阅读说明：本技术 一种基于原子接收机的距离测量雷达系统和方法 (Distance measurement radar system and method based on atomic receiver ) 是由 林沂 刘燚 吴逢川 王延正 武博 付云起 于 2021-03-25 设计创作，主要内容包括：本申请涉及一种基于原子接收机的距离测量雷达系统和方法。所述系统使用信号源发送雷达测距信号,使用原子接收机接收雷达测距信号经目标反射后产生的回波信号,利用目标回波信号会导致EIT谱产生AT分裂使EIT透射峰幅度降低原理,根据原子接收机在收到回波信号后其输出信号中EIT透射峰值下降处的时间参数,以及根据雷达测距信号的发射时间,根据雷达测距原理计算回波信号对应的目标的距离测量值。基于原子接收机尺寸与雷达工作波长无关、不需要下变频混频器及额外的微波本振信号通道以及电场强度测量灵敏度可逼近标准量子极限的优点,上述系统具有硬件简单、尺寸较小且测距结果准确的特点,可实现更远距离的目标探测。(The application relates to a distance measuring radar system and method based on an atomic receiver. The system uses a signal source to send radar ranging signals, uses an atomic receiver to receive echo signals generated after the radar ranging signals are reflected by a target, uses the principle that the target echo signals can cause an EIT spectrum to generate AT splitting so as to reduce the amplitude of EIT transmission peaks, calculates the distance measurement value of the target corresponding to the echo signals according to the radar ranging principle and the time parameters of the EIT transmission peak value falling part in the output signals of the atomic receiver after the atomic receiver receives the echo signals and the transmitting time of the radar ranging signals. Based on the advantages that the size of the atomic receiver is irrelevant to the working wavelength of the radar, a down-conversion frequency mixer and an additional microwave local oscillation signal channel are not needed, and the electric field intensity measurement sensitivity can approach to the standard quantum limit, the system has the characteristics of simple hardware, small size and accurate distance measurement result, and can realize target detection at longer distance.)

1. A distance measurement radar system based on an atomic receiver is characterized by comprising a pulse signal source, the atomic receiver and a signal processing module;

the pulse signal source is used for sending radar ranging signals according to preset signal emission time;

the atomic receiver is used for receiving an echo signal generated by the radar ranging signal through target reflection at preset non-signal transmitting time;

the signal processing module is used for processing an output signal after the atomic receiver receives the echo signal, acquiring a time parameter of a descending position of an EIT transmission peak value in the output signal, and acquiring a distance measurement value of the target according to the acquired time parameter and the transmitting time of the radar ranging signal.

2. The system of claim 1, further comprising a timing control module;

and the time sequence control module is used for setting the working time sequences of the pulse signal source and the atomic receiver.

3. The system of claim 2, wherein the timing control module sets the operating timing to:

the signal initial transmitting time of the pulse signal source isThe pulse width of the pulse signal is tau, the repetition period of the pulse signal is T, and the pulse width of the isolation protection pulse signal is TAnd is andthe repetition period of the isolation protection pulse signal is T;

the atomic receiver performs signal reception with a non-signal transmission time of++nT＜And (n + 1) T, where n is the number of repetition periods of the pulse signal.

4. The system according to any one of claims 1 to 3, wherein the atomic receiver comprises a detection laser, a coupling laser, a detection dichroic mirror, a coupling dichroic mirror, an atomic gas cell, and a photodetector;

the detection light emitted by the detection laser passes through the atomic gas chamber through the detection light dichroic mirror;

the coupling light emitted by the coupling laser passes through the atomic gas chamber through the coupling light dichroic mirror;

the transmitted light generated by the atom gas chamber is converted into an electric signal by the photoelectric detector, and the electric signal is an output signal of the atom receiver.

5. The system of claim 4, wherein the atomic plenum is a closed glass vessel filled with alkali metal atomic vapor.

6. The system of claim 5, wherein the alkali metal atoms are cesium atoms or rubidium atoms.

7. A method for measuring distance based on an atomic receiver, the method comprising:

sending a radar ranging signal by a pulse signal source according to preset signal transmitting time;

receiving an echo signal generated by the radar ranging signal through target reflection at preset non-signal transmitting time by an atomic receiver;

and acquiring a time parameter of a descending position of an EIT transmission peak value in an output signal of the atomic receiver after the atomic receiver receives the echo signal, and acquiring a distance measurement value of the target according to the acquired time parameter and the transmitting time of the radar ranging signal.

