RU2496117C1 - Method of measuring displacement parameters of probing signal source - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method involves successively measuring time intervals between reception of a plurality of probing signals, calculating the difference between intervals of neighbouring pairs of measurements, determining distance travelled by a moving sonar between neighbouring radiations as a product of the difference between intervals and the speed of sound, determining the average interval between two consecutive probing signals, the average interval between three probing signals, the average interval between four probing signals and the average time between the average intervals, then determining radial speed of the moving sonar, and in order to determine radiation distance of the last probing signal, the difference between the time of receiving the last signal and the time of receiving the previous signal is determined; the difference is then used to calculate the time interval between probing signals and the last difference is multiplied by the speed of sound.

EFFECT: measurement of the speed of a mobile carrier and distance thereto.

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Description

The invention relates to the field of sonar and can be used to build systems for the detection of sonar signals (OGS) in modern sonar systems.

Probing signals emitted by sonars located on various carriers, including mobile ones, can be detected at long distances using known sonar signal detection systems.

(Yu.A. Koryakin S.A. Smirnov G.V. Yakovlev “Shipborne hydroacoustic equipment”, St. Petersburg, Nauka, 2004, pp. 89-92). When these signals are detected, the problem arises of measuring the parameters of the probing signal, as well as the task of determining the velocity of the source of the probing signal and the distance to it.

Known methods for detecting the location of the source of the probing signals described in A.A. Prostakov “Hydroacoustic means of the fleet” M., 1974, p. 90. The paper considers the problem of determining the location of a random target emitting pulsed signals when using multiple receiving posts. The differences in the time of sound arrival to each receiver are measured, which in turn correspond to the difference in distances from the sound source to the respective receivers. As you know, the geometrical location of the points of the difference in the distances of which to the receivers is constant is a hyperbole. Having determined the intersection point of the calculated hyperbole, we can find the place of the sound source and, accordingly, the distance to it.

In some cases, this problem can be solved using the triangulation method using several receivers or by evaluating several bearings. (V.I. Dmitriev et al. “Navigation and the Locus” M., 2009, p. 278). Similarly, you can determine the location of the object when receiving a series of pulses and with complex maneuvering, which requires a long operating time of the sonar and a long time of fixed maneuvering, which is not always possible and advisable (Collection “50 years of the Central Research Institute“ Morphizpribor ”St. Petersburg, 1999, p. .149. Yu.A. Koryakin, S. A. Smirnov, G. V. Yakovlev “Shipborne sonar equipment”, St. Petersburg, Nauka, 2004, p. 67). However, this method is the closest analogue and can be taken as a prototype.

The method contains the following operations:

- produce sequential reception of sounding signals,

- determine the time of arrival of the first received sounding signal

- measure the direction of arrival of the signal,

- change the own position of the receiver of the probing signals,

- determine the speed of the receiver of the probing signals,

- determine the reception time of the next signal at a new location point of the receiver,

- measure the direction of the signal source at a new location of the receiver.

From the measured bearings and the measured distance traveled determine the position of the point of intersection;

The sides of the triangle are determined by two angles and a side, which will be equal to the distance to the source of the probing signals.

By repeating the measurements and obtaining a new distance, one can determine the speed of the radiation source.

To implement this method, it is necessary that the source of the probe signal (sonar), the parameters of which are determined, operate continuously, and this does not always happen. Another disadvantage of this method is the need for a complex scheme of maneuvering the receiver of the probing signals, which requires a lot of time. During this time, the position of the moving sonar can significantly change, which will lead to an error in determining the speed of movement of the source of the probing signal and the distance to it

In the problems of detecting sonar signals, signals are received from sonars mounted on moving carriers, while the radiation time of these signals is limited, and the problem of determining the radial speed of a moving sonar and its distance to it cannot be solved by existing methods.

The technical result of the proposed technical solution is the ability to determine the speed of movement of the source of the probing signal and the distance to it.

To achieve the indicated technical result, a method comprising, sequentially receiving the probing signals of a moving source, determining the time of arrival of the first received sounding signal, introduces additional features, namely: the moments of time t _{i of} receiving another n sounding signals, where n is at least 3 x, determine the time interval T _k between the moments of arrival of each two consecutive sounding signals T _k = t _{i + 1} -t _i , determine the difference of the measured time intervals ΔT _m = T _{k + 1} -T _k , measure the speed of sound C, determine the distance traveled by the moving source of the sounding signal during the time between two consecutive sounding signals L = СΔT _m , determine the half time interval between the moments of arrival of the first two recorded next one after other sounding signals T _cpk = (t _{i + 1-} t _i ) / 3, determine the average time interval between the moments of arrival of the first and third sounding signals T _{cpk + 1} = (t _{i + 2-} t _i ) / 3, the first and fourth sounding signals T _{cpk + 2} = (t _{i + 3} -t _i ) / 4, determine the average the time interval T _cp as T _cp = (T _cpk + T _{cpk + 1} + T _{cpk + 2} ) / 3, and the radial velocity of the moving source of the probing signal V _p is defined as V _p = L / T _cp , and to determine the distance D _n before moving source probing signal in the time t _n determined by receiving a sounding signal propagation time T of the probe signal as a _camshaft time interval between receiving the probe signal at time t _n and the time of receiving the previous probing signal T _k = t _n- t _n-1 minus the average interval between the probing signals T _{distribution.} = T _k -T _cf and D _{p are} defined as D _p = T _{distribution.} C, and the distance to the moving source of the probe signal at the time of radiation of the first received probe signal D ₀ is determined from the expression D ₀ = D _p -nL taking into account the measurement sign L.

