CN114355372B - Terahertz wave ranging method, device and equipment based on time-of-flight counting - Google Patents
Terahertz wave ranging method, device and equipment based on time-of-flight counting Download PDFInfo
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Abstract
The application relates to a terahertz wave ranging method, a terahertz wave ranging device, a terahertz wave ranging computer device and a terahertz wave storage medium based on time-of-flight counting. The method comprises the following steps: radiating the collimated terahertz wave beam to a target at a specific divergence angle by utilizing a transmitting front end, and generating a terahertz echo by reflecting the target; collecting and detecting terahertz echoes by using a terahertz detector, and outputting an electric response signal; filtering and amplifying the response electric signal by using a filter and a pre-voltage amplifier; triggering constant voltage values of rising edges of the synchronous electric signal and the amplified signal respectively by using a constant ratio phase discriminator to obtain a timing starting signal and a timing ending signal; measuring the time delay of the timing start signal and the timing end signal in the semiconductor logic gate by using a time-to-digital converter to obtain a time difference value; counting and counting the time difference value in the measuring time, and calculating the target distance according to the terahertz pulse flight time. The method can improve the ranging accuracy.
Description
Technical Field
The application relates to the field of terahertz radar ranging, in particular to a terahertz wave ranging method, a terahertz wave ranging device, computer equipment and a storage medium based on time-of-flight counting.
Background
Terahertz (THz) waves refer to electromagnetic waves with frequencies between 0.1 and 10THz (wavelengths between 30 μm and 3 mm), whose frequency bands lie between microwaves and infrared light in the electromagnetic spectrum, in the transition region of micro-photonics and macro-electronics. The terahertz radar has the unique advantages of large bandwidth, high resolution, doppler sensitivity, interference resistance and the like, is an important development direction in the field of target detection and identification, and has wide application prospects in multiple fields.
In the case of ranging using terahertz pulses, since it is difficult to obtain a high power output at a high frequency band of 1THz or more by conventional electronics, terahertz pulses are generally optically generated. The distance measurement precision of the current terahertz wave flight time distance measurement method is mainly limited by factors such as terahertz wave detection and flight time measurement precision.
Disclosure of Invention
In view of the foregoing, it is necessary to provide a terahertz wave ranging method, apparatus, computer device, and storage medium based on time-of-flight counting, which can improve ranging accuracy.
A terahertz wave ranging method based on time-of-flight counting, the method comprising:
electrically modulating the QCL through a modulation power supply to continuously emit terahertz pulses, and outputting synchronous electric signals;
shaping the terahertz pulse space beam to obtain a collimated terahertz beam;
Radiating the collimated terahertz wave beam to a target at a specific divergence angle by utilizing a transmitting front end, and generating a terahertz echo by reflecting the target; the emission front end comprises an off-axis parabolic mirror and a reflecting mirror;
collecting and detecting terahertz echoes by using a terahertz detector, and outputting an electric response signal;
The electric response signal output by the terahertz detector is filtered and amplified through a filter and a front-end voltage amplifier to obtain an amplified signal;
triggering constant voltage values of rising edges of the synchronous electric signal and the amplified signal respectively by using a constant ratio phase discriminator to obtain a timing starting signal and a timing ending signal;
Measuring the time delay of the timing start signal and the timing end signal in the semiconductor logic gate by using a time-to-digital converter to obtain a time difference value;
carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, and reading the terahertz pulse flight time from the statistical distribution diagram;
and calculating the target distance according to the terahertz pulse flight time.
In one embodiment, electrically modulating the QCL by the modulating power supply continuously transmits terahertz pulses and outputs synchronous electrical signals, comprising: the QCL is powered by a modulation power supply and modulates the transmitting pulse, so that the QCL transmits terahertz pulses with specific repetition frequency and pulse width, and outputs a synchronous electric signal.
In one embodiment, the step of obtaining a specific divergence angle includes: and calculating a specific divergence angle according to the spot radius of the collimated terahertz wave beam and the focal length of the off-axis parabolic mirror in the transmitting front end.