8. The method according to claim 7, wherein obtaining the distance measurement value of the target according to the acquired time parameter and the transmission time of the radar ranging signal comprises:

wherein the content of the first and second substances,a distance measurement representing the target, c represents the speed of light in free space,represents the time of transmission of the radar ranging signal,representing the arrival time of the echo signal as a function of the time at which the EIT transmission peak in the output signal falls.

9. The method according to claim 7 or 8, wherein the step of obtaining a time parameter of the output signal at which the EIT transmission peak falls and obtaining the range measurement of the target according to the obtained time parameter and the transmission time of the radar ranging signal comprises:

and distinguishing a plurality of targets according to the peak value descending amplitude value at the EIT transmission peak value descending position in the output signal, and obtaining the distance measurement value of each target according to the emission time of the radar ranging signal and the time parameter at the EIT transmission peak value descending position corresponding to each target.

10. A computer device comprising a memory and a processor, the memory storing a computer program, wherein the processor implements the steps of the method of any one of claims 7 to 9 when executing the computer program.

Technical Field

The present application relates to the field of radar ranging technologies, and in particular, to a distance measurement radar system and method based on an atomic receiver.

Background

The radar is one of the main means for detecting a space target, and is widely applied to the civil field and the military field, and typical radar systems comprise millimeter wave automobile anti-collision radars, liquid level meter measuring radars, synthetic aperture imaging radars and the like. The existing radar system usually adopts a receiver with a zero intermediate frequency architecture or a superheterodyne architecture, and the working principle is as follows: and collecting space microwave signals by a receiving antenna, converting the collected signals into baseband signals after passing through a down-conversion mixer, and finally performing data acquisition and processing on the baseband signals to finish target parameter estimation.

Such radar systems have the following drawbacks:

1) the antenna aperture size of a radar system receiver is limited by the Chu limit [ Chu L J. Physical limitations of omni-directional antennas [ J ]. Journal of applied physics, 1948, 19(12): 1163-.

2) The radar system usually adopts a receiver with a zero intermediate frequency architecture or a superheterodyne architecture, and the radar system must include a down-conversion mixer, an intermediate frequency filter, a microwave local oscillation source and other modules, so that the hardware complexity of the radar system is difficult to reduce.

3) The sensitivity of the radar system receiver is limited by the background thermal noise which is difficult to reduce further.

Disclosure of Invention

In view of the foregoing, there is a need to provide a distance measuring radar system and method based on atomic receiver, which can overcome the drawbacks of the existing radar system.

A distance measurement radar system based on an atom receiver comprises a pulse signal source, the atom receiver and a signal processing module.

The pulse signal source is used for sending radar ranging signals according to preset signal sending time.

The atomic receiver is used for receiving an echo signal generated by the radar ranging signal after the radar ranging signal is reflected by a target at a preset non-signal transmitting time.

The signal processing module is used for processing an output signal of the atomic receiver after the echo signal is received, acquiring a time parameter of an EIT transmission peak value descending position in the output signal, and acquiring a distance measurement value of a target according to the acquired time parameter and the transmitting time of the radar ranging signal.

In one embodiment, the system further comprises a timing control module for setting the operation timing of the pulse signal source and the atomic receiver.

In one embodiment, the working time sequence set by the time sequence control module is as follows:

the signal initial transmitting time of the pulse signal source isThe pulse width of the pulse signal is tau, the repetition period of the pulse signal is T, and the pulse width of the isolation protection pulse signal is TAnd is and>τ, the repetition period of the isolation protection pulse signal is T.

The atomic receiver performs signal reception with a non-signal transmission time of++nT＜And (n + 1) T, where n is the number of repetition periods of the pulse signal.

In one embodiment, the atomic receiver comprises a detection laser, a coupling laser, a detection light dichroic mirror, a coupling light dichroic mirror, an atomic gas cell and a photoelectric detector. And the detection light emitted by the detection laser passes through the atomic gas chamber through the detection light dichroic mirror. The coupling light emitted by the coupling laser passes through the atomic gas chamber through the coupling light dichroic mirror. The transmitted light generated by the atom gas cell is converted into an electrical signal by the photodetector, and the electrical signal is an output signal of the atom receiver.

In one embodiment, the atomic gas cell is a closed glass vessel filled with alkali metal atom vapor.

In one embodiment, the alkali metal atoms are cesium atoms or rubidium atoms.

A distance measurement method based on an atomic receiver comprises the following steps:

and sending the radar ranging signal by the pulse signal source according to the preset signal transmitting time.

And the atomic receiver receives an echo signal generated by the radar ranging signal after the radar ranging signal is reflected by the target at a preset non-signal transmitting time.

