CN114325680A - Active power range measurement method in millimeter wave radar - Google Patents
Active power range measurement method in millimeter wave radar Download PDFInfo
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- CN114325680A CN114325680A CN202111613669.4A CN202111613669A CN114325680A CN 114325680 A CN114325680 A CN 114325680A CN 202111613669 A CN202111613669 A CN 202111613669A CN 114325680 A CN114325680 A CN 114325680A
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Abstract
The invention provides an active motor distance measuring method in a millimeter wave radar, which comprises the following steps: transmitting a frequency modulation signal in a target frequency range to a target direction based on a millimeter wave radar antenna, and receiving an echo signal of the frequency modulation signal; determining a difference frequency signal based on the frequency modulation signal and the echo signal, and determining a peak position of the difference frequency signal based on discrete transformation; controlling the millimeter wave radar antenna to move towards the peak position, and continuously measuring until the peak value jumps, stopping the millimeter wave radar antenna and recording the current measured distance; and obtaining the target distance between the measured object and the millimeter wave range finder based on the moving distance of the millimeter wave radar antenna and the measured distance. The distance between the measured object and the millimeter wave range finder is detected through millimeter radar waves, and meanwhile, the frequency resolution of difference frequency signal discrete transformation is improved through actively moving the millimeter wave radar antenna in the range finding process, so that the measuring result is more accurate, and the accuracy and reliability of the measuring result are ensured.
Description
Technical Field
The invention relates to the technical field of radar ranging, in particular to an active motor ranging method in a millimeter wave radar.
Background
Currently, the ranging principle of a radar ranging device is to transmit a radar signal through a transmitter of the radar ranging device, receive an echo signal corresponding to a target generated by the radar signal reflected by the target within a field of view through a receiver of the radar ranging device, and calculate a distance between the target and the radar ranging device by measuring a delay time from the transmission of the radar signal to the reception of the echo signal of the target;
however, in practical applications, a single FFT is mainly used, and since some signals of the radar signal may be reflected by the inner wall or the window of the radar ranging device during transmission, stray echo signals are generated, and thus the echo signals received by the receiver range the target, and the accuracy is low;
therefore, the invention provides an active maneuvering distance measuring method in a millimeter wave radar, which is used for detecting the distance between a measured object and a millimeter wave distance meter through millimeter radar waves, and meanwhile, the frequency resolution of difference frequency signal discrete transformation is improved by actively moving a millimeter wave radar antenna in the distance measuring process, so that the measuring result is more accurate, and the accuracy and reliability of the measuring result are ensured.
Disclosure of Invention
The invention provides an active maneuvering distance measuring method in a millimeter wave radar, which is used for detecting the distance between a measured object and a millimeter wave distance meter through millimeter radar waves, and meanwhile, the frequency resolution of difference frequency signal discrete transformation is improved by actively moving a millimeter wave radar antenna in the distance measuring process, so that the measuring result is more accurate, and the accuracy and reliability of the measuring result are ensured.
The invention provides an active motor distance measuring method in a millimeter wave radar, which comprises the following steps:
step 1: transmitting a frequency modulation signal in a target frequency range to a target direction based on a millimeter wave radar antenna, and receiving an echo signal of the frequency modulation signal;
step 2: determining a difference frequency signal based on the frequency modulation signal and the echo signal, and determining a peak position of the difference frequency signal based on discrete transformation;
and step 3: controlling the millimeter wave radar antenna to move towards the peak position, and continuously measuring until the peak value jumps, stopping the millimeter wave radar antenna and recording the current measured distance;
and 4, step 4: and obtaining the target distance between the measured object and the millimeter wave range finder based on the moving distance of the millimeter wave radar antenna and the measured distance.
Preferably, in step 1, the method for active power ranging in a millimeter wave radar transmits a frequency modulation signal in a target frequency range to a target direction based on a millimeter wave radar antenna, and includes:
acquiring an initial millimeter wave signal generated by a millimeter wave range finder, and determining an initial frequency value corresponding to the initial millimeter wave signal;
the millimeter wave range finder calls a preset linear frequency modulation pulse based on the target frequency range to perform frequency continuous increasing or continuous decreasing modulation on an initial frequency value corresponding to the initial millimeter wave signal in the target frequency range, and performs power amplification on the modulated initial millimeter wave to obtain a frequency modulation signal;
and transmitting the frequency modulation signal to a target direction based on a millimeter wave radar antenna.
Preferably, in step 1, the method for active vehicle ranging in a millimeter wave radar, receiving an echo signal of the frequency modulation signal, includes:
acquiring the echo signal, and performing analog-to-digital conversion on the echo signal to obtain a digital echo signal corresponding to the echo signal, wherein the echo signal is obtained by reflecting the frequency modulation signal after encountering an object to be detected in a target direction;
and multiplying the digital echo signal by a preset reference local oscillator signal, and removing the target interference frequency in the digital echo signal to obtain a target echo signal.
