Adaptive double-threshold detector of modular digital panoramic receiver signals

FIELD: radio engineering, communication.

SUBSTANCE: detector comprises a main detection channel, an additional detection channel and a subtractor unit, as well as a register for storing given signal detection probability values, a unit for calculating a lower detection threshold level, a register for storing a confidence coefficient, a unit for calculating an upper detection threshold level, a switch, an additional threshold device which is the output of the device, a display and a programmable interface, wherein the main detection channel includes two quadrature phase detectors, a cosine-sine generator, two integrators, two square-law detectors, an adder and a threshold device; the additional detection channel includes a third square-law detector and a third integrator. The listed devices are connected to each other in a certain manner and a binary level of an additive mixture of the signal and noise in form of digital readings is transmitted to the combined inputs of the main and additional detection channels, which are the input of the device.

EFFECT: fewer false alarms at the output of a digital panoramic detector.

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The invention relates to electrical engineering and can be used in a panoramic receivers, radio stations, radio direction finders, radio monitoring tools and similar devices for the detection of emitters (IRI), operating in conditions of unknown noise intensity.

Known energy detector of the unknown signal only on the estimation of the power (energy) of the observed process, which includes connected in series receiving antenna, linear (wideband) channel receiver, bandpass filter, a square-law detector, a threshold device that implements the most commonly used in the panoramic receivers criterion decision of the Neyman-Pearson [see V. Borisov and other Spatial and probabilistic-temporal characteristics of effectiveness stations reciprocal interference of the suppression of radio communication systems./Ed. by V. Borisov. - M.: Radiosoftware, 2008. p.62]. The advantage of such a detector is the ability to provide the required probability of missing a signal at a given false alarm probability in the absence of a priori data about the radiation detection signal with unknown phase and fluctuating amplitude background noise of unknown intensity. However, the application of such processing involves high requirements to the potential for the spine of the transfer signal and the specified receiver sensitivity high probability of false alarms due to the fixed level detection threshold, which leads to the inadequacy of the display electronic environment (REO) (electromagnetic environment (EME)in the analyzed frequency band and, consequently, to an increase in the duration analysis, REO, due to the need for identification procedures to exclude from processing false alarms.

Known detector [VG Repin, G.P. Tartakovsky. Statistical synthesis under a priori uncertainty and adaptation of information systems. M: Owls. radio, 1977, s] noise uncorrelated fluktuiruyushchem signal with unknown statistics of the fluctuations that implements the method for detecting signals according to the criterion of Neyman-Pearson, containing the first and second quadrature phase detectors, frequency, phase shifter 90°, the first and second integrators, the first and second quadratic detectors, adder and a threshold device. Moreover, the combined first inputs of the first and second quadrature phase detectors are input device, to the second input of the first quadrature phase detector voltage reference frequency from the reference frequency generator, the second input of the second quadrature phase detector voltage reference frequency from the output of the phase shifter 90°, the inlet of which is connected to the generator output frequency reference, the outputs of the first and second quadrature the phase detectors are connected to the inputs of the first and second integrators, respectively, the outputs of the first and second integrators are connected, respectively, to the inputs of the first and second quadratic detectors, the outputs of the first and second quadratic detectors connected to respective inputs of the adder, the output of the adder connected to the input of the threshold device whose output is the output of the detector.

A significant drawback of the detector of this type is that the fixation of the detection threshold in terms of noise intensity, unknown at the time of observation, reducing the efficiency of the detection signal of the IRI by increasing the number of false alarms in high demands on the detection signal, which leads to inadequate results of the analysis of REO at the a priori uncertainty busiest emitters controlled bandwidth and increase the time of analysis, REO, due to the need identification signal components from the noise.

