TW202507326A - Laser jammer and operation method thereof - Google Patents

Abstract

A laser jammer and an operating method thereof. The laser jammer according to the present invention may include: a laser signal receiving unit that receives a received signal including a monitor laser signal and a noise signal transmitted by a laser-based speed monitor; a laser signal transmitting unit that transmits a jamming signal for the monitor laser signal; and a control unit that changes a noise reference potential for removing the noise signal from the received signal to detect the monitor laser signal from the received signal, and generates a jamming signal corresponding to the detected monitor laser signal.

Description

Laser jammer and method of operating the same

The present invention relates to a laser interferometer and an operating method thereof.

Recently, various speed guns using different microwaves or lasers and safety warning transmitters that warn of various dangerous situations on the road have begun to be used. In other words, speed guns that detect vehicle speed to prevent vehicles from speeding include guns that use X-band, Ku-band, K-band, and lasers. In addition, safety warning systems that inform vehicles of road information for safe operation send information such as railroad crossings and emergency vehicles under construction. The safety warning system will encode and send 64 types of information such as foggy areas, construction, school areas, and speed reduction.

For example, a laser jammer is a system that senses laser or ultra-high frequency emitted from a speed gun for speed measurement and informs the driver through voice, text, signal tone, etc. Some developed countries have developed a variety of radar detectors using microwaves or lasers for safe operation of vehicles.

The laser jammer consists of a transmitter that sends a strong laser pulse (interference signal) and a receiver that detects the laser pulse signal of the laser radar (LIDAR).

The laser receiver is a device that receives the laser pulse signal emitted by the laser radar. In order to sense the weak laser pulse signal, it is necessary to accurately grasp the noise flowing into the receiver.

That is, the size and frequency of the noise generated by the laser jammer changes all the time due to the combination of the noise generated in the internal circuit and the noise generated in the external environment. Therefore, in order to receive accurate laser pulse signals and generate corresponding interference signals, it is extremely important to accurately grasp the noise size in a short time.

Technical issues

In order to solve the above-mentioned problems of the prior art, the present invention proposes a laser jammer capable of adaptively removing noise and an operating method thereof. Technical Solution

In order to achieve the above-mentioned object, according to an embodiment of the present invention, a laser jammer is provided, comprising: a laser signal receiving unit, which receives a received signal including a monitor laser signal and a noise signal transmitted by a laser-based speed monitor; a laser signal transmitting unit, which transmits a jamming signal for the monitor laser signal; and a control unit, which changes a noise reference potential for removing the noise signal from the received signal to detect the monitor laser signal from the received signal, and generates a jamming signal corresponding to the detected monitor laser signal.

The laser signal receiving section may include: a noise comparator that compares the voltage of the received signal with the noise reference potential determined by the control section to output a pulse equivalent to the difference; a noise density correction section that converts the pulse output by the noise comparator into a voltage potential corresponding to the noise density and outputs it; and a signal comparator that detects the monitor laser signal from which the noise is removed by comparing and superimposing a first voltage potential output from the noise density correction section and a second voltage potential determined by the control section to determine a signal reference potential and the voltage of the received signal.

The laser signal receiving section includes: a conversion section, which converts the received signal into a photocurrent through a first photodiode; an amplifier, which amplifies the photocurrent; and a filter section, which selectively monitors the laser signal in the amplified photocurrent to output a filtered signal according to the signal of the control section and the noise band potential, wherein the signal passing through the filter section also contains a noise signal, and the noise comparator outputs a pulse corresponding to the comparison result by comparing the voltage corresponding to the filtered signal and the noise reference potential, and the signal comparator can output a pulse corresponding to the comparison result by comparing the voltage corresponding to the filtered signal and the signal reference potential.

The conversion unit includes: a first resistor, which is connected between a DC voltage source (V _dc ) and an anode of a first photodiode; a second resistor, which is connected between an anode of the first photodiode and ground; and a third resistor, which is connected between the DC voltage source and a cathode of the first photodiode. The third resistor may have a value several times greater than that of the first resistor and the second resistor.

The monitor laser signal is an infrared laser signal, and the conversion unit includes a plurality of photodiodes connected in parallel between a third resistor and ground. The voltage at both ends of the third resistor is suppressed by the distributed voltage of the first resistor and the second resistor, thereby preventing the voltage of the first photodiode from decreasing.

The amplifier may include a field effect transistor (FET), a fourth resistor connected to a source terminal of the field effect transistor, and a first capacitor.

