RU2792087C1 - Method for tracking moving objects by radio station with radiometer - Google Patents

Abstract

FIELD: air objects movement tracking.

SUBSTANCE: invention relates to systems for tracking moving air objects using a transceiver radio station that processes reflection signals from objects. Unlike the prototype, in which, based on the results of detection of several objects, objects are tracked - their trajectory tracking is carried out without taking into account the energy characteristics of objects, in the proposed method, when trajectory tracking of objects, their radio brightness temperature is measured using a radiometer combined with a radio station, which allows you to classify objects according to their energy characteristics.

EFFECT: ensuring the elimination of object classification errors by sharing a scanning radiometer with the radio station.

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Description

The invention relates to systems for tracking moving air objects using a transceiver radio station that processes reflection signals from objects.

When tracking moving objects with the help of a radio station, estimates of the angular coordinates of signal sources are found by amplitude, monopulse or phase methods [1], as well as determining the radial distances to objects and tracking them (tracking) in time by constructing their motion trajectories. In this case, additional information about the objects is extracted from the characteristics of the received signals, for example, amplitudes.

At the same time, to increase the probability of detecting objects, as well as to recognize the types of objects by their energy characteristics, signal information is not enough. An energy characteristic in the form of temperature can be given by thermal imagers operating in the optical wavelength range. However, their work is limited by the conditions of observation. Radiometers measure the radiobrightness temperature of objects in the radio wavelength range and allow measurements to be made under any conditions [2, 3]. However, they have a long signal accumulation time (from 0.1 to 1 s), which does not allow them to be used for tracking moving objects.

The problem arises of using radiometers as part of a radio station for tracking objects. Known methods of tracking objects by constructing the trajectories of their movement in the sequence of periods of radar coverage [1, 4, 5].

Consider as a prototype the method of detection and trajectory tracking of objects [4, p. 108] in the sequence of review periods, which can be algorithmically implemented as follows.

1. In the first two periods of the review, the received signals are subjected to primary processing, the results of which determine the vectors of estimates of the spatial coordinates of the sources of reflected signals and the amplitude of the signals. The evaluation vectors found in adjacent survey periods are combined into pairs of vectors that give the initial linear trajectory model.

2. In the third and subsequent review periods, each trajectory obtained in the previous period is put in correspondence with newly determined vectors that fall into the confidence region constructed relative to the extrapolated trajectory coordinates. Extrapolation is carried out taking into account the trajectory model and the duration of the survey period.

3. All vectors that fell into the confidence region of the previously obtained trajectory give continuations of the trajectory by attaching them to the trajectory and refining the estimates of the parameters of its adopted model (linear or higher order). The likelihood index of each trajectory is calculated as a sum of squared residuals - deviations of all attached vectors relative to the trajectory model. Additionally, the squares of the residuals of the signal amplitudes can be included in the index.

4. If there is not a single vector in the trust region, then a gap is fixed for the previously obtained trajectory. For such a trajectory, a confidence region is built for the next review period, taking into account the extrapolation error. With a given number of skips in a row, the trajectory is discarded from consideration as false or a conclusion is made about the object going out of visibility.

5. Vectors that are not included in the trajectories are considered as initial vectors for the formation of new trajectories. In the next review period, I add paired vectors to them and thereby set the initial linear trajectories, which are processed in subsequent periods in accordance with paragraphs. 2-4 for the received trajectory model.

6. All trajectories formed in the current review period and not attached vectors (with a certain label) receive a new numbering. The vectors attached to the trajectories (or their numbers in the general list), trajectory parameters and likelihood indicators are remembered.

7. If there is a certain number of vectors attached to the trajectories, groups with the smallest total squares of residuals and no common vectors are sequentially selected (a small number of intersections is allowed). Such groups are considered detected and transferred to the tracking of their trajectories.

8. Further, at the stage of tracking the trajectories, the belonging of the object to a certain class is recognized by speed, maneuverability (change in the position of the velocity vector) and characteristics of the reflection signal.

This method has the following disadvantage. It does not take into account the energy characteristics of objects when maintaining, which can lead to classification errors and incorrect subsequent decisions.

The proposed technical solution is aimed at eliminating this disadvantage, namely, using a scanning radiometer together with a radio station to measure the radio brightness temperature of objects subject to trajectory tracking in order to more effectively recognize the type of objects.