Let us explain the achievement of the technical result.

As a rule, the operation of the sonar, which is the source of the probing signal, has as its aim the survey of space and the detection of any object by the presence of an echo signal from it. The propagation range of the probing sonar signal is significantly greater than the detection range of the reflected echo signal. Therefore, the probe signal is detected by the receiver of the OGS system almost always with the first radiation signals, the probability of skipping such a direct propagation signal is extremely small. Radiation of the probe signal occurs at fixed points along the distance when the sonar moves, after a certain time interval, the value of which is selected depending on the scale of the sonar and is determined by the frequency of the probe signal or the duty cycle of the radiation. If the sonar is stationary and the receiver is stationary, then the time interval between the probing signals and the time interval between the signals received by the receiver of the OGS system will be the same. If the emitter is moving or the receiver is moving, then the time interval between the received sounding signals will be different from the time interval between the radiated sounding signals. When objects approach each other, the time interval between the received sounding signals will be less than the time interval between the radiated sounding signals. If the objects diverge, the time interval between the received signals will be longer than the time interval between the emitted signals. The change in the value of the interval will be determined by the rate of change of distance. The magnitude of the change in the time interval between the received sounding signals can be determined by measuring the difference between the time intervals of the arrival of several consecutive sounding signals, the first signal of which is taken as the reference. For this, it is necessary to fix the arrival time of the first sounding signal and relative to it, fix the arrival time of three consecutive sounding signals. After that, the time intervals between the moments of arrival of these sounding signals are determined in pairs. In the next step, the difference in time intervals measured in pairs is measured. This difference in intervals will determine the rate of change of the distance between the received sounding signals, which depends on the speed of the sonar and on the time of radiation of the sounding signals of the sonar. A certain difference has a fluctuation character and is determined by the error in the accuracy of measuring the time of signal reception, fluctuation of the propagation of the probe signal in the medium, and the stability of the position of the probe signal source in space and the receiver. The distance traveled by the sonar for the time interval between the probing signals can be obtained by multiplying the measured time interval by the measured speed of sound propagation in sea water. This is the distance between the points along the distance at which the sounding signals of the sonar moving at a constant speed occur. To determine the magnitude of the approach speed or divergence of the sonar, it is necessary to determine the time between the probing signals of the sonar or the duty cycle of the radiation.

The time interval between the probing signals can be determined as the average value from the three obtained time estimates. The first time estimate corresponds to half the time between the moments of reception of the first two sounding signals, the second time estimate corresponds to the time between the first sounding signal and the third sounding signal divided by 3, the third estimate corresponds to the time between the reception of the first sounding signal and the reception time of the fourth sounding signal divided by four.

The final estimate of the duty cycle of the radiation of the probing signals can be obtained by determining the average of the three received estimates. The final estimate obtained will be approximately close to the desired time interval between the radiations of the probing sonar signals. Thus, there is the distance traveled by the sonar during the time between the moments of reception of the sounding signal and the average estimate of the interval between the moments of reception of the sounding signal. Dividing the measured distance traveled by the sonar between the moments of radiation of the probing signal by the average estimate of the interval between the moments of reception of the sounding signals, we obtain the speed of the sonar. To determine the radiation distance of the last received sonar probe signal, it is necessary to determine the propagation time of the last sonar signal to the location of the receiver of the OGS system. For this purpose, the time interval between the moment of receiving the last signal and the moment of receiving the previous signal is determined, after which the average estimate of the time interval between the received sounding signals is subtracted from the obtained difference and the propagation time of the last sounding signal from the sonar to the receiver is obtained. Multiplying the propagation time of the last probing sonar signal to the receiver by the speed of sound, you can get the distance from the receiver of the OGS system to the point of emission of the last probing sonar signal. The distance at which the first received sonar probe signal was emitted is defined as the difference between the radiation distance of the last sonar probe sound and the product of the number of transmissions by the measured distance traveled by the sonar between the radiated probe signals, taking into account the sign of the measured distance estimate. The last condition determines the proximity of the receiver and sonar or their divergence. When approaching, the measured distance estimate has a negative sign, which indicates a reduction in distance, and when calculating the initial distance, the last distance and the distance traveled between the probing signals are added. If the sonar and the receiver diverge, the value of the distance estimate between the sonar probing signals has a positive sign, and when calculating the initial distance of the first received sonar sonar signal, the product of the number of packages without one and the measured distance will be subtracted from the distance estimate of the last sonar signal.

