CN114966708A - Distance measuring method and system - Google Patents
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- CN114966708A CN114966708A CN202210494263.7A CN202210494263A CN114966708A CN 114966708 A CN114966708 A CN 114966708A CN 202210494263 A CN202210494263 A CN 202210494263A CN 114966708 A CN114966708 A CN 114966708A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
- G01S15/06—Systems determining the position data of a target
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
- G01S7/539—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
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Abstract
The invention discloses a distance measuring method and a system, wherein the method comprises the following steps: generating a monophonic signal and an orthogonal signal of the monophonic signal; transmitting the single-tone signal to a reflecting surface and receiving a reflected signal of the single-tone signal; calculating the propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and a preset sliding integration time; and calculating the propagation delay of the reflected signal according to the propagation delay phase of the reflected signal and the generation time of the single-tone signal so as to obtain the distance between the reflecting surface and the signal emission position. The preset sliding integration time is set to be integral multiple of half period of the single-tone signal, so that the propagation delay phase obtained by calculation is irrelevant to the amplitude of the reflected signal, and the distance measurement precision is improved; the invention can also effectively avoid the influence of the module processing time delay and the environment temperature on the distance measurement result, and further improve the distance measurement precision.
Description
Technical Field
The invention relates to the technical field of intelligent equipment, in particular to a distance measuring method and system for wearable equipment.
Background
With the rapid development of wearable devices (such as bluetooth headsets, telephone watches, etc.), how to know the distance between the device and the reflecting surface has become a research hotspot and also becomes a key for judging the wearing state of the device. At present, a distance measurement method based on ultrasonic waves is generally adopted to measure the distance between the wearable device and the reflecting surface, and the distance measurement principle is as follows: the sensor on the wearable device transmits ultrasonic waves and receives the ultrasonic waves reflected by the reflecting surface so as to obtain the path propagation delay of the ultrasonic waves and further obtain the distance between the reflecting surface and the wearable device.
However, the ultrasonic wave spreads spherically while propagating, so that the energy is more severely attenuated the farther the ultrasonic wave propagates; meanwhile, when the ultrasonic wave is transmitted in the medium, a part of energy can be absorbed by air, and the ultrasonic wave can be reflected, scattered, diffracted and the like after encountering a reflecting object, so that the ultrasonic wave which is really reflected back can be greatly attenuated. That is, the ultrasonic wave amplitude received at different time periods can be greatly changed due to the influence of thermal noise, the change of the shape and angle of the ultrasonic wave reflection surface and the change of the reflection distance. In order to improve the distance measurement accuracy, gain control is usually performed on signals at the receiving front end; because the gain control at the front end of the receiver needs a period of stabilization time, the ultrasonic pulse width has certain requirements, and the situation that the gain control is not adjusted and is finished due to too narrow pulse width is easy to occur, and finally the distance measurement fails. Therefore, in the existing ultrasonic-based distance measurement method, the reliability and the stabilization time of the gain control of the receiving front end directly influence the distance measurement precision of the wearable device.
In addition, a distance measurement method based on the phase can be adopted to measure the distance between the wearable device and the reflecting surface, and the method can realize high-precision phase delay measurement by counting the number of phase zero crossing point changes; however, this method is also affected by the amplitude of the received signal, and if the received signal is too weak, the phase decision is affected, which may result in a failure of the distance measurement. It can be seen that the phase-based ranging method also depends on the reliability and settling time of the gain control of the receive front-end.
Disclosure of Invention
The invention aims to provide a distance measuring method and a distance measuring system, which can calculate the propagation delay phase of a reflected signal according to a single-tone signal, an orthogonal signal of the single-tone signal, the reflected signal of the single-tone signal and preset sliding integration time; the preset sliding integration time is set to be integral multiple of the half period of the single-tone signal, so that the propagation delay phase obtained through calculation is irrelevant to the amplitude of the reflected signal, and the distance measurement precision is improved.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a distance measurement method comprising:
generating a monophonic signal and an orthogonal signal of the monophonic signal;
transmitting the single-tone signal to a reflecting surface and receiving a reflected signal of the single-tone signal;
calculating the propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and a preset sliding integration time; and
and calculating the propagation delay of the reflected signal according to the propagation delay phase of the reflected signal and the generation time of the single-tone signal so as to obtain the distance between the reflecting surface and the signal emission position.
Preferably, the preset sliding integration time is an integer multiple of a half period of the single-tone signal.
Preferably, the step of calculating the propagation delay phase of the reflected signal according to the mono signal, the quadrature signal, the reflected signal and a preset sliding integration time comprises:
performing sliding correlation integration on the single-tone signal and the reflection signal according to the preset sliding integration time to obtain a first sliding correlation result;
performing sliding correlation integration on the orthogonal signal and the reflection signal according to the preset sliding integration time to obtain a second sliding correlation result; and
and calculating the propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result.
Preferably, the first sliding correlation result is calculated by using the following formula:
wherein CORI (T) is the first sliding correlation result; sin (ω t) is the monophonic signal, and ω is the frequency of the monophonic signal, t is time; a. the 1 sin(ωt+θ 1 ) Is the reflected signal, and A 1 Is the amplitude of the reflected signal, θ 1 Is the propagation delay phase of the reflected signal; t is the preset sliding integration time; tau to tau + T is an integration time period, and tau is an integration starting time;
the second sliding correlation result is calculated by the following formula:
wherein CORQ (T) is the second sliding correlation result; cos (ω t) is the quadrature signal;
the propagation delay phase of the reflected signal is calculated by adopting the following formula:
preferably, the step of calculating the propagation delay of the reflected signal according to the propagation delay phase of the reflected signal and the generation time of the mono signal comprises:
selecting the corresponding time when the propagation delay phase of the reflected signal is greater than a first preset threshold value for the first time as a first correlation peak stabilization time;
calculating the whole period number of the propagation delay of the reflected signal according to the first correlation peak stable time and the generation time of the single-tone signal;
calculating the propagation delay of the reflected signal according to the whole period number of the propagation delay of the reflected signal and the period of the single-tone signal; and
and calculating the distance between the reflecting surface and the signal transmitting position according to the propagation delay of the reflected signal.
Preferably, the number of the whole period of the propagation delay of the reflected signal is calculated by using the following formula:
wherein N is 1 The number of the whole period of the propagation delay of the reflected signal; floor () is rounded down; t is 0 Generating a tone signal for the tone signal; t is 1 Is the first correlation peak settling time; t is tone Is the period of the single tone signal;
the propagation delay of the reflected signal is calculated by adopting the following formula:
T a ＝N 1 ·T tone +T corr
wherein, T a Is the propagation delay of the reflected signal; and T corr The following formula is used for calculation:
the distance between the reflecting surface and the signal transmitting position is calculated by adopting the following formula:
S 0 ＝T a ·V/2
wherein S is 0 The distance between the reflecting surface and a signal transmitting position is obtained; and V is the signal propagation speed corresponding to the distance measurement environment temperature.
