RU2235342C2 - Method for measuring angular coordinates of object and radiolocation station for its realization - Google Patents

Abstract

FIELD: radiolocation technologies.

SUBSTANCE: method includes emitting probing signals, receiving and searching for signals reflected from an object, measuring and memorizing of levels of received signals and of angular coordinates of beam, matching received signals, detection of angular packets of received signals, and calculation of angular coordinates of object, in angular packet of received signals power of signal is determined, which matches location of object on direction of beam maximum, after which calculation of each angular coordinate of object is performed. Device for realizing said method includes transmitter, antenna switch, antenna, receiver, threshold device, synchronizer, angular coordinates estimation block, which includes memorizing device for detected signals, angular packets detection block, signal power determining block and calculating device.

EFFECT: higher precision of measurements of angular coordinates of object with limited time for estimation of angular coordinates.

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Description

The proposed technical solutions relate to the field of radar and can be used to measure the angular coordinates of objects.

A known method of measuring the angular coordinates of an object in the process of viewing space by a radar station, including emitting sounding signals, receiving signals reflected from the object, measuring their parameters, detecting angular packets of received signals, calculating the angular coordinates of the object (Samsonenko S.V. Digital optimal methods processing of radar signals. - M.: Military Publishing House of the Ministry of Defense of the USSR, 1968, p. 109).

A known radar station that implements the indicated method for measuring the coordinates of an object (Samsonenko S.V. Digital methods for optimal processing of radar signals. - M.: Military Publishing House of the Ministry of Defense of the USSR, 1968, p. 110, Fig. 4.23).

A known radar station contains a series-connected antenna, a radio receiving device, a signal detection device including a threshold device, a computer, and a current angular coordinate sensor, the input of which is connected to the coordinate output of the antenna, and the output to the input of the computer.

Let us explain the concept of “angular packet of received signals”.

During the space survey of the radar station, the signals reflected from the object and received by the receiver are compared with the detection threshold. As a result, for each range discrete, in each position of the antenna beam in the plane, the elevation angle (ε) - azimuth (β) at the output of the threshold device contains a received signal, if it exceeds the threshold level, there is no signal at the output of the threshold device (signal detection skip) if the received signal is below the threshold level. Signals form an angular packet if in any region of the field of view in the εβ plane there are no beam positions with gaps in signals (Kuzmin S.Z. Fundamentals of the theory of digital processing of radar information. M: Soviet Radio, 1974, p. 30, Fig. 1.7) . Figure 1 shows examples of angular packets of received signals that differ in size and configuration. When viewing the space in which the detection occurred, the beam positions are shown in gray; in the beam positions indicated in white, there is no detection. Three signal packets are shown: a single packet (a packet consists of one beam position), a packet consisting of two beam positions (the magnitude of the packet is equal to unity in elevation, two in azimuth), and a packet consisting of five ray positions (packet size elevation is equal to two, in azimuth - four).

In the known method for measuring the angular coordinates of an object and a device that implements this method, the arithmetic average of two samples is taken as the angular coordinate of the object θ - the beginning (θ _n ) and the end (θ _k ) of the angular signal packet along the measured coordinate:

A disadvantage of the known method and device is the low accuracy of measuring angular coordinates. This is due to the fact that they do not take into account the unevenness of signal levels in the angular packet of received signals.

The closest way to measure the angular coordinates of an object during the inspection of space by a radar station is a method that includes emitting sounding signals, receiving signals reflected from the object, measuring and storing the levels of received signals and the angular coordinates of the beam corresponding to the received signals, detecting angular packets of received signals, calculating angular coordinates of the object. In this case, the angular coordinate of the object θ is estimated based on the calculation of the maximum likelihood function, in accordance with the well-known formula (Samsonenko S.V. Digital methods of optimal processing of radar signals. - M.: Military Publishing House of the Ministry of Defense of the USSR, 1968, pp. 254-258 ):

where n is the number of beam positions in the angular packet of received signals according to the measured angular coordinate of the object θ;

TO $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ - signal-to-noise ratio for the i-th (i / = 1, ..., n) signal of the angular packet of received signals;

Q _i = Q (θ-θ _i ) is the antenna radiation pattern (BOTTN) normalized to its maximum at the beam position corresponding to the ith signal of the angular packet of received signals;

TO $\genfrac{}{}{0ex}{}{\text{''}}{\text{i}}$ is the derivative of Q _{i with} respect to the angular coordinate θ;

θ _i is the angular coordinate of the beam corresponding to the ith signal of the angular packet of received signals, θ _i = θ _l + (i-1) Δθ;

θ _l is the angular coordinate of the beam corresponding to the first (i = 1) signal of the angular packet of received signals;

Δθ is the step of the ray moving along the measured angular coordinate;

ρ $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ - power of the i-th signal of the packet of received signals, normalized to the rms value of the noise of the receiving path.

