RU2387584C1 - Small-sized system for video surveillance of ground environment - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention can be used for rapid analysis of the environment in conditions for limited observation due to presence of natural and artificial obstacles. The system for video surveillance of the ground environment has a small uncontrolled non-stabilised platform for mounting an onboard observation complex, where the said platform is joined to a parachute. The said observation complex comprises series-connected onboard observation chamber, analogue-to-digital converter, onboard formatting device, data compression unit, noise-immune coder, spectrum spreading unit, phase modulator and a transmitter with a transmission antenna. The ground complex comprises series-connected radio receiver with a reception antenna, a matched filter, noise-immune code decoder, video signal generation unit and a monitor.

EFFECT: shorter reconnaissance time, simplification of the procedure of controlling a video surveillance system and reduction of weight and size of the load carrying platform with preservation of the image transmission quality.

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Description

The proposed small-sized system relates to the field of video surveillance and can be used to quickly study the environment in conditions of limited monitoring capabilities due to the presence of natural and artificial obstacles, in particular mountain structures, forests, quarries, dams, etc. Moreover, the proposed small-sized video surveillance system can be used to solve the following problems:

- operational reconnaissance in unfamiliar areas, in particular the detection of an ambush when the column moves in dangerous places;

- detection of natural and artificial formations (reservoirs, buildings, quarries, etc.) in the immediate vicinity of the location;

- detection of abandoned, stolen or disguised equipment (cars, etc.);

- detection of missing tourists, stolen animals (for example, a flock of sheep or a herd of cattle), etc.

Currently, to solve various problems of observing the earth's surface, methods, systems and devices for video surveillance of the terrestrial situation are known, namely:

- RF patent RU 2.279.999 C2, B64D 47/08, published July 20, 2006;

- RF patent RU 2.272.753 C2, B64C 39/02, published 03/27/2006;

- RF patent RU 2.248.307 C1, B64C 29/00, G08C 21/00, published March 20, 2005;

- US patent US 6.712.312 VA, B64C 33/02, published March 30, 2004;

- US patent US 5.575.438 A, B64D 47/00, published November 19, 1994;

- French patent FR 02.707.386 A1, F41H 13/00, B64C 39/10, B64C 39/02, B64D 47/00, published 01/13/1995;

- EPO patent EP 1.391.681 A1, F41G 3/02, published February 25, 2004;

- ROSTICH R. Development of promising unmanned aerial vehicles for the Navy in the USA // Foreign Military Review. 2003, No. 7, pp. 61-63.

Of the known systems and devices for video surveillance of the earth’s surface, the closest solution to the proposed system is the “Surveillance System for Terrestrial Situation” (RF patent RU 2.248.307 C1, B64C 29/00, G08C 21/00, published March 20, 2005), selected in as a base object.

The basic prototype system relates to systems using unmanned aerial vehicles (UAVs) for air observation of terrain and objects on it and for transmitting video images of the earth’s surface and objects to a mobile ground monitoring and control complex (ground terminal).

To transmit image signals of the terrain and objects in the field of view of the surveillance equipment, an on-board surveillance and tracking system is installed on the UAV, including surveillance and tracking cameras, an analog-to-digital converter, an onboard formatting device, a data compression unit, and an image transmitter (information signal transmitter) , providing the transmission of an information signal over the air to a mobile ground-based monitoring and control system.

In addition, the on-board monitoring and tracking system contains an altimeter, a strapdown inertial unit, two memory units, a correlation device, a microprocessor, a block of steering machines and actuators. In this case, the correlation device provides the formation of the signal of the correlation function of two images coming from the memory blocks, and supplying this signal to one of the inputs of the microprocessor, which converts the specified signal of the correlation function into control commands of the UAV steering machine block.

In the mobile ground-based monitoring and control system, there is an image receiver that provides the reception of information image signals from the image transmitter via a radio channel, and a portable personal computer designed to display the received images of the terrain and objects in the field of view of the observation equipment.

In addition, the mobile ground-based monitoring and control system includes a transmitter that provides radio channel transmission of control signals (commands) for UAV flight and its orientation in space to a command receiver located on board the UAV, as well as a frame shaper.