In one embodiment, filtering and amplifying the electric response signal output by the terahertz detector through a filter and a pre-voltage amplifier to obtain an amplified signal, including:
Filtering the electric response signal output by the terahertz detector through a filter to obtain a filtered signal; the frequency range of the filter covers the frequency of the modulated power supply; amplifying the filtered signal by using a pre-voltage amplifier to obtain an amplified signal; the amplification factor g satisfies that V t＜g×Vf＜1.5Vt,Vf is pulse voltage output after filtering by a band-pass filter, and V t is trigger voltage of a constant ratio phase discriminator.
In one embodiment, calculating the target distance from the terahertz pulse time-of-flight includes: and calculating the distance according to the initial terahertz pulse flight time and the terahertz pulse flight time to obtain the distance from the target to the transmitting front end.
In one embodiment, performing distance calculation according to the initial terahertz pulse flight time and the terahertz pulse flight time to obtain a distance from a target to a transmitting front end, including:
L＝c×(t-t1)/2
Wherein L is the distance from the target to the transmitting front end, c is the light speed, t is the terahertz pulse flight time, and t 1 is the initial terahertz pulse flight time.
In one embodiment, before calculating the target distance according to the terahertz pulse flight time, the method further includes: and aligning the terahertz detector with the transmitting front end in a short distance to obtain the initial terahertz pulse flight time when the target is not placed.
A terahertz wave ranging device based on time-of-flight counting, the device comprising:
The transmission module is used for carrying out electric modulation on the QCL through the modulation power supply to continuously transmit terahertz pulses and outputting synchronous electric signals; shaping the terahertz pulse space beam to obtain a collimated terahertz beam; radiating the collimated terahertz wave beam to a target at a specific divergence angle by utilizing a transmitting front end, and generating a terahertz echo by reflecting the target; the emission front end comprises an off-axis parabolic mirror and a reflecting mirror;
the receiving module is used for collecting and detecting terahertz echoes by using the terahertz detector and outputting an electric response signal;
The filtering and amplifying module is used for filtering and amplifying the electric response signal output by the terahertz detector through the filter and the front-end voltage amplifier to obtain an amplified signal;
the signal processing module is used for triggering constant voltage values of rising edges of the synchronous electric signal and the amplified signal by utilizing the constant ratio phase discriminator to obtain a timing starting signal and a timing ending signal;
The time-of-flight counting module is used for measuring the time delay of the timing starting signal and the timing ending signal in the semiconductor logic gate by utilizing the time-to-digital converter to obtain a time difference value; carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, and obtaining the terahertz pulse flight time from the statistical distribution diagram; and calculating the target distance according to the terahertz pulse flight time.
A computer device comprising a memory storing a computer program and a processor which when executing the computer program performs the steps of:
electrically modulating the QCL through a modulation power supply to continuously emit terahertz pulses, and outputting synchronous electric signals;
shaping the terahertz pulse space beam to obtain a collimated terahertz beam;
Radiating the collimated terahertz wave beam to a target at a specific divergence angle by utilizing a transmitting front end, and generating a terahertz echo by reflecting the target; the emission front end comprises an off-axis parabolic mirror and a reflecting mirror;
collecting and detecting terahertz echoes by using a terahertz detector, and outputting an electric response signal;
The electric response signal output by the terahertz detector is filtered and amplified through a filter and a front-end voltage amplifier to obtain an amplified signal;
Triggering constant voltage values of rising edges of the synchronous electric signal and the amplified signal by using a constant ratio phase discriminator to obtain a timing starting signal and a timing ending signal;
Measuring the time delay of the timing start signal and the timing end signal in the semiconductor logic gate by using a time-to-digital converter to obtain a time difference value;
carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, and reading the terahertz pulse flight time from the statistical distribution diagram;
and calculating the target distance according to the terahertz pulse flight time.
A computer readable storage medium having stored thereon a computer program which when executed by a processor performs the steps of:
electrically modulating the QCL through a modulation power supply to continuously emit terahertz pulses, and outputting synchronous electric signals;
shaping the terahertz pulse space beam to obtain a collimated terahertz beam;
Radiating the collimated terahertz wave beam to a target at a specific divergence angle by utilizing a transmitting front end, and generating a terahertz echo by reflecting the target; the emission front end comprises an off-axis parabolic mirror and a reflecting mirror;
collecting and detecting terahertz echoes by using a terahertz detector, and outputting an electric response signal;
The electric response signal output by the terahertz detector is filtered and amplified through a filter and a front-end voltage amplifier to obtain an amplified signal;
Triggering constant voltage values of rising edges of the synchronous electric signal and the amplified signal by using a constant ratio phase discriminator to obtain a timing starting signal and a timing ending signal;
Measuring the time delay of the standard digital signal in the semiconductor logic gate by using a time-to-digital converter to obtain a time difference value;
carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, and reading the terahertz pulse flight time from the statistical distribution diagram;
and calculating the target distance according to the terahertz pulse flight time.
