RU193652U1 - A device for detecting objects by a long-range portrait with multilevel quantization - Google Patents

Abstract

A device for detecting objects by a long-range portrait with multilevel quantization refers to devices for the automated detection of surface and ground targets in the presence of interfering reflections from underlying surfaces (agitated water areas) and objects that are not objects of location, and can be used to solve problems of ensuring navigational safety of navigation. EFFECT: increased probability of detection of small surface targets. The essence of the utility model consists in the fact that the device containing a correlation filter, a target signal generator, a shaper of reference signals of interfering objects and a threshold element, moreover, signals of radiolocation standards are received at the second input of the correlation filter range target portraits from the target signal generator, to the third input of the correlation filter, signals of distance portrait standards of the interfering objects from the source generator of the disturbing objects and the digital signals from the shift register output, which are fed to the first input of the correlation filter, from which the correlation coefficient value transmitted to the first input of the threshold element, the second and third inputs of which receive clock pulses and threshold voltage is applied, led the cause of which is determined in accordance with the given probabilities of detection and false alarm, and from the output of the threshold element, the signal about the detection of targets enters the parallel-connected parallel register and indicator. 1 ill.

Description

The invention relates to devices for automated detection of surface and ground targets in the presence of interfering reflections from underlying surfaces (agitated water areas) and objects that are not objects of location. The device is designed to ensure the detection of surface and ground targets against the background of powerful reflections from underlying surfaces and interfering objects with a given detection probability when using radar range portraits (RLDP) (the intensity distribution of the reflected signal from the object along the line of sight, corresponding to a discrete radar resolution element in range) location objects formed by radar stations with high resolution in range (of the order of 1.0-0.15 m).

The proposed utility model may find application for solving the problems of ensuring navigational safety of navigation.

Currently, the implementation of the tasks of effective ship management requires the reliable detection of location objects in the water area against the background of powerful interfering reflections from the excited water surface.

The most famous and common methods for detecting surface objects by energy parameters, the essence of which is to calculate the ratio of the power of the reflected signal from the target to the power of noise interference and the reflected signal from the background (the signal-to-target / noise + background ratio) and deciding on target detection when exceeding a predetermined threshold level.

So in [1], a solution is considered in which, for the detection of targets, the formation of estimates of unknown parameters of signals and interference or their distributions is used based on the observations made.

In [2], a radar receiver with pulsed ultra-wideband radio signals is considered, which in structure is a linear broadband amplifier.

A known detector of radar signals [3], based on the delay of the received signal with subsequent subtraction.

The closest in technical essence and the achieved result (prototype) is the method of adaptive digital signal detection [4], which consists in the fact that the analog-to-digital signal conversion is performed, complex correlation sums of the signal sample and reference quadrature signals in the resolution elements in the detection area are calculated, a detection threshold is determined for each window, the analysis of which makes a decision about the presence of a target in the resolution element.

However, as a rule, in all these devices and methods, energy, spectral and amplitude signs are considered that undergo significant fluctuations and significantly depend on the distance to the target, which leads to a decrease in the reliability of detection. The use of polarization detection methods requires a significant complication of the design of the radar.

And, most importantly, all these methods and devices operate effectively with a significant excess - by 13-14 dB - of the signal level from the target at the level of the total signal "noise + background", which is technically difficult to provide.

In this case, the detected targets (large vessels, yachts) and interfering objects (shrubby vegetation, toljak, the excitement of the water surface) differ significantly in their radial extent.

It is known from the prior art that with a large frequency band of probing signals with a continuous spectrum (broadband signals), and in some cases with a discrete spectrum (multi-frequency signals), it is possible to separately observe target elements along the line of sight and observe their radar laser radiation. With the frequency bands of the probing signals ΔF = 30 ... 3000 MHz, it is possible to provide a coordinated resolving power over a range of about 1.0-0.15 m, which makes it possible to obtain RLDPs of surface, air, space and other targets of various lengths.

Moreover, the basis of target detection as an informative sign of detection can be based on the size of the target. It is measured at a certain level from the maximum of the RLDP or from the maximum of the correlation function with square-wave reference signals of various lengths [5].

It is the determination of the size of the target that can be the basis of the proposed automated detection device: when the calculated size exceeds the threshold value, a decision is made whether the target is in the resolution element, otherwise a decision is made about the absence of the target. Moreover, the requirements for the level of the signal from target / noise + background ratio are significantly lower than with traditional detection methods.

The objective of the proposed utility model is to create a device for the automated detection of sea and river vessels of various tonnages, against the background of powerful interfering reflections from an agitated water surface with an increased level of detection probability through the use of long-range portraits with multi-level quantization, formed using high-resolution radar with a range.

The technical result when using this utility model is to increase the likelihood of detecting small surface targets.