Based on the same inventive concept, the invention also provides a distance measuring system, which is used for wearable equipment and comprises:
the signal generating module is used for generating a single-tone signal and an orthogonal signal of the single-tone signal;
the signal transmitting module is connected with the signal generating module and is used for transmitting the single-tone signal to a reflecting surface;
a signal receiving module for receiving a reflected signal of the single tone signal;
the phase calculation module is respectively connected with the signal receiving module and the signal generation module and is used for calculating the propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and preset sliding integration time; and
and the measurement control module is respectively connected with the phase calculation module and the signal generation module and is used for calculating the propagation delay of the reflected signal according to the propagation delay phase of the reflected signal and the generation time of the single-tone signal so as to obtain the distance between the reflecting surface and the distance measurement system.
Preferably, the preset sliding integration time is an integer multiple of a half period of the single-tone signal.
Preferably, the phase calculation module includes:
the correlation integration unit is respectively connected with the signal receiving module and the signal generating module and is used for performing sliding correlation integration on the single-tone signal and the reflection signal according to the preset sliding integration time to obtain a first sliding correlation result; performing sliding correlation integration on the orthogonal signal and the reflection signal according to the preset sliding integration time to obtain a second sliding correlation result;
and the phase calculation unit is connected with the correlation integration unit and used for calculating the propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result.
Preferably, the first sliding correlation result is calculated by using the following formula:
wherein CORI (T) is the first sliding correlation result; sin (ω t) is the monophonic signal, and ω is the frequency of the monophonic signal, t is time; a. the 1 sin(ωt+θ 1 ) Is the reflected signal, and A 1 Is the amplitude of the reflected signal, θ 1 Is the propagation delay phase of the reflected signal; t is the preset sliding integration time; tau to tau + T is an integration time period, and tau is an integration starting time;
the second sliding correlation result is calculated by the following formula:
wherein CORQ (T) is the second sliding correlation result; cos (ω t) is the quadrature signal;
the propagation delay phase of the reflected signal is calculated by adopting the following formula:
preferably, the measurement control module comprises:
the propagation delay calculating unit is respectively connected with the phase calculating unit and the signal generating module and is used for selecting the corresponding time when the propagation delay phase of the reflected signal is greater than a first preset threshold value for the first time as a first correlation peak stable time; calculating the whole period number of the propagation delay of the reflected signal according to the first correlation peak stable time and the generation time of the single-tone signal; calculating the propagation delay of the reflected signal according to the whole period number of the propagation delay of the reflected signal and the period of the single-tone signal;
and the distance calculation unit is connected with the propagation delay calculation unit and used for calculating the distance between the reflecting surface and the distance measurement system according to the propagation delay of the reflected signal.
Preferably, the whole period number of the propagation delay of the reflected signal is calculated by using the following formula:
wherein N is 1 The number of the whole period of the propagation delay of the reflected signal; floor () is rounded down; t is 0 Generating a tone signal for the tone signal; t is 1 Is the first correlation peak settling time; t is tone Is the period of the single tone signal;
the propagation delay of the reflected signal is calculated by adopting the following formula:
T a ＝N 1 ·T tone +T corr
wherein, T a Is the propagation delay of the reflected signal; and T corr The following formula is used for calculation:
the distance between the reflecting surface and the distance measuring system is calculated by adopting the following formula:
S 0 ＝T a ·V/2
wherein S is 0 The distance between the reflecting surface and the distance measuring system is obtained; and V is the signal propagation speed corresponding to the distance measurement environment temperature.
Preferably, the measurement control module further comprises:
the processing time delay calculation unit is respectively connected with the propagation time delay calculation unit and the distance calculation unit and is used for calculating module processing time delay at a preset environment temperature so as to correct the distance between the reflecting surface and the distance measurement system; the module processing time delay is the sum of the processing time delay from the signal generating module to the signal transmitting module and the processing time delay from the signal receiving module to the correlation integration unit;
and the propagation speed calculation unit is respectively connected with the propagation delay calculation unit, the processing delay calculation unit and the distance calculation unit and is used for calculating the signal propagation speed when the temperature of the distance measurement environment is unknown.
Preferably, the signal receiving module is further configured to receive an attenuated signal of the single-tone signal;
the correlation integration unit is further configured to perform sliding correlation integration on the monophonic signal and the attenuated signal according to the preset sliding integration time to obtain a third sliding correlation result; performing sliding correlation integration on the orthogonal signal and the attenuation signal according to the preset sliding integration time to obtain a fourth sliding correlation result;
the phase calculation unit is further configured to calculate a propagation delay phase of the attenuated signal according to the third sliding correlation result and the fourth sliding correlation result;
the propagation delay calculation unit is further configured to select, as a second correlation peak stabilization time, a time corresponding to a time when the propagation delay phase of the attenuated signal is first greater than a second preset threshold; calculating the whole period number of the propagation delay of the attenuation signal according to the second correlation peak stability time and the transmitting time of the single-tone signal; and calculating the propagation delay of the attenuation signal according to the whole cycle number of the propagation delay of the attenuation signal and the cycle of the single-tone signal so as to acquire the module processing delay.
Preferably, the third sliding correlation result is calculated by using the following formula:
wherein, CORI r (T) is the third sliding correlation result; a. the 2 sin(ωt+θ 2 ) Is the attenuated signal, and A 2 Is the amplitude of the attenuated signal, θ 2 Is the propagation delay phase of the attenuated signal;
the fourth sliding correlation result is calculated by the following formula:
wherein, CORQ r (T) isA fourth sliding correlation result;
the propagation delay phase of the attenuation signal is calculated by adopting the following formula:
the whole period number of the propagation delay of the attenuation signal is calculated by adopting the following formula:
wherein N is 2 The number of the whole period of the propagation delay of the attenuation signal; t is 2 Is the second correlation peak settling time;
the propagation delay of the attenuation signal is calculated by adopting the following formula:
wherein, T b Is the propagation delay of the attenuated signal; and is
The following formula is used for calculation:
preferably, the module processing delay is calculated by using the following formula:
T d ＝T b ′-T c
T c ＝d/v
wherein, T d Processing a time delay for the module; t is b ' is the propagation delay of the attenuated signal at a preset ambient temperature; t is c For transmission between the signal transmitting module and the signal receiving module at a preset ambient temperatureBroadcasting time; d is the distance between the signal transmitting module and the signal receiving module; v is a signal propagation speed corresponding to a preset environment temperature;
the distance correction value of the reflecting surface and the distance measuring system is calculated by adopting the following formula:
S 1 ＝(T a -T d )·V/2
wherein S is 1 A distance correction value for the reflecting surface and the distance measuring system; and V is the signal propagation speed corresponding to the distance measurement environment temperature.