Preferably, in step 2, the method for active vehicle ranging in millimeter wave radar, determining a difference frequency signal based on the frequency modulation signal and the echo signal, and determining a peak position of the difference frequency signal based on discrete transformation includes:
acquiring a frequency modulation signal transmitted by a millimeter wave range finder and a received echo signal, determining a calculation expression of an instantaneous phase of the frequency modulation signal, and simultaneously performing frequency mixing processing on the frequency modulation signal and the echo signal;
acquiring a carrier frequency, a frequency modulation bandwidth and a frequency modulation period of the frequency modulation signal, determining a transmission speed of the frequency modulation signal based on the carrier frequency, the frequency modulation bandwidth and the frequency modulation period, and determining a time delay value between the frequency modulation signal and the echo signal based on a frequency mixing processing result and the transmission speed of the frequency modulation signal;
carrying out substitution calculation on the time delay value based on a calculation expression of the instantaneous phase of the frequency modulation signal to obtain the instantaneous phase of the difference frequency signal to be determined, and meanwhile, determining the corresponding relation between the carrier frequency and the frequency modulation bandwidth of the difference frequency signal to be determined and the carrier frequency and the frequency modulation bandwidth of the frequency modulation signal;
obtaining a target difference frequency signal based on the instantaneous phase and the corresponding relation of the difference frequency signal to be determined;
preprocessing the target difference frequency signal, and performing FFT operation on the preprocessed target difference frequency signal to obtain a signal spectrum of the target difference frequency signal;
determining amplitude values of the target difference frequency signal at different positions based on the signal spectrum, and determining the maximum amplitude value in the amplitude values as the peak value of the target difference frequency signal;
and analyzing the peak value by the millimeter wave range finder, determining a target position corresponding to the peak value, and recording the target position.
Preferably, the method for measuring the active vehicle distance in the millimeter wave radar, which obtains the target difference frequency signal based on the instantaneous phase and the corresponding relationship of the difference frequency signal to be determined, includes:
acquiring an obtained target difference frequency signal, and extracting a frequency value of the target difference frequency signal;
comparing the frequency value with a preset frequency value;
if the frequency value is larger than or equal to the preset frequency value, judging that the target difference frequency signal is wrong, and controlling the millimeter wave radar antenna to transmit the frequency modulation signal to the target direction again;
otherwise, judging that the target error frequency signal is correct, determining the current transmitting frequency and the frequency modulation period of the frequency modulation signal, and recording and storing the transmitting frequency and the modulation period.
Preferably, in step 3, the method for measuring the active vehicle distance in the millimeter wave radar controls the millimeter wave radar antenna to move to the peak position, and continuously measures until the peak value jumps, the millimeter wave radar antenna stops moving and records the current measured distance, and includes:
acquiring a peak position of a difference frequency signal, and controlling the millimeter wave radar antenna to actively move towards the peak position by a preset distance measurement controller, wherein the peak position is a position of a measured object;
the millimeter wave radar antenna continuously transmits the frequency modulation signal to a target direction based on an active moving process and determines whether the peak value of the difference frequency signal jumps in real time;
when the peak value of the difference frequency signal jumps, the preset distance measurement controller controls the millimeter wave radar antenna to stop moving and determines a phase change value when the peak value jumps;
determining a critical point of a distance bin where the position of the measured object is located based on the phase change value, and determining a frequency value of a difference frequency signal generated between the measured object and the millimeter wave radar antenna based on the critical point;
determining a propagation time of the difference frequency signal based on the frequency value, while determining a propagation speed of the difference frequency signal;
determining a final distance value from the measured object to the millimeter wave radar antenna based on the propagation time and the propagation speed;
otherwise, the preset ranging controller controls the millimeter wave radar antenna to continuously and actively move towards the direction of the peak position until the peak value of the difference frequency signal jumps.
Preferably, the method for active power ranging in a millimeter wave radar, when a peak value of the difference frequency signal jumps, the preset ranging controller controls the millimeter wave radar antenna to stop moving, and determines a phase change value when the peak value jumps, includes:
acquiring current position information of the millimeter radar antenna when the preset ranging controller controls the millimeter radar antenna to stop moving, and monitoring whether a measured object is displaced in real time;
when the measured object is displaced, determining the peak value change condition of the difference frequency signal after FFT operation in real time, and recording the peak value change condition in real time;
determining the final distance between the object to be measured and the millimeter wave radar antenna after the displacement of the object to be measured is generated based on the real-time recording result;
otherwise, completing the detection of the distance of the measured object.
Preferably, the active power ranging method in the millimeter wave radar includes that a preset ranging controller controls the millimeter wave radar antenna to actively move towards the peak position direction, and the preset ranging controller comprises a stepping motor, a screw rod and the millimeter wave radar antenna;
the preset distance measuring controller is connected with the stepping motor;
the stepping motor is connected with the screw rod;
the screw rod is connected with the millimeter wave radar antenna;
the preset distance measurement controller controls the stepping motor to push the screw rod to move forwards, and the screw rod drives the millimeter wave radar antenna to move actively towards the direction of the peak position.