According to the terahertz wave ranging method, the terahertz wave ranging device, the computer equipment and the storage medium based on the time-of-flight counting, the QCL is electrically modulated by the modulating power supply to continuously emit terahertz pulses, and the synchronous electric signals are output, wherein the synchronous signals are used for determining the timing starting time of the time-of-flight; collecting and detecting terahertz echoes by using a terahertz detector, and outputting an electric response signal; filtering and amplifying the response electric signal by using a filter and a pre-voltage amplifier to obtain an amplified signal; triggering constant voltage values of rising edges of the synchronous electric signal and the amplified signal respectively by using a constant ratio phase discriminator to obtain a timing start signal and a timing stop signal; measuring the time delay of the timing start signal and the timing stop signal in the semiconductor logic gate by using a time-to-digital converter to obtain a time difference value; and carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, reading the terahertz pulse flight time from the statistical distribution diagram, and finally calculating the target distance according to the terahertz pulse flight time. According to the application, the time of flight is accumulated in a high-precision time resolution scale by counting the terahertz pulse time of flight in the time domain, so that the signal-to-noise ratio and the precision of the measured time of flight can be effectively improved, and higher ranging precision and accuracy are obtained.
Drawings
Fig. 1 is a schematic flow chart of a terahertz wave ranging method based on time-of-flight counting in one embodiment;
FIG. 2 is a schematic diagram of a terahertz wave ranging device based on time-of-flight counting in one embodiment;
FIG. 3 is a diagram of a target echo time-of-flight statistics count in another embodiment;
FIG. 4 is a block diagram of a terahertz wave ranging apparatus based on time-of-flight counting in one embodiment;
Fig. 5 is an internal structural diagram of a computer device in one embodiment.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
In one embodiment, as shown in fig. 1, there is provided a terahertz wave ranging method based on time-of-flight counting, including the steps of:
102, electrically modulating the QCL through a modulation power supply to continuously emit terahertz pulses, and outputting synchronous electric signals; shaping the terahertz pulse space beam to obtain a collimated terahertz beam; radiating the collimated terahertz wave beam to a target at a specific divergence angle by utilizing a transmitting front end, and generating a terahertz echo by reflecting the target; the emission front comprises an off-axis parabolic mirror and a reflecting mirror.
As shown in fig. 2, the repetition frequency and pulse width of the rectangular electric pulse generated by the modulation power supply 1 are set, and the quantum cascade laser 2 is electrically modulated, the quantum cascade laser 2 can output high-power terahertz waves with the frequency range of 2-5 THz, and meanwhile, the modulation power supply 1 generates a synchronous electric signal to the constant ratio phase discriminator 8 for determining the timing starting time, and the modulated terahertz quantum cascade laser 2 continuously emits the rectangular terahertz pulse. The transmitted terahertz wave enters a space beam shaping component 3, enters a transmitting front end 4 after beam shaping, utilizes the transmitting front end 4 (an off-axis parabolic mirror and a reflecting mirror) to focus and reflect the terahertz wave beam, and the reflecting mirror is placed at the focus of the off-axis parabolic mirror to radiate the terahertz wave beam to a target at a divergence angle theta. Wherein, the pulse width range of the rectangular electric pulse output by the modulation power supply 1 is 500 ns-5 ms, and the repetition frequency range is 100 Hz-100 kHz.
And 104, collecting and detecting terahertz echoes by using a terahertz detector, and outputting an electric response signal.
The terahertz detector and the transmitting front end adopt a quasi-single station mode, namely the space positions of the transmitting front end and the terahertz detector coincide, the terahertz detector 5 is a Nb 5N6 micro-bolometer and is provided with a high-resistance silicon lens, and the collected terahertz wave beam can be focused to a terahertz chip and a response signal is output through a reading circuit.
And 106, filtering and amplifying the electric response signal output by the terahertz detector through a filter and a pre-voltage amplifier to obtain an amplified signal.
