Distance measurement method and system

Abstract

The present invention discloses a distance measurement method and system, the method 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 a propagation delay phase of the reflected signal based on 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 based on 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 transmission point. The present invention sets the preset sliding integration time to an integer multiple of the single-tone signal half-cycle, so that the calculated propagation delay phase is independent of the amplitude of the reflected signal, thereby improving the distance measurement accuracy. The present invention can also effectively avoid the influence of the module processing delay and ambient temperature on the distance measurement result, further improving the distance measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of smart devices, and in particular to a distance measurement method and system for wearable devices. Background Art

[0002] With the rapid development of wearable devices (such as Bluetooth headsets and smartwatches), determining the distance between a device and a reflective surface has become a research hotspot and a key factor in determining the wearable state of the device. Currently, ultrasonic ranging methods are commonly used to measure the distance between a wearable device and a reflective surface. The ranging principle is: a sensor on the wearable device transmits an ultrasonic wave and receives the ultrasonic wave reflected by the reflective surface. This wave's propagation delay is then used to determine the distance between the reflective surface and the wearable device.

[0003] However, ultrasonic waves diffuse spherically during propagation, resulting in greater energy attenuation with greater propagation distance. Furthermore, as ultrasonic waves propagate through a medium, some of their energy is absorbed by the air. Furthermore, upon encountering reflective objects, ultrasonic waves undergo reflection, scattering, and diffraction, resulting in significant attenuation of the actual reflected ultrasonic waves. Furthermore, due to the influence of thermal noise, changes in the shape and angle of the ultrasonic reflective surface, and variations in the reflection distance, the amplitude of the received ultrasonic waves can vary significantly over time. To improve distance measurement accuracy, gain control is typically performed on the receiving front end. Because gain control requires a settling time, certain requirements are placed on the ultrasonic pulse width. If the pulse width is too narrow, gain control can easily terminate before the adjustment is complete, ultimately leading to distance measurement failure. Therefore, in existing ultrasonic ranging methods, the reliability and settling time of gain control in the receiving front end directly impact the distance measurement accuracy of wearable devices.

[0004] Alternatively, a phase-based ranging method can be used to measure the distance between the wearable device and the reflective surface. This method achieves highly accurate phase delay measurement by counting the number of phase zero-crossing changes. However, this method is also affected by the amplitude of the received signal. If the received signal is too weak, the phase decision will be affected, resulting in distance measurement failure. Therefore, phase-based ranging methods also rely on the reliability and settling time of the gain control of the receiving front end. Summary of the Invention

[0005] The object of the present invention is to provide a distance measurement method and system, which can calculate the propagation delay phase of a reflected signal based on a single-tone signal, an orthogonal signal of the single-tone signal, a reflected signal of the single-tone signal and a preset sliding integration time; by setting the preset sliding integration time to an integer multiple of a half-period of the single-tone signal, the calculated propagation delay phase is independent of the amplitude of the reflected signal, thereby improving the distance measurement accuracy.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A distance measurement method, comprising:

[0008] generating a single tone signal and a quadrature signal of the single tone signal;

[0009] transmitting the single-tone signal toward a reflecting surface and receiving a reflected signal of the single-tone signal;

[0010] 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

[0011] The propagation delay of the reflected signal is calculated according to the propagation delay phase of the reflected signal and the generation time of the single-tone signal to obtain the distance between the reflecting surface and the signal transmission point.

[0012] Preferably, the preset sliding integration time is an integer multiple of a half period of the single tone signal.

[0013] Preferably, the step of 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 includes:

[0014] Performing sliding correlation integration on the single tone signal and the reflected signal according to the preset sliding integration time to obtain a first sliding correlation result;

[0015] Performing sliding correlation integration on the orthogonal signal and the reflected signal according to the preset sliding integration time to obtain a second sliding correlation result; and

[0016] The propagation delay phase of the reflected signal is calculated according to the first sliding correlation result and the second sliding correlation result.

[0017] Preferably, the first sliding correlation result is calculated using the following formula:

[0018]

[0019] Wherein, CORI(T) is the first sliding correlation result; sin(ωt) is the single tone signal, ω is the frequency of the single tone signal, and t is time; A1sin(ωt+θ1) is the reflected signal, A1 is the amplitude of the reflected signal, and θ1 is the propagation delay phase of the reflected signal; T is the preset sliding integration time; τ~τ+T is the integration time period, and τ is the integration start time;

[0020] The second sliding correlation result is calculated using the following formula:

[0021]

[0022] Wherein, CORQ(T) is the second sliding correlation result; cos(ωt) is the orthogonal signal;

[0023] The propagation delay phase of the reflected signal is calculated using the following formula:

[0024]

[0025] 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 single-tone signal includes:

[0026] Selecting the time corresponding to when the propagation delay phase of the reflected signal is greater than a first preset threshold for the first time as the first correlation peak stabilization time;

[0027] Calculating the number of whole cycles of the propagation delay of the reflected signal according to the first correlation peak stabilization time and the generation time of the single-tone signal;

[0028] Calculating the propagation delay of the reflected signal according to the number of whole cycles of the propagation delay of the reflected signal and the period of the single-tone signal; and

[0029] The distance between the reflection surface and the signal transmission location is calculated according to the propagation delay of the reflection signal.

[0030] Preferably, the number of whole cycles of the propagation delay of the reflected signal is calculated using the following formula:

[0031]

[0032] Wherein, N1 is the number of whole cycles of the propagation delay of the reflected signal; floor() is rounded down; T0 is the generation time of the single tone signal; T1 is the first correlation peak stabilization time; T tone is the period of the single tone signal;

[0033] The propagation delay of the reflected signal is calculated using the following formula:

[0034] T a =N1·T tone +T corr

[0035] Among them, T a is the propagation delay of the reflected signal; and T corr The calculation is performed using the following formula:

[0036]

[0037] The distance between the reflecting surface and the signal transmitting point is calculated using the following formula:

[0038] S0=T a V / 2

[0039] Wherein, S0 is the distance between the reflecting surface and the signal transmitting location; V is the signal propagation speed corresponding to the ambient temperature of the distance measurement.