Preferably, the method for measuring the active maneuvering distance in the millimeter wave radar, in step 4, the target distance between the object to be measured and the millimeter wave distance meter is obtained based on the moving distance of the millimeter wave radar antenna and the measured distance, and includes:
acquiring current position information of the millimeter wave radar antenna when the millimeter wave radar antenna stops moving, and simultaneously determining initial position information of the millimeter wave radar antenna;
determining an active maneuvering distance of the millimeter wave radar antenna based on the current position information and the initial position information, and simultaneously obtaining a current measured distance recorded when the millimeter wave radar antenna stops moving;
and summing the active maneuvering distance of the millimeter wave radar antenna and the current measured distance to obtain the target distance between the measured object and the millimeter wave distance meter.
Preferably, the method for active maneuvering distance measurement in a millimeter wave radar to obtain the target distance between the object to be measured and the millimeter wave distance meter includes:
obtaining the target distance between the measured object and the millimeter wave range finder, and simultaneously determining the relative direction of the measured object and the millimeter wave range finder;
determining the number of items to be recorded based on the target distance and the relative direction, and matching a target record report form in a preset record report template base based on the number of the items to be recorded;
and recording the target distance and the relative direction based on the target recording report sheet, and transmitting a recording result to a management terminal for storage management.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a flow chart of an active maneuvering distance measuring method in a millimeter wave radar according to an embodiment of the invention;
fig. 2 is a schematic diagram illustrating processing of a frequency modulation signal and an echo signal in an active maneuvering distance measuring method in a millimeter wave radar according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a distance measurement in an active vehicle distance measurement method in a millimeter-wave radar according to an embodiment of the present invention;
fig. 4 is a structural diagram of a millimeter wave range finder in an active vehicle ranging method in a millimeter wave radar according to an embodiment of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
Example 1:
the embodiment provides an active maneuvering distance measuring method in a millimeter wave radar, as shown in fig. 1, including:
step 1: transmitting a frequency modulation signal in a target frequency range to a target direction based on a millimeter wave radar antenna, and receiving an echo signal of the frequency modulation signal;
step 2: determining a difference frequency signal based on the frequency modulation signal and the echo signal, and determining a peak position of the difference frequency signal based on discrete transformation;
and step 3: controlling the millimeter wave radar antenna to move towards the peak position, and continuously measuring until the peak value jumps, stopping the millimeter wave radar antenna and recording the current measured distance;
and 4, step 4: and obtaining the target distance between the measured object and the millimeter wave range finder based on the moving distance of the millimeter wave radar antenna and the measured distance.
In this embodiment, the target direction refers to a direction in which whether a detected object is included needs to be detected by the millimeter wave radar antenna, for example, when the millimeter wave radar antenna is loaded on an airplane, whether a foreign object exists in front of an airplane flight path needs to be detected, where the front of the airplane flight path is the target direction.
In this embodiment, the target frequency range is set in advance for frequency setting of the transmission signal in the frequency range.
In this embodiment, the frequency modulation signal means that the generation signal is continuously increased or decreased within the target frequency range, thereby forming a frequency modulation signal.
In this embodiment, the echo signal refers to a millimeter wave signal returned after the frequency modulated signal contacts the object to be measured, and has the same shape as the frequency modulated signal but has a delay in time.
In this embodiment, the difference frequency signal refers to a frequency difference between the frequency-modulated signal and the echo signal at a certain time, that is, the difference frequency signal.
In this embodiment, determining the peak position of the difference frequency signal based on discrete transformation means that, when the device is turned on, the transmitted millimeter waves perform fuzzy detection on the object to be measured, and determine an approximate initial position of the object to be measured.
In this embodiment, the step of stopping the movement of the millimeter wave radar antenna and recording the current measured distance means that when the millimeter wave radar antenna detects a peak value bounce in the movement process, it indicates that the millimeter wave radar antenna detects the measured object, and at this time, the distance between the measured object and the millimeter radar antenna can be obtained through calculation.
In this embodiment, obtaining the target distance between the object to be measured and the millimeter wave distance meter based on the moving distance of the millimeter wave radar antenna and the measured distance means that the final detection distance is obtained by combining the final detection distance after the movement of the millimeter wave radar antenna and the moving distance of the millimeter wave radar antenna.
The beneficial effects of the above technical scheme are: the distance between the measured object and the millimeter wave range finder is detected through millimeter radar waves, and meanwhile, the frequency resolution of difference frequency signal discrete transformation is improved through actively moving the millimeter wave radar antenna in the range finding process, so that the measuring result is more accurate, and the accuracy and reliability of the measuring result are ensured.
Example 2:
on the basis of the foregoing embodiment 1, this embodiment provides an active power ranging method in a millimeter wave radar, where in step 1, a frequency modulation signal in a target frequency range is transmitted to a target direction based on a millimeter wave radar antenna, and the method includes:
acquiring an initial millimeter wave signal generated by a millimeter wave range finder, and determining an initial frequency value corresponding to the initial millimeter wave signal;
the millimeter wave range finder calls a preset linear frequency modulation pulse based on the target frequency range to perform frequency continuous increasing or continuous decreasing modulation on an initial frequency value corresponding to the initial millimeter wave signal in the target frequency range, and performs power amplification on the modulated initial millimeter wave to obtain a frequency modulation signal;
and transmitting the frequency modulation signal to a target direction based on a millimeter wave radar antenna.
