RU2634453C1 - Method of preventing threat to planet by estimating dimensions of passive space objects - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method includes radar sounding of space objects (SO) rotating during flight, with a periodic sequence of high-resolution radio signals of nanosecond duration. The number of these pulses corresponds to the number of the SO angles during the period of its rotation, the maximum of all the periods of the SO rotation around its axes. The probing sequence is passed through a block of adjustable delay, multiplied with the reflected sequence of high-resolution signals, the time delay is fixed, the distance between the SO and the Earth is determined. Simultaneously, the probing sequence is multiplied with the reflected one, a low-frequency voltage is extracted, proportional to the Doppler frequency offset, by which the magnitude of the SO radial velocity direction is determined, the time of the probable collision of the SO with the Earth is estimated and measures are taken to avoid collision.

EFFECT: increasing the effectiveness of protecting the Earth from large meteorites and asteroids.

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Description

The proposed method relates to the field of radar passive space objects (large meteorites and asteroids) and can be used in a radar survey of near-Earth space in order to highlight space objects that are dangerous in a collision with the Earth.

There is an analogue for protection against asteroid-comet hazard (AKO), provoking the development of space protection systems [1]. A disadvantage of the analogue is the lack of an estimate of the size of passive space objects, which excludes the possibility of their selection by degree of danger.

An analogue of the asteroid-comet hazard assessment is also known [2], according to which cosmic bodies less than 10 m in size usually do not reach the Earth’s surface, burning in the atmosphere, and pose no danger to the planet and population. A disadvantage of the known analogue is that bodies several tens of meters in size, when burned, are capable of exploding and causing serious damage, while objects of hundreds or more meters in size lead to regional or global disasters. Moreover, it is precisely bodies of 50-100 meters in size that pose the greatest danger to humanity at the characteristic time of its existence, since the probability of their collision with the Earth is higher than that of larger bodies, and their average destructive effect is maximum.

Thus, the issues of estimating the sizes of cosmic bodies crossing the Earth’s orbit are relevant at present and interest in them will only increase with the development of technology.

The prior art method for determining the geometric characteristics (eg, diameters) of celestial bodies by an optical system by angular dimensions [3]. The disadvantage of optical methods is that the error in estimating the linear dimensions of asteroids from the angular dimensions of celestial bodies increases in proportion to the distance to the measured object. In addition, all ground-based optical methods are subject to the state of optical transparency and atmospheric turbulence.

These shortcomings are deprived of the methods of radar sounding of outer space, the resolution of which along the line of sight is determined by the properties of the signals used and does not depend on the distance to the object.

In addition, methods and systems for preventing threats to the planet are known (author's certificate. USSR No. 590.687, 1.748.086; RF patents No. 2.059.280, 2.099.735, 2.175.139, 2.182.341, 2.247.395, 2.250.476 , 2.323.860, 2.374.597, 2.390.730, 2.436.611, 2.518.108, 2.526.401, 2.527.252, 2.535.487, 2.555.247, 2.568.628, 2.578.003; US patents No. 5.594. 454, 5.920.278, 5.995.039, 5.147.638, 6.683.518, 7.119.732, 7.463.181; patents EP No. 1,026.519, 1.229.347; patents WO No. 2.005.017.583, 2.006.087.421; Lozorenko O .V, Chernogor LF Ultrawideband signals and physical processes. Basic concepts, models and description methods. // Radiophysics and Radio Astronomy, 2008, v. 13, No. 2, pp. 166-194 and others).

Of the known methods and systems, the closest to the proposed one is “A way to prevent threats to the planet by assessing the size of passive space objects” (RF patent No. 2.527.252, B64G 3/00, 2013), which is chosen as the base object.

The known method includes radar sensing of a space object (KO), rotating during the flight, a periodic sequence of high-resolution radio signals of nanosecond duration. The number of these pulses corresponds to the number of KO angles for the period of its rotation, the maximum of all periods of KO rotation around its axes. This period is determined by the repeatability of the radar portraits (RLP), giving a range resolution equal to one tenth of the minimum size of the TO. In this case, a multiple measurement of the radar station duration of the illuminated part of the CO is performed. For this duration, the average radius of the QoS is then estimated by half the averaged spatial length of the radar signals and the linear size by twice the average radius.

The known method allows us to estimate the size of passive space objects, for example, large meteorites and asteroids (sizes of more than ten meters), which can be dangerous in a collision with the Earth. At the same time, such distances between the spacecraft and the Earth, the radial velocity of the spacecraft's approach to the Earth, and the time of their probable collision, knowledge of which is necessary in order to activate the orbital means of space protection in a timely manner, are important.