[0040] Based on the same inventive concept, the present invention also provides a distance measurement system for a wearable device, comprising:

[0041] A signal generating module, configured to generate a single tone signal and an orthogonal signal of the single tone signal;

[0042] A signal transmitting module, connected to the signal generating module, for transmitting the single tone signal toward the reflecting surface;

[0043] A signal receiving module, configured to receive a reflected signal of the single tone signal;

[0044] a phase calculation module, connected to the signal receiving module and the signal generating module respectively, for 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

[0045] A measurement control module is connected to the phase calculation module and the signal generation module respectively, and is used 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 to obtain the distance between the reflecting surface and the distance measurement system.

[0046] Preferably, the preset sliding integration time is an integer multiple of a half period of the single tone signal.

[0047] Preferably, the phase calculation module includes:

[0048] a correlation integration unit, connected to the signal receiving module and the signal generating module, respectively, configured to perform sliding correlation integration on the single tone signal and the reflected signal according to the preset sliding integration time to obtain a first sliding correlation result; and perform sliding correlation integration on the orthogonal signal and the reflected signal according to the preset sliding integration time to obtain a second sliding correlation result;

[0049] A phase calculation unit is connected to the correlation integration unit and is used to calculate the propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result.

[0050] Preferably, the first sliding correlation result is calculated using the following formula:

[0051]

[0052] Wherein, CORI(T) is the first sliding correlation result; sin(ωt) is the single tone signal, ω is the frequency of the single tone signal, and t is time; A1sin(ωt+θ1) is the reflected signal, A1 is the amplitude of the reflected signal, and θ1 is the propagation delay phase of the reflected signal; T is the preset sliding integration time; τ~τ+T is the integration time period, and τ is the integration start time;

[0053] The second sliding correlation result is calculated using the following formula:

[0054]

[0055] Wherein, CORQ(T) is the second sliding correlation result; cos(ωt) is the orthogonal signal;

[0056] The propagation delay phase of the reflected signal is calculated using the following formula:

[0057]

[0058] Preferably, the measurement control module includes:

[0059] A propagation delay calculation unit, connected to the phase calculation unit and the signal generation module, respectively, for selecting the time corresponding to when the propagation delay phase of the reflected signal is first greater than a first preset threshold as a first correlation peak stabilization time; calculating the number of whole cycles of the propagation delay of the reflected signal according to the first correlation peak stabilization time and the generation time of the single-tone signal; and calculating the propagation delay of the reflected signal according to the number of whole cycles of the propagation delay of the reflected signal and the period of the single-tone signal;

[0060] A distance calculation unit is connected to the propagation delay calculation unit and is used to calculate the distance between the reflection surface and the distance measurement system according to the propagation delay of the reflected signal.

[0061] Preferably, the number of whole cycles of the propagation delay of the reflected signal is calculated using the following formula:

[0062]

[0063] Wherein, N1 is the number of whole cycles of the propagation delay of the reflected signal; floor() is rounded down; T0 is the generation time of the single tone signal; T1 is the first correlation peak stabilization time; T tone is the period of the single tone signal;

[0064] The propagation delay of the reflected signal is calculated using the following formula:

[0065] T a =N1·T tone +T corr

[0066] Among them, T a is the propagation delay of the reflected signal; and T corr The calculation is performed using the following formula:

[0067]

[0068] The distance between the reflecting surface and the distance measurement system is calculated using the following formula:

[0069] S0=T a V / 2

[0070] Wherein, S0 is the distance between the reflecting surface and the distance measurement system; V is the signal propagation speed corresponding to the distance measurement environment temperature.

[0071] Preferably, the measurement control module further includes:

[0072] a processing delay calculation unit, connected to the propagation delay calculation unit and the distance calculation unit, respectively, for calculating a module processing delay at a preset ambient temperature to correct the distance between the reflecting surface and the distance measurement system; wherein the module processing delay is the sum of a processing delay from the signal generating module to the signal transmitting module and a processing delay from the signal receiving module to the correlation integration unit;

[0073] The propagation speed calculation unit is connected to the propagation delay calculation unit, the processing delay calculation unit and the distance calculation unit respectively, and is used to calculate the signal propagation speed when the distance measurement environment temperature is unknown.

[0074] Preferably, the signal receiving module is further used to receive an attenuated signal of the single tone signal;

[0075] The correlation integration unit is further configured to perform a sliding correlation integration on the single tone signal and the attenuated signal according to the preset sliding integration time to obtain a third sliding correlation result; and perform a sliding correlation integration on the orthogonal signal and the attenuated signal according to the preset sliding integration time to obtain a fourth sliding correlation result;

[0076] The phase calculation unit is further configured to calculate the propagation delay phase of the attenuated signal according to the third sliding correlation result and the fourth sliding correlation result;

[0077] The propagation delay calculation unit is also used to select the time corresponding to the first time that the propagation delay phase of the attenuated signal is greater than a second preset threshold as the second correlation peak stabilization time; calculate the number of whole cycles of the propagation delay of the attenuated signal according to the second correlation peak stabilization time and the transmission time of the single-tone signal; and calculate the propagation delay of the attenuated signal according to the number of whole cycles of the propagation delay of the attenuated signal and the period of the single-tone signal to obtain the module processing delay.

[0078] Preferably, the third sliding correlation result is calculated using the following formula:

[0079]

[0080] Among them, CORI r (T) is the third sliding correlation result; A2sin(ωt+θ2) is the attenuation signal, A2 is the amplitude of the attenuation signal, and θ2 is the propagation delay phase of the attenuation signal;

[0081] The fourth sliding correlation result is calculated using the following formula:

[0082]

[0083] Among them, CORQ r (T) is the fourth sliding correlation result;

[0084] The propagation delay phase of the attenuated signal is calculated using the following formula:

[0085]

[0086] The number of whole cycles of the propagation delay of the attenuated signal is calculated using the following formula:

[0087]

[0088] Wherein, N2 is the number of whole cycles of the propagation delay of the attenuated signal; T2 is the stabilization time of the second correlation peak;

[0089] The propagation delay of the attenuated signal is calculated using the following formula:

[0090]

[0091] Among them, T b is the propagation delay of the attenuated signal; and The calculation is performed using the following formula:

[0092]

[0093] Preferably, the module processing delay is calculated using the following formula:

[0094] T d =T b ′-T c

[0095] T c =d / v

[0096] Among them, T d T is the processing delay of the module; b ' is the propagation delay of the attenuated signal at the preset ambient temperature; T c is the propagation time between the signal transmitting module and the signal receiving module at a preset ambient temperature; d is the distance between the signal transmitting module and the signal receiving module; v is the signal propagation speed corresponding to the preset ambient temperature;

[0097] The distance correction value between the reflecting surface and the distance measurement system is calculated using the following formula:

[0098] S1=(T a -T d )·V / 2

[0099] Wherein, S1 is the distance correction value between the reflecting surface and the distance measurement system; V is the signal propagation speed corresponding to the distance measurement environment temperature.