In this embodiment, the initial millimeter wave signal refers to an initial signal generated by the millimeter wave range finder itself, and is a signal without frequency modulation.
In this embodiment, the initial frequency value refers to a frequency value corresponding to the initial millimeter wave signal, and the frequency value does not necessarily satisfy the radar detection requirement and needs to be frequency-modulated.
In this embodiment, the preset chirp is set in advance and is used to modulate the initial millimeter wave signal frequency value.
The beneficial effects of the above technical scheme are: the frequency value and the power of the generated initial millimeter wave signal are adjusted, so that the object to be measured in the target direction can be more effectively detected, and the distance between the object to be measured and the millimeter wave distance meter can be accurately measured.
Example 3:
on the basis of the foregoing embodiment 1, this embodiment provides an active power ranging method in a millimeter wave radar, where in step 1, receiving an echo signal of the frequency modulation signal includes:
acquiring the echo signal, and performing analog-to-digital conversion on the echo signal to obtain a digital echo signal corresponding to the echo signal, wherein the echo signal is obtained by reflecting the frequency modulation signal after encountering an object to be detected in a target direction;
and multiplying the digital echo signal by a preset reference local oscillator signal, and removing the target interference frequency in the digital echo signal to obtain a target echo signal.
In this embodiment, the analog-to-digital conversion means to convert the acquired echo signal and the analog signal into digital signals, so as to analyze the signals, thereby determining the approximate position range of the object to be measured.
In this embodiment, the preset reference local oscillation signal is set in advance, and is used for performing an operation with the echo signal, canceling out a secondary phase term of a frequency linearly changing with time in the digital echo signal, and leaving a dot frequency signal only related to a target position to provide a preparation for subsequent processing of the echo signal.
In this embodiment, the target interference frequency refers to removing a local signal in the echo signal, where the local signal is interfered by the outside world to cause frequency abnormality.
In this embodiment, the target echo signal refers to a millimeter wave signal that is obtained by processing a received original echo signal and can be directly used for signal analysis.
The beneficial effects of the above technical scheme are: by receiving the echo signals and processing the echo signals, convenience is provided for determining bilateral critical points of the distance bin where the measured object is located according to the echo signals, and therefore guarantee is provided for ensuring accuracy and reliability of measuring results.
Example 4:
on the basis of embodiment 1 above, this embodiment provides an active power ranging method in a millimeter wave radar, where in step 2, a difference frequency signal is determined based on the frequency modulation signal and the echo signal, and a peak position of the difference frequency signal is determined based on discrete transformation, including:
acquiring a frequency modulation signal transmitted by a millimeter wave range finder and a received echo signal, determining a calculation expression of an instantaneous phase of the frequency modulation signal, and simultaneously performing frequency mixing processing on the frequency modulation signal and the echo signal;
acquiring a carrier frequency, a frequency modulation bandwidth and a frequency modulation period of the frequency modulation signal, determining a transmission speed of the frequency modulation signal based on the carrier frequency, the frequency modulation bandwidth and the frequency modulation period, and determining a time delay value between the frequency modulation signal and the echo signal based on a frequency mixing processing result and the transmission speed of the frequency modulation signal;
carrying out substitution calculation on the time delay value based on a calculation expression of the instantaneous phase of the frequency modulation signal to obtain the instantaneous phase of the difference frequency signal to be determined, and meanwhile, determining the corresponding relation between the carrier frequency and the frequency modulation bandwidth of the difference frequency signal to be determined and the carrier frequency and the frequency modulation bandwidth of the frequency modulation signal;
obtaining a target difference frequency signal based on the instantaneous phase and the corresponding relation of the difference frequency signal to be determined;
preprocessing the target difference frequency signal, and performing FFT operation on the preprocessed target difference frequency signal to obtain a signal spectrum of the target difference frequency signal;
determining amplitude values of the target difference frequency signal at different positions based on the signal spectrum, and determining the maximum amplitude value in the amplitude values as the peak value of the target difference frequency signal;
and analyzing the peak value by the millimeter wave range finder, determining a target position corresponding to the peak value, and recording the target position.
In this embodiment, the calculation expression of the instantaneous phase is determined according to an expression of the frequency modulated signal wave, wherein the expression of the frequency modulated signal wave can be theoretically calculated by a microwave technique.
In this embodiment, the mixing process refers to mixing the frequency of the frequency-modulated signal with the echo signal to obtain a third microwave signal, and the specific schematic diagram is shown in fig. 2.
In this embodiment, the delay value refers to that the frequency modulated signal and the echo signal are the same in shape, the echo signal is obtained when the frequency modulated signal contacts the measured object, and the echo signal has a difference from the frequency modulated signal in phase during transmission, that is, the delay.
In this embodiment, the difference frequency signal refers to a microwave signal corresponding to a frequency difference between the frequency modulated signal and the echo signal at a certain time.