When determining the angular coordinate of the object θ, equality (2) is checked for various possible positions of the object by the measured angular coordinate, i.e. repeatedly. The value of the angular coordinate θ at the time condition (2) is satisfied is taken as the angular coordinate of the object.

Closest to the claimed one is a radar (figure 2), containing a transmitter 1, an antenna switch 2, an antenna 3, a receiver 4, a threshold device 5, a synchronizer 6, an angular coordinate estimation unit 7, while the output of the transmitter 1 is connected to the input of the antenna switch 2 the input / output of which is connected to the antenna 3, the output of the antenna switch 2 is connected to the input of the receiver 4, the output of which is connected to the input of the threshold device 5, the output of the threshold device 5 and the coordinate output of the antenna 3 are connected respectively to the first and second inputs b In order to evaluate the angular coordinates 7, the first and second outputs of the synchronizer 6 are connected to the sync inputs of the transmitter 1 and the block for estimating the angular coordinates 7, respectively, while the block for estimating the angular coordinates 7 includes a memory for detected signals 8, a block for detecting angular packets 9, and a computer 10 with M inputs moreover, the first and second inputs of the memory of the detected signals 8 are the first and second inputs of the unit for evaluating the angular coordinates 7, respectively, M outputs of the memory of the detected signals 8 connected to the M inputs of the angular packet detection unit 9, the M outputs of which are connected to the M inputs of the calculator 10, the output of the calculator 10 is the output of the angular coordinate estimation unit 7 (Theoretical basis of radar. Ed. POISON. Shirman. M .: Sov. Radio, 1970, p. 221).

The work closest to the claimed radar when measuring the angular coordinates of the object is as follows. In the transmitter 1, according to the commands of the synchronizer 5 (synchronization pulses), probing signals are generated, which are radiated into the space during the survey of the space using the antenna 3. The signals reflected from the object are received by antenna 3 and fed to receiver 4. From the output of receiver 4, the signals are fed to the input of threshold device 5, where they are compared with a threshold that is set based on the admissible probability of false alarms. Signals whose level exceeds the threshold pass to the output of the threshold device 5. Signals from the output of the threshold device 5 and signals proportional to the angular coordinates of the beam of the antenna 3 are received in the block for estimating the angular coordinates 7. The signal power values with the corresponding angular coordinates of the beam as the beam moves antennas when viewing the space are recorded in the storage device of the detected signals 8 and stored there. By commands from the synchronizer 6 from the storage device of the detected signals 8, the data recorded in them is extracted and fed to the detection unit of the corner packets 9, where the detection of the angular packet of the received signals occurs (figure 4). The levels of the received signals and the angular coordinates of the beam corresponding to the received signals are supplied to the first M inputs of the calculator 12, the pre-recorded weight coefficients from the memory weighting device 13 are supplied to the second M inputs of the calculator 12. In the calculator 12, the signal power and the corresponding weighting factors are multiplied and summed received works. A signal proportional to the sum received is supplied to a comparison device with a threshold 14, where it is compared with a predetermined threshold. The threshold level is set based on the allowable probability of false detection of the corner packet. If the threshold is exceeded, an impulse is issued at the output of the comparison device with threshold 14, which means that an angular signal packet is detected. This pulse allows the passage of the received signals and beam coordinates corresponding to the received signals through the key 15 to the output of the angular packet detection unit 9 and then to the M inputs of the calculator 10. In the calculator 10, the angular coordinates of the object are determined in accordance with formula (2). In this case, multiple calculations are performed according to the formula (2).

The disadvantage of the closest method and device is the low accuracy of determining the angular coordinates of the object with a limited time evaluation of the angular coordinates. This drawback makes it difficult to use them, in particular, in mobile surveillance radars, in which the time allocated for estimating the angular coordinates of the object is very small.

The invention is aimed at eliminating these disadvantages.