[0100] Preferably, when the ambient temperature of the distance measurement environment is unknown, the signal propagation speed is calculated using the following formula:

[0101]

[0102] in, The propagation delay of the attenuated signal at ambient temperature is measured for distance.

[0103] Compared with the prior art, the present invention has at least one of the following advantages:

[0104] The present invention provides a distance measurement method and system, which can generate a single-tone signal and its orthogonal signal, and receive a reflected signal after the single-tone signal is transmitted, so as to calculate the propagation delay phase of the reflected signal based on the single-tone signal, the orthogonal signal, the reflected signal and a preset sliding integration time, thereby combining the generation time of the single-tone signal to obtain the propagation delay of the reflected signal, and further obtain the distance between the reflecting surface and the distance measurement system.

[0105] The present invention presets a sliding integration time as an integer multiple of a half-cycle of a single-tone signal, so that the propagation delay phase obtained through the sliding correlation integral operation and phase calculation is independent of the amplitude of the reflected signal. This can avoid problems such as distance measurement failure caused by amplitude jitter of the reflected signal in the prior art, thereby improving the distance measurement accuracy. At the same time, it does not require a complex receiving front-end amplification circuit, and has low requirements for the width of the single-tone signal.

[0106] The setting of the integration time period in the present invention reduces the amount of data that needs to be cached during the sliding correlation integral operation and phase calculation process, reduces the requirements for computing resources and storage resources, and increases the processing speed.

[0107] The present invention can be applied not only to the case where the signal propagation speed corresponding to the measured ambient temperature is known, but also to the case where the signal propagation speed corresponding to the measured ambient temperature is unknown, and has good applicability.

[0108] The present invention utilizes the known distance between the signal sending module and the signal receiving module to measure the internal transmission delay of the device, that is, the module processing delay, thereby improving the distance measurement accuracy. At the same time, the present invention also effectively avoids the influence of temperature on the signal propagation speed, further improving the distance measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] Figure 1 is a flow chart of a distance measurement method provided by one embodiment of the present invention;

[0110] Figure 2 It is a structural diagram of a distance measurement system provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0111] The following is a further detailed description of a distance measurement method and system proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will become clearer. It should be noted that the drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the implementation conditions of the present invention. Therefore, they have no technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0112] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0113] Combined with attachment Figure 1 As shown, this embodiment provides a distance measurement method, including: step S110, generating a single-tone signal and an orthogonal signal of the single-tone signal, and recording the generation time of the single-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 transmission point.

[0114] Specifically, in the present embodiment, in step S110, the single-tone signal can be an ultrasonic wave, and the frequency of the single-tone signal is the frequency corresponding to the ultrasonic wave (40KHz to 120KHz); after the single-tone signal is generated, the orthogonal signal of the single-tone signal can be generated by performing phase rotation on the single-tone signal or using a lookup table rule. In step S120, after the single-tone signal is transmitted in pulse form as a transmitting signal, the ultrasonic wave reflected back by the reflecting surface is the reflected signal. More specifically, the frequency, period, and propagation speed of the single-tone signal, the orthogonal signal, and the reflected signal are all the same, but the present invention is not limited thereto.

[0115] In other embodiments, the frequency of the single tone signal may also be a frequency corresponding to an infrasound wave, a frequency within the hearing range of the human ear, or a frequency higher than an ultrasonic wave.

[0116] Please continue to refer to Figure 1, the step S130 includes: performing a sliding correlation integration on the single-tone signal and the reflected signal according to the preset sliding integration time to obtain a first sliding correlation result; performing a sliding correlation integration on the orthogonal signal and the reflected 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.

[0117] It is understandable that, in some other embodiments, the first sliding-related result is calculated using the following formula:

[0118]

[0119] Wherein, CORI(T) is the first sliding correlation result; sin(ωt) is the single tone signal, ω is the frequency of the single tone signal, and t is time; A1sin(ωt+θ1) is the reflected signal, A1 is the amplitude of the reflected signal, and θ1 is the propagation delay phase of the reflected signal; T is the preset sliding integration time; τ~τ+T is the integration time period, and τ is the integration start time;

[0120] The second sliding correlation result is calculated using the following formula:

[0121]

[0122] Wherein, CORQ(T) is the second sliding correlation result; cos(ωt) is the orthogonal signal;

[0123] The propagation delay phase of the reflected signal is calculated using the following formula:

[0124]

[0125] In some embodiments, the preset sliding integration time is an integer multiple of a half period of the single tone signal.

[0126] Specifically, in this embodiment, formula (1) is expanded to obtain

[0127]

[0128] After expanding formula (2), we can get

[0129]

[0130] Since the preset sliding integration time T is an integer multiple of the half period of the single tone signal, only the first term remains in formulas (4) and (5), namely:

[0131] CORI(T)=A1Tcos(θ1) / 2 (6)

[0132] CORQ(T)=A1Tsin(θ1) / 2 (7)

[0133] Formula (3) can be derived from formula (6) and formula (7). More specifically, since the single-tone signal, the orthogonal signal, the reflected signal and the preset sliding integration time are all known, the first sliding integration result and the second sliding integration result can be obtained according to formulas (1) and (2); the first sliding integration result and the second sliding integration result are substituted into formula (3) to obtain the propagation delay phase θ1 of the reflected signal. In addition, it can be seen from formula (3) that the calculation of the propagation delay phase θ1 of the reflected signal does not involve the amplitude of the reflected signal, so that the subsequent calculation of the distance between the reflecting surface and the signal transmission point does not depend on the amplitude of the reflected signal, thereby improving the distance measurement accuracy, but the present invention is not limited to this.