The closest to the technical nature of the claimed solution is the detector [Borisov, V.I. and other Spatial and probabilistic-temporal characteristics of effectiveness stations reciprocal interference of the suppression of radio communication systems./Ed. by V. Borisov. - M.: Radiosoftware, 2008. - RIS, p.131] signals with random amplitude and the initial phase of the noise is unknown intensively the tee maintaining a constant level of false alarms and a decision by the criterion of Neyman-Pearson, containing the main channel detection, comprising first and second quadrature phase detectors, cosine-sine generator (KSG), the first and second integrators, the first and second quadratic detectors, adder and a threshold device which United the first inputs of the first and second quadrature phase detectors are input devices, the second inputs of the first and second quadrature phase detectors are connected, respectively, to the outputs of the quadrature components (sine and cosine) frequency reference DRG, the outputs of the first and second quadrature phase detectors are connected to the inputs of the first and second integrators, respectively, the outputs of the first and second integrators connected, respectively, to the inputs of the first and second quadratic detectors whose outputs are connected to first and second inputs of the adder, respectively, the output of which is connected with United first input block subtraction and threshold devices, respectively, the output of which is the output of the detector, additional discovery channel, consisting of series-connected third quadratic detector and integrator, the input channel connected to the input device, and the output is connected to the second input of the subtraction, the output of which is connected to the second input porogo the CSOs device.

The disadvantage of the considered detector signals with random amplitude and the initial phase in the unknown intensity noise is that the noise variance is estimated assuming no input signal is detected. In addition, the detection of a signal with random amplitude and the initial phase in noise of unknown intensity to maintain a constant level of false alarms and a decision by the criterion of Neyman-Pearson explained by the presence of a sufficiently high level of probability of false alarm when set high requirements for the probability of detection of the signal and the receiver sensitivity. This increases the time of analysis REO.

The characteristics of the prototype, coinciding with the essential features of the claimed invention are: main channel detection, comprising first and second quadrature phase detectors, KSG, the first and second integrator, the first and second quadratic detectors, adder, a threshold device, an additional channel detection, including quadratic detector, integrator and subtractive device.

The task, which is aimed by the invention is the reduction of analysis time REO given the reliability of its results in terms of a priori uncertainty about downloading sources of radio emission control Studio strobe, flash is emnd bandwidth digital panoramic receiver, carrying out detection with fluctuating amplitude and random initial phase in noise with unknown, at the time of observation, intensity, by reducing the number of false alarms based on the implementation of the detector procedures adaptive changes in the level of the detection threshold based on the simultaneous estimation of the average signal power and the average variance of the noise in the channel detection, and improving its performance through the use of digital signal processing.

The technical result of the invention is to reduce the number of false alarms (false IRI) at the output of detector digital panoramic receiver in the process of analyzing the REO based on the simultaneous estimation of the average signal power and the average variance of the noise in the channel detection and improve performance of the detector based on the use of digital signal processing.

The technical result is achieved due to the fact that it is known to the detector, taken as a prototype, containing the main channel detection, comprising first and second quadrature phase detectors, KSG, the first and second integrators, the first and second quadratic detectors, adder and a threshold device which United the first inputs of the first and second quadrature phase detectors are input devices, W which are the inputs of the first and second quadrature phase detectors are connected, respectively, to the outputs of the quadrature components (sine and cosine) frequency reference DRG, the outputs of the first and second quadrature phase detectors are connected to the inputs of the first and second integrators, respectively, the outputs of the first and second integrators are connected, respectively, to the inputs of the first and second quadratic detectors whose outputs are connected to first and second inputs of the adder, respectively, the output of which is connected with United first input of the subtraction unit and the threshold device, respectively, an additional channel detection, consisting of series-connected third quadratic detector and the third integrator, the input channel connected to the input device and the output is connected to the second input of the subtraction, the output of which is connected to the second input of the threshold device, in block subtraction is the average of the noise variance, which is the threshold level of the threshold device on the second input, wherein in the combined inputs of the primary and secondary channels of detection, which are input devices, receives the binary code level additive mixture of signal and noise in the form of digital samples, serially connected register storing set values of probability of detection the Oia signal P 0and computing unit lower H1level detection threshold, connected in series register storing the confidence factor Kdand computing unit upper H2level detection threshold, a switch, an additional threshold device, an indicator, and programmable interface, the input of which is connected to the control bus panoramic radio; the first and second outputs programmable interface connected to the storage register set values of the detection probability signal P0and the register storing the confidence factor Kdaccordingly, the third output programmable interface connected to the indicator, the first input switch connected to the output of the threshold device, second and third inputs of the switch are connected, respectively, to the outputs of the blocks calculate the lower H1and the top H2levels of detection threshold, the output of the switch is connected to the second input of the threshold device, the first input of which is connected to the output of the third integrator, the output of the additional threshold device is the output of the detector.