The invention is illustrated in figure 1, which shows a block diagram of a device that implements the proposed method.

The device comprises an antenna 1 connected through a receiving device 2, a unit 4 for determining the times of reception of the sounding signals, a first output of the unit 5 for determining the time intervals between the moments of arrival of the probing signals, a unit 6 for determining time intervals with the input of the unit 8 for determining the radial velocity of the source of the probing signals. The sound velocity meter 3 through the first input of the unit 7 for determining the distance traveled by the sonar for the time interval between the moments of radiation of the probing signals is connected to the second input of the unit 8, and the second output of the unit 5 is connected to the second input of the unit 7. The second output of the unit 4 is connected to the second input unit 6. The third output of unit 4 is connected to the first input of the unit 9 for determining the distance at which the received sounding signal was radiated. The second input of block 9 is connected to the second output of block 6, and its third input with the third output of block 7.

The work of the proposed method, it is advisable to consider together with a description of the operation of the device that implements the method.

The probing signals of a moving source (sonar) are received by the antenna 1 and fed to the input of the receiving device 2, where they are amplified, filtered and converted into digital form, convenient for further processing and measurement with the necessary accuracy. Antenna 1, receiving device 2 are known devices implemented in systems for detecting sonar signals of OGS. Signals converted to digital form are processed by special digital processors based on the developed algorithms (see Yu.A. Koryakin, S.A. Smirnov, G.V. Yakovlev, “Shipborne hydroacoustic equipment”, St. Petersburg, Nauka, 2004, p. 164-176, pp. 278-295). The processor implements all the blocks of the proposed device. In block 4, the moments of arrival of the sequence of received sounding signals are determined, the times of arrival are stored, and the measured estimates are transmitted to block 5 for determining the time intervals between successive signals and the determination of the difference in time intervals of the received serial signals. The measured estimate of the difference in time intervals enters block 7 to determine the distance traveled by a moving sonar between the moments of radiation of the probing signals, the second input of which receives the average value of the speed of sound for a given area of work from block 3 of the sound velocity meter. The sound velocity meter is a well-known device that is used in all sonar systems (see Yu.A. Koryakin, S. A. Smirnov, G. V. Yakovlev, “Ship sonar equipment,” St. Petersburg, Nauka, 2004, p. 300) . In block 7, the distance traveled by a moving sonar between the radiations of the sounding signal is determined; the obtained estimate of the distance between the sounding signals is transmitted to block 8 for measuring the radial speed of movement. From the second output of block 4, time moments are transmitted to the second input of block 6, where the average time interval between the received signals of the moving sonar is determined, which is fed to the second input of block 8. To determine the distance to the source at the time of the last received sounding signal, the time interval between the moment of receiving the last sounding signal and the moment of receiving the previous sounding signal, which come from block 4 determining the moments of time of receiving the sequence of signals the signals in block 9 determine the distance, the second input of which receives the value of the average time interval between the probing signals from block 6, and the third input from block 7 receives the distance between the signals and the speed of sound used. In block 9, elementary computational operations are performed, the results of which are an estimate of the distance from the receiver to the point at which the last received signal was radiated and an estimate of the distance to the point at which the first received signal was radiated.

Thus, without maneuvering, only by measuring time intervals and the speed of sound, as well as simple mathematical operations on them, it is possible to determine the distance to the moving source of the probing signal and its radial velocity.

Claims (1)

A method for measuring the movement parameters of a sounding signal source, comprising sequentially receiving the sounding signals of a moving source, determining a time point of arrival of the first received sounding signal, characterized in that: the time moments t _{i of} receiving another n sounding signals are measured sequentially, where n is at least 3, determine the time interval T _k between the moments of arrival of each two consecutive sounding signals T _k = t _{i + 1} -t _i , determine the difference of the measured time intervals ΔT _m = T _{k + 1} - T _k , measure the speed of sound C, determine the distance traveled by the moving source of the sounding signal during the time between two consecutive sounding signals L = СΔТ _m , determine the half time interval between the moments of arrival of the first two consecutive sounding signals T _cpk = ( t _{i + 1} -t _i ) / 2, determine the average time interval between the moments of arrival of the first and third sounding signals T _{cpk + 1} = (t _{i + 2} -t _i ) / 3, the first and fourth sounding signals T _{cpk + 2} = (t _{i + 3} -t _i) / 4, define the average time intervals T _cp as T _cp = (T _{cpk +} T _cpk + _{1 +} T _cpk + ₂₎ / 3, and the radial velocity of the moving source probing signal V _p is defined as V _p = L / T _cp, and for determining the distance to a moving source of probing signal D _p determine the propagation time of the last signal as the difference between the reception time of the last signal and the reception time of the previous signal T _k = t _n -t _n-1 minus the average interval between the received sounding signals T _{distribution.} = T _k -T _cf and D _{p are} defined as D _p = T _pacpr. C, a distance to the moving source of the sounding signal at the time of the emission of the first received sounding signal D ₀ is determined from the expression D ₀ = D _p -nL taking into account the measurement sign L.