[0134] Specifically, in this embodiment, the preset sliding integration time T is generally on the order of milliseconds. Then, within the integration time period τ to τ + T, the relative position of the emission point of the single-tone signal and the reflecting surface remains fixed. At this time, the amplitude A1 and the propagation delay phase θ1 of the reflected signal are short-term stable. Therefore, the amplitude A1 and the propagation delay phase θ1 of the reflected signal can be regarded as constant values ​​within the integration time period τ to τ + T. The setting of the integration time period τ to τ + T can change the prior art from calculating n multiplication and accumulation results (n is the number of sampling points included in the sampling time interval) for one sampling time interval to only calculating one multiplication and accumulation result, which greatly saves computing logic resources. At the same time, due to the time-sharing processing between the current integration time period and its previous and next integration time periods, it is no longer necessary to cache the data of all integration time periods, which can reduce storage resources. Furthermore, this embodiment changes the prior art approach of outputting a single phase result per sampling point to outputting a single propagation delay phase per integration period. While outputting a single phase result per sampling point may appear more accurate and more real-time, the two phase results outputted by adjacent sampling points are highly correlated, resulting in minimal variation. To detect phase variations in these correlated results, a longer time interval is required. In this embodiment, the current integration period is adjacent to, but not overlapping with, the previous and next integration periods. This results in a longer time interval between adjacent integration periods, enabling better differentiation between the two calculated propagation delay phases. However, the present invention is not limited to this.

[0135] Please continue to refer to Figure 1, the step S140 includes: selecting the time corresponding to the first time that the propagation delay phase of the reflected signal is greater than the first preset threshold as the first correlation peak stabilization time; calculating the number of whole cycles of the propagation delay of the reflected signal according to the first correlation peak stabilization time and the generation time of the single-tone signal; calculating the propagation delay of the reflected signal according to the number of whole cycles 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 transmission point according to the propagation delay of the reflected signal.

[0136] It is understandable that, in some other embodiments, the number of whole cycles of the propagation delay of the reflected signal is calculated using the following formula:

[0137]

[0138] Wherein, N1 is the number of whole cycles of the propagation delay of the reflected signal; floor() is rounded down; T0 is the generation time of the single tone signal; T1 is the first correlation peak stabilization time; T tone is the period of the single tone signal;

[0139] The propagation delay of the reflected signal is calculated using the following formula:

[0140] T a =N1·T tone +T corr (9)

[0141] Among them, T a is the propagation delay of the reflected signal; where T corr The propagation delay phase θ1 of the reflected signal can be calculated according to formula (3), and the calculation formula is as follows:

[0142]

[0143] The distance between the reflecting surface and the signal transmitting point is calculated using the following formula:

[0144] S0=T a ·V / 2 (11)

[0145] Wherein, S0 is the distance between the reflecting surface and the signal transmitting location; V is the signal propagation speed corresponding to the ambient temperature of the distance measurement.

[0146] Specifically, since the propagation delay phase of the reflected signal calculated in step S130 has a phase ambiguity of an entire cycle, the propagation delay of the reflected signal cannot be directly calculated based on the propagation delay phase of the reflected signal. It is necessary to calculate the number of entire cycles of the propagation delay of the reflected signal using formula (8), and then calculate the propagation delay of the reflected signal using formula (9) and formula (10). More specifically, in this embodiment, it is also necessary to record the output time of the propagation delay phase of the reflected signal corresponding to each integration time period in real time (i.e., the time τ+T in each integration time period); when the propagation delay phase of the reflected signal exceeds the first preset threshold for the first time, the output time of the propagation delay phase of the reflected signal is used as the first correlation peak stabilization time, and is substituted into formula (8) to calculate the number of entire cycles of the propagation delay of the reflected signal. Preferably, the first preset threshold is the average value of the propagation delay phase of the reflected signal obtained by multiple measurements and stabilized in a laboratory environment, but the present invention is not limited thereto.

[0147] Specifically, in this embodiment, since the propagation speed of sound waves in the air medium is related to the ambient temperature, when the ambient temperature changes, the propagation speed of the signal in the air medium will also change. Therefore, when calculating the distance between the reflecting surface and the signal transmitting point according to formula (11), it is necessary to first determine the temperature of the current environment, i.e., the distance measurement environment, so as to determine the signal propagation speed corresponding to the distance measurement environment temperature, and then obtain the distance between the reflecting surface and the signal transmitting point, thereby improving the distance measurement accuracy. In addition, in this embodiment, when calculating the distance between the reflecting surface and the signal transmitting point based on the distance measurement method, it is assumed that the signal transmitting point, the signal receiving point, and the signal processing point (including the sliding correlation integral operation point and the propagation delay phase calculation point, etc.) are all located at the same point, that is, it is assumed that there is no hardware processing delay. Otherwise, the processing delay is calculated according to the method or formula below, and the distance between the reflecting surface and the signal transmitting point is corrected, but the present invention is not limited to this.

[0148] Based on the same inventive concept, combined with the attached Figure 2As shown, the present embodiment also provides a distance measurement system for wearable devices, including: a signal generating module 201, for generating a single-tone signal and an orthogonal signal of the single-tone signal, and recording the generation time of the single-tone signal; a signal transmitting module 202, connected to the signal generating module 201, for transmitting the single-tone signal to the reflecting surface; a signal receiving module 203, for receiving the reflected signal of the single-tone signal; a phase calculation module 204, respectively connected to the signal receiving module 203 and the signal generating module 201, for calculating the propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and the preset sliding integration time; and a measurement control module 205, respectively connected to the phase calculation module 204 and the signal generating module 201, 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.

[0149] Specifically, in this embodiment, a digital-to-analog converter (DAC) 206 is further provided between the signal generating module 201 and the signal transmitting module 202 for converting the digital signal format of the monophonic signal into an analog signal format. An analog-to-digital converter (ADC) 207 is further provided between the signal receiving module 203 and the phase calculation module 204, and the signal receiving module 203 can convert the acoustic signal format of the reflected signal into an analog signal format through the analog circuit at its front end, and then convert it into a digital signal format through the analog-to-digital converter (ADC) 207 and transmit it to the phase calculation module 204. Preferably, a filter 208 is further provided 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 used as the signal transmitting module 202 and the signal receiving module 203 respectively; in some embodiments, the speaker in the wearable device can also be used as the signal transmitting module 202, and the microphone in the wearable device can be used as the signal receiving module 203, but the present invention is not limited to this.