Thus, the problem to be solved (technical result) is to increase the accuracy of measuring the angular coordinates of an object with a limited time for estimating angular coordinates.

The specified technical result is achieved by the fact that in the method of measuring the angular coordinates of the object during the inspection of space by a radar station, including the emission of sounding signals, receiving and detecting signals reflected from the object, measuring and storing the levels of received signals and the angular coordinates of the beam corresponding to the received signals, detecting angular packets of received signals, the calculation of the angular coordinates of the object, according to the invention in the angular packet of received signals determine the signal power, s corresponding to the location of the object in the direction of the maximum of the beam, after which they calculate each angular coordinate of the object in accordance with the formula:

where θ is the angular coordinate of the object;

L ₁₁ - the value determined at k = 1, m = 1 from the formula

n is the number of beam positions in the angular packet of received signals according to the measured angular coordinate of the object θ,

θ _i - the angular coordinate of the beam corresponding to the i-th signal of the packet of received signals, determined from the formula θ _i = θ _l + (i-1) Δθ;

θ _l is the angular coordinate of the beam corresponding to the first (i = 1) signal of the packet of received signals;

Δθ is the step of the ray moving along the measured angular coordinate;

ρ $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ - the power of the i-th signal of the packet, normalized to the rms value of the noise of the receiving path;

TO $\genfrac{}{}{0ex}{}{\text{2}}{\text{m}}$ - the signal-to-noise ratio for the signal corresponding to the location of the object in the direction of the maximum beam;

D = q ² + p ³ ;

sign (q) is the sign of q;

The technical result is also achieved by the fact that in the angular packet of received signals as the signal corresponding to the location of the object in the direction of the maximum beam, select the signal with the highest power.

The technical result is also achieved by the fact that in a radar station containing a transmitter, an antenna switch, an antenna, a receiver, a threshold device, a synchronizer, an angular coordinate estimation unit, the output of the transmitter is connected to the input of the antenna switch, the input / output of which is connected to the antenna, the output the antenna switch is connected to the input of the receiver, the output of which is connected to the input of the threshold device, the output of the threshold device and the coordinate output of the antenna are connected respectively to the first and second m inputs of the block for estimating angular coordinates, the first and second outputs of the synchronizer are connected to the synchro inputs of the transmitter and block for estimating angular coordinates, respectively, while the block for estimating angular coordinates includes a memory for detected signals, a block for detecting angular packets and a computer with M inputs, the first and second inputs the memory device of the detected signals are the first and second inputs of the block estimates the angular coordinates, respectively, M outputs of the memory device of the detected signals connected to the M inputs of the angular packet detection unit, the output of the calculator is the output of the angular coordinate estimation unit, according to the invention, the M + 1 input of the calculator and the signal power determining unit corresponding to the location of the object in the direction of the maximum beam are introduced, the M inputs of which are connected to the M outputs of the memory devices of detected signals, and M + 1 outputs are connected to M + 1 inputs of the calculator.

Introduction of the operation of determining the signal power in the angular packet of signals corresponding to the location of the object in the direction of the maximum of the beam K $\genfrac{}{}{0ex}{}{\text{2}}{\text{m}}$ , allows us to evaluate the angular coordinates of the object θ by a single calculation according to formula (3). This significantly reduces the time of determining the coordinates of the detected object and thereby increases the accuracy of determining the angular coordinates of objects in a limited time allocated for this purpose in modern mobile radars.

The invention is illustrated by the following drawings:

Figure 1 - examples of angular packets of received signals.

Figure 2 is a block diagram of a known radar.

Figure 3 - block diagram of the inventive radar.

Figure 4 - block detection of angular packets of signals 9.

The inventive method for measuring the angular coordinates of an object is implemented using a radar station, which contains (Fig. 3) a transmitter 1, an antenna switch 2, an antenna 3, a receiver 4, a threshold device 5, a synchronizer 6, an angular coordinate estimator 7, while the output of the transmitter 1 connected to the input of the antenna switch 2, the input / output of which is connected to the antenna 3, the output of the antenna switch 2 is connected to the input of the threshold device 5, the output of the threshold device 5 and the coordinate output of the antenna 3 are connected respectively to the first m and the second inputs of the block for estimating the angular coordinates 7, each of the two outputs of the synchronizer 6 is connected to the sync inputs of the transmitter 1 and the unit for estimating the angular coordinates 7, while the unit for estimating the angular coordinates 7 includes a memory for the detected signals 8, the unit for detecting angular packets 9, and the computer 10 with M inputs, the first and second inputs of the memory of the detected signals 8 being the first and second inputs of the block for estimating the angular coordinates 7, respectively, M outputs of the memory of the detected signal Ovs 8 are connected to M inputs of the angular packet detection unit 9, the output of the computer 10 is the output of the angular coordinate estimation unit 7, M inputs of the signal power determining unit corresponding to the location of the object in the direction of the beam maximum 11 are connected to M outputs of the angular packet detection unit 9, and M +1 outputs are connected to M + 1 inputs of calculator 10.