The filter 6 is a band-pass filter, the center frequency of the filter is set to be the repetition frequency of a modulation power supply, noise signals can be effectively filtered, and the front voltage amplifier 7 is a low-noise amplifier and can amplify the voltage of the echo impulse response signal to be above the trigger voltage value required by the constant-ratio phase detector 8.
And step 108, triggering constant voltage values of rising edges of the synchronous electric signal and the amplified signal by using a constant ratio phase discriminator to obtain a timing start signal and a timing end signal.
The constant ratio phase discriminator is used for triggering constant ratio points of the rising edge or the falling edge of the pulse signal to obtain a timing start signal and a timing end signal. The synchronous electric signal output by the modulation power supply 1 and the signal output by the pre-voltage amplifier are respectively triggered by the constant ratio phase detectors 8 and 9 to obtain a timing start signal and a timing end signal, and the timing start signal and the timing end signal are input into the time-to-digital converter 10.
Step 110, measuring the time delay of the timing start signal and the timing end signal in the semiconductor logic gate by using a time-to-digital converter to obtain a time difference value; and carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, acquiring the terahertz pulse flight time from the statistical distribution diagram, and calculating the target distance according to the terahertz pulse flight time.
The time-to-digital converter 10 obtains a time difference value by measuring the time delay of the timing start signal and the timing end signal in the semiconductor logic gate, the time difference value is the flight time of one pulse, and the time difference value is converted into a digital signal to be transmitted to the counter 11, the counter 11 counts the flight time, and transmits the data to the computer 12, and the statistical distribution of the flight time in the time domain is displayed in the computer 12, and the statistical distribution map of the flight time of terahertz pulses is obtained by counting the flight time of a plurality of pulses.
In the terahertz wave ranging method based on the time-of-flight counting, firstly, the QCL is electrically modulated by the modulating power supply to continuously emit terahertz pulses, and a synchronous electric signal is output, wherein the synchronous signal is used for determining the timing starting time of the time-of-flight; the terahertz detector receives the echo pulse and then filters and amplifies the output electric response signal to obtain an amplified signal; triggering constant voltage values of rising edges of synchronous electric signals and amplified signals by using a constant ratio phase discriminator to obtain timing starting signals and timing ending signals, and measuring time delays of the timing starting signals and the timing ending signals in a semiconductor logic gate by using a time-to-digital converter to obtain time difference values; and carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, reading the terahertz pulse flight time from the statistical distribution diagram, and finally calculating the target distance according to the terahertz pulse flight time. According to the application, the time of flight is accumulated in a high-precision time resolution scale by counting the terahertz pulse time of flight in the time domain, so that the signal-to-noise ratio and the precision of the measured time of flight can be effectively improved, and higher ranging precision and accuracy are obtained.
In one embodiment, electrically modulating the QCL by the modulating power supply continuously transmits terahertz pulses and outputs synchronous electrical signals, comprising: the QCL is powered by the modulation power supply and modulates the transmitting pulse, so that the QCL transmits terahertz pulses with specific repetition frequency and pulse width, and the modulation power supply outputs one path of synchronous electric signals.
The synchronization signal is used to determine the timing start of the time of flight.
In one embodiment, the step of obtaining a specific divergence angle includes: and obtaining a specific divergence angle according to the spot radius of the collimated terahertz wave beam and the focal length of the off-axis parabolic mirror in the transmitting front end.
The terahertz wave output by the quantum cascade laser is collimated by designing an optical path, so that the spot radius of the collimated terahertz wave beam is obtained, the transmitting front end 4 mainly comprises a reflecting mirror and an off-axis parabolic mirror and is used for transmitting the collimated terahertz wave beam at a specific divergence angle after focusing and reflecting, and a specific emission angle is obtained by the following formula: θ=2 arctan (R/f), where R represents the spot radius of the collimated terahertz beam and f represents the focal length of the off-axis parabolic mirror in the transmit front.
In one embodiment, filtering and amplifying the electric response signal output by the terahertz detector through a filter and a pre-voltage amplifier to obtain an amplified signal, including:
Filtering the electric response signal output by the terahertz detector through a filter to obtain a filtered signal; the frequency range of the filter covers the frequency of the modulated power supply; amplifying the filtered signal by using a pre-voltage amplifier to obtain an amplified signal; the amplification factor g satisfies that V t＜g×Vf＜1.5Vt,Vf is pulse voltage output after filtering by a band-pass filter, and V t is trigger voltage of a constant ratio phase discriminator.