And acquiring a time parameter of the EIT transmission peak value falling position in the output signal, and acquiring a distance measurement value of the target according to the acquired time parameter and the transmitting time of the radar ranging signal.

In one embodiment, the method for obtaining the distance measurement value of the target according to the obtained time parameter and the transmission time of the radar ranging signal includes:

wherein the content of the first and second substances,a distance measurement representing the target, c represents the speed of light in free space,represents the time of transmission of the radar ranging signal,representing the arrival time of the echo signal as a function of the time at which the EIT transmission peak in the output signal falls.

In one embodiment, the step of obtaining a time parameter of a drop of an EIT transmission peak in an output signal and obtaining a distance measurement value of a target according to the obtained time parameter and the transmission time of a radar ranging signal includes:

and distinguishing a plurality of targets according to the peak value descending amplitude value at the EIT transmission peak value descending position in the output signal, and obtaining the distance measurement value of each target according to the emission time of the radar ranging signal and the time parameter at the EIT transmission peak value descending position corresponding to each target.

A computer device comprising a memory and a processor, the memory storing a computer program, the processor implementing the following steps when executing the computer program:

and sending the radar ranging signal by the pulse signal source according to the preset signal transmitting time.

And the atomic receiver receives an echo signal generated by the radar ranging signal after the radar ranging signal is reflected by the target at a preset non-signal transmitting time.

And acquiring a time parameter of the EIT transmission peak value falling position in the output signal, and acquiring a distance measurement value of the target according to the acquired time parameter and the transmitting time of the radar ranging signal.

A computer-readable storage medium, on which a computer program is stored which, when executed by a processor, carries out the steps of:

and sending the radar ranging signal by the pulse signal source according to the preset signal transmitting time.

And the atomic receiver receives an echo signal generated by the radar ranging signal after the radar ranging signal is reflected by the target at a preset non-signal transmitting time.

And acquiring a time parameter of the EIT transmission peak value falling position in the output signal, and acquiring a distance measurement value of the target according to the acquired time parameter and the transmitting time of the radar ranging signal.

Compared with the prior art, the distance measuring radar system, the method, the computer equipment and the storage medium based on the atomic receiver can calculate the distance measuring value of the target corresponding to the echo signal according to the radar ranging principle by using the pulse signal source to send the radar ranging signal, using the atomic receiver to receive the echo signal generated after the radar ranging signal is reflected by the target, utilizing the principle that the target echo signal can cause the EIT spectrum to generate AT splitting to reduce the amplitude of the EIT transmission peak, and according to the time parameter of the descending position of the EIT transmission peak in the output signal of the atomic receiver after the atomic receiver receives the echo signal and the transmitting time of the radar ranging signal. The atomic receiver utilizes the quantum interference effect of the rydberg atoms and the microwaves to realize the reception of microwave signals, so the size of the receiver is irrelevant to the working wavelength of the radar; the atomic receiver has the capability of directly recording baseband signals in real time, and does not need a down-conversion frequency mixer and an additional microwave local oscillation signal channel, so that the hardware complexity can be reduced; in addition, the electric field intensity measurement sensitivity based on the atomic receiver can approach the standard quantum limit, so that the distance measurement radar system based on the atomic receiver also has higher receiving sensitivity. Based on the above advantages of the atomic receiver, the method and the device can reduce the size and complexity of the receiver of the ranging radar system, improve the accuracy of the ranging result of the system, and realize target detection at a longer distance under the condition that the power of the transmitted signal is unchanged.

Drawings

FIG. 1 is a schematic diagram of an apparatus of a distance measurement system based on an atomic receiver, according to an embodiment;

FIG. 2 is a diagram of a time domain pulse signal in one embodiment;

FIG. 3 is a diagram of a time domain isolation protection pulse signal in one embodiment;

FIG. 4 is a diagram illustrating non-signal transmission times for receiving signals by an atomic receiver in accordance with one embodiment;

FIG. 5 is a diagram illustrating the components of an atomic receiver in one embodiment;

FIG. 6 is a diagram of the steps of a method for distance measurement based on an atomic receiver, in one embodiment;

FIG. 7 is a graph of EIT transmission peak time domain signals in the output signal of an atomic receiver in one embodiment;

FIG. 8 is a diagram illustrating an internal structure of a computer device according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

A distance measurement radar system based on an atom receiver comprises a pulse signal source, the atom receiver and a signal processing module.

The pulse signal source is used for sending radar ranging signals according to preset signal sending time.

The atomic receiver is used for receiving an echo signal generated by the radar ranging signal after the radar ranging signal is reflected by a target at a preset non-signal transmitting time.