[0150] Please continue to refer to Figure 2The phase calculation module 204 includes: a correlation integration unit 2041, which is respectively connected to the signal receiving module 203 and the signal generating module 201, and is used to perform sliding correlation integration on the single-tone signal and the reflected signal according to the preset sliding integration time to obtain a first sliding correlation result; and perform sliding correlation integration on the orthogonal signal and the reflected signal according to the preset sliding integration time to obtain a second sliding correlation result; a phase calculation unit 2042, which is connected to the correlation integration unit 2041, and is used to calculate the propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result.

[0151] It is understandable that, in some other embodiments, the first sliding-related result is calculated using the following formula:

[0152]

[0153] Wherein, CORI(T) is the first sliding correlation result; sin(ωt) is the single-tone signal, ω is the frequency of the single-tone signal, and t is time; A1sin(ωt+θ1) is the reflected signal, A1 is the amplitude of the reflected signal, and θ1 is the propagation delay phase of the reflected signal; T is the preset sliding integration time, and the preset sliding integration time is an integer multiple of the half-cycle of the single-tone signal; τ~τ+T is the integration time period, and τ is the integration start time;

[0154] The second sliding correlation result is calculated using the following formula:

[0155]

[0156] Wherein, CORQ(T) is the second sliding correlation result; cos(ωt) is the orthogonal signal;

[0157] The propagation delay phase of the reflected signal is calculated using the following formula:

[0158]

[0159] Please continue to refer to Figure 2, the measurement control module 205 includes: a propagation delay calculation unit 2051, which is connected to the phase calculation unit 2042 and the signal generation module 201 respectively, and is used to select the time corresponding to the first time when the propagation delay phase of the reflected signal is greater than the first preset threshold as the first correlation peak stabilization time; the whole cycle number of the propagation delay of the reflected signal is calculated according to the first correlation peak stabilization time and the generation time of the single-tone signal; and the propagation delay of the reflected signal is calculated according to the whole cycle number of the propagation delay of the reflected signal and the period of the single-tone signal; a distance calculation unit 2052, which is connected to the propagation delay calculation unit 2051, and is used to calculate the distance between the reflecting surface and the distance measurement system according to the propagation delay of the reflected signal. In addition, the measurement control module 205 is also provided with a control unit, which is connected to the signal generation module 201, and is used to control the period interval of transmitting the single-tone signal, the pulse duration of the single-tone signal, and the duration of the integration time period.

[0160] It is understandable that, in some other embodiments, the number of whole cycles of the propagation delay of the reflected signal is calculated using the following formula:

[0161]

[0162] Wherein, N1 is the number of whole cycles of the propagation delay of the reflected signal; floor() is rounded down; T0 is the generation time of the single tone signal; T1 is the first correlation peak stabilization time; T tone is the period of the single tone signal;

[0163] The propagation delay of the reflected signal is calculated using the following formula:

[0164] T a =N1·T tone +T corr (9)

[0165] Among them, T a is the propagation delay of the reflected signal; and T corr The calculation is performed using the following formula:

[0166]

[0167] The distance between the reflecting surface and the distance measurement system is calculated using the following formula:

[0168] S0=T a ·V / 2 (11)

[0169] Wherein, S0 is the distance between the reflecting surface and the distance measurement system; V is the signal propagation speed corresponding to the distance measurement environment temperature.

[0170] Please continue to refer to Figure 2 The measurement control module 205 also includes: a processing delay calculation unit 2053, which is respectively connected to the propagation delay calculation unit 2051 and the distance calculation unit 2051, and is used to calculate the module processing delay at a preset ambient temperature to correct the 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 speed calculation unit 2054, which is respectively connected to the propagation delay calculation unit 2051, the processing delay calculation unit 2053 and the distance calculation unit 2052, and is used to calculate the signal propagation speed when the distance measurement ambient temperature is unknown.

[0171] Specifically, in this embodiment, when calculating the distance between the reflecting surface and the distance measurement system based on the distance measurement system, since the modules are located at different positions, there will be a certain distance between the modules, so that the propagation delay of the reflected signal calculated according to formulas (9) and (10) includes the module processing delay (i.e., the 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 integration unit 2041). Therefore, in order to ensure the ranging accuracy of the distance measurement system, it is also necessary to calculate the module processing delay and correct the distance between the reflecting surface and the distance measurement system calculated according to formula (11). 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 integration unit 2041 via a data line, the module processing delay is not affected by the ambient temperature. At the same time, the module processing delay can be stored as a fixed deviation in the distance calculation unit or other storage medium, but the present invention is not limited to this.

[0172] Specifically, in this embodiment, after the single-tone signal is transmitted as a transmission signal in pulse form, not only the reflected signal will be received, but the transmission signal will also be received after passing through a certain path; because the received transmission signal has path propagation delay and attenuation, the received transmission signal is different from the generated single-tone signal, and the received transmission signal can be recorded as the attenuated signal of the single-tone signal. More specifically, the signal receiving module 203 is also used to receive the attenuated signal of the single-tone signal; the phase calculation module 204 is also used to calculate the propagation delay phase of the attenuated signal based on the single-tone signal, the orthogonal signal, the attenuated signal and the preset sliding integration time; the propagation delay calculation unit 2051 is also used to calculate the propagation delay of the attenuated signal based on the propagation delay phase of the attenuated signal and the generation time of the single-tone signal to obtain the module processing delay.

[0173] More specifically, in this embodiment, the correlation integration unit 2041 is used to perform sliding correlation integration on the single-tone signal and the attenuated signal according to the preset sliding integration time to obtain a third sliding correlation result; and to perform sliding correlation integration on the orthogonal signal and the attenuated signal according to the preset sliding integration time to obtain a fourth sliding correlation result; the phase calculation unit 2042 is used to calculate the 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 used to select the time corresponding to the first time the propagation delay phase of the attenuated signal is greater than the second preset threshold as the second correlation peak stabilization time; calculate the number of whole cycles of the propagation delay of the attenuated signal according to the second correlation peak stabilization time and the transmission time of the single-tone signal; and calculate the propagation delay of the attenuated signal according to the number of whole cycles of the propagation delay of the attenuated signal and the period of the single-tone signal.