Preferably, the signal propagation speed when the distance measurement environment temperature is unknown is calculated by adopting the following formula:
wherein the content of the first and second substances,
the propagation delay of the attenuated signal at ambient temperature is measured for distance.
Compared with the prior art, the invention has at least one of the following advantages:
the invention provides a distance measuring method and a distance measuring system, which can generate a single-tone signal and an orthogonal signal thereof, receive a reflected signal after the single-tone signal is transmitted, and calculate the propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and preset sliding integration time, so that the propagation delay of the reflected signal is obtained by combining the generation time of the single-tone signal, and the distance between a reflecting surface and the distance measuring system is further obtained.
In the invention, the preset sliding integration time is integral multiple of a half period of a single-tone signal, so that the propagation delay phase obtained by sliding correlation integration operation and phase calculation is irrelevant to the amplitude of a reflected signal, the problems of distance measurement failure and the like caused by amplitude jitter of the reflected signal in the prior art can be avoided, and the distance measurement precision is further improved; meanwhile, a complex receiving front-end amplifying circuit is not needed, and the requirement on the width of the single-tone signal is low.
The setting of the integral time period in the invention ensures that the data amount required to be cached in the sliding correlation integral operation and the phase calculation process is small, the requirements on calculation resources and storage resources are low, and the processing speed is high.
The method and the device can be applied to the condition that the signal propagation speed corresponding to the measured environment temperature is known, can also be applied to the condition that the signal propagation speed corresponding to the measured environment temperature is unknown, and have better applicability.
The invention utilizes the characteristic that the distance between the signal sending module and the signal receiving module is known, can measure the internal transmission delay of the equipment, namely the processing delay of the module, thereby improving the distance measurement precision, and simultaneously effectively avoids the influence of temperature on the signal propagation speed and further improves the distance measurement precision.
Drawings
Fig. 1 is a flowchart of a distance measuring method according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a distance measuring system according to an embodiment of the present invention.
Detailed Description
The following describes a distance measuring method and system according to the present invention in detail with reference to the accompanying drawings and the detailed description. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are all used in a non-precise scale for the purpose of facilitating and distinctly aiding in the description of the embodiments of the present invention. To make the objects, features and advantages of the present invention comprehensible, reference is made to the accompanying drawings. It should be understood that the structures, ratios, sizes, etc. shown in the drawings and attached to the description are only for understanding and reading the disclosure of the present disclosure, and are not for limiting the scope of the present disclosure, so they do not have the essential meaning in the art, and any modifications of the structures, changes of the ratio relationships, or adjustments of the sizes, should fall within the scope of the present disclosure without affecting the efficacy and the achievable purpose of the present disclosure.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Referring to fig. 1, the present embodiment provides a distance measuring method, including: step S110, generating a tone signal and an orthogonal signal of the tone signal, and recording the generation time of the tone signal; step S120, transmitting the single tone signal to a reflecting surface, and receiving a reflected signal of the single tone signal; step S130, calculating the propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and a preset sliding integration time; and step S140, calculating the propagation delay of the reflected signal according to the propagation delay phase of the reflected signal and the generation time of the single-tone signal so as to obtain the distance between the reflecting surface and the signal emission position.
Specifically, in this embodiment, in the step S110, the single tone signal may adopt ultrasonic waves, and the frequency of the single tone signal is a frequency (40KHz to 120KHz) corresponding to the ultrasonic waves; after the monophonic signal is generated, the orthogonal signals of the monophonic signal may be generated by phase rotating the monophonic signal or using a table look-up method. In step S120, after the single-tone signal is transmitted in a pulse form as a transmission signal, the ultrasonic wave reflected by the reflection surface is the reflection signal. More specifically, the frequency, period, and propagation speed of the single-tone signal, the orthogonal signal, and the reflected signal are the same, but the invention is not limited thereto.
In other embodiments, the frequency of the single tone signal may also be a frequency corresponding to infrasonic waves, a frequency within the range of human ear hearing, or a frequency higher than ultrasonic waves.
With continued reference to fig. 1, the step S130 includes: performing sliding correlation integration on the single-tone signal and the reflection signal according to the preset sliding integration time to obtain a first sliding correlation result; performing sliding correlation integration on the orthogonal signal and the reflection signal according to the preset sliding integration time to obtain a second sliding correlation result; and calculating the propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result.
It will be appreciated that in some other embodiments, the first sliding correlation result is calculated using the following equation:
wherein CORI (T) is the first sliding correlation result; sin (ω t) is the monophonic signal, and ω is the frequency of the monophonic signal, t is time; a. the 1 sin(ωt+θ 1 ) Is the reflected signal, and A 1 Is the amplitude of the reflected signal, θ 1 Is the propagation delay phase of the reflected signal; t is the preset sliding integration time; tau to tau + T is an integration time period, and tau is an integration starting time;
the second sliding correlation result is calculated by the following formula:
wherein CORQ (T) is the second sliding correlation result; cos (ω t) is the quadrature signal;
the propagation delay phase of the reflected signal is calculated by adopting the following formula:
in some embodiments, the preset sliding integration time is an integer multiple of a half period of the single-tone signal.
Specifically, in this embodiment, the formula (1) is developed to obtain
After the formula (2) is developed, the product can be obtained
Since the predetermined sliding integration time T is an integer multiple of the half period of the monophonic signal, the first term remains in both equations (4) and (5), which is:
CORI(T)＝A 1 Tcos(θ 1 )/2 (6)
CORQ(T)＝A 1 Tsin(θ 1 )/2 (7)
from equations (6) and (7), equation (3) can then be derived. More specifically, since the mono signal, the quadrature signal, the reflection signal and the predetermined sliding integration time are known, the first sliding integration result and the second sliding integration result can be obtained according to equations (1) and (2); substituting the first sliding integration result and the second sliding integration result into a formula (3) to obtain the propagation delay phase theta of the reflected signal 1 . Further, as can be seen from equation (3), the propagation delay phase θ of the reflected signal 1 The calculation of (2) does not involve the amplitude of the reflected signal, so that the subsequent distance calculation between the reflecting surface and the signal emission place is independent of the amplitude of the reflected signal, thereby improving the distance measurement accuracy, but the invention is not limited thereto.