The signal processing module is used for processing an output signal of the atomic receiver after the echo signal is received, acquiring a time parameter of an EIT transmission peak value descending position in the output signal, and acquiring a distance measurement value of a target according to the acquired time parameter and the transmitting time of the radar ranging signal.

A rydberg atom is an atom in which one electron is in a high energy state and whose energy level transition satisfies the rydberg equation. The atom receiver is realized based on a rydberg atom, the realization principle is an Electromagnetic Induced Transparency (EIT) effect, a laser in an atom receiving antenna generates detection light and coupling light, the two beams of light and an alkaline metal atom generate nonlinear quantum interaction, and a photoelectric detector in the atom receiver can receive a transmission peak of the detection light, namely an EIT transmission peak. When the atomic receiver receives the microwave signal, the microwave signal causes the EIT transmission peak to generate AT splitting, so that the amplitude of the EIT transmission peak is reduced.

By using the principle, a radar ranging system based on an atomic receiver can be constructed in the embodiment, a microwave signal for ranging is sent by a pulse signal source, and an EIT transmission peak of the atomic receiver is monitored. When a target is present in the space and a radar ranging signal is reflected, the resulting echo signal will enter the atomic receiver and cause a reduction in the amplitude of its EIT transmission peak. Therefore, according to the time difference between the sending of the radar ranging signal and the arrival of the corresponding echo signal, the distance value between the target and the ranging system can be calculated based on the radar echo ranging principle.

The radar ranging system is constructed based on the atomic receiver, the size and the complexity of the receiver of the ranging radar system can be reduced by utilizing the advantages of the atomic receiver, the ranging result accuracy of the system is improved, and the target detection at a longer distance is realized under the condition that the power of a transmitted signal is unchanged.

In one embodiment, as shown in fig. 1, a distance measuring radar system based on an atomic receiver is provided, which includes an atomic receiver, a data acquisition module, a signal processing module, a timing control module, a pulse signal source, a power amplifier, and a transmitting antenna.

And the time sequence control module is used for setting the working time sequences of the pulse signal source and the atomic receiver.

The pulse signal source is controlled by the time sequence control module, and the initial signal transmitting time isThe pulse width of the pulse signal is τ, and the repetition period of the pulse signal is T, as shown in fig. 2; the pulse width of the isolation protection pulse signal isAnd is and>τ and the repetition period of the isolation protection pulse signal is T, as shown in fig. 3.

The power amplifier is used for amplifying the power of the pulse signal, and the amplified pulse signal is radiated to a free space through the transmitting antenna.

The atomic receiver receives under the control of the sequential control moduleEcho signal, which is received at non-signal transmission time of++nT＜And (n + 1) T, where n is the number of repetition periods of the pulse signal, as shown in FIG. 4.

The data acquisition module is used for acquiring output signals of the atomic receiver.

The signal processing module is used for processing an output signal of the atomic receiver after the echo signal is received, acquiring a time parameter of an EIT transmission peak value descending position in the output signal, and acquiring a distance measurement value of a target according to the acquired time parameter and the transmitting time of the radar ranging signal.

In one embodiment, as shown in fig. 5, the atomic receiver includes a detection laser 501, a coupling laser 502, a detection dichroic mirror 503, a coupling dichroic mirror 504, an atomic gas cell 505, and a photodetector 506. The detection light emitted by the detection laser passes through the atomic gas chamber through the detection light dichroic mirror. The coupling light emitted by the coupling laser passes through the atomic gas chamber through the coupling light dichroic mirror. The transmitted light generated by the atom gas cell is converted into an electrical signal by the photodetector, and the electrical signal is an output signal of the atom receiver.

Specifically, let the detection laser output detection light at a wavelength ofThe wavelength of the coupled light output by the coupled laser isAlkali metal atoms in the atom gas chamber are excited to a Reedberg state under the action of the two beams of laser to generate an EIT effect, and the photoelectric detector outputs an EIT spectrum signal. When no target exists in the space, the radar detection signal can not be inputLine reflection, namely when no target echo signal exists, the EIT spectrum signal output by the atomic receiver keeps stable, and the EIT transmission peak amplitude is set as. When a target with a distance R exists in the space, the target echo signal causes AT splitting of an EIT spectrum, so that the EIT transmission peak amplitude is reduced, and the EIT transmission peak amplitude is setThen there is<。

Further, the atomic gas cell is a closed glass vessel filled with vapor of alkali metal atoms, which may be cesium atoms or rubidium atoms.