The number of outputs of the storage device for the detected signals 8, inputs and outputs of the block for detecting angular packets 9, inputs and outputs of the unit for determining the signal power corresponding to the location of the object in the direction of the maximum of the beam 11, inputs of the computer 10, the first and second inputs of the computer 12, the outputs of the memory weight factors 13, the inputs and outputs of the key 15 (M value) is determined by the largest possible value of the angular packet of received signals at both angular coordinates. The value of M for specific parameters of the radar (the smallest step of the beam during the survey of space, the power of the probing signal, the type of detected objects) can be determined in advance. So, for example, in a medium-range radar for the step of moving the antenna beam Δθ of the order of 0.5 of the antenna beam width when detecting large aircraft, an angular signal packet is generated along one angular coordinate from no more than 5 beam positions. Thus, in this case, the largest value of the angular packet is 5, i.e. M = 5.

The radar station can be performed using the following functional elements.

Transmitter 1 - pulse type (Reference to the basics of radar technology. - M., 1967, p. 278).

Antenna switch 2 - is made on the circulator (Reference on the basics of radar technology. - M., 1967, p.146-147).

Antenna 3 - phased antenna array with electronic scanning along one or both angular coordinates and with circular mechanical rotation (Radar Reference. Edited by M. Skolnik. T.2. - M .: Sov. Radio, 1977, p.132- 138).

Receiver 4 - superheterodyne type (Handbook on the basics of radar technology. - M., 1967, S. 343-344).

Digital elements: memory of the detected signals 8, calculator 10, a unit for determining the signal power corresponding to the location of the object in the direction of the maximum of the beam 11, calculator 12, memory weight 13, a comparison device with a threshold 14, key 15 - are made on standard microcircuits (Integrated microcircuits. Handbook edited by T.V. Tarabrin. - M.: Radio and Communications, 1984).

The angular packet detection unit 9 (Fig. 4) is built on the basis of the well-known block diagram (Kuzmin SZ Fundamentals of the theory of digital processing of radar information. M: Soviet Radio, 1974, pp. 38-40, Fig. 11.11).

The calculator 10 implements the calculations in accordance with the formula (3).

, где η_i - весовые коэффициенты, определенные заранее (Кузьмин С.З. Основы теории цифровой обработки радиолокационной информации. М.: Советское радио, 1974, стр.39, формула (1, 3, 6а)).The calculator 12 implements the calculations in accordance with the formula:

, where η _i are weights determined in advance (Kuzmin S.Z. Fundamentals of the theory of digital processing of radar information. M: Soviet Radio, 1974, p. 39, formula (1, 3, 6a)).

The unit for determining the signal power corresponding to the location of the object in the direction of the maximum of the beam 11 can be performed as a device in which the highest signal power is determined among the set of signals (in the packet of received signals), for example, on comparison devices (Integrated circuits. Reference, ed. B .V. Tarabrina. - M.: Radio and Communications, 1984).