The invention consists in the following. In order to reduce the time of analysis REO (electromagnetic environment (EME)for a given accuracy of its analysis when implementing Optima is inogo method of processing additive mixture signal with random amplitude and the initial phase in noise with unknown, at the time of observation, the intensity of the proposed adaptive discrete level adjustment of the detection threshold, the upper level which automatically connects on the comparison of the average power signaland noisein the primary and secondary channels of detection. Detection in unknown noise intensity narrow-band radio signals with unknown amplitude and the initial phase is the energy detector of the main channel.

The physical basis for the reduction of analysis time REO (EMO) in unknown workload of the analyzed frequency band IRI is adaptive switching threshold level of detection of the condition of H1in H2by comparing the measured values of the average power of the noiseand the average signal powerin the discovery channel (item permissions) for his analysis. Average powernoise n(t) is monitored at the output of the band pass filter (channel detection element permits) linear tract of panoramic radio receiver (additional channel) by the known law (see, for example, Kulikov, H. Methods of measurement of random processes. M: Nauka, 1985). Measurement of average powernoise in the analog detection (the resolution) is possible due to the existing differences in the levels of the variance of the noise component at the output of the correlation device (main channel) and the autocorrelation of the device (additional channel) [see, for example, Denisenko A.N. Signals. Theoretical radio engineering. The Handbook. M: Hot line. Telecom, 2005], which is about 3 dB, which allows the evaluation of the average power of the noise component at the output of the main channel detection and channel algorithmically (subtraction) to determine the average powernoise, respectively, then the average powersignal, and then the measured value is used to distinguish between signal and noise at the outputs of both channels of detection, and the results compare them to implement adaptive switching threshold levels of detection (H1or H2). It is the use of information about the average power of the noisein accordance with the proposed actions on the signal and the conditions of their implementation, can reduce the number of false alarms with unknown intensity noise. This provides the opportunity to conduct analysis REO (EMO) in a given frequency band with minimal time cost, quickly looking through the parts of the swath, free of signal components is selected (this is the upper level of the detection threshold H2corresponding to the required accuracy of the analysis REO (EMO)), and automatically reducing the level of threshold detection the Oia to the lower level of H 1corresponding to the desired probability of detection and sensitivity of the panoramic receiver in the permission entry when the next signal component in the channel detection. Thereby, the required reliability analysis REO (EMO) at a given frequency and a given probability of detection, discovery channel (item permissions) [see, for example, Bubenikova A.A., Vladimirov V.I. impact Evaluation of detection algorithms panoramic receivers on the authenticity of the autopsy (control) electronic environment. Telecommunications, No. 10, 2006, pp.2-7]. Comparative analysis with the prototype shows that the claimed device contains additional elements for the formation and adaptive switching threshold level of detection and digital signal processing, which corresponds to the criteria of the invention of "novelty."

Comparative analysis with other technical solutions showed that there are no technical solutions with similar features distinguishing the claimed technical solution to the prototype that allows to make a conclusion about the technical solutions according to the criteria of the invention "significant differences".

Figure 1 shows the structural diagram of the device.

Figure 2 presents a structural diagram of the version block subtraction.

Adaptive TLD is a threshold detector signals digital panoramic receiver module type contains the main channel detection, including the first 1.1 and 1.2 second quadrature phase detectors, DRG 2, 3.1 and 3.2 second integrators, the first 4.1 and 4.2 second quadratic detectors, the adder 5, the subtraction unit 6 and a threshold device 7.1, an additional channel that includes the third 4.3 quadratic detector and 3.3 third integrator, the register 10.1 storing set values of the detection probability signal P0the register 10.2 storage coefficient of reliability of Kdblock 9.1 calculate the lower H1and block 9.2 the calculation of the upper H2the threshold levels of detection, the switch 8, an additional threshold device 7.2, programmable interface 11 and the led 12.

The subtraction unit 6 includes a multiplier 13, the adder 14, the register 15 storing multiplier "-1".

Digital cosine-sine generator can be performed according to the scheme given in (see, for example, in the book. Receiving device: Textbook for universities / edited by N.N. Fomin. - 3rd edition, the stereotype. - M.: Hot line. Telecom, 2007, RIS, s).

Programmable interface can be performed, for example, on the controller keypad and display type KRW (see ibid at s-295, RIS).

Integrators are made on the basis of the digital lowpass filter (CFNC).