The technical result from the use of the prototype is expressed in simplifying the system, reducing the size of the onboard equipment of the UAV and the ground, as well as to increase the usability.

A diagram showing the structure and principle of application of the basic prototype system is shown in figure 1.

The basic prototype system works as follows.

After the UAV is launched by transmitting control signals (commands) generated in the mobile ground-based monitoring and control complex and transmitted over the air using the command transmitter to the command receiver located on board the UAV, the operator displays in the area of application (in the area where the objects of interest are located). In the area of application, the UAV is controlled by control signals that are generated using a correlation device and a microprocessor and are fed to the block of steering machines of the UAV. During the flight of the UAV in the area of application using an onboard surveillance and tracking system containing surveillance and tracking cameras, images of terrain and objects are formed in the field of view of the surveillance equipment. The resulting images are converted into information signals, which are transmitted via an information signal transmitter over the air to a mobile ground-based monitoring and control system. The operator of a mobile ground-based monitoring and control system has the ability to observe the resulting image on the screen of a portable personal computer. The image of the object is transmitted from the board of a remotely controlled UAV in the current time.

The described basic prototype system is intended for use at the operational-tactical level and is characterized by such an application of UAVs, when the carrier of the surveillance equipment can travel tens or even hundreds of kilometers to the objects of observation. In addition, the UAV can provide a long observation time, determined by its tactical and technical characteristics. In such conditions, the achieved effect (the effectiveness of the monitoring system) justifies the cost of launching the UAV, its management, the cost of the UAV itself and ensures the proper level of the Efficiency-Cost criterion. However, the use of such a system for monitoring terrain and objects at a tactical level is completely ineffective. The fact is that the solution of problems by a small mobile group, as a rule, is carried out on areas of the area with sizes ranging from hundreds of meters to one or two kilometers. Under such conditions, launching a UAV, taking it to a small area of the terrain, which the UAV will fly very quickly, returning and repeatedly repeating these operations is inefficient, especially from the point of view of time spent on reconnaissance operations. In addition, existing UAVs, including UAVs in the prototype system, are cumbersome for transportation by a small mobile group and expensive systems in terms of tactical level of application.

To address these shortcomings of the prototype system, a small-sized video surveillance system for terrestrial conditions is proposed.

The proposed small-sized video surveillance system for terrestrial conditions includes a small-sized uncontrolled unstabilized platform mechanically connected with a parachute, an on-board surveillance system including a surveillance camera, an analog-to-digital converter, an on-board formatting device, a data compression unit (optoelectronic unit) and image transmission path (information signal), providing the transmission of the information signal over the air to the ground-based mobile observation complex Eden. In addition, the proposed small-sized video surveillance system has a mobile ground-based monitoring complex (ground terminal) containing an image receiving path for receiving information signals from the image transmitter via a radio channel, and a portable personal computer designed to display the received images of the terrain and objects located in the field view of observation equipment.

The image (information signal) transmission path contains a noise-resistant encoder connected in series, an information signal spectrum expansion unit, a phase modulator, a transmitter itself, and a transmitting antenna. The interference-free encoder and the spreading spectrum block of the transmitted signal together provide the required quality of image transmission (information signal). Indeed, the use of noise-resistant coding in the radio line allows detecting and correcting a certain number of errors that can occur when transmitting signals over the air. The number of detected and correctable errors is determined by the type and parameters of the error-correcting code used. The procedure for expanding the spectrum of the transmitted signal (forming a complex signal), together with optimal reception using a matched filter in the ground terminal, provides an improvement in signal-to-noise ratio and thereby improving the quality of signal transmission. The application of measures to increase the noise immunity of the radio line in the proposed small-sized video surveillance system for terrestrial conditions is fundamental in view of the following factors:

- a significant decrease in the amplitude of the transmitted signal, which can occur in a radio line when working with mobile unstabilized objects;

- low power of the transmitter, located on a small platform, where it is difficult to provide any significant power source.