The task with the achievement of the above technical result provides that the device for detecting objects by a long-range portrait with multi-level quantization, proposed as a utility model, contains serially connected block for automatic stabilization of the detection threshold, an amplitude detector, an analog-to-digital converter, a clock generator, a shift register, parallel register and indicator. A feature of this device is that for the purpose of detecting objects with given probabilities, it additionally contains a correlation filter, a shaper of target targets, a shaper of reference signals of interfering objects and a threshold element, and the signals of the standards of radar long-range portraits of targets from the shaper of reference are fed to the second input of the correlation filter target signals, the third input of the correlation filter receives the signals of the standards of interfering objects from the shaper standard s signals interfering objects and digitized signals output from the shift register are supplied to the first input of the correlation filter, the output of which the value of the correlation coefficient is transferred to a first input of the threshold element in the second and third inputs of which receives the clock pulses and the threshold voltages U _por fed magnitude which is determined in accordance with the given probabilities of detection and false alarm. From the output of the threshold element, a signal about the detection of targets is fed to a parallel-connected parallel register and indicator.

The essence of the utility model is illustrated by the block diagram of the device for detecting objects from a long-range portrait with multi-level quantization, shown in FIG. 1, the composition of which includes:

1 - block automatic stabilization of the detection threshold;

2 - amplitude detector;

3 - clock generator;

4 - analog-to-digital Converter;

5 - shift register;

6 - shaper of reference signals of targets;

7 - shaper of reference signals of interfering objects;

8 - correlation filter;

9 - threshold element;

10 - parallel register;

11 - indicator.

The device operates as follows.

. С помощью аналого-цифрового преобразователя (4) и генератора (3) тактовых импульсов осуществляется аналого-цифровое преобразование сигнала по нескольким уровням.An additive mixture of signal and noise from the output of the receiver is fed to the input of the block (1) for automatic stabilization of the detection threshold. Amplitude detector 2 highlights the envelope of the reflected signal

. Using an analog-to-digital converter (4) and a clock generator (3), analog-to-digital signal conversion is performed at several levels.

The digitized signal from the output of the analog-to-digital converter (4) is fed to the information input of the shift register (5), in which, for each clock pulse, the received signals are shifted. The number of information outputs of the shift register (5) is selected from the ratio of the radial extent of the largest detectable target l l _max to the radar resolution in range:

where c is the speed of electromagnetic waves in free space;

T _ti is the repetition period of clock pulses.

In each cycle, the signal from the output of the shift register (5) (S ₁ , ... S _N ) is fed to the first input of the correlation filter (8). The second and third inputs of the correlation filter (8) are fed, in accordance with a priori information about the portraits of the standards, multilevel digitized signals of generalized RLDP targets and interfering objects from the outputs of the target signal generator (6) and the signal generator of the interfering objects (7), respectively.

In the correlation filter (8), which uses the generalized reference portrait of targets as the impulse response, the degree (coefficient) of correlation between the RLDP of the detected target and the RLDP of the target standards and interfering objects is determined.

The obtained value of the correlation coefficient from the output of the correlation filter (8) is transmitted to the first input of the threshold element (9), the second and third inputs of which receive clock pulses and threshold voltage U _por . Based on the results of comparison with threshold voltages in the threshold element (9), a decision is made on the presence or absence of a target in the resolution element.

Information on the results of detection is stored in the parallel register (10) and displayed on the indicator (11).

The proposed device is made on commercially available industrial electronic elements and is implemented in the locator of a mobile automated radar control system based on high-speed programmable logic arrays (PLM) of the Xilinx type.

This confirms the industrial implementation of the above device, which allows to determine the extent of targets and interfering objects, according to the results of the analysis of which it is possible to make a decision to detect an object against the background of interfering reflections.

The developed device has advanced functionality and an increased level of correct detection of sea and river vessels of various tonnage.

Sources of information used:

1. “Digital radar. Introduction to Theory ”, S.Z. Kuzmin, Kiev: Publishing house "KViTS", 2000. - 428 p.

2. Astanin L.Yu., Kostylev A.A. Basics of ultra-wideband radar measurements. - M.: Radio and Communications, 1989 .-- 192 p.

3. Russian patent RU 2409821 C2, Detector of radar signals.

4. Russian patent RU 2237258 C2, Adaptive digital signal detection method.

5. "Radio-electronic systems: Fundamentals of construction and theory", Reference, Ed. 2nd rev. and add. / Ed. POISON. Shirman. - M .: Radio engineering, 2007, - 512 p.

Claims (1)

A device for detecting objects by a long-range portrait with multilevel quantization, comprising a series-connected block of automatic stabilization of the detection threshold, an amplitude detector, an analog-to-digital converter and a shift register, and also containing a clock generator, the output of which is connected to the input of an analog-to-digital converter, a parallel register and indicator, characterized in that the device further includes a correlation filter, a shaper of reference signals of targets, the receiver of the reference signals of interfering objects and a threshold element, and the signals of the standards of long-range portraits of targets from the shaper of the targets of interfering objects from the generator of the reference signals of interfering objects, digitized signals from the correlation filter the output of the shift register are fed to the first input of the correlation filter, from the output of which the value of the correlation coefficient per goes to the first input of the threshold element, the second and third inputs of which receive clock pulses from the output of the clock generator and threshold voltage is applied, the value of which is determined in accordance with the given probabilities of detection and false alarm, and from the output of the threshold element the signal about the detection of targets is transmitted to consecutively connected parallel register and indicator.

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