In this embodiment, the difference frequency signal to be determined refers to a difference frequency signal derived from the frequency modulated signal and the echo signal.
In this embodiment, the preprocessing the target difference frequency signal refers to removing an interference frequency or an interference signal in the target difference frequency signal, where the interference frequency or the interference signal is a microwave signal unrelated to the object to be measured.
In this embodiment, the FFT operation refers to discrete transform, and the phase condition and the peak condition of the difference frequency signal are obtained by the discrete transform, and the spectrogram is discontinuous, and has a concept of frequency resolution, which is convenient for determining the approximate position of the object to be measured.
In this embodiment, the signal spectrum refers to a chart showing the phase of the difference frequency signal and the corresponding amplitude value.
In this embodiment, the millimeter wave distance meter analyzes the peak value, and determining the target position corresponding to the peak value refers to analyzing the peak value and the phase corresponding to the peak value by a professional instrument to obtain the approximate position of the object to be measured.
The beneficial effects of the above technical scheme are: the frequency modulation signal and the echo signal are processed, the obtained difference frequency signal is ensured to be accurate enough, meanwhile, the approximate position of the measured object is accurately judged according to the difference frequency signal, and therefore the distance between the measured object and the millimeter wave distance meter is guaranteed for accurate detection.
Example 5:
on the basis of the foregoing embodiment 4, this embodiment provides an active power ranging method in a millimeter wave radar, where obtaining a target difference frequency signal based on an instantaneous phase and a corresponding relationship of the difference frequency signal to be determined includes:
acquiring an obtained target difference frequency signal, and extracting a frequency value of the target difference frequency signal;
comparing the frequency value with a preset frequency value;
if the frequency value is larger than or equal to the preset frequency value, judging that the target difference frequency signal is wrong, and controlling the millimeter wave radar antenna to transmit the frequency modulation signal to the target direction again;
otherwise, judging that the target error frequency signal is correct, determining the current transmitting frequency and the frequency modulation period of the frequency modulation signal, and recording and storing the transmitting frequency and the modulation period.
In this embodiment, the preset frequency value is set in advance, and is used to measure whether the frequency value of the obtained difference frequency signal is within the normal cognitive range, so as to facilitate the verification of the validity of the difference frequency signal.
The beneficial effects of the above technical scheme are: by detecting the frequency value of the difference frequency signal, the obtained difference frequency signal is ensured to be accurate and effective, meanwhile, the critical point of the distance bin where the measured object is located is conveniently and accurately detected according to the difference frequency signal, and convenience is brought to detection of the distance between the measured object and the millimeter wave range finder.
Example 6:
on the basis of embodiment 1, this embodiment provides an active power ranging method in a millimeter wave radar, where in step 3, the millimeter wave radar antenna is controlled to move to the peak position, and the millimeter wave radar antenna is controlled to stop moving and record a current measured distance when the peak value jumps, and the method includes:
acquiring a peak position of a difference frequency signal, and controlling the millimeter wave radar antenna to actively move towards the peak position by a preset distance measurement controller, wherein the peak position is a position of a measured object;
the millimeter wave radar antenna continuously transmits the frequency modulation signal to a target direction based on an active moving process and determines whether the peak value of the difference frequency signal jumps in real time;
when the peak value of the difference frequency signal jumps, the preset distance measurement controller controls the millimeter wave radar antenna to stop moving and determines a phase change value when the peak value jumps;
determining a critical point of a distance bin where the position of the measured object is located based on the phase change value, and determining a frequency value of a difference frequency signal generated between the measured object and the millimeter wave radar antenna based on the critical point;
determining a propagation time of the difference frequency signal based on the frequency value, while determining a propagation speed of the difference frequency signal;
determining a final distance value from the measured object to the millimeter wave radar antenna based on the propagation time and the propagation speed;
otherwise, the preset ranging controller controls the millimeter wave radar antenna to continuously and actively move towards the direction of the peak position until the peak value of the difference frequency signal jumps.
In this embodiment, the preset distance measuring controller is a part of the millimeter wave distance measuring instrument, and is used for controlling the stepping motor to push the screw rod to move back and forth, so that the millimeter wave radar antenna is actively moved.
In this embodiment, the real-time determination of whether the peak value of the difference frequency signal is jittered is to accurately find the critical point of the distance bin where the measured object is located, so as to conveniently eliminate the problem that the detection result is inaccurate simply by millimeter wave distance measurement.
In this embodiment, the phase change value refers to a jump condition of the peak position of the difference frequency signal after FFT operation, and whether the peak value jumps or not can be accurately determined by the phase change value.
In this embodiment, the distance bin is to perform an FFI operation on the difference frequency signal, where FFT is a discrete transform, a spectrogram thereof is discontinuous, and there is a concept of frequency resolution, so that the distance in front of the millimeter wave range finder is divided into a plurality of distance segments, and each segment is a distance bin, in order to improve the resolution of distance solution, that is, improve the accuracy of distance detection.