The information signal receiving path at the ground terminal contains a receiving antenna, a radio receiver, a matched filter, in which a complex signal is compressed and thereby improving the signal-to-noise ratio, an error-correcting code decoder, an image video signal generating unit, which is sent to the monitor to restore the image received in airborne surveillance system.

The technical result from the use of the proposed small-sized system for operational video surveillance of the terrestrial situation is expressed in increasing the efficiency (reducing time) of conducting reconnaissance operations on the ground, reducing the weight and size characteristics of the on-board equipment, increasing the usability of the system, and also significantly reducing the cost of this system in relation to the level being solved tasks. The proposed small-sized system for operational video surveillance of the terrestrial situation is today the only option for solving problems of this level.

Structural diagrams of the airborne observation complex and the receiving path of the ground terminal of the proposed small-sized video surveillance system for terrestrial situation are presented in figure 2.

In figure 2, the following notation:

- 1 - surveillance camera;

- 2 - analog-to-digital converter;

- 3 - on-board formatting device;

- 4 - data compression unit;

- 5 - noise-resistant encoder;

- 6 - block expansion of the spectrum;

- 7 - phase modulator;

- 8 - a transmitter connected to a transmitting antenna;

- 9 - a radio with a receiving antenna;

- 10 - matched filter for the phase-shifted signal;

- 11 - decoder error-correcting code;

- 12 - block forming the video signal of the image;

- 13 - monitor (PC).

The principle of expanding the spectrum of the information signal (image signal) is presented in figure 3.

A diagram depicting the structure and principle of application of the proposed small-sized video surveillance system for terrestrial situation is depicted in figure 4, where the following notation is accepted:

- 14 - parachute;

- 15 - small-sized uncontrolled unstabilized platform;

- 16 - camera;

- 17 - mobile ground surveillance system (ground terminal);

- 18 - observation area.

The on-board monitoring complex of the proposed small-sized video surveillance system for terrestrial conditions contains a serially connected surveillance camera 1, analog-to-digital converter 2, on-board formatting device 3, data compression unit 4, noise-resistant encoder 5, spectrum expansion unit 6, phase modulator 7 and transmitter 8, output which is connected to the transmitting antenna.

In turn, the receiving path of the ground terminal of the proposed small-sized video surveillance system for terrestrial conditions contains a receiving antenna, a radio receiver 9, a matched filter 10, an error-correcting code decoder 11, an image video signal generating unit 12, and a monitor 13.

In this composition, the radio link for transmitting images from a small platform to a ground terminal provides the quality of image transmission not worse than in the prototype, in the conditions of a mobile unstabilized platform and low power supply to the system.

The composition of the proposed small-sized video surveillance system includes the following main elements (figure 4).

The parachute 14 is mechanically connected to a small uncontrolled (unstabilized) platform 15, which houses an airborne surveillance system, including a camera 16 and a transmission path.

The mobile ground-based observation complex (ground terminal) 17 contains an image signal receiving path for receiving image information signals from an image transmitter via a radio channel, and a portable personal computer designed to display received terrain images (observation zone) 18 and objects.

The proposed small-sized video surveillance system for terrestrial conditions operates as follows.

A small-sized uncontrolled unstabilized platform with an on-board observation complex and a transmitting path 15 is brought to the required height (for example, to a height of 200 m) using a powder charge and a launching device (by analogy with lighting missiles). At a given height, the parachute device 14 is opened, and the small-sized uncontrolled unstabilized platform 15 starts a smooth descent (for example, at a speed of 0.5 m / s), which ensures that the platform hangs over the study area (observation zone) 18. So, for example, at a descent rate 0.5 m / s decrease from a height of 200 m to a height of 150 m occurs in 100 s. The indicated time is quite sufficient for the formation of a stable image by the camera 16, its processing and registration at the ground terminal 17 for subsequent study and analysis by the operator.

Depending on the tasks and local conditions, the launch of a small-sized uncontrolled platform can be carried out with a shift to the right (left), forward, right forward (left forward) in the direction of travel or at the place of deployment (Fig. 4).