Specifically, in this embodiment, the preset sliding integration time T is generally in the order of milliseconds, and the relative position between the emission position of the monophonic signal and the reflection surface is kept fixed within the integration time period τ to τ + T, at this time, the amplitude a of the reflection signal is kept constant 1 And propagation delay phase theta 1 Short time stationary, so the amplitude A of the reflected signal 1 And propagation delay phase theta 1 And can be regarded as a constant value within the integration time period tau-tau + T. The setting of the integral time interval tau-tau + T can change the calculation of n multiply-accumulate results (n is a sampling point contained in the sampling time interval) required by one sampling time interval in the prior art into the calculation of only one multiply-accumulate result, thereby greatly saving the calculation logic resource. Meanwhile, as the time-sharing processing is carried out between the current integration time period and the previous integration time period and the next integration time period, the data of all the integration time periods do not need to be cached any more, and the storage resources can be reduced. In addition, in this embodiment, each sampling point in the prior art outputs a phase result, which is changed into an integration time period to output a propagation delay phase; although it seems that the accuracy is higher and the real-time performance is better when each sampling point outputs one phase result, two phase results output by adjacent sampling points have great correlation, so that the change is not great, and a great time interval is needed for seeing the phase change of the correlation result. In this embodiment, the current integration time period is adjacent to, but not overlapping with, the previous integration time period and the next integration time period, a longer time interval exists between the adjacent integration time periods, so that the two calculated adjacent propagation delay phases have a better discrimination, but the present invention is not limited thereto.
With continued reference to fig. 1, the step S140 includes: selecting the corresponding time when the propagation delay phase of the reflected signal is greater than a first preset threshold value for the first time as a first correlation peak stabilization time; calculating the whole period number of the propagation delay of the reflected signal according to the first correlation peak stable time and the generation time of the single-tone signal; calculating the propagation delay of the reflected signal according to the whole period number of the propagation delay of the reflected signal and the period of the single-tone signal; and calculating the distance between the reflecting surface and the signal transmitting position according to the propagation delay of the reflected signal.
It will be appreciated that in some other embodiments, the number of whole periods of the propagation delay of the reflected signal is calculated using the following equation:
wherein, N 1 The number of the whole period of the propagation delay of the reflected signal; floor () is rounded down; t is 0 Generating a tone signal for the tone signal; t is 1 Is the first correlation peak settling time; t is tone Is the period of the single tone signal;
the propagation delay of the reflected signal is calculated by adopting the following formula:
T a ＝N 1 ·T tone +T corr (9)
wherein, T a Is the propagation delay of the reflected signal; wherein, T corr The propagation delay phase θ of the reflected signal can be calculated according to the formula (3) 1 And calculating according to the following formula:
the distance between the reflecting surface and the signal emission position is calculated by adopting the following formula:
S 0 ＝T a ·V/2 (11)
wherein S is 0 The distance between the reflecting surface and a signal transmitting position is obtained; and V is the signal propagation speed corresponding to the distance measurement environment temperature.
Specifically, since the propagation delay phase of the reflected signal calculated in step S130 has a phase ambiguity of a whole period, the propagation delay of the reflected signal cannot be directly calculated according to the propagation delay phase of the reflected signal, and it is necessary to calculate the whole period number of the propagation delay of the reflected signal through formula (8), and then calculate the propagation delay of the reflected signal through formula (9) and formula (10). More specifically, in this embodiment, it is further required to record, in real time, an output time of the propagation delay phase of the reflection signal corresponding to each integration time period (i.e., at time τ + T in each integration time period); and when the propagation delay phase of the reflected signal is greater than the first preset threshold for the first time, taking the output time of the propagation delay phase of the reflected signal as the first correlation peak stabilization time, and substituting the first correlation peak stabilization time into a formula (8) to calculate the whole cycle number of the propagation delay of the reflected signal. Preferably, the first preset threshold is an average value of propagation delay phases of the reflected signals measured multiple times in a laboratory environment and stable, but the invention is not limited thereto.
Specifically, in the present embodiment, since the propagation speed of the sound wave in the air medium is related to the ambient temperature, the propagation speed of the signal in the air medium changes when the ambient temperature changes. Therefore, when the distance between the reflecting surface and the signal transmitting position is calculated according to the formula (11), the temperature of the current environment, namely the distance measurement environment, needs to be determined first, so that the signal propagation speed corresponding to the temperature of the distance measurement environment is determined, and the distance between the reflecting surface and the signal transmitting position is obtained, so that the distance measurement precision is improved. In addition, in this embodiment, when the distance between the reflection surface and the signal transmission location is calculated based on the distance measurement method, it is considered that the signal transmission location, the signal reception location, and the signal processing location (including the sliding correlation integration operation location and the propagation delay phase calculation location) are all located at the same point, that is, it is considered that there is no hardware processing delay, otherwise, the processing delay is calculated according to the following method or formula, and the distance between the reflection surface and the signal transmission location is corrected, but the invention is not limited thereto.
Based on the same inventive concept, as shown in fig. 2, the present embodiment further provides a distance measuring system for a wearable device, including: a signal generating module 201, configured to generate a tone signal and an orthogonal signal of the tone signal, and record a generation time of the tone signal; a signal transmitting module 202, connected to the signal generating module 201, for transmitting the single tone signal to a reflecting surface; a signal receiving module 203, configured to receive a reflected signal of the single tone signal; a phase calculation module 204, connected to the signal receiving module 203 and the signal generating module 201, respectively, for calculating a propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and a preset sliding integration time; and a measurement control module 205, connected to the phase calculation module 204 and the signal generation module 201, respectively, and configured to calculate the propagation delay of the reflected signal according to the propagation delay phase of the reflected signal and the generation time of the single-tone signal, so as to obtain the distance between the reflecting surface and the distance measurement system.
Specifically, in this embodiment, a digital-to-analog converter (DAC)206 is further disposed between the signal generating module 201 and the signal transmitting module 202, and is configured to convert a digital signal format of the single-tone signal into an analog signal format. An analog-to-digital converter (ADC)207 is further disposed between the signal receiving module 203 and the phase calculating module 204, and the signal receiving module 203 may convert the acoustic signal format of the reflected signal into an analog signal format through an analog circuit at a front end thereof, and then convert the acoustic signal format into a digital signal format through the analog-to-digital converter (ADC)207 and transmit the digital signal format to the phase calculating module 204. Preferably, a filter 208 is further disposed between the analog-to-digital converter (ADC)207 and the phase calculation module 204 to filter out interference such as low-frequency noise and human voice in the reflected signal. Preferably, different ultrasonic sensors can be respectively used as the signal transmitting module 202 and the signal receiving module 203; in some embodiments, a speaker in the wearable device may be used as the signal transmitting module 202, and a microphone in the wearable device may be used as the signal receiving module 203, but the invention is not limited thereto.