[0174] It is understandable that, in some other embodiments, the third sliding correlation result is calculated using the following formula:

[0175]

[0176] Among them, CORI r (T) is the third sliding correlation result; A2sin(ωt+θ2) is the attenuation signal, A2 is the amplitude of the attenuation signal, and θ2 is the propagation delay phase of the attenuation signal;

[0177] The fourth sliding correlation result is calculated using the following formula:

[0178]

[0179] Among them, CORQ r(T) is the fourth sliding correlation result;

[0180] The propagation delay phase of the attenuated signal is calculated using the following formula:

[0181]

[0182] The number of whole cycles of the propagation delay of the attenuated signal is calculated using the following formula:

[0183]

[0184] Wherein, N2 is the number of whole cycles of the propagation delay of the attenuated signal; T2 is the stabilization time of the second correlation peak;

[0185] The propagation delay of the attenuated signal is calculated using the following formula:

[0186]

[0187] Among them, T b is the propagation delay of the attenuated signal; and The calculation is performed using the following formula:

[0188]

[0189] In some embodiments, the module processing delay is calculated using the following formula:

[0190] T d =T b ′-T c (18)

[0191] T c =d / v (19)

[0192] Among them, T d The module processing delay; T' b is the propagation delay of the attenuated signal at the preset ambient temperature, i.e., the propagation delay of the attenuated signal calculated according to formulas (12) to (17) at the preset ambient temperature; T c is the propagation time between the signal transmitting module and the signal receiving module at a preset ambient temperature; d is the distance between the signal transmitting module and the signal receiving module; and v is the signal propagation speed corresponding to the preset ambient temperature.

[0193] The distance correction value between the reflecting surface and the distance measurement system is calculated using the following formula:

[0194] S1=(T a -T d )·V / 2 (20)

[0195] Wherein, S1 is the distance correction value between the reflecting surface and the distance measurement system; V is the signal propagation speed corresponding to the distance measurement environment temperature.

[0196] Specifically, in this embodiment, since the relative positions of the signal transmitting module 202 and the signal receiving module 203 remain fixed, the amplitude A2 and the propagation delay phase θ2 of the attenuated signal are stable, that is, both are constant values, within the integration time period τ to τ+T. Since the propagation delay phase of the attenuated signal calculated according to formula (14) has a phase ambiguity of an entire cycle, the propagation delay of the attenuated signal cannot be directly calculated based on the propagation delay phase of the attenuated signal. It is also necessary to calculate the entire cycle number of the propagation delay of the attenuated signal using formula (15), and then calculate the propagation delay of the attenuated signal according to formula (16) and formula (17). More specifically, in this embodiment, it is also necessary to record the output time of the propagation delay phase of the attenuated signal corresponding to each integration time period in real time (i.e., the τ+T moment in each integration time period); when the propagation delay phase of the attenuated signal is greater than the second preset threshold for the first time, the output time of the propagation delay phase of the attenuated signal is used as the second correlation peak stabilization time, and is brought into formula (15) to calculate the entire cycle number of the propagation delay of the attenuated signal. Preferably, the second preset threshold is an average value of the propagation delay phase of the stable attenuation signal measured multiple times in a laboratory environment, but the present invention is not limited thereto.

[0197] Specifically, in this embodiment, based on the distance measurement system, the module processing delay calculation step specifically includes: first, utilizing the fixed position characteristics of the signal transmitting module 202 and the signal receiving module 203, measuring the distance d between the signal transmitting module 202 and the signal receiving module 203 in advance. Then, setting up a laboratory environment, where the laboratory environment temperature (i.e., the preset environment temperature) is known, the signal propagation speed corresponding to the laboratory environment temperature (i.e., the preset environment temperature) is known; based on the signal propagation speed corresponding to the laboratory environment temperature (i.e., the preset environment temperature), the signal propagation time T between the signal transmitting module 202 and the signal receiving module 203 can be calculated. c , and Tc=d / v, where v is the signal propagation speed corresponding to the laboratory environment (i.e., the preset ambient temperature). Finally, in the laboratory environment, the distance measurement system is operated in the first mode, and in the first mode, the signal receiving module 203 only receives the attenuated signal of the single-tone signal. The propagation delay T' of the attenuated signal under the laboratory ambient temperature (i.e., the preset ambient temperature) can be obtained by formulas (12) to (17). bSince the propagation delay of the attenuated signal corresponds to the path 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 position of the transmitting surface, the propagation delay T' of the attenuated signal under the laboratory ambient temperature (ie, the preset ambient temperature) is b The propagation time T of the signal between the signal transmitting module 202 and the signal receiving module 203 c The difference is the module processing delay T d , and T d =T b —T c .

[0198] Please continue to refer to Figure 2 When the ambient temperature of the distance measurement environment is unknown, the signal propagation speed is calculated using the following formula:

[0199]

[0200] in, is the propagation delay of the attenuated signal at the distance measurement ambient temperature, that is, the propagation delay of the attenuated signal calculated according to formulas (12) to (17) at the distance measurement ambient temperature.

[0201] Specifically, in some distance measurement scenarios, there may be a situation where the temperature of the distance measurement environment cannot be determined, that is, it is unknown, so that the signal propagation speed corresponding to the distance measurement environment temperature cannot be determined, which in turn leads to the inability to accurately measure the distance between the reflecting surface and the distance measurement system. In order to overcome this defect, based on the distance measurement system, the steps for calculating the signal propagation speed when the distance measurement environment temperature is unknown specifically include: in the distance measurement environment, firstly, the distance measurement system is operated in the first mode, that is, the signal receiving module 203 only receives 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 formulas (12) to (17). Since the distance d between the signal transmitting module 202 and the signal receiving module 203 is known, and the module processing delay T d Known, the signal propagation speed between the signal transmitting module 202 and the signal receiving module 203 at the distance measurement ambient temperature can be obtained according to formula (21), which is the signal propagation speed V corresponding to the distance measurement ambient temperature; at this time, formula (20) becomes

[0202]

[0203] Then, the distance measurement system is operated in the 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 formulas (1), (2), (3), (8), (9) and (10): a ; The propagation delay T of the reflected signal a Substituting into formula (22) can obtain the distance correction value between the reflecting surface and the distance measurement system.