The filter section includes an operational amplifier (OPAMP), a plurality of capacitors, a fifth resistor (R5), a sixth resistor (R6) and a first diode (D2), and can output a filter signal of a monitor laser signal including a preset frequency band by comparing the voltage of a signal input from the amplifier section with the signal and the noise frequency band potential.

The noise density correction unit includes a second diode (D3), a second capacitor connected to the cathode of the second diode (D3), a seventh resistor connected to the second capacitor, and a third capacitor connected to the seventh resistor. The noise density correction unit can output a pulse output by the noise comparator through the second diode (D3) and the second capacitor, then through the seventh resistor and accumulate in the third capacitor a first voltage potential corresponding to the pulse.

The control unit can periodically count the pulses output by the noise comparator and signal comparator, respectively, and change the noise reference potential and signal reference potential by calculating the relevant values stored in the internal database and outputting them.

According to another aspect of the present invention, a method for operating a laser jammer is provided, comprising: a step in which a laser signal receiving unit receives a received signal including a monitor laser signal and a noise signal transmitted by a laser-based speed monitor; a step in which a laser signal transmitting unit transmits a jamming signal for the monitor laser signal; and a step in which a control unit detects the monitor laser signal from the received signal by changing a noise reference potential for removing the noise signal from the received signal, and generates a jamming signal corresponding to the detected monitor laser signal. Effect of the invention

According to the present invention, the reference noise potential can be adaptively changed according to the noise contained in the received signal to improve the detection efficiency of the monitor laser signal.

In order to better understand the above and other aspects of the present invention, the following embodiments are specifically described in detail with reference to the accompanying drawings:

The present invention can be subjected to various modifications and can have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the specification. However, it should be understood that the purpose is not to limit the present invention to specific embodiments, but to include all modifications, equivalents and even substitutes included in the concept and technical scope of the present invention.

The terms used in this specification are only used to illustrate specific embodiments and are not intended to limit the present invention. Singular descriptions include plural descriptions unless otherwise expressly indicated in the text. Terms such as "including" or "having" in this specification are intended to specify the features, numbers, steps, actions, constituent elements, components or combinations thereof recorded in the specification, and do not exclude one or more other features, numbers, steps, actions, constituent elements, components or combinations thereof in advance.

Furthermore, the constituent elements of the embodiments described in the various figures are not applicable only to the embodiments, but can be implemented as included in other embodiments within the scope of the technical idea of the present invention, and even if additional descriptions are omitted, it is natural that multiple embodiments can be implemented as a comprehensive embodiment.

Furthermore, in describing the drawings, regardless of the drawing numbers, the same or related drawing marks are assigned to the same components, and repeated descriptions thereof are omitted. When describing the present invention, if it is judged that a specific description of the relevant known technology may unnecessarily confuse the subject matter of the present invention, its detailed description is omitted.

FIG. 1 is a schematic diagram schematically illustrating the structure of a laser interferometer according to an embodiment of the present invention.

1 , a laser interferometer 10 according to an embodiment of the present invention includes a laser signal receiving unit 11, a laser signal transmitting unit 12, and a control unit 13.

The laser signal receiving unit 11 receives a monitor laser signal transmitted from the speed monitor 20 using laser.

For example, the laser-based speed monitor 20 may be a speed gun that uses laser to measure the speed of a moving object, and the monitor laser signal may be an infrared laser signal.

The laser signal transmitting unit 12 transmits a jamming signal for the received monitor laser signal according to the control of the control unit 13 .

The control unit 13 controls the overall operation of the laser interferometer 10. For example, the control unit 13 may be configured to include a memory storing a program for executing the operation method of the laser interferometer according to the embodiment of the present invention and a microprocessor operating according to the program stored in the memory.

In particular, the control unit 13 receives a received signal including a monitor laser signal and a noise signal transmitted by the laser-based speed monitor 20 through the laser signal receiving unit 11, adaptively removes the noise contained in the received signal to detect the monitor laser signal, generates an interference signal corresponding thereto, and transmits it through the laser signal transmitting unit 12.

More specifically, the laser signal receiving unit 11 according to the present embodiment includes a plurality of comparators, each of which compares the voltage of the monitor laser signal containing noise with a noise reference potential that changes according to the noise.

When the noise increases, the number of pulses output by the comparator increases, so the noise reference level also increases. Conversely, when the noise decreases, the number of pulses output by the comparator decreases, and the noise reference level also decreases.

According to this embodiment, the noise contained in the monitor laser signal is adaptively removed by changing the noise reference potential of the output of each comparator.

According to this embodiment, noise density is utilized for adaptive noise removal.

FIG. 2 is a diagram schematically showing general noise characteristics.