The primary and secondary channels, threshold devices, units calculating levels of detection threshold (H1and the and H 2) can be performed on a programmable logic integrated circuits (e.g., FPGA series FPGA Cyclone III ALTERA).

Adaptive two detector signals digital panoramic receiver module type operates as follows.

Panoramic receiver is characterized by a threshold value of the ratio of the capacity of the signal/noise ratio at the input of the channel detection (item resolution bandwidth ∆ F0)that for detectors with constant false alarm level of PLTdetermines the desired detection probability P0(q0) signal in the permission entry.

To corresponding inputs of the first and second quadrature phase detectors 1.1 and 1.2 at the same time receives the binary code level (digital counts) xi=si+niadditive mixture signal (si) and noise (interference) (ni), where i is the number of the digital readout, which is multiplication with a binary code level (digital counts) quadrature components of the reference signal coming from DRG 2 to corresponding inputs of a quadrature phase detector 1.1 (sine) and 1.2 (cosine), respectively. Next multiplied signals y1i=(si+nis*iand y2i=(si+nis*i+niwhere n=1, 2, 3, ...L - the number of samples corresponding to the belts delay (phase shift), arrives at the inputs of the integrators (CFNC) 3.1 and 3.2, respectively, where the signal accumulation during analysis, where C is the speed adjustment panoramic receiver, NPEthe number of concurrently analyzed elements resolution frequency. From the outputs of the integrators 3.1 and 3.2 quadrature signalsandarrive at the corresponding inputs of a quadratic detectors 4.1 and 4.2, where the selection of the squared envelope signal (si), the value of which is fed to the corresponding inputs of the adder 5. From the output of the adder 5 signalfed to corresponding inputs of a threshold device 7.1 and subtraction unit 6.

Binary code (digital counts) xi=si+niadditive mixture signal (si) and noise (interference) (ni) is also a quadratic detector 4.3, where is the separation of the envelope of the additive mixture of signal and noise, the value of which is then fed to the input of the integrator 3.3, in which the accumulation of additive mixture of signal and noise during analysis. Next, the combined signal from the output of the integrator 3.3 is supplied to the corresponding inputs of the subtraction unit 6 and an additional threshold of the new device 7.2.

From the output of the integrator 3.3 average power of the additive mixture of signal and noise (interference)supplied to the first input of the subtraction unit 6, the second input is from the output of the adder 5 receives the average signal power. In block subtraction is the average of the noise variancethat is the threshold level of the threshold device 7.1 on the second entry.

In the presence of the input signal of the quadrature channel detection automatically, on the comparison of the average power signaland noise(if)at the output of the threshold device 7.1, sets the level of the detection threshold H1determined by the false alarm probability PLTcorresponding to the threshold signal-to-noisethat the probability of a detection signal corresponds to the desired value of.

Setting the upper threshold level H2subjectwhich corresponds to a false alarm probability PLTcorresponding to the desired value of reliability analysis REO (EMO) using the estimated values of the lower bounds is of efficient congestion controlled bandwidth.

As a measure for the effectiveness of the proposed device will choose the average time of the review of the analyzed frequency band.

1. In previously known when the detector is parallel-sequential review analyzes the span:

where NEis the number of elements resolution frequency;

ΔFVET=NPEΔF0- band simultaneous panoramic receiver;

NPE- the number of concurrently analyzed elements resolution frequency;

ΔF0- the size of a single element resolution frequency determined by the bandwidth of the intermediate frequency filter.

The frequency band ∆ FPanalyzed with an average review. When this is viewed NEof cells:

P0(q0NE- "signal" (the threshold is exceeded by the signal IRI);

PLTNE- "noise" (noise threshold is exceeded),

NE-NEP0(q0)-NEPLT- "empty" (the threshold was not exceeded, neither signal nor noise),

where PLT- the probability of false alarm.

Then the average time of surveycan be written in the form:

where Ta- time analysis of one element resolution frequency;

TIDthe time, strachen the e on the identification signal component from the noise, determined by the skill of the operator.

After transformation, we obtain the expression (2) in the form:

For example, for fixed parameters NE=2800, ∆ F0=25 kHz and NPE=3 band review is ∆ FP=70 MHz, while the average duration of the reviewdetermined by the time of identification of TIDand the number of cells with noise emissions that exceeded the detection threshold NEPLT. Then for the required detection probability P0(q0)=0.8 and the ratio signal/noisefixed probability of false alarm by the criterion of Neyman-Pearson will be PLT>0.3. While the average duration of the review will behours, with an average time of identification of TID=5 seconds and the time of analysis one element resolution frequency Tand=120·10-6seconds.