[0204] In addition, the distance calculation unit 2052 can directly use formula (22) to calculate the distance between the reflecting surface and the distance measurement system, which can effectively avoid the influence of the module processing delay and ambient temperature on the distance measurement result, thereby improving the distance measurement accuracy, but the present invention is not limited to this.

[0205] In this embodiment, based on the distance measurement system, when the signal propagation speed is calculated when the distance measurement environment temperature is unknown, since the distance between the reflecting 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 emission 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, that is, the distance measurement system operates in the first mode; when the signal transmitting module 202 stops transmitting the single-tone signal, the signal receiving module 203 will only receive the reflected signal and will not receive the attenuated signal, that is, the distance measurement system operates in the second mode. It should be noted that if the reflected signal has arrived before the signal transmitting module 202 stops transmitting the single-tone signal, the propagation delay of the attenuated signal measured will be inaccurate. Assuming that the shortest distance between the reflecting surface and the signal receiving module 203 is 5 mm, the time it takes for the reflected signal to reach the signal receiving module 203 is 5*2*10 -3 / 340s = 29.4us, when the duration of transmitting the single-tone signal is less than 29.4us (i.e., the arrival time of the reflected signal under the shortest distance), the above problem can be avoided. In fact, in application, the distance between the reflecting surface and the signal receiving module 203 is generally much larger than 5mm, so when transmitting the single-tone signal of 1 cycle length 40KHz, the above requirement can be met completely. In addition, the propagation delay phase of the attenuated signal under the range measurement ambient temperature can also be tracked. If jitter occurs in the correlation peak and phase, it is explained that there is reflected wave interference, and this range measurement result can be discarded. At the same time, the time of transmitting the single-tone signal is shortened and remeasured.

[0206] In summary, the present embodiment provides a distance measurement method and system, which can generate a single-tone signal and its orthogonal signal, and receive a reflected signal after the single-tone signal is transmitted, so as to calculate the propagation delay phase of the reflected signal according to the single-tone signal, the orthogonal signal, the reflected signal and the preset sliding integration time, thereby obtaining the propagation delay of the reflected signal in combination with the generation time of the single-tone signal, so as to obtain the distance between the reflecting surface and the distance measurement system. In this embodiment, the preset sliding integration time is an integer multiple of the half-cycle of the single-tone signal, so that the propagation delay phase obtained by the sliding correlation integral operation and the phase calculation is independent of the amplitude of the reflected signal, which can avoid the problems such as distance measurement failure caused by the amplitude jitter of the reflected signal in the prior art, thereby improving the distance measurement accuracy; at the same time, it does not require a complex receiving front-end amplifier circuit, and has low requirements for the width of the single-tone signal; the setting of the integration time period makes the amount of data required to be cached during the sliding correlation integral operation and phase calculation small, has low requirements for computing resources and storage resources, and has a fast processing speed. In addition, this embodiment utilizes the known distance between the signal sending module and the signal receiving module to measure the internal transmission delay of the device, that is, the module processing delay, thereby improving the distance measurement accuracy. At the same time, the present invention also effectively avoids the influence of temperature on the signal propagation speed, further improving the distance measurement accuracy.

[0207] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A distance measurement method, characterized in that: include: Generate a single tone signal and an orthogonal signal of the single tone signal, and record the generation time of the single tone signal; transmitting the single-tone signal toward 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; as well as 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 to obtain the distance between the reflecting surface and the signal transmission point; The step of 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 comprises: Performing sliding correlation integration on the single tone 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 reflected signal according to the preset sliding integration time to obtain a second sliding correlation result; and Calculating a propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result; 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 single tone signal comprises: Selecting the time corresponding to when the propagation delay phase of the reflected signal is greater than a first preset threshold for the first time as the first correlation peak stabilization time; Calculating the number of whole cycles of the propagation delay of the reflected signal according to the first correlation peak stabilization time and the generation time of the single-tone signal; Calculating the propagation delay of the reflected signal according to the number of whole cycles of the propagation delay of the reflected signal and the period of the single-tone signal; and Calculating the distance between the reflection surface and the signal transmission location according to the propagation delay of the reflected signal; The number of whole cycles of the propagation delay of the reflected signal is calculated using the following formula: Wherein, N1 is the number of whole cycles of the propagation delay of the reflected signal; floor() is rounded down; T0 is the generation time of the single tone signal; T1 is the first correlation peak stabilization time; T tone is the period of the single tone signal; T is the preset sliding integration time; The propagation delay of the reflected signal is calculated using the following formula: T a =N1·T tone +T corr Among them, T a is the propagation delay of the reflected signal; and T corr The calculation is performed using the following formula: Wherein, CORI(T) is the first sliding correlation result, CORQ(T) is the second sliding correlation result; θ1 is the propagation delay phase of the reflected signal; The distance between the reflecting surface and the signal transmitting point is calculated using the following formula: S0=T a ·V / 2 Wherein, S0 is the distance between the reflecting surface and the signal transmitting location; V is the signal propagation speed corresponding to the ambient temperature of the distance measurement.

2. The distance measurement method according to claim 1, wherein: The preset sliding integration time is an integer multiple of a half period of the single tone signal.

3. The distance measurement method according to claim 2, wherein: The first sliding correlation result is calculated using the following formula: Wherein, CORI(T) is the first sliding correlation result; sin(ωt) is the single tone signal, ω is the frequency of the single tone signal, and t is time; A1sin(ωt+θ1) is the reflected signal, A1 is the amplitude of the reflected signal, and θ1 is the propagation delay phase of the reflected signal; T is the preset sliding integration time; τ~τ+T is the integration time period, and τ is the integration start time; The second sliding correlation result is calculated using the following formula: Wherein, CORQ(T) is the second sliding correlation result; cos(ωt) is the orthogonal signal; The propagation delay phase of the reflected signal is calculated using the following formula:

4. A distance measurement system for a wearable device, characterized in that: include: A signal generation module, configured to generate a single tone signal and an orthogonal signal of the single tone signal, and record the generation time of the single tone signal; A signal transmitting module, connected to the signal generating module, for transmitting the single tone signal toward the reflecting surface; A signal receiving module, configured to receive a reflected signal of the single tone signal; a phase calculation module, connected to the signal receiving module and the signal generating module respectively, for 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; as well as a measurement control module, connected to the phase calculation module and the signal generation module, respectively, 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; The phase calculation module includes: a correlation integration unit, connected to the signal receiving module and the signal generating module, respectively, configured to perform sliding correlation integration on the single tone signal and the reflected signal according to the preset sliding integration time to obtain a first sliding correlation result; and perform sliding correlation integration on the orthogonal signal and the reflected signal according to the preset sliding integration time to obtain a second sliding correlation result; a phase calculation unit, connected to the correlation integration unit, and configured to calculate the propagation delay phase of the reflected signal according to the first sliding correlation result and the second sliding correlation result; The measurement control module includes: A propagation delay calculation unit, connected to the phase calculation unit and the signal generation module, respectively, for selecting the time corresponding to when the propagation delay phase of the reflected signal is first greater than a first preset threshold as a first correlation peak stabilization time; calculating the number of whole cycles of the propagation delay of the reflected signal according to the first correlation peak stabilization time and the generation time of the single-tone signal; and calculating the propagation delay of the reflected signal according to the number of whole cycles of the propagation delay of the reflected signal and the period of the single-tone signal; a distance calculation unit, connected to the propagation delay calculation unit, and configured to calculate the distance between the reflecting surface and the distance measurement system according to the propagation delay of the reflected signal; The number of whole cycles of the propagation delay of the reflected signal is calculated using the following formula: Wherein, N1 is the number of whole cycles of the propagation delay of the reflected signal; floor() is rounded down; T0 is the generation time of the single tone signal; T1 is the first correlation peak stabilization time; T tone is the period of the single tone signal; T is the preset sliding integration time; The propagation delay of the reflected signal is calculated using the following formula: T a =N1·T tone +T corr Among them, T a is the propagation delay of the reflected signal; and T corr The calculation is performed using the following formula: Wherein, CORI(T) is the first sliding correlation result, CORQ(T) is the second sliding correlation result; θ1 is the propagation delay phase of the reflected signal; The distance between the reflecting surface and the distance measurement system is calculated using the following formula: S0=T a ·V / 2 Wherein, S0 is the distance between the reflecting surface and the distance measurement system; V is the signal propagation speed corresponding to the distance measurement environment temperature.

5. The distance measurement system according to claim 4, wherein: The preset sliding integration time is an integer multiple of a half period of the single tone signal.

6. The distance measurement system according to claim 5, wherein: The first sliding correlation result is calculated using the following formula: Wherein, CORI(T) is the first sliding correlation result; sin(ωt) is the single tone signal, ω is the frequency of the single tone signal, and t is time; A1sin(ωt+θ1) is the reflected signal, A1 is the amplitude of the reflected signal, and θ1 is the propagation delay phase of the reflected signal; T is the preset sliding integration time; τ~τ+T is the integration time period, and τ is the integration start time; The second sliding correlation result is calculated using the following formula: Wherein, CORQ(T) is the second sliding correlation result; cos(ωt) is the orthogonal signal; The propagation delay phase of the reflected signal is calculated using the following formula:

7. The distance measurement system according to claim 6, wherein: The measurement control module further includes: a processing delay calculation unit, connected to the propagation delay calculation unit and the distance calculation unit, respectively, for calculating a module processing delay at a preset ambient temperature to correct the distance between the reflecting surface and the distance measurement system; wherein the module processing delay is the sum of a processing delay from the signal generating module to the signal transmitting module and a processing delay from the signal receiving module to the correlation integration unit; The propagation speed calculation unit is connected to the propagation delay calculation unit, the processing delay calculation unit and the distance calculation unit respectively, and is used to calculate the signal propagation speed when the distance measurement environment temperature is unknown.

8. The distance measurement system according to claim 7, wherein: 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 single tone signal and the attenuated signal according to the preset sliding integration time to obtain a third sliding correlation result; and 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 the 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 also used to select the time corresponding to the first time that the propagation delay phase of the attenuated signal is greater than a second preset threshold as the second correlation peak stabilization time; calculate the number of whole cycles of the propagation delay of the attenuated signal according to the second correlation peak stabilization time and the transmission time of the single-tone signal; and calculate the propagation delay of the attenuated signal according to the number of whole cycles of the propagation delay of the attenuated signal and the period of the single-tone signal to obtain the module processing delay.

9. The distance measurement system according to claim 8, wherein: The third sliding correlation result is calculated using the following formula: Among them, CORI r (T) is the third sliding correlation result; A2sin(ωt+θ2) is the attenuation signal, A2 is the amplitude of the attenuation signal, and θ2 is the propagation delay phase of the attenuation signal; The fourth sliding correlation result is calculated using the following formula: Among them, CORQ r (T) is the fourth sliding correlation result; The propagation delay phase of the attenuated signal is calculated using the following formula: The number of whole cycles of the propagation delay of the attenuated signal is calculated using the following formula: Wherein, N2 is the number of whole cycles of the propagation delay of the attenuated signal; T2 is the stabilization time of the second correlation peak; The propagation delay of the attenuated signal is calculated using the following formula: Among them, T b is the propagation delay of the attenuated signal; and The calculation is performed using the following formula:

10. The distance measurement system according to claim 9, wherein: The module processing delay is calculated using the following formula: T d =T b ′-T c T c =d / v Among them, T d T is the processing delay of the module; b ' is the propagation delay of the attenuated signal at the preset ambient temperature; T c is the propagation time between the signal transmitting module and the signal receiving module at a preset ambient temperature; d is the distance between the signal transmitting module and the signal receiving module; v is the signal propagation speed corresponding to the preset ambient temperature; The distance correction value between the reflecting surface and the distance measurement system is calculated using the following formula: S1=(T a -T d )·V / 2 Wherein, S1 is the distance correction value between the reflecting surface and the distance measurement system; V is the signal propagation speed corresponding to the distance measurement environment temperature.

11. The distance measurement system according to claim 10, wherein: When the ambient temperature of the distance measurement environment is unknown, the signal propagation speed is calculated using the following formula: in, The propagation delay of the attenuated signal at the ambient temperature is measured for distance.

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