As shown in Figure 2, the general noise characteristic has a Gaussian probability distribution, so the density (number) of noise is high at the center axis of the noise, and the density (number) of noise decreases more significantly as it moves away from the center axis.

The probability distribution of this noise remains constant regardless of the size or type of the noise. Therefore, if the noise reference potential is set by comparing the noise density on the central axis with the noise density at a certain interval, an optimized noise reference potential corresponding to each instantaneous noise change can be obtained.

According to the laser jammer 10 of the present embodiment, if the signal is sensed by comparing a certain difference with the above-mentioned noise reference potential, the monitor laser signal can be detected with a high receiving sensitivity using a minimum signal-to-noise ratio (S/N ratio).

FIG. 3 is a block diagram of a laser signal receiving unit according to the present embodiment, and FIG. 4 is a schematic diagram showing a circuit diagram of the laser signal receiving unit according to the present embodiment.

The following explanation focuses on the monitor laser signal being an infrared laser signal.

3 to 4 , the laser signal receiving unit 11 according to the present embodiment may include a transforming unit 300 , an amplifying unit 302 , a filtering unit 304 , a noise comparator 306 , a noise density correction unit 308 and a signal comparator 310 .

The conversion unit 300 receives a received signal including a monitor laser signal and a noise signal transmitted by a laser-based speed monitor, and converts the received signal into a photocurrent.

As shown in FIG. 4 , the conversion unit 300 converts the received signal into a photocurrent through the first photodiode D1.

Furthermore, the conversion unit 300 may include a first resistor R1 connected between the DC voltage source V _dc and the anode of the first photodiode D1, a second resistor R2 connected between the anode of the first photodiode D1 and ground, and a third resistor R3 connected between the DC voltage source V _dc and the cathode of the first photodiode D1.

The third resistor R3 has a value several times greater than that of the first resistor R1 and the second resistor R2, thereby improving the current-voltage efficiency of the first photodiode D1.

According to the present embodiment, the monitor laser signal may be an infrared laser signal, and the conversion unit 300 may include a plurality of photodiodes connected in parallel between the third resistor R3 and the ground.

According to the present embodiment, when the noise signal generated by the external light is higher than the preset potential, that is, when strong external light flows into the first photodiode D1, the voltage on the first photodiode D1 decreases and the voltage on the third resistor R3 increases. Here, the voltage at both ends of the third resistor R3 is suppressed by the voltage shared by the first resistor R1 and the second resistor R2, so as described above, it is possible to prevent the voltage of the first photodiode D1 from being excessively reduced (saturated) and causing a decrease in the sensing function.

That is, when the external light is strong, current is further supplied to the first photodiode D1 through the first resistor R1 so that photocurrent conversion is performed normally.

The amplifier 302 amplifies the photocurrent.

The amplifier 302 according to this embodiment may include a field effect transistor (FET), a fourth resistor R4 connected to a source terminal of the field effect transistor FET, and a first capacitor C1.

A fourth resistor R4 connected to the source terminal of the field effect transistor FET and a first capacitor C1 form a self-bias, which has band selectivity and selectively increases the amplification of a band including a monitor laser signal.

The filter section 304 allows the monitor laser signal in the amplified photocurrent to pass therethrough and output a filtered signal according to the control of the control section 13.

More specifically, by comparing the voltage of the signal input from the amplifier 302 and the control voltage input from the control unit 13, a filter signal including the monitor laser signal of a preset frequency band is output.

4 , the filter unit 304 includes an operational amplifier (OPAMP), a plurality of capacitors, a fifth resistor R5, a sixth resistor R6 and a diode D2. The operational amplifier inputs a voltage V2 as a filter signal and a control voltage V3 of the control unit 13.

The capacitance of the filter 304 is changed by V3, the passband of the filter 304 is determined by the value of the negative feedback resistor R6, and the time constant of the fifth resistor R5 and the diode D2 is determined by the frequency response of the non-inverting terminal, so the output of the operational amplifier undergoes a change in amplification associated with the frequency band adjustment of the control voltage V3.

According to the present embodiment, the control voltage V3 is determined by the control unit 13 by comparing the output of the noise comparator 306 and the output of the signal comparator 310 described below with the information stored in the internal database.

The signal output from the filter unit 304 also contains noise signals (high-frequency noise).

The noise comparator 306 removes high-frequency noise included in the filtered signal, and outputs a pulse corresponding to the difference by comparing the voltage of the received signal with the noise reference potential determined by the control unit 13.

The higher the noise reference potential is, the fewer the number of pulses output by the noise comparator 306 is; and the lower the noise reference potential is, the more the number of pulses output by the noise comparator 306 is.