In this embodiment, the propagation time is calculated from the frequency value of the difference signal.
In this embodiment, determining the final distance value from the measured object to the millimeter wave radar antenna means that the distance between the measured object and the millimeter wave radar antenna at the current position is measured after the millimeter wave radar antenna stops moving.
In this embodiment, when detecting the distance by using the difference frequency signal, a high-speed ADC is generally used to acquire the IF signal, and then an FFT algorithm is used to obtain the frequency peak of the IF signal. The method is also suitable for multi-target monitoring, because objects with different distances can correspond to different peak values on the FFT, and the distance measurement schematic diagram is shown in FIG. 3.
In this embodiment, when the preset ranging controller controls the millimeter wave radar antenna to actively move toward the peak position, a two-way distance bin critical point may be searched, so as to obtain two ranging values, and a more accurate ranging value may be obtained by averaging the two ranging values.
The beneficial effects of the above technical scheme are: by controlling the millimeter wave radar antenna to move actively, the distance between the measured object and the millimeter wave radar antenna can be accurately detected under the condition of determining the approximate position of the measured object, and reliable and accurate guarantee is provided for accurately obtaining the actual distance between the measured object and the millimeter wave range finder.
Example 7:
on the basis of the foregoing embodiment 6, this embodiment provides an active machine distance measuring method in a millimeter wave radar, where when a peak value of the difference frequency signal jumps, the preset distance measuring controller controls the millimeter wave radar antenna to stop moving, and determines a phase change value when the peak value jumps, including:
acquiring current position information of the millimeter radar antenna when the preset ranging controller controls the millimeter radar antenna to stop moving, and monitoring whether a measured object is displaced in real time;
when the measured object is displaced, determining the peak value change condition of the difference frequency signal after FFT operation in real time, and recording the peak value change condition in real time;
determining the final distance between the object to be measured and the millimeter wave radar antenna after the displacement of the object to be measured is generated based on the real-time recording result;
otherwise, completing the detection of the distance of the measured object.
In this embodiment, the current position information refers to a position obtained after the millimeter wave range finder stops moving for the first time after being turned on.
In this embodiment, determining the final distance between the object to be measured and the millimeter wave radar antenna after displacement based on the real-time recording result means that the millimeter wave range finder does not need to move again after moving in sequence when a subsequent object is displaced, and the peak position and the corresponding phase condition can be tracked in real time through the difference frequency signal, so that the detection distance can be accurately obtained.
The beneficial effects of the above technical scheme are: after the transmitting position of the millimeter radar antenna is determined, the object distance is accurately detected along with the position change condition, the millimeter radar antenna does not need to be moved repeatedly, the distance detection efficiency is improved, and meanwhile, accurate calculation of the distance is facilitated.
Example 8:
on the basis of the foregoing embodiment 6, this embodiment provides an active power ranging method in a millimeter wave radar, as shown in fig. 4, where the preset ranging controller controls the millimeter wave radar antenna to actively move toward the peak position, and the preset ranging controller includes a stepping motor, a lead screw, and a millimeter wave radar antenna;
the preset distance measuring controller is connected with the stepping motor;
the stepping motor is connected with the screw rod;
the screw rod is connected with the millimeter wave radar antenna;
the preset distance measurement controller controls the stepping motor to push the screw rod to move forwards, and the screw rod drives the millimeter wave radar antenna to move actively towards the direction of the peak position.
The beneficial effects of the above technical scheme are: thereby realize promoting millimeter wave radar antenna through the electronic lead screw motion of step motor and carry out the seesaw, realize carrying out accurate control to the motion of millimeter wave radar antenna, also provide convenience for accurately detecting the actual distance between measured object and the millimeter wave distancer.
Example 9:
on the basis of the foregoing embodiment 1, this embodiment provides an active maneuvering distance measuring method in a millimeter wave radar, where in step 4, obtaining a target distance between a measured object and a millimeter wave range finder based on a moving distance of a millimeter wave radar antenna and the measured distance includes:
acquiring current position information of the millimeter wave radar antenna when the millimeter wave radar antenna stops moving, and simultaneously determining initial position information of the millimeter wave radar antenna;
determining an active maneuvering distance of the millimeter wave radar antenna based on the current position information and the initial position information, and simultaneously obtaining a current measured distance recorded when the millimeter wave radar antenna stops moving;
and summing the active maneuvering distance of the millimeter wave radar antenna and the current measured distance to obtain the target distance between the measured object and the millimeter wave distance meter.
In this embodiment, the initial position information refers to a position situation where the millimeter wave radar antenna is located when not moving.
In this embodiment, the active moving distance is the length of the distance that the bit millimeter wave radar antenna moves when searching for the critical point of the record bin.
In this embodiment, the target distance refers to a distance between the measured object and the millimeter wave distance meter.
The beneficial effects of the above technical scheme are: the distance obtained by detection after the millimeter wave radar antenna is actively moved is summed with the distance moved by the millimeter wave radar antenna, so that the error rate of detecting the distance only through discrete transformation is avoided, and the accuracy of distance detection is improved by combining the millimeter wave radar antenna and the distance.