With continued reference to fig. 2, the phase calculation module 204 includes: a correlation integration unit 2041, connected to the signal receiving module 203 and the signal generating module 201, respectively, and configured to perform sliding correlation integration on the mono signal and the reflected signal according to the preset sliding integration time to obtain a first sliding correlation result; performing sliding correlation integration on the orthogonal signal and the reflection signal according to the preset sliding integration time to obtain a second sliding correlation result; a phase calculating unit 2042, connected to the correlation integrating unit 2041, configured to calculate a propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result.
It will be appreciated that in some other embodiments, the first sliding correlation result is calculated using the following equation:
wherein CORI (T) is the first sliding correlation result; sin (ω t) is the monophonic signal, and ω is the frequency of the monophonic signal, t is time; a. the 1 sin(ωt+θ 1 ) Is the reflected signal, and A 1 Is the amplitude of the reflected signal, θ 1 Is the propagation delay phase of the reflected signal; t is the preset sliding integration time, and the preset sliding integration time is an integral multiple of a half period of the single-tone signal; tau to tau + T is an integration time period, and tau is an integration starting time;
the second sliding correlation result is calculated by the following formula:
wherein CORQ (T) is the second sliding correlation result; cos (ω t) is the quadrature signal;
the propagation delay phase of the reflected signal is calculated by adopting the following formula:
referring to fig. 2, the measurement control module 205 includes: a propagation delay calculating unit 2051, respectively connected to the phase calculating unit 2042 and the signal generating module 201, configured to select, as a first correlation peak settling time, a time when a propagation delay phase of the reflected signal is first greater than a first preset threshold; calculating the whole period number of the propagation delay of the reflected signal according to the first correlation peak stable time and the generation time of the single-tone signal; calculating the propagation delay of the reflected signal according to the whole period number of the propagation delay of the reflected signal and the period of the single-tone signal; and a distance calculation unit 2052, connected to the propagation delay calculation unit 2051, configured to calculate a distance between the reflection surface and the distance measurement system according to the propagation delay of the reflection signal. In addition, the measurement control module 205 is further provided with a control unit, connected to the signal generation module 201, for controlling the period interval of transmitting the tone signal, the pulse duration of transmitting the tone signal once, the integration period duration, and the like.
It will be appreciated that in some other embodiments, the number of whole periods of the propagation delay of the reflected signal is calculated using the following equation:
wherein N is 1 The number of the whole period of the propagation delay of the reflected signal; floor () is rounded down; t is 0 Generating a tone signal for the tone signal; t is 1 Is the first correlation peak settling time; t is tone Is the period of the single tone signal;
the propagation delay of the reflected signal is calculated by adopting the following formula:
T a ＝N 1 ·T tone +T corr (9)
wherein, T a Is the propagation delay of the reflected signal; and T corr The following formula is used for calculation:
the distance between the reflecting surface and the distance measuring system is calculated by adopting the following formula:
S 0 ＝T a ·V/2 (11)
wherein S is 0 The distance between the reflecting surface and the distance measuring system is obtained; and V is the signal propagation speed corresponding to the distance measurement environment temperature.
Referring to fig. 2, the measurement control module 205 further includes: a processing delay calculation unit 2053, respectively connected to the propagation delay calculation unit 2051 and the distance calculation unit 2051, and configured to calculate a module processing delay at a preset ambient temperature, so as to correct a distance between the reflecting surface and the distance measurement system; and the module processing delay is the sum of the processing delay from the signal generating module 201 to the signal transmitting module 202 and the processing delay from the signal receiving module 203 to the correlation integration unit 2041; a propagation velocity calculating unit 2054, connected to the propagation delay calculating unit 2051, the processing delay calculating unit 2053, and the distance calculating unit 2052, respectively, is configured to calculate a signal propagation velocity when the temperature of the distance measurement environment is unknown.
Specifically, in this embodiment, when the distance between the reflection surface and the distance measurement system is calculated based on the distance measurement system, since the modules are located at different positions, a certain distance exists between the modules, so that the propagation delay of the reflection signal calculated according to equations (9) and (10) includes the module processing delay (i.e., hardware processing delay); and the module processing delay is the sum of the transmission processing delay (i.e. the delay from the signal generating module 201 to the signal transmitting module 202) and the reception processing delay (i.e. the delay from the signal receiving module 203 to the correlation integrating unit 2041). Therefore, in order to ensure the distance measurement accuracy of the distance measurement system, the module processing time delay needs to be calculated, and the distance between the reflecting surface and the distance measurement system calculated according to the formula (11) needs to be corrected. In addition, since the signal is transmitted from the signal generating module 201 to the signal transmitting module 202 and from the signal receiving module 203 to the correlation integrating unit 2041 through data lines, the module processing delay is not affected by the ambient temperature, and the module processing delay may be stored in the distance calculating unit or other storage media as a fixed deviation, but the invention is not limited thereto.
Specifically, in this embodiment, after the single-tone signal is transmitted as a transmission signal in a pulse form, not only the reflection signal but also the transmission signal is received after passing through a certain path; due to the path propagation delay and attenuation of the received transmission signal, the received transmission signal is different from the generated tone signal, and the received transmission signal can be regarded as the attenuation signal of the tone signal. More specifically, the signal receiving module 203 is further configured to receive an attenuated signal of the single-tone signal; the phase calculation module 204 is further configured to calculate a propagation delay phase of the attenuated signal according to the single-tone signal, the orthogonal signal, the attenuated signal and the preset sliding integration time; the propagation delay calculation unit 2051 is further configured to calculate the propagation delay of the attenuated signal according to the propagation delay phase of the attenuated signal and the generation time of the mono-tone signal, so as to obtain the module processing delay.
More specifically, in this embodiment, the correlation integration unit 2041 is configured to perform sliding correlation integration on the mono signal and the attenuated signal according to the preset sliding integration time to obtain a third sliding correlation result; performing sliding correlation integration on the orthogonal signal and the attenuation signal according to the preset sliding integration time to obtain a fourth sliding correlation result; the phase calculation unit 2042 is configured to calculate a propagation delay phase of the attenuated signal according to the third sliding correlation result and the fourth sliding correlation result; the propagation delay calculation unit 2051 is configured to select, as a second correlation peak settling time, a time corresponding to a time when the propagation delay phase of the attenuated signal is first greater than a second preset threshold; calculating the whole period number of the propagation delay of the attenuation signal according to the second correlation peak stable time and the emission time of the single-tone signal; and calculating the propagation delay of the attenuation signal according to the whole period number of the propagation delay of the attenuation signal and the period of the single-tone signal.