The technical result of the proposed technical solution is achieved by using the method of tracking moving objects by a radio station with a radiometer, which consists in the primary processing of the received signals in the periods of the review of the radio station, determining the results of the initial processing of the vectors of estimates of the coordinates of the signal sources, connecting the vectors found in adjacent periods of the review into groups by belonging to trajectories and transmission to tracking of trajectories with non-intersecting groups and least sum squares of residuals of vectors, characterized in that the scanning radiometer is combined with the radio station and at the stage of tracking objects the objects are ranked according to the degree of importance and, in the ranking order, the line of sight of the radiometer antenna is sequentially transferred in the direction of the extrapolated position of each object with an angular velocity equal to the angular velocity of the object along the trajectory, and the radio brightness temperature is measured during the time the object moves to the extreme the polished position, after which the objects are classified according to belonging to certain classes, taking into account the measured radio brightness temperature and trajectory parameters.

Algorithmically, the method is carried out as follows.

1. Perform the operations of paragraphs. 1-7 prototype ways.

2. The trajectories to be tracked are ranked in order of importance depending on the range and direction of the velocity vector.

на момент времени t_i+τ_i, где τ_i - длительность промежутка времени, необходимого для вывода линии визирования радиометра в упрежденную точку

, и осуществляют перевод линии визирования антенны радиометра с угловой скоростью движения объекта по траектории (относительно радиометра) в направлении.

.3. In the order of ranking, find the predicted position of each object in the form of a vector of extrapolated coordinates

at the time t _i +τ _i , where τ _i is the duration of the time period required to bring the line of sight of the radiometer to the predicted point

, and transfer the line of sight of the radiometer antenna with the angular velocity of the object along the trajectory (relative to the radiometer) in the direction.

.

4. To do this, determine the angle between the vectors of direction vectors to the current and extrapolated positions of the object (using the scalar product of vectors) and divide the angle by the time the object moves from the current to the extrapolated position. Rectilinear motion of the object is assumed during the time of signal accumulation by the radiometer, which does not exceed a fraction of a second or a second.

5. Using a radiometer, the radiobrightness temperature of the object is measured during its movement to the extrapolated position and memorized. Similar operations are repeated for measuring the brightness temperature for each object in the order of ranking.

6. Classify objects according to belonging to certain classes, taking into account the measured radio brightness temperature and trajectory parameters.

Conclusion

The application of the proposed method will increase the probability of correct classification of detected objects when they are accompanied by measuring the radio brightness temperature during the movement of objects to extrapolated positions. The method can be used in existing radio engineering systems for finding objects.

Literature

1. Bakulev P.A. Radar systems: a textbook for universities. M.: Radiotehnika, 2007. 376 p.

2. Sharkov E.A. Radiothermal remote sensing of the Earth: physical foundations: in 2 volumes / V. 1. IKI RAS, 2014. 544 p.

3. Passive radar: methods of object detection / Ed. R.P. Bystrov and A.V. Sokolov. M: Radio engineering, 2008. 320 p.

4. Kuzmin S.Z. Fundamentals of designing systems for digital processing of radar information. Moscow: Radio and communication, 1986. 352 p.

5. Farina A., Studer F. Digital processing of radar information. Accompanying goals: Per. from English. / Ed. A.N. Yurieva, A.M. Bochkareva. Moscow: Radio and communication, 1993. 319 p.

Claims (1)

A method for tracking moving objects by a radio station with a radiometer, which consists in the primary processing of received signals in the survey periods of the radio station, determining the vectors of estimates of the coordinates of signal sources based on the results of the initial processing, connecting the vectors found in adjacent survey periods into groups according to their belonging to the trajectories and transferring the trajectories to tracking with non-intersecting groups and the least total squares of the residuals of the vectors, characterized in that the scanning radiometer is combined with the radio station and at the stage of tracking objects the objects are ranked according to the degree of importance and in the ranking order the line of sight of the radiometer antenna is sequentially transferred in the direction of the extrapolated position of each object with an angular velocity equal to the angular velocity the speed of the object along the trajectory, and measure the radio brightness temperature during the movement of the object to the extrapolated position, after which the objects are classified according to belonging to a certain th classes, taking into account the measured radio brightness temperature and trajectory parameters.