Example 10:
on the basis of embodiment 9, this embodiment provides an active maneuvering distance measuring method in a millimeter wave radar, and obtaining a target distance between the object to be measured and a millimeter wave range finder includes:
obtaining the target distance between the measured object and the millimeter wave range finder, and simultaneously determining the relative direction of the measured object and the millimeter wave range finder;
determining the number of items to be recorded based on the target distance and the relative direction, and matching a target record report form in a preset record report template base based on the number of the items to be recorded;
and recording the target distance and the relative direction based on the target recording report sheet, and transmitting a recording result to a management terminal for storage management.
In this embodiment, the relative direction refers to a specific orientation of the object to be measured on the millimeter wave distance meter, and may be an east direction or a west direction, for example.
In this embodiment, the number of items to be recorded refers to the number of items recorded in the report, that is, the target distance and the relative direction are two items.
In this embodiment, the report template library is set in advance, and a plurality of report templates are stored in the report template library.
In this embodiment, the target report refers to a report template adapted to record the current target distance and relative direction, and is one of the preset record report template libraries.
The beneficial effects of the above technical scheme are: the distance obtained by detection and the relative direction of the measured object and the millimeter wave range finder are recorded, so that the measured object in the target direction can be found in time by the management terminal, corresponding measures can be taken in time, and the practicability of distance detection is improved.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. An active power ranging method in a millimeter wave radar is characterized by comprising the following steps:
step 1: transmitting a frequency modulation signal in a target frequency range to a target direction based on a millimeter wave radar antenna, and receiving an echo signal of the frequency modulation signal;
step 2: determining a difference frequency signal based on the frequency modulation signal and the echo signal, and determining a peak position of the difference frequency signal based on discrete transformation;
and step 3: controlling the millimeter wave radar antenna to move towards the peak position, and continuously measuring until the peak value jumps, stopping the millimeter wave radar antenna and recording the current measured distance;
and 4, step 4: and obtaining the target distance between the measured object and the millimeter wave range finder based on the moving distance of the millimeter wave radar antenna and the measured distance.
2. The active motor ranging method in millimeter wave radar according to claim 1, wherein in step 1, the emitting of the frequency-modulated signal in the target frequency range to the target direction based on the millimeter wave radar antenna comprises:
acquiring an initial millimeter wave signal generated by a millimeter wave range finder, and determining an initial frequency value corresponding to the initial millimeter wave signal;
the millimeter wave range finder calls a preset linear frequency modulation pulse based on the target frequency range to perform frequency continuous increasing or continuous decreasing modulation on an initial frequency value corresponding to the initial millimeter wave signal in the target frequency range, and performs power amplification on the modulated initial millimeter wave to obtain a frequency modulation signal;
and transmitting the frequency modulation signal to a target direction based on a millimeter wave radar antenna.
3. The active motor ranging method in millimeter wave radar as claimed in claim 1, wherein the step 1 of receiving the echo signal of the frequency modulation signal comprises:
acquiring the echo signal, and performing analog-to-digital conversion on the echo signal to obtain a digital echo signal corresponding to the echo signal, wherein the echo signal is obtained by reflecting the frequency modulation signal after encountering an object to be detected in a target direction;
and multiplying the digital echo signal by a preset reference local oscillator signal, and removing the target interference frequency in the digital echo signal to obtain a target echo signal.
4. The active maneuvering distance measuring method in millimeter wave radar as claimed in claim 1, characterized in that in step 2, determining a difference frequency signal based on the frequency modulation signal and the echo signal, and determining a peak position of the difference frequency signal based on discrete transformation comprises:
acquiring a frequency modulation signal transmitted by a millimeter wave range finder and a received echo signal, determining a calculation expression of an instantaneous phase of the frequency modulation signal, and simultaneously performing frequency mixing processing on the frequency modulation signal and the echo signal;
acquiring a carrier frequency, a frequency modulation bandwidth and a frequency modulation period of the frequency modulation signal, determining a transmission speed of the frequency modulation signal based on the carrier frequency, the frequency modulation bandwidth and the frequency modulation period, and determining a time delay value between the frequency modulation signal and the echo signal based on a frequency mixing processing result and the transmission speed of the frequency modulation signal;
carrying out substitution calculation on the time delay value based on a calculation expression of the instantaneous phase of the frequency modulation signal to obtain the instantaneous phase of the difference frequency signal to be determined, and meanwhile, determining the corresponding relation between the carrier frequency and the frequency modulation bandwidth of the difference frequency signal to be determined and the carrier frequency and the frequency modulation bandwidth of the frequency modulation signal;
obtaining a target difference frequency signal based on the instantaneous phase and the corresponding relation of the difference frequency signal to be determined;
preprocessing the target difference frequency signal, and performing FFT operation on the preprocessed target difference frequency signal to obtain a signal spectrum of the target difference frequency signal;
determining amplitude values of the target difference frequency signal at different positions based on the signal spectrum, and determining the maximum amplitude value in the amplitude values as the peak value of the target difference frequency signal;
and analyzing the peak value by the millimeter wave range finder, determining a target position corresponding to the peak value, and recording the target position.