An object of the invention is to increase the efficiency of space protection of the Earth from large meteorites and asteroids (with dimensions greater than ten meters), by determining the distance between the spacecraft and the earth, the radial velocity of the spacecraft approaching the earth and the probable time of their collision.

The problem is solved in that a way to prevent threats to the planet by estimating the size of passive space objects larger than ten meters in diameter, rotating during the flight, including, in accordance with the closest analogue, radar sounding of a space object, a periodic sequence of high-resolution nanosecond radio signals of the number N , which corresponds to the number of angles of the object for the period of its rotation, the maximum of the periods of rotation along the axes of the object, which determined by the repeatability of the radar portraits, providing a range resolution equal to one tenth of the minimum size of the object, and repeatedly measure the duration of the radar portrait of the illuminated part of the object, then measure the average radius of the object from the measured values of the duration of the radar portrait by half the average spatial length of the signal of the radar portrait and the linear size of the object at twice the average radius, excellent are separated from the closest analogue by the fact that a probing sequence of high-resolution radio signals of nanosecond duration is passed through an adjustable delay unit, multiplied with a reflected sequence of high-resolution radio signals of nanosecond duration, a low-frequency voltage is proportional to the correlation function R (τ), where τ is the current time delay by changing the current time delay delays τ provide the maximum value of the correlation function R (τ), maintain it at max At the local level, the time delay τ = τ ₃ corresponding to the maximum value of the correlation function R (τ) is fixed, and the distance R between the space object and the Earth is determined by the formula:

where c is the propagation velocity of radio waves.

At the same time, the probing sequence of high-resolution nanosecond radio signals is multiplied with the reflected one, a low-frequency voltage is allocated that is proportional to the Doppler frequency offset, the magnitude and sign of which determine the magnitude and direction of the radial velocity of the space object, and the time of the probable collision of the space object with the Earth is estimated from the measured distance and radial velocity take measures to prevent this collision.

A diagram for generating a radar portrait of a space object is shown in FIG. 1. A block diagram of a device that implements the proposed method is presented in FIG. 2.

The device comprises serially connected control unit 1, shock excitation generator 2, power amplifier 3, duplexer 4, the input-output of which is connected to the planetary radar transceiver antenna 5, high-frequency amplifier 6, the first multiplier 9, the second input of which is connected through the adjustable delay unit 8 with the output of the generator 2 of the shock excitation, the first low-pass filter 10 and an extreme regulator 11, the output of which is connected to the second input of the adjustable delay unit 8, to the second output of which n LED 12 range. To the output of the high-frequency amplifier 6, a second multiplier 13 is connected in series, the second input of which is connected to the output of the shock excitation generator 2, a second low-pass filter 14, a Doppler frequency displacement meter 15 and a radial speed indicator 16.

The adjustable delay unit 8, the first multiplier 9, the first low-pass filter 10 and the extreme regulator 11 form a correlator 4. High-resolution signals are used to estimate the size of the asteroid. In radar, high-resolution signals are those with a large absolute spectral width Δf and a high average frequency f ₀ that have a large range resolution

where c is the speed of light propagation,

and - the characteristic dimensions of the object reflecting the signal [5].

In this case, the quantity cτ _and , where τ _and is the signal duration, makes sense of the spatial length of the signal.

These signals make it possible to obtain a radar portrait of the object, the response X (t) to a high-resolution signal, which is determined by the radial size r _{k of the} illuminated part of the object (Fig. 1). For a radial size of ≈5 m, it is necessary to provide a range resolution of Δr≈0.5 m, which corresponds to a pulse duration (width of the autocorrelation function) of ≈3.5 ns.

радиолокационного портрета X(t) при различных ракурсах, возникающих при вращении, и усредняя результаты измерений, можно довольно точно оценить средний радиус космического объекта (величину

)It is known that a characteristic feature of passive space objects is their rotation due to the lack of air resistance [2, 5]. The surface of the object, reflecting the probe signal in the process of radar, changes its position during the rotation of the asteroid. Measuring duration

of the radar portrait X (t) at various angles arising during rotation, and averaging the measurement results, it is possible to fairly accurately estimate the average radius of a space object (value

)

where r _k is the duration of the radar portrait at the Kth measurement,

N is the number of measurements

c is the speed of light propagation.

With periodic sounding, the number N should be selected from the condition

where T _v - the period of rotation of the asteroid (10-100 min), determined by the repeatability of the radar portrait,

F is the repetition frequency of the probe signal, chosen so

so that the number of measurements is N> 100-1000.

If there are several axes of rotation, the largest of the periods T _v should be taken into account.

A way to prevent threats to the planet by estimating the size of passive space objects is as follows.