In one embodiment, as shown in fig. 6, a distance measuring method based on an atomic receiver is provided, which includes the following steps:

step 602, a pulse signal source sends a radar ranging signal according to a preset signal transmission time.

And step 604, receiving an echo signal generated by the radar ranging signal after the target is reflected by the atomic receiver at a preset non-signal transmitting time.

And 606, acquiring a time parameter of the EIT transmission peak value falling position in the output signal, and obtaining a distance measurement value of the target according to the acquired time parameter and the transmitting time of the radar ranging signal.

Specifically, according to the acquired time parameter and the transmitting time of the radar ranging signal, the method for obtaining the distance measurement value of the target is as follows:

wherein the content of the first and second substances,a distance measurement representing the target, c represents the speed of light in free space,represents the time of transmission of the radar ranging signal,representing the arrival time of the echo signal as a function of the time at which the EIT transmission peak in the output signal falls.

Specifically, when the signal source is a pulsed signal source, the EIT transmission peaks in the atomic receiver output signal are shown in fig. 7. In the signal processing process, the time domain signal in fig. 7 is detected by adopting a classical pulse signal detection method to detect the signal falling edge, and the arrival time of the target echo signal is estimatedA distance measurement of the target can be obtained.

It should be understood that, although the steps in the flowchart of fig. 6 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least a portion of the steps in fig. 6 may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, and the order of performance of the sub-steps or stages is not necessarily sequential, but may be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

For specific limitations of the distance measurement method based on the atomic receiver, reference may be made to the above limitations of the distance measurement system based on the atomic receiver, and details are not repeated here. The various modules in the above-described atomic receiver-based distance measurement method may be implemented in whole or in part by software, hardware, and combinations thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as shown in fig. 8. The computer device includes a processor, a memory, a network interface, and a database connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The database of the computer device is used for storing the data of the emission time of the radar ranging signal and the EIT transmission peak value change. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a method of distance measurement based on an atomic receiver.

Those skilled in the art will appreciate that the architecture shown in fig. 8 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.

In one embodiment, there is provided a computer device comprising a memory storing a computer program and a processor implementing the following steps when the processor executes the computer program:

and sending the radar ranging signal by the pulse signal source according to the preset signal transmitting time.

And the atomic receiver receives an echo signal generated by the radar ranging signal after the radar ranging signal is reflected by the target at a preset non-signal transmitting time.

And acquiring a time parameter of the EIT transmission peak value falling position in the output signal, and acquiring a distance measurement value of the target according to the acquired time parameter and the transmitting time of the radar ranging signal.

In one embodiment, the processor, when executing the computer program, further performs the steps of:

wherein the content of the first and second substances,a distance measurement representing the target, c represents the speed of light in free space,represents the time of transmission of the radar ranging signal,representing the arrival time of the echo signal as a function of the time at which the EIT transmission peak in the output signal falls.

In one embodiment, there are multiple dips in the EIT transmission peak in the output signal. The processor, when executing the computer program, further performs the steps of: and distinguishing a plurality of targets according to the peak value descending amplitude value at the EIT transmission peak value descending position in the output signal, and obtaining the distance measurement value of each target according to the emission time of the radar ranging signal and the time parameter at the EIT transmission peak value descending position corresponding to each target.

In one embodiment, a computer-readable storage medium is provided, having a computer program stored thereon, which when executed by a processor, performs the steps of:

and sending the radar ranging signal by the pulse signal source according to the preset signal transmitting time.

And the atomic receiver receives an echo signal generated by the radar ranging signal after the radar ranging signal is reflected by the target at a preset non-signal transmitting time.

And acquiring a time parameter of the EIT transmission peak value falling position in the output signal, and acquiring a distance measurement value of the target according to the acquired time parameter and the transmitting time of the radar ranging signal.

In one embodiment, the computer program when executed by the processor further performs the steps of:

wherein the content of the first and second substances,a distance measurement representing the target, c represents the speed of light in free space,represents the time of transmission of the radar ranging signal,representing the arrival time of the echo signal as a function of the time at which the EIT transmission peak in the output signal falls.

In one embodiment, there are multiple dips in the EIT transmission peak in the output signal. The computer program when executed by the processor further realizes the steps of: and distinguishing a plurality of targets according to the peak value descending amplitude value at the EIT transmission peak value descending position in the output signal, and obtaining the distance measurement value of each target according to the emission time of the radar ranging signal and the time parameter at the EIT transmission peak value descending position corresponding to each target.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the embodiments provided herein may include non-volatile and/or volatile memory, among others. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus Direct RAM (RDRAM), direct bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.