The noise density correction unit 308 converts the pulse output from the noise comparator 306 into a first voltage potential corresponding to the noise density and outputs it.

According to the present embodiment, the noise density correction unit 308 outputs a first voltage potential corresponding to the pulse output by the noise comparator 306 without passing through the control unit 13.

As shown in FIG. 4 , the noise density correction unit 308 according to the present embodiment includes a diode D3, a second capacitor C2 connected to the cathode of the diode D3, a seventh resistor R7 connected to the second capacitor C2, and a third capacitor C3 connected to the seventh resistor R7.

According to this embodiment, the pulse output by the noise comparator 306 passes through the diode D3 and the second capacitor C2, then passes through the seventh resistor R7 and is accumulated in the third capacitor C3 to output a first voltage potential corresponding to the pulse, so that the signal reference potential input to the signal comparator 310 is output quickly.

The noise density correction unit 308 according to this embodiment plays a role in compensating for the problem of control output delay in the operation process of the control unit 13.

The signal comparator 310 detects the monitor laser signal from which noise is removed by comparing the first voltage potential output from the noise density correction unit 308 with the voltage of the received signal, more specifically, the voltage of the filtered signal.

The first voltage potential output by the noise density correction unit 308 and the second voltage potential determined by the control unit 13 are superimposed to determine the signal reference potential input to the signal comparator 310.

According to the present embodiment, the control unit 13 periodically counts the output pulses of the noise comparator 306 and the signal comparator 310, calculates the correlation values stored in the internal database, and determines the noise reference potential and the signal reference potential input to the noise comparator 306 and the signal comparator 310.

The control unit 13 receives signal pulses from the noise density correction unit 308 and the signal comparator 310, respectively, and outputs voltage signals such as the voltage for the filter unit 304, the reference noise potential to the noise comparator 306 and the signal comparator 310, and the signal reference potential.

The voltage output by the control unit 13 is output through a digital to analog converter (DAC) inside or outside the control unit 13 .

Refer to Figure 4. The noise pulse and compensation interface is an input and output terminal that performs the input of the compensation for noise pulse counting and the output of the signal potential control of large noise inflow.

An internal database stores the relevant values of the noise reference level and the signal reference level for quickly determining them in a variety of environments with minimal loss of receiver sensitivity.

For example, the correlation value may be a scaling constant from 0.1 to 100.

The relevant values can be expressed as follows: In the following, Pn is a conversion constant, which can be defined as the pulse increase or decrease number.

Noise level control (the noise reference level to be output) = Noise level control (the current noise reference level) ± (Noise level (the increase or decrease of the output pulse of the noise comparator) * P1)

Signal level control (the signal reference level to be output) = (Signal level control (the current signal reference level) ± (Signal level (the increase or decrease of the output pulse of the signal comparator) * P2))

Signal & Noise Band width control (the signal and noise band level to be output) = (Noise level control (the current noise reference level) * P3) ± (Signal level control (the current signal reference level) * P4)

According to this embodiment, the noise reference potential is set to an initial value according to a general noise potential, and the process of the noise reference potential rising according to the size of the noise and then falling to the initial potential or the process of the noise reference potential falling and then rising to the initial potential is repeatedly performed.

According to the present embodiment, when the noise increases, the voltage signal higher than the initial noise reference potential increases, and the number of output pulses of the noise comparator 306 increases. Therefore, the control unit 13 outputs a high reference noise potential to the noise comparator 306 and the signal comparator 310 according to the correlation value, and the signal comparator 310 extracts the monitor laser signal from the received signal according to the difference of the increased voltage potential.

As described above, when the noise reference potential increases, the number of output pulses of the noise comparator 306 decreases, and the number of output pulses of the noise comparator 306 always remains constant.

In addition, when the noise in the received signal is reduced, the signal higher than the initial noise reference level is reduced, and the number of output pulses of the noise comparator 306 is reduced.

Therefore, the control unit 13 outputs a low reference noise potential to the noise comparator 306 and the signal comparator 310 according to the correlation value, and the signal comparator 310 extracts the monitor laser signal from the received signal according to the difference in the reduced voltage potential.

As described above, when the noise reference potential decreases, the number of output pulses of the noise comparator 306 increases, and the number of output pulses of the noise comparator 306 always remains constant.

The above-mentioned embodiments of the present invention are disclosed for the purpose of illustration. A person having ordinary knowledge in the art may make various modifications, changes, and additions within the concept and scope of the present invention. Such modifications, changes, and additions should be deemed to belong to the scope of the attached claims.

In summary, although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. A person having ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope defined in the attached patent application.