A space object is probed with a periodic sequence of high-resolution nanosecond radio signals that provide a range resolution of one tenth of the minimum size of an object.

At the command of the control unit 1, the shock excitation generator 2 generates a probe ultra-wideband signal

which, after amplification in the power amplifier 3, through the duplexer 4 enters the transceiver antenna 5 and is radiated by it in the direction of the space object. According to the received sequence of reflected signals (radar portraits)

where ± Δω _d is the Doppler frequency shift.

the number N is selected, which is determined by the repeatability of the radar portraits of the object for the period of its rotation T _v or for the largest of the periods when the object rotates along several axes. In this case, a multiple measurement of the duration of the radar portraits τ _k (k = 1,2, ..., N), the illuminated part of the space object, the duration τ _{k the} reflected signal of the radar portrait of the illuminated part of the object is performed. Then, the measured values of τ _k are averaged over the number of measurements

≈0,5 с (τ_к) и линейного размера

and the average radius of the object is estimated by half averaging the spatial signal length of the radar portrait

≈0.5 s (τ _k ) and linear size

The probe ultra-wideband signal u ₃ (t) is passed through the adjustable delay unit 8 and multiplied with the reflected signal u ₀ (t). At the output of the multiplier 9, a low-frequency voltage is generated proportional to the correlation function R (τ), where τ is the current time delay, which is allocated by the low-pass filter 10. By changing the current time delay τ using the extreme controller 11 provide the maximum value of the correlation function R (τ) and maintain it at the maximum level. The time delay τ = τ ₃ corresponding to the maximum value of the correlation function R (x) is fixed, and the distance to the space object is determined

where c is the propagation speed of the radio signal.

The range indicator 12, associated with the scale of the adjustable delay unit 8, captures the distance R from the space object to the Earth. At the output of the multiplier 13, a low-frequency voltage is formed

Where

ϕ _d = ϕ ₃ -ϕ ₀ ,

which is allocated by the low-pass filter 14 and is fed to the input of the Doppler shift meter 15. The magnitude and sign of the Doppler shift ± Δω _d indicate the magnitude and direction of the radial velocity of the space object, which are recorded by indicator 16. By measuring the range R and the radial velocity V _{1 of the} space object, we can estimate the time of the probable collision of the space object with the Earth and take appropriate measures to prevent this event.

Thus, the proposed method, in comparison with the prototype and other technical solutions of a similar purpose, provides an increase in the effectiveness of the Earth’s space protection from large meteorites and asteroids (with dimensions of more than ten meters). This is achieved not only by estimating the size of passive space objects, but also by determining the distance between the space object and the Earth, the radial velocity of the space object approaching the Earth, and the probable time of their collision.

Information sources

1. RF patent №2.302.605 (RF). A way to repel an attack from space. / Bolotin N.B. Publ. 07/10/2007.

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

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

4. 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.

5. Lazorenko OV, Chernogor L. F. Ultra-wideband signals and physical processes. Basic concepts, models, and description methods // Radiophysics and Radio Astronomy. 2008, t. 13, No. 2. - S. 166-194.

Claims (3)

A way to prevent a threat to the planet by assessing the size of passive space objects larger than ten meters in diameter, rotating during the flight, including radar sounding of a space object by a periodic sequence of high-resolution nanosecond radio signals of the number N, which corresponds to the number of camera angles for the period of its rotation, the maximum of the periods rotation along the axes of the object, which is determined by the repeatability of radar portraits providing range resolution equal to one tenth of the maximum size of the object, moreover, multiple measurements of the duration of the radar portrait of the illuminated part of the object are performed, then, according to the measured values of the duration of the radar portrait, the average radius of the object is estimated by half the average spatial length of the signal of the radar portrait and the linear size of the object by twice medium radius, characterized in that the probing sequence of high-resolution radio signals of nanosecond-duration pulses is passed through an adjustable delay unit, multiplied with a reflected sequence of high-resolution nanosecond-duration radio signals, a low-frequency voltage is proportional to the correlation function R (τ), where τ is the current time delay, by changing the current time delay, the maximum value of the correlation function R (τ ), maintain it at the maximum level, fix the time delay τ = τ _s corresponding to the maximum value of function R (τ), and determine the distance R between the space object and the Earth by the formula

where c is the propagation velocity of radio waves, at the same time, the probing sequence of high-resolution nanosecond radio signals is multiplied with the reflected one, a low-frequency voltage is proportional to the Doppler frequency offset, the magnitude and sign of which determine the magnitude and direction of the radial velocity of the space object, and the time of the probable collision of the space object with the Earth is estimated from the measured values of the distance and radial velocity take measures to prevent this collision.

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