It will be appreciated that in some other embodiments, the third sliding correlation result is calculated using the following formula:
wherein, CORI r (T) is the third sliding correlation result; a. the 2 sin(ωt+θ 2 ) Is the attenuated signal, and A 2 Is the amplitude of the attenuated signal, θ 2 Is the propagation delay phase of the attenuated signal;
the fourth sliding correlation result is calculated by the following formula:
wherein, CORQ r (T) is the fourth sliding correlation result;
the propagation delay phase of the attenuation signal is calculated by adopting the following formula:
the whole period number of the propagation delay of the attenuation signal is calculated by adopting the following formula:
wherein N is 2 The number of the whole period of the propagation delay of the attenuation signal; t is 2 Is the second correlation peak settling time;
the propagation delay of the attenuation signal is calculated by adopting the following formula:
wherein, T b Is the propagation delay of the attenuated signal; and is
The following formula is adopted for calculation:
in some embodiments, the module processing delay is calculated using the following formula:
T d ＝T b ′-T c (18)
T c ＝d/v (19)
wherein, T d Processing a time delay for the module; t' b Calculating the propagation delay of the attenuation signal at a preset ambient temperature according to the equations (12) to (17); t is c The propagation time between the signal transmitting module and the signal receiving module at a preset ambient temperature is set; d is the distance between the signal transmitting module and the signal receiving module; v is a signal propagation speed corresponding to the preset environment temperature.
The distance correction value of the reflecting surface and the distance measuring system is calculated by adopting the following formula:
S 1 ＝(T a -T d )·V/2 (20)
wherein S is 1 A distance correction value for the reflecting surface and the distance measuring system; and V is the signal propagation speed corresponding to the distance measurement environment temperature.
Specifically, in this embodiment, since the relative positions of the signal emitting module 202 and the signal receiving module 203 are kept fixed, the amplitude a of the attenuated signal is within the integration time period τ to τ + T 2 And propagation delay phaseθ 2 Plateau values are all constant values. Since the propagation delay phase of the attenuated signal calculated according to the formula (14) has a phase ambiguity of a whole period, the propagation delay of the attenuated signal cannot be directly calculated according to the propagation delay phase of the attenuated signal, the whole period number of the propagation delay of the attenuated signal needs to be calculated according to the formula (15), and then the propagation delay of the attenuated signal is calculated according to the formula (16) and the formula (17). More specifically, in this embodiment, it is further required to record, in real time, an output time of the propagation delay phase of the attenuated signal corresponding to each integration time period (i.e., at time τ + T in each integration time period); and when the propagation delay phase of the attenuation signal is greater than the second preset threshold for the first time, taking the output time of the propagation delay phase of the attenuation signal as the second correlation peak stabilization time, and substituting the second correlation peak stabilization time into a formula (15) to calculate the whole cycle number of the propagation delay of the attenuation signal. Preferably, the second preset threshold is an average value of propagation delay phases of the attenuated signals measured and stabilized multiple times in a laboratory environment, but the invention is not limited thereto.
Specifically, in this embodiment, based on the distance measurement system, the step of calculating the module processing delay includes: preferably, the distance d between the signal transmitting module 202 and the signal receiving module 203 is measured in advance by using the fixed position characteristics of the signal transmitting module 202 and the signal receiving module 203. Then setting a laboratory environment, wherein the laboratory environment temperature (namely the preset environment temperature) is known, and the signal propagation speed corresponding to the laboratory environment temperature (namely the preset environment temperature) is known; according to the signal propagation speed corresponding to the laboratory environment temperature (i.e. the preset environment temperature), the propagation time T of the signal between the signal transmitting module 202 and the signal receiving module 203 can be calculated c And Tc is d/v, where v is the signal propagation speed corresponding to the laboratory environment (i.e., the preset ambient temperature). Finally, in a laboratory environment, the distance measuring system is operated in a first mode, and the signal receiving module 203 receives only the attenuation signal of the monophonic signal in the first mode, which can be achieved by equations (12) to (17)Obtaining the propagation delay T 'of the attenuation signal under the environment temperature of a laboratory (namely the preset environment temperature)' b (ii) a Since the path corresponding to the propagation delay of the attenuated signal is from the signal generating module 201 to the signal transmitting module 202 to the signal receiving module 203 to the correlation integration unit 2041, and is independent of the transmitting surface position, the propagation delay T 'of the attenuated signal is determined at a laboratory environment temperature (i.e. a preset environment temperature)' b And the propagation time T of the signal between the signal transmitting module 202 and the signal receiving module 203 c The difference value is the module processing time delay T d And T is d ＝T b —T c 。
With continued reference to fig. 2, the propagation velocity of the signal when the temperature of the distance measurement environment is unknown is calculated by the following formula:
wherein the content of the first and second substances,
the propagation delay of the attenuated signal at the distance measurement ambient temperature is calculated according to equations (12) to (17) at the distance measurement ambient temperature.
Specifically, in some distance measurement scenarios, there may be a case where the temperature of the distance measurement environment cannot be determined, that is, unknown, so that the signal propagation speed corresponding to the temperature of the distance measurement environment cannot be determined, and further, the distance between the reflection surface and the distance measurement system cannot be accurately measured. To overcome this drawback, based on the distance measurement system, the step of calculating the propagation velocity of the signal when the temperature of the distance measurement environment is unknown specifically includes: in the distance measurement environment, the distance measurement system is first operated in the first mode, that is, the signal receiving module 203 receives only the attenuated signal of the single tone signal, and calculates the propagation delay of the attenuated signal at the distance measurement environment temperature according to the equations (12) to (17)
Since the distance d between the signal transmitting module 202 and the signal receiving module 203 is known, and the module handles the time delay T d If known, the signal propagation speed between the signal transmitting module 202 and the signal receiving module 203 at the distance measurement environment temperature can be obtained according to the formula (21), that is, the signal propagation speed V corresponding to the distance measurement environment temperature; at this time, the formula (20) becomes
Then, the distance measuring system is operated in a second mode, and in the second mode, the signal receiving module 203 only receives the reflected signal of the single tone signal, and calculates the propagation delay T of the reflected signal according to the formulas (1), (2), (3), (8), (9) and (10) a (ii) a Delaying the propagation of the reflected signal by a time T a Substituting the formula (22) can obtain the distance correction value of the reflecting surface and the distance measuring system.
In addition, the distance calculating unit 2052 may directly calculate the distance between the reflecting surface and the distance measuring system by using a formula (22), and may effectively avoid the influence of the module processing delay and the ambient temperature on the distance measuring result, thereby improving the distance measuring accuracy, but the invention is not limited thereto.