10: Laser jammer 11: Laser signal receiving unit 12: Laser signal transmitting unit 13: Control unit 20: Laser-based speed monitor 300: Conversion unit 302: Amplification unit 304: Filter unit 306: Noise comparator 308: Noise density correction unit 310: Signal comparator

FIG. 1 is a schematic diagram schematically illustrating the configuration of a laser jammer according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing general noise characteristics. FIG. 3 is a block diagram showing a laser signal receiving unit according to the present embodiment. FIG. 4 is a schematic diagram showing a circuit diagram of a laser signal receiving unit according to the present embodiment.

10: Laser jammer

11: Laser signal receiving unit

12: Laser signal transmission unit

13: Control Department

20: Laser-based speed monitor

Claims (10)

A laser jammer includes: a laser signal receiving unit, receiving a received signal including a monitor laser signal and a noise signal transmitted by a laser-based speed monitor; a laser signal transmitting unit, transmitting a jamming signal for the monitor laser signal; and a control unit, detecting the monitor laser signal from the received signal by changing a noise reference potential for removing the noise signal from the received signal, and generating the jamming signal corresponding to the detected monitor laser signal. A laser jammer as described in claim 1, wherein the laser signal receiving section comprises: a noise comparator, which compares the voltage of the received signal with the noise reference potential determined by the control section to output a pulse equivalent to the difference; a noise density correction section, which converts the pulse output by the noise comparator into a voltage potential corresponding to the noise density and outputs it; and a signal comparator, which detects the monitor laser signal from which the noise is removed by comparing and superimposing a first voltage potential output from the noise density correction section and a second voltage potential determined by the control section to determine a signal reference potential and the voltage of the received signal. The laser interferometer as described in claim 2, wherein the laser signal receiving section comprises: a conversion section, which converts the received signal into a photocurrent through a first photodiode; an amplifier section, which amplifies the photocurrent; and a filter section, which selectively outputs a filter signal through the monitor laser signal in the amplified photocurrent according to a signal of the control section and the noise band potential, wherein the signal passing through the filter section also contains the noise signal; wherein the noise comparator outputs a pulse corresponding to the comparison result by comparing the voltage corresponding to the filter signal with the noise reference potential; The signal comparator outputs a pulse corresponding to the comparison result by comparing the voltage corresponding to the filtered signal with the signal reference potential. A laser interferometer as described in claim 3, wherein the conversion section includes: a first resistor connected between a DC voltage source (V _dc ) and the anode of the first photodiode; a second resistor connected between the anode of the first photodiode and ground; and a third resistor connected between the DC voltage source and the cathode of the first photodiode; wherein the third resistor has a value that is several times greater than that of the first resistor and the second resistor. A laser jammer as described in claim 4, wherein: the monitor laser signal is an infrared laser signal; the conversion unit includes a plurality of photodiodes connected in parallel between the third resistor and ground; the voltage across the third resistor is suppressed by the shared voltage of the first resistor and the second resistor, thereby preventing the voltage of the first photodiode from decreasing. A laser interferometer as described in claim 3, wherein: The amplifier includes a field effect transistor (FET), a fourth resistor connected to the source terminal of the field effect transistor, and a first capacitor. A laser jammer as described in claim 3, wherein: The filter section includes an operational amplifier (OPAMP), a plurality of capacitors, a fifth resistor (R5), a sixth resistor (R6) and a first diode (D2), and outputs the filter signal of the monitor laser signal including a preset frequency band by comparing the voltage of the signal input from the amplifier section and the signal with the noise frequency band potential. A laser jammer as described in claim 6, wherein: The noise density correction section includes a second diode (D3), a second capacitor connected to the cathode of the second diode (D3), a seventh resistor connected to the second capacitor, and a third capacitor connected to the seventh resistor, The noise density correction section outputs the pulse output by the noise comparator through the second diode (D3) and the second capacitor, passes through the seventh resistor and accumulates in the third capacitor the first voltage potential corresponding to the pulse. The laser jammer as described in claim 8, wherein: The control unit periodically counts the pulses outputted by the noise comparator and the signal comparator respectively, and changes the noise reference potential and the signal reference potential by calculating the relevant values stored in the internal database and outputs them. A method for operating a laser jammer includes: a step of receiving a received signal including a monitor laser signal and a noise signal transmitted by a laser-based speed monitor by a laser signal receiving unit; a step of transmitting a jamming signal for the monitor laser signal by a laser signal transmitting unit; and a step of detecting the monitor laser signal from the received signal by a control unit by changing a noise reference potential for removing the noise signal from the received signal, and generating the jamming signal corresponding to the detected monitor laser signal.