the third bandpass filter and the fourth phase detector, the second input of which is is dined with the local oscillator output, and the output is connected to the fourth input of the registration unit and to the second input of the computing unit, to the second receiving antenna located in the elevation plane, the fourth high-frequency amplifier, the fifth multiplier, the second input of which is connected to the output of the differential frequency filter, are connected in series a fourth bandpass filter and a fifth phase detector, the second input of which is connected to the output of the local oscillator, and the output is connected to the fifth input of the registration unit and to the third input of the computing unit, the output of the third bandpass filter is connected in series to the sixth multiplier, the second input of which is connected to the output of the fourth bandpass filter, and a phase meter, the output of which is connected to the fourth input of the computing unit.

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