5. The active motor ranging method in millimeter wave radar according to claim 4, wherein obtaining a target difference frequency signal based on the instantaneous phase and the corresponding relationship of the difference frequency signal to be determined comprises:
acquiring an obtained target difference frequency signal, and extracting a frequency value of the target difference frequency signal;
comparing the frequency value with a preset frequency value;
if the frequency value is larger than or equal to the preset frequency value, judging that the target difference frequency signal is wrong, and controlling the millimeter wave radar antenna to transmit the frequency modulation signal to the target direction again;
otherwise, judging that the target error frequency signal is correct, determining the current transmitting frequency and the frequency modulation period of the frequency modulation signal, and recording and storing the transmitting frequency and the modulation period.
6. The active motor distance measuring method in millimeter wave radar as claimed in claim 1, wherein in step 3, controlling the millimeter wave radar antenna to move towards the peak position, and continuing to measure until the peak value jumps, the millimeter wave radar antenna stops moving and records the current measured distance, comprising:
acquiring a peak position of a difference frequency signal, and controlling the millimeter wave radar antenna to actively move towards the peak position by a preset distance measurement controller, wherein the peak position is a position of a measured object;
the millimeter wave radar antenna continuously transmits the frequency modulation signal to a target direction based on an active moving process and determines whether the peak value of the difference frequency signal jumps in real time;
when the peak value of the difference frequency signal jumps, the preset distance measurement controller controls the millimeter wave radar antenna to stop moving and determines a phase change value when the peak value jumps;
determining a critical point of a distance bin where the position of the measured object is located based on the phase change value, and determining a frequency value of a difference frequency signal generated between the measured object and the millimeter wave radar antenna based on the critical point;
determining a propagation time of the difference frequency signal based on the frequency value, while determining a propagation speed of the difference frequency signal;
determining a final distance value from the measured object to the millimeter wave radar antenna based on the propagation time and the propagation speed;
otherwise, the preset ranging controller controls the millimeter wave radar antenna to continuously and actively move towards the direction of the peak position until the peak value of the difference frequency signal jumps.
7. The active motor distance measuring method in the millimeter wave radar as claimed in claim 6, wherein when the peak value of the difference frequency signal is jumping, the preset distance measuring controller controls the millimeter wave radar antenna to stop moving, and determines the phase change value when the peak value is jumping, comprising:
acquiring current position information of the millimeter radar antenna when the preset ranging controller controls the millimeter radar antenna to stop moving, and monitoring whether a measured object is displaced in real time;
when the measured object is displaced, determining the peak value change condition of the difference frequency signal after FFT operation in real time, and recording the peak value change condition in real time;
determining the final distance between the object to be measured and the millimeter wave radar antenna after the displacement of the object to be measured is generated based on the real-time recording result;
otherwise, completing the detection of the distance of the measured object.
8. The active motor distance measuring method in the millimeter wave radar as claimed in claim 6, wherein the preset distance measuring controller controls the millimeter wave radar antenna to actively move towards the peak position direction, and comprises a stepping motor, a screw rod and the millimeter wave radar antenna;
the preset distance measuring controller is connected with the stepping motor;
the stepping motor is connected with the screw rod;
the screw rod is connected with the millimeter wave radar antenna;
the preset distance measurement controller controls the stepping motor to push the screw rod to move forwards, and the screw rod drives the millimeter wave radar antenna to move actively towards the direction of the peak position.
9. The active maneuvering distance measuring method in millimeter wave radar according to claim 1, characterized in that in step 4, obtaining the target distance between the object to be measured and the millimeter wave range finder based on the millimeter wave radar antenna moving distance and the measured distance comprises:
acquiring current position information of the millimeter wave radar antenna when the millimeter wave radar antenna stops moving, and simultaneously determining initial position information of the millimeter wave radar antenna;
determining an active maneuvering distance of the millimeter wave radar antenna based on the current position information and the initial position information, and simultaneously obtaining a current measured distance recorded when the millimeter wave radar antenna stops moving;
and summing the active maneuvering distance of the millimeter wave radar antenna and the current measured distance to obtain the target distance between the measured object and the millimeter wave distance meter.
10. The method of claim 9, wherein obtaining the target distance between the object to be measured and the millimeter wave range finder comprises:
obtaining the target distance between the measured object and the millimeter wave range finder, and simultaneously determining the relative direction of the measured object and the millimeter wave range finder;
determining the number of items to be recorded based on the target distance and the relative direction, and matching a target record report form in a preset record report template base based on the number of the items to be recorded;
and recording the target distance and the relative direction based on the target recording report sheet, and transmitting a recording result to a management terminal for storage management.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115327522A (en) * | 2022-08-19 | 2022-11-11 | 山东高速工程检测有限公司 | Bridge monitoring method and system based on millimeter wave radar |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115327522A (en) * | 2022-08-19 | 2022-11-11 | 山东高速工程检测有限公司 | Bridge monitoring method and system based on millimeter wave radar |
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