In one embodiment, calculating the target distance from the terahertz pulse time-of-flight includes: and calculating the distance according to the initial terahertz pulse flight time and the terahertz pulse flight time to obtain the distance from the target to the transmitting front end.
In one embodiment, performing distance calculation according to the initial terahertz pulse flight time and the terahertz pulse flight time to obtain a distance from a target to a transmitting front end, including:
L＝c×(t-t1)/2
Wherein L is the distance from the target to the transmitting front end, c is the light speed, t is the terahertz pulse flight time, and t 1 is the initial terahertz pulse flight time.
In one embodiment, before the terahertz wave ranging according to the terahertz pulse flight time, the method further includes: and aligning the terahertz detector with the transmitting front end in a short distance to obtain the initial terahertz pulse flight time when the target is not placed.
The time measuring unit T bin, the constant ratio phase detector trigger voltage V t and the measurement accumulation time T are set in the computer program, and the flight time T is read out through the time counting result. When the target is not placed, the terahertz detector is aligned with the transmitting front end in a short distance, and the flight time of the terahertz pulse is measured to be t 1. The distance from the target to the emission front can be calculated by: l=c× (t-t 1)/2, ranging accuracy is c×t bin., where c is the speed of light. In this embodiment, the time measurement unit t bin can reach 13ps at the lowest, and the corresponding ranging accuracy can reach 3.9mm.
In one embodiment, the center frequency of the QCL source is 4.3THz, the repetition frequency and pulse width of the setting of the modulation power supply are 2kHz and 10 μs respectively, the radius of the collimated terahertz beam spot is 38mm, the focal length f of the off-axis parabolic mirror in the transmitting front end is 250mm, the calculated divergence angle θ is 17 °, the filtering frequency of the band-pass filter is 1kHz-3kHz, the amplification factor g is 5000 times, the trigger voltage V t is 0.4V, the time measurement unit T bin is 100ps, and the accumulation time T is 30s. The terahertz pulse flight time t and the initial terahertz pulse flight time t 1 are respectively 29.5ns and 25.5ns, which are read out by using the time statistics count, and the target echo flight time statistics count result is shown in fig. 3. The distance L between the target and the transmitting front end is calculated to be 0.6m, the error between the target and the actual distance is smaller than 2%, and terahertz wave ranging based on time-of-flight counting is realized.
It should be understood that, although the steps in the flowchart of fig. 1 are shown in sequence as indicated by the arrows, the steps are not necessarily performed in sequence as indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in fig. 1 may include multiple sub-steps or stages that are not necessarily performed at the same time, but may be performed at different times, nor do the order in which the sub-steps or stages are performed necessarily performed in sequence, but may be performed alternately or alternately with at least a portion of other steps or sub-steps of other steps.
In one embodiment, as shown in fig. 4, there is provided a terahertz wave ranging apparatus based on time-of-flight counting, including: a transmit module 402, a receive module 404, a filter amplification module 406, a signal processing module 408, and a time-of-flight count module 410, wherein:
A transmitting module 402, configured to electrically modulate the QCL by a modulating power supply to continuously transmit terahertz pulses, and output a synchronous electrical signal; shaping the terahertz pulse space beam to obtain a collimated terahertz beam; radiating the collimated terahertz wave beam to a target at a specific divergence angle by utilizing a transmitting front end, and generating a terahertz echo by reflecting the target; the emission front end comprises an off-axis parabolic mirror and a reflecting mirror;
The receiving module 404 is configured to collect and detect terahertz echoes by using a terahertz detector, and output an electrical response signal;
the filtering and amplifying module 406 is configured to filter and amplify the electrical response signal output by the terahertz detector through a filter and a pre-voltage amplifier, so as to obtain an amplified signal;
The signal processing module 408 is configured to trigger constant voltage values of rising edges of the synchronous electrical signal and the amplified signal by using a constant ratio phase detector, so as to obtain a timing start signal and a timing end signal;
A time-of-flight counting module 410, configured to measure, with a time-to-digital converter, a time delay of the timing start signal and the timing end signal in the semiconductor logic gate to obtain a time difference value; carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, and obtaining the terahertz pulse flight time from the statistical distribution diagram; and calculating the target distance according to the terahertz pulse flight time.