In this embodiment, when the signal propagation speed is calculated when the temperature of the distance measurement environment is unknown based on the distance measurement system, since the distance between the reflection surface and the signal receiving module 203 is much greater than the distance between the signal transmitting module 202 and the signal receiving module 203, the distance measurement system can be operated in the first mode or the second mode by controlling the transmission of the single-tone signal. More specifically, when the signal transmitting module 202 starts to transmit the single tone signal, the signal receiving module 203 will only receive the attenuated signal and will not receive the reflected signal, i.e. the distance measuring system operates at the second stageA mode; when the signal transmitting module 202 stops transmitting the single tone signal, the signal receiving module 203 receives only the reflected signal and does not receive the attenuated signal, i.e., the distance measuring system operates in the second mode. It should be noted that, before the signal transmitting module 202 stops transmitting the single-tone signal, if the reflected signal arrives, the measured propagation delay of the attenuated signal will be inaccurate. Here, assuming that the shortest distance between the reflection surface and the signal receiving module 203 is 5mm, the time of the reflected signal reaching the signal receiving module 203 is 5 × 2 × 10 -3 29.4us, this problem is avoided when the duration of time for which the monophonic signal is transmitted is less than 29.4us (i.e., the arrival time of the reflected signal at the shortest distance). In practice, the distance between the reflecting surface and the signal receiving module 203 is usually much larger than 5mm, so that the above requirement can be fully satisfied when transmitting the single tone signal with 1 cycle length of 40 KHz. In addition, the propagation delay phase of the attenuation signal under the temperature of the distance measurement environment can be tracked, if the relevant peak and the phase are jittered, the interference of a reflected wave is indicated, the distance measurement result can be thrown away, and meanwhile, the time for transmitting the single-tone signal is shortened, and the measurement is carried out again.
In summary, the present embodiment provides a distance measurement method and system, which can generate a single-tone signal and an orthogonal signal thereof, and receive a reflected signal after the single-tone signal is transmitted, so as to calculate a propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and a preset sliding integration time, thereby obtaining a propagation delay of the reflected signal by combining the generation time of the single-tone signal, so as to obtain a distance between a reflecting surface and the distance measurement system. In the embodiment, the sliding integration time is preset to be integral multiple of a half period of a single-tone signal, so that the propagation delay phase obtained through sliding correlation integration operation and phase calculation is irrelevant to the amplitude of a reflected signal, the problems of distance measurement failure and the like caused by amplitude jitter of the reflected signal in the prior art can be avoided, and the distance measurement precision is further improved; meanwhile, a complex receiving front-end amplifying circuit is not needed, and the requirement on the width of a single-tone signal is low; the setting of the integral time period enables the data amount required to be cached in the sliding correlation integral operation and the phase calculation process to be small, the requirements on calculation resources and storage resources to be low, and the processing speed to be high. In addition, the present embodiment utilizes the characteristic that the distance between the signal sending module and the signal receiving module is known, and can measure the internal transmission delay of the device, i.e. the module processing delay, thereby improving the distance measurement precision.
While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.
Claims (17)
1. A distance measuring method, characterized by comprising:
generating a single-tone signal and an orthogonal signal of the single-tone signal;
transmitting the single-tone signal to a reflecting surface and receiving a reflected signal of the single-tone signal;
calculating the propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and a preset sliding integration time; and
and calculating the propagation delay of the reflected signal according to the propagation delay phase of the reflected signal and the generation time of the single-tone signal so as to obtain the distance between the reflecting surface and the signal emission position.
2. The distance measuring method of claim 1, wherein the preset sliding integration time is an integer multiple of a half period of the mono signal.
3. The distance measuring method of claim 2, wherein the step of calculating the propagation delay phase of the reflected signal based on the mono signal, the quadrature signal, the reflected signal and a preset sliding integration time comprises:
performing sliding correlation integration on the single-tone signal and the reflection signal according to the preset sliding integration time to obtain a first sliding correlation result;
performing sliding correlation integration on the orthogonal signal and the reflection signal according to the preset sliding integration time to obtain a second sliding correlation result; and
and calculating the propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result.
4. The distance measuring method according to claim 3,
the first sliding correlation result is calculated by the following formula:
wherein CORI (T) is the first sliding correlation result; sin (ω t) is the monophonic signal, and ω is the frequency of the monophonic signal, t is time; a. the 1 sin(ωt+θ 1 ) Is the reflected signal, and A 1 Is the amplitude of the reflected signal, θ 1 Is the propagation delay phase of the reflected signal; t is the preset sliding integration time; tau to tau + T is an integration time period, and tau is an integration starting time;
the second sliding correlation result is calculated by the following formula:
wherein CORQ (T) is the second sliding correlation result; cos (ω t) is the quadrature signal;
the propagation delay phase of the reflected signal is calculated by adopting the following formula:
5. the distance measurement method of claim 4 wherein said step of calculating the propagation delay of said reflected signal based on the propagation delay phase of said reflected signal and the generation time of said single tone signal comprises:
selecting the corresponding time when the propagation delay phase of the reflected signal is greater than a first preset threshold value for the first time as a first correlation peak stabilization time;
calculating the whole period number of the propagation delay of the reflected signal according to the first correlation peak stable time and the generation time of the single-tone signal;
calculating the propagation delay of the reflected signal according to the whole period number of the propagation delay of the reflected signal and the period of the single-tone signal; and
and calculating the distance between the reflecting surface and the signal transmitting position according to the propagation delay of the reflected signal.
6. The distance measuring method according to claim 5,
the whole period number of the propagation delay of the reflected signal is calculated by adopting the following formula:
wherein N is 1 The number of the whole period of the propagation delay of the reflected signal; floor () is rounded down; t is 0 Generating time for the tone signal; t is 1 Is the first correlation peak settling time; t is tone Is the period of the single tone signal;
the propagation delay of the reflected signal is calculated by adopting the following formula:
T a ＝N 1 ·T tone +T corr
wherein, T a Is the propagation delay of the reflected signal; and T corr The following formula is used for calculation:
the distance between the reflecting surface and the signal transmitting position is calculated by adopting the following formula:
S 0 ＝T a ·V/2
wherein S is 0 The distance between the reflecting surface and a signal transmitting position is obtained; and V is the signal propagation speed corresponding to the distance measurement environment temperature.
7. A distance measurement system for wearing equipment, characterized by comprising:
the signal generating module is used for generating a single-tone signal and an orthogonal signal of the single-tone signal;
the signal transmitting module is connected with the signal generating module and is used for transmitting the single-tone signal to a reflecting surface;
a signal receiving module for receiving a reflected signal of the single tone signal;
the phase calculation module is respectively connected with the signal receiving module and the signal generation module and is used for calculating the propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and preset sliding integration time; and
and the measurement control module is respectively connected with the phase calculation module and the signal generation module and is used for calculating the propagation delay of the reflected signal according to the propagation delay phase of the reflected signal and the generation time of the single-tone signal so as to obtain the distance between the reflecting surface and the distance measurement system.