2. In the proposed device the average time of surveynot depend on the time of identification of the operator TIDas this process is automated, and is determined by the formula:

where PLTthe probability of false alarm is defined by the second threshold based on the required accuracy of the analysis REO (EMO).

After simple transformations, we obtain irginia (4) in the following form:

As can be seen from expression (5), the gain in reduction of time for analysis REO (EMO) is determined by the gain in reducing the probability of false alarm.

For example, for a false alarm probability PLT=10-6defining the upper level of the detection threshold and the respective set of reliability analysis EMO Kd=0.95, the average time of the review will comprise units of seconds.

Thus, the gain in the reduction of analysis time REO (EMO) of the proposed adaptive two-detector signals digital panoramic receiver is more than 2 orders of magnitude, compared with the known detector.

The effectiveness of the invention is expressed not only in providing in the analysis of REO (EMO) the required probability of detection by the criterion of Neyman-Pearson in each element permission (by setting a threshold H1(PLT,) and the hypothesis of the presence of a signal), as well as reduce the time of analysis REO (EMO) in the analyzed frequency band (due to the installation when the hypothesis of no signal upper threshold level H2(P2K) at a given reliability analysis REO (EMO) for a priori unknown load bandwidth Iran.

Adaptive two detector signals digital panoramic receiver module type, the content is a first main channel detection, including first and second quadrature phase detectors, cosine-sine generator (KSG), the first and second integrators, the first and second quadratic detectors, adder and a threshold device which United the first inputs of the first and second quadrature phase detectors are input devices, the second inputs of the first and second quadrature phase detectors are connected, respectively, to the outputs of the quadrature components (sine and cosine) frequency reference DRG, the outputs of the first and second quadrature phase detectors are connected to the inputs of the first and second integrators, respectively, the outputs of the first and second integrators are connected, respectively, to the inputs the first and second quadratic detectors whose outputs are connected to first and second inputs of the adder, respectively, the output of which is connected with United first input block subtraction and threshold devices, respectively, an additional channel detection, consisting of series-connected third quadratic detector and the third integrator, the input channel connected to the input device, and the output is connected to the second input of the subtraction, the output of which is connected to the second input of the threshold device, in block subtraction is the estimation of the average variance of W is mA which is the threshold level of the threshold device on the second input, wherein in the combined inputs of the primary and secondary channels of detection, which are input devices, receives the binary code level additive mixture of signal and noise in the form of digital samples, and entered serially connected register storing the set values of the detection probability signal P0and the computing unit lower H1level detection threshold, connected in series register storing the confidence factor Kdand the computing unit upper H2level detection threshold, a switch, an additional threshold device, an indicator, and programmable interface, the input of which is connected to the control bus panoramic radio; the first and second outputs programmable interface connected to the storage register set values of the detection probability signal P0and the register storing the confidence factor Kdaccordingly, the third output programmable interface connected to the indicator, the first input switch connected to the output of the threshold device, second and third inputs of the switch are connected, respectively, to the outputs of the blocks calculate the lower H1and the top H2threshold levels of detection, in the course of the switch is connected to the second input of the threshold device, the first input of which is connected to the output of the third integrator, the output of the additional threshold device is the output of the detector.



 

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The invention relates to the field of radar technology, in particular to the field of electronic indicator device overview radar (radar)

FIELD: radio engineering, communication.

SUBSTANCE: detector comprises a main detection channel, an additional detection channel and a subtractor unit, as well as a register for storing given signal detection probability values, a unit for calculating a lower detection threshold level, a register for storing a confidence coefficient, a unit for calculating an upper detection threshold level, a switch, an additional threshold device which is the output of the device, a display and a programmable interface, wherein the main detection channel includes two quadrature phase detectors, a cosine-sine generator, two integrators, two square-law detectors, an adder and a threshold device; the additional detection channel includes a third square-law detector and a third integrator. The listed devices are connected to each other in a certain manner and a binary level of an additive mixture of the signal and noise in form of digital readings is transmitted to the combined inputs of the main and additional detection channels, which are the input of the device.

EFFECT: fewer false alarms at the output of a digital panoramic detector.

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