After the output of the platform and its freezing, the on-board observation complex and the transmitting path are switched on. In this case, the image of the terrain in the space of the optical system of the surveillance camera 16 is converted into electrical signals in digital form (blocks 1 and 2), which are formatted to form a digital image stream (block 3) and additional processing to reduce the redundancy of data representation (data compression ) (block 4).

The digital image signal prepared for transmission from the output of the data compression unit is subjected to noise-resistant coding (block 5) and spreading of the spectrum (block 6). In this case, to expand the spectrum of the transmitted signal, the procedure is used to multiply information symbols (image signals) and pseudo-random sequence symbols with a multiplicative representation of symbols (x∈ {1, -1}), (Fig. 3) or the modulo-two addition procedure for the additive representation of symbols (x∈ {0,1}). To illustrate, figure 3 presents the procedure for expanding the spectrum of data (x∈ {1, -1}) using a linear recursive sequence of maximum length (M-sequence) with the forming polynomial A (X) = X ⁴ + X ¹ +1 and length N = 15. The expansion of the spectrum of information signals allows the formation of carrier signals with a large base equal to the length N of the expanding pseudorandom sequence.

The digital information stream from the output of the spectrum expansion unit is fed to a phase modulator to transfer the spectrum of the digital signal to the radio frequency (carrier frequency), from where it enters the transmitter and is emitted by the transmitting antenna.

On the receiving side of the radio line, radio signals are received and amplified in the radio receiver (block 9), the symbols of the information message (image) are selected using the matched filter 10, the error-correcting code is decoded to detect and correct errors (block 11), image signals are generated (the reverse procedure data compression procedure) (block 12) and display on the monitor (block 13).

The parameters of the radio line, the radiation power, the type and parameters of the error-correcting code, the type and parameters of the expanding pseudo-random sequence are selected and justified at the stage of development and creation of a small-sized video surveillance system. Moreover, the presence of a direct spectrum extension unit and a matched filter is a fundamental difference between the proposed system and the basic prototype system.

This circumstance is due to the need to ensure the required quality of image transmission under conditions of limited power supply and a possible sharp decrease in the amplitude of radio signals. Limited power supply and the possibility of a sharp decrease in the amplitude of radio signals are the result of the transition to a small-sized unstabilized platform. At the same time, the use of carrier signals with a large base equal to the length N of the extension sequence, by expanding the spectrum of information signals, provides an output signal-to-noise ratio improvement of 2 · N times (with coherent matched filtering) and N times with incoherent consistent filtering. This circumstance is the most important tool for ensuring the required quality of image transmission.

Thus, the proposed small-sized video surveillance system for terrestrial situations, compared with the basic prototype system and other similar systems in relation to tactical level situations, significantly reduces reconnaissance time (in some situations, the time factor can be extremely critical), simplifies the video surveillance system management procedure, significantly reduces weight and size characteristics of the supporting platform, and also has a significantly lower cost and at the same time retains the qualities about transferring images.

The technical result from the application of the proposed small-sized video surveillance system for terrestrial conditions is expressed in a significant reduction in reconnaissance time, simplification of the video surveillance system control procedure, reduction of the overall dimensions of the carrier platform while maintaining image transmission quality, as well as in a significant reduction in the cost of this system in relation to the level of tasks being solved.

Claims (1)

A small-sized video surveillance system for terrestrial conditions, containing a series-connected on-board surveillance camera, an analog-to-digital converter, an on-board formatting device and a data compression unit, series-connected an on-board transmitter and a transmitting antenna, as well as a series-connected receiving antenna and a radio receiver and series-connected video image forming unit and a monitor, characterized in that a parachute is inserted into it, a small-sized uncontrolled unstable this platform for placement of an on-board observation complex, a noise-resistant encoder, a spreading unit and a phase modulator connected in series, as well as a matched filter and a noise-free code decoder in series, while the small-sized uncontrolled unstabilized platform is mechanically connected with a parachute, the output of the data compression block is connected to the input of the noise-resistant encoder, the output of the phase modulator is connected to the input of the transmitter, the output of the radio is connected to the input consistently filter, and the output of the error-correcting code decoder is connected to the input of the video image forming unit.

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