8. The distance measurement system of claim 7 wherein the preset sliding integration time is an integer multiple of a half period of the monophonic signal.
9. The distance measurement system of claim 8 wherein said phase calculation module comprises:
the correlation integration unit is respectively connected with the signal receiving module and the signal generating module and is used for performing sliding correlation integration on the single-tone signal and the reflection signal according to the preset sliding integration time to obtain a first sliding correlation result; performing sliding correlation integration on the orthogonal signal and the reflection signal according to the preset sliding integration time to obtain a second sliding correlation result;
and the phase calculation unit is connected with the correlation integration unit and used for calculating the propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result.
10. The distance measurement system of claim 9,
the first sliding correlation result is calculated by the following formula:
wherein CORI (T) is the first sliding correlation result; sin (ω t) is the monophonic signal, and ω is the frequency of the monophonic signal, t is time; a. the 1 sin(ωt+θ 1 ) Is the reflected signal, and A 1 Is the amplitude of the reflected signal, θ 1 Is the propagation delay phase of the reflected signal; t is the preset sliding integration time; tau to tau + T is an integration time period, and tau is an integration starting moment;
the second sliding correlation result is calculated by the following formula:
wherein CORQ (T) is the second sliding correlation result; cos (ω t) is the quadrature signal;
the propagation delay phase of the reflected signal is calculated by adopting the following formula:
11. the distance measurement system of claim 10 wherein said measurement control module comprises:
the propagation delay calculating unit is respectively connected with the phase calculating unit and the signal generating module and is used for selecting the corresponding time when the propagation delay phase of the reflected signal is greater than a first preset threshold value for the first time as a first correlation peak stable time; calculating the whole period number of the propagation delay of the reflected signal according to the first correlation peak stable time and the generation time of the single-tone signal; calculating the propagation delay of the reflected signal according to the whole period number of the propagation delay of the reflected signal and the period of the single-tone signal;
and the distance calculation unit is connected with the propagation delay calculation unit and used for calculating the distance between the reflecting surface and the distance measurement system according to the propagation delay of the reflected signal.
12. The distance measurement system of claim 11,
the whole period number of the propagation delay of the reflected signal is calculated by adopting the following formula:
wherein N is 1 The number of the whole period of the propagation delay of the reflected signal is set; floor () is rounded down; t is 0 Generating time for the tone signal; t is 1 Is the first correlation peak settling time; t is tone Is the single tone signalA period of (c);
the propagation delay of the reflected signal is calculated by adopting the following formula:
T a ＝N 1 ·T tone +T corr
wherein, T a Is the propagation delay of the reflected signal; and T corr The following formula is used for calculation:
the distance between the reflecting surface and the distance measuring system is calculated by adopting the following formula:
S 0 ＝T a ·V/2
wherein S is 0 The distance between the reflecting surface and the distance measuring system is obtained; and V is the signal propagation speed corresponding to the distance measurement environment temperature.
13. The distance measurement system of claim 12 wherein said measurement control module further comprises:
the processing time delay calculation unit is respectively connected with the propagation time delay calculation unit and the distance calculation unit and is used for calculating module processing time delay at a preset environment temperature so as to correct the distance between the reflecting surface and the distance measurement system; the module processing time delay is the sum of the processing time delay from the signal generating module to the signal transmitting module and the processing time delay from the signal receiving module to the correlation integration unit;
and the propagation speed calculation unit is respectively connected with the propagation delay calculation unit, the processing delay calculation unit and the distance calculation unit and is used for calculating the signal propagation speed when the temperature of the distance measurement environment is unknown.
14. The distance measurement system of claim 13,
the signal receiving module is further used for receiving an attenuation signal of the single tone signal;
the correlation integration unit is further configured to perform sliding correlation integration on the monophonic signal and the attenuated signal according to the preset sliding integration time to obtain a third sliding correlation result; performing sliding correlation integration on the orthogonal signal and the attenuation signal according to the preset sliding integration time to obtain a fourth sliding correlation result;
the phase calculation unit is further configured to calculate a propagation delay phase of the attenuated signal according to the third sliding correlation result and the fourth sliding correlation result;
the propagation delay calculation unit is further configured to select, as a second correlation peak stabilization time, a time corresponding to a time when the propagation delay phase of the attenuated signal is first greater than a second preset threshold; calculating the whole period number of the propagation delay of the attenuation signal according to the second correlation peak stability time and the transmitting time of the single-tone signal; and calculating the propagation delay of the attenuation signal according to the whole cycle number of the propagation delay of the attenuation signal and the cycle of the single-tone signal so as to acquire the module processing delay.
15. The distance measurement system of claim 14,
the third sliding correlation result is calculated by adopting the following formula:
wherein, CORI r (T) is the third sliding correlation result; a. the 2 sin(ωt+θ 2 ) Is the attenuated signal, and A 2 Is the amplitude of the attenuated signal, θ 2 Is the propagation delay phase of the attenuated signal;
the fourth sliding correlation result is calculated by the following formula:
wherein, CORQ r (T) is the fourth sliding correlation result;
the propagation delay phase of the attenuation signal is calculated by adopting the following formula:
the whole period number of the propagation delay of the attenuation signal is calculated by adopting the following formula:
wherein, N 2 The number of the whole period of the propagation delay of the attenuation signal; t is a unit of 2 Is the second correlation peak settling time;
the propagation delay of the attenuation signal is calculated by adopting the following formula:
wherein, T b Is the propagation delay of the attenuated signal; and is
The following formula is used for calculation:
16. the distance measurement system of claim 15,
the module processing time delay is calculated by adopting the following formula:
T d ＝T b ′-T c
T c ＝d/v
wherein, T d Processing a time delay for the module; t is b ' is the propagation delay of the attenuated signal at a preset ambient temperature; t is c The propagation time between the signal transmitting module and the signal receiving module at a preset ambient temperature is set; d is the distance between the signal transmitting module and the signal receiving module; v is a signal propagation speed corresponding to a preset environment temperature;
the distance correction value of the reflecting surface and the distance measuring system is calculated by adopting the following formula:
S 1 ＝(T a -T d )·V/2
wherein S is 1 A distance correction value for the reflecting surface and the distance measuring system; and V is the signal propagation speed corresponding to the distance measurement environment temperature.
17. The distance measurement system of claim 16,
when the distance measurement environment temperature is unknown, the signal propagation speed is calculated by adopting the following formula:
wherein the content of the first and second substances,
the propagation delay of the attenuated signal at ambient temperature is measured for distance.
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