The operation of the claimed radar when measuring the angular coordinates of the object is as follows. In the transmitter 1, according to the commands of the synchronizer 5 (synchronization pulses), probing signals are generated, which are radiated into the space during the survey of the space using the antenna 3. The signals reflected from the object are received by antenna 3 and fed to receiver 4. From the output of receiver 4, the signals are fed to the input of threshold device 5, where they are compared with a threshold that is set based on the admissible probability of false alarms. Signals whose level exceeds the threshold pass to the output of the threshold device 5. The detected signals from the output of the threshold device 5 and signals proportional to the angular coordinates of the beam of the antenna 3 are sent to the angular coordinate estimation unit 7. Signal power values with the corresponding angular coordinates of the beam as it moves antenna beam when viewing the space are recorded in the storage device of the detected signals 8 and stored there. By commands from the synchronizer 6 from the storage device of the detected signals 8, the data recorded in them is extracted and fed to the detection unit of the angular packets 9, where the angular packets of the received signals are detected (Fig. 4). The levels of the received signals and the angular coordinates of the beam corresponding to the received signals are supplied to the first M inputs of the calculator 12, the second M inputs of the calculator 12 receive the weight coefficients from the mass storage device 13. In the computer 12, the signal power and the corresponding values previously recorded in the storage device are multiplied weighting factors 13, weighting factors and summation of the resulting products. A signal proportional to the sum received is supplied to a comparison device with a threshold 14, where it is compared with a predetermined threshold. The threshold level is set based on the allowable probability of false detection of the corner packet. If the threshold is exceeded, an impulse is issued at the output of the comparison device with threshold 14, which means that an angular signal packet is detected. This pulse allows the passage of the received signals and the beam coordinates corresponding to the received signals through the key 15 to the output of the angular packet detection unit 9 and then to the M inputs of the signal power determining unit corresponding to the location of the object in the direction of the maximum of the beam 11. In this block, the power is determined, which would have a signal reflected from the object, if the object was at the maximum of the bottom. The maximum signal power in the packet of received signals can be taken as the power determined in this block. A signal proportional to the power thus determined, together with the signal data in the angular packet, enters the calculator 10. In the calculator 10, in accordance with formula (3), the angular coordinate of the object is determined. The second angular coordinate of the object is determined in the same way. Moreover, each angular coordinate of the object is determined in one operation.

Thus, the claimed technical solutions ensure the achievement of a technical result - improving the accuracy of measuring the angular coordinates of the object with a limited time evaluation of the angular coordinates.

Claims (3)

1. A method of measuring the angular coordinates of an object during a survey of space by a radar station, including the emission of sounding signals, receiving and detecting signals reflected from the object, measuring and storing the levels of received signals and the angular coordinates of the beam corresponding to the received signals, detecting angular packets of received signals, calculating angular object coordinates, characterized in that in the angular packet of received signals determine the signal power corresponding to the location of the object in the direction of ma beam maximum, after which each angular coordinate of the object is calculated in accordance with the formula:

where θ is the angular coordinate of the object; L ₁₁ - the value determined at k = 1, m = 1 from the formula

where n is the number of beam positions in the angular packet of received signals according to the measured angular coordinate of the object θ; θ _i - the angular coordinate of the beam corresponding to the i-th signal of the packet of received signals, determined from the formula θ _i = θ _l + (i-1) Δθ; θ _l is the angular coordinate of the beam corresponding to the first (i = 1) signal of the packet of received signals; Δθ is the step of beam movement along the angular coordinate;

- the power of the i-th signal of the angular packet of received signals, normalized to the rms value of the noise of the radar receiving path;

TO $\genfrac{}{}{0ex}{}{\text{2}}{\text{m}}$ - the signal-to-noise ratio for the signal corresponding to the location of the object in the direction of the maximum beam;

D = q ² + p ³ ;

sign (q) is the sign of q;

2. The method according to claim 1, characterized in that in the angular packet of received signals as the signal corresponding to the location of the object in the direction of the maximum beam, select the signal with the highest power. 3. A radar station containing a transmitter, an antenna switch, an antenna, a receiver, a threshold device, a synchronizer, an angular coordinate estimation unit, wherein the output of the transmitter is connected to the input of the antenna switch, the input / output of which is connected to the antenna, the output of the antenna switch is connected to the input of the receiver the output of which is connected to the input of the threshold device, the output of the threshold device and the coordinate output of the antenna are connected respectively to the first and second inputs of the block for estimating angular coordinates, the first the second outputs of the synchronizer are connected to the sync inputs of the transmitter and the block for estimating the angular coordinates, respectively, while the block for estimating the angular coordinates includes a memory for the detected signals, a block for detecting angular packets and a computer with M inputs, the first and second inputs of the memory of the detected signals being the first and second inputs block estimates the angular coordinates, respectively, M outputs of the storage device of the detected signals are connected to the M inputs of the block detection of angular ket, the output of the calculator is the output of the block for estimating the angular coordinates, characterized in that M + 1 is the input of the calculator and the block for determining the signal power corresponding to the location of the object in the direction of the maximum beam, the M inputs of which are connected to the M outputs of the block for detecting angular packets, and M + 1 outputs are connected to M + 1 inputs of the calculator.

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