In one embodiment, the transmitting module 402 is further configured to electrically modulate the QCL by a modulating power supply to continuously transmit terahertz pulses and output a synchronous electrical signal, including: the QCL is powered by a modulation power supply and modulates the transmitting pulse, so that the QCL transmits terahertz pulses with specific repetition frequency and pulse width, and outputs a synchronous electric signal.
In one embodiment, the step of obtaining a specific divergence angle includes: and calculating a specific divergence angle according to the spot radius of the collimated terahertz wave beam and the focal length of the off-axis parabolic mirror in the transmitting front end.
In one embodiment, the filtering and amplifying module 406 is further configured to filter and amplify the electrical response signal output by the terahertz detector through a filter and a pre-voltage amplifier, so as to obtain an amplified signal, where the filtering and amplifying module includes:
Filtering the electric response signal output by the terahertz detector through a filter to obtain a filtered signal; the frequency range of the filter covers the frequency of the modulated power supply; amplifying the filtered signal by using a pre-voltage amplifier to obtain an amplified signal; the amplification factor g satisfies that V t＜g×Vf＜1.5Vt,Vf is pulse voltage output after filtering by a band-pass filter, and V t is trigger voltage of a constant ratio phase discriminator.
In one embodiment, the time-of-flight counting module 410 is further configured to calculate a target distance from the terahertz pulse time-of-flight, including: and calculating the distance according to the initial terahertz pulse flight time and the terahertz pulse flight time to obtain the distance from the target to the transmitting front end.
In one embodiment, the time-of-flight counting module 410 is further configured to perform distance calculation according to the initial terahertz pulse time-of-flight and the terahertz pulse time-of-flight, so as to obtain a distance from the target to the transmitting front end, including:
L＝c×(t-t1)/2
Wherein L is the distance from the target to the transmitting front end, c is the light speed, t is the terahertz pulse flight time, and t 1 is the initial terahertz pulse flight time.
In one embodiment, the time-of-flight counting module 410 is further configured to, prior to the terahertz wave ranging according to the terahertz pulse time-of-flight, further include: and aligning the terahertz detector with the transmitting front end in a short distance to obtain the initial terahertz pulse flight time when the target is not placed.
For a specific limitation of the terahertz wave ranging apparatus based on the time-of-flight count, reference may be made to the limitation of the terahertz wave ranging method based on the time-of-flight count hereinabove, and the description thereof will not be repeated here. The above-described modules in the terahertz wave ranging apparatus based on the time-of-flight count may be implemented in whole or in part by software, hardware, and combinations thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.
In one embodiment, a computer device is provided, which may be a terminal, and the internal structure of which may be as shown in fig. 5. The computer device includes a processor, a memory, a network interface, a display screen, and an input device 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 includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program, when executed by a processor, implements a terahertz wave ranging method based on time-of-flight counting. The display screen of the computer equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, can also be keys, a track ball or a touch pad arranged on the shell of the computer equipment, and can also be an external keyboard, a touch pad or a mouse and the like.
It will be appreciated by those skilled in the art that the structure shown in FIG. 5 is merely a block diagram of some of the structures associated with the present inventive arrangements and is not limiting of the computer device to which the present inventive arrangements may be applied, and that a particular computer device may include more or fewer components than shown, or may combine some of the components, or have a different arrangement of components.
In an embodiment a computer device is provided comprising a memory storing a computer program and a processor implementing the steps of the method of the above embodiments when the computer program is executed.
In one embodiment, a computer storage medium is provided, on which a computer program is stored which, when executed by a processor, implements the steps of the method of the above embodiments.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile 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 (SYNCHLINK) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (10)
1. A terahertz wave ranging method based on time-of-flight counting, the method comprising:
electrically modulating the QCL through a modulation power supply to continuously emit terahertz pulses, and outputting synchronous electric signals;
Shaping the terahertz pulse space beam to obtain a collimated terahertz beam;
Radiating the collimated terahertz wave beam to a target at a specific divergence angle by utilizing a transmitting front end, and generating terahertz echo by reflection of the target; the emission front end comprises an off-axis parabolic mirror and a reflecting mirror;
Collecting and detecting the terahertz echo by using a terahertz detector, and outputting an electric response signal;
the electric response signal output by the terahertz detector is filtered and amplified through a filter and a front-end voltage amplifier to obtain an amplified signal;
Triggering constant voltage values of rising edges of the synchronous electric signal and the amplified signal by using a constant ratio phase discriminator to obtain a timing starting signal and a timing ending signal;
measuring the time delay of the timing starting signal and the timing ending signal in the semiconductor logic gate by using a time-to-digital converter to obtain a time difference value;
and carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, reading the terahertz pulse flight time from the statistical distribution diagram, and calculating a target distance according to the terahertz pulse flight time.
2. The method of claim 1, wherein electrically modulating the QCL by the modulating power supply continuously emits terahertz pulses and outputs the synchronous electrical signal, comprising:
The QCL is powered by a modulation power supply and modulates the transmitting pulse, so that the QCL transmits terahertz pulses with specific repetition frequency and pulse width, and outputs a synchronous electric signal.
3. The method of claim 2, wherein the step of obtaining the terahertz beam divergence angle comprises:
And obtaining the divergence angle of the terahertz wave beam according to the light spot radius of the collimation terahertz wave beam and the focal length of the off-axis parabolic mirror in the transmitting front end.
4. A method according to claim 3, wherein filtering and amplifying the electrical response signal output from the terahertz detector by a filter and a pre-voltage amplifier to obtain an amplified signal comprises:
filtering the electric response signal output by the terahertz detector through a filter to obtain a filtered signal; the frequency range of the filter covers the modulation frequency of the modulation power supply;
Amplifying the filtered signal by using the pre-voltage amplifier to obtain an amplified signal; the amplification factor g satisfies that V t＜g×Vf＜1.5Vt,Vf is pulse voltage output after filtering by a band-pass filter, and V t is trigger voltage of a constant ratio phase discriminator.
5. A method according to claim 3, wherein calculating a target distance from the terahertz pulse time-of-flight comprises:
And calculating the distance according to the initial terahertz pulse flight time and the terahertz pulse flight time to obtain the distance from the target to the transmitting front end.
6. The method of claim 5, wherein performing a distance calculation based on an initial terahertz pulse time-of-flight and the terahertz pulse time-of-flight to obtain a distance from a target to a transmit front end comprises:
L＝c×(t-t1)/2
Wherein L is the distance from the target to the transmitting front end, c is the light speed, t is the terahertz pulse flight time, and t 1 is the initial terahertz pulse flight time.
7. The method of claim 6, further comprising, prior to calculating the target distance from the terahertz pulse time-of-flight:
And aligning the terahertz detector with the transmitting front end in a short distance to obtain the initial terahertz pulse flight time when the target is not placed.
8. Terahertz wave ranging device based on time-of-flight counting, characterized in that it comprises:
The transmission module is used for carrying out electric modulation on the QCL through the modulation power supply to continuously transmit terahertz pulses and outputting synchronous electric signals; shaping the terahertz pulse space beam to obtain a collimated terahertz beam; radiating the collimated terahertz wave beam to a target at a specific divergence angle by utilizing a transmitting front end, and generating terahertz echo by reflection of the target; the emission front end comprises an off-axis parabolic mirror and a reflecting mirror;
The receiving module is used for collecting and detecting the terahertz echo by using a terahertz detector and outputting an electric response signal;
the filtering and amplifying module is used for filtering and amplifying the electric response signal output by the terahertz detector through the filter and the front-end voltage amplifier to obtain an amplified signal;
The signal processing module is used for respectively triggering constant voltage values of rising edges of the synchronous electric signal and the amplified signal by utilizing a constant ratio phase discriminator to obtain a timing starting signal and a timing ending signal;
The time-of-flight counting module is used for measuring the time delay of the timing starting signal and the timing ending signal in the semiconductor logic gate by utilizing the time-to-digital converter to obtain a time difference value; carrying out time domain accumulation counting statistics on the time difference value in the measurement time through a counter to obtain a statistical distribution diagram of the terahertz pulse flight time, and obtaining the terahertz pulse flight time from the statistical distribution diagram; and calculating the target distance according to the terahertz pulse flight time.
9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any of claims 1 to 7 when the computer program is executed.
10. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1 to 7.
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