A distance measurement method

Abstract

The application discloses a distance measuring method, which comprises the following steps: integrating and sampling an echo signal, wherein the time width of the sampling is one quarter of the period of the echo signal; and integrating and sampling the echo signal four times, wherein the four times of integration sampling form a group, and the starting time interval between adjacent integration samples is one quarter of the period. The four times of integration sampling values are D1, D2, D3 and D4 respectively, and the time of flight t of the photons is calculated by the following formula: T / 4 (D1+D2+D3+D4) / 4, wherein T is the period of the periodic echo signal; and the propagation distance of the photons can be calculated according to the time of flight t. The application can avoid the problems of high requirement of circuit hardware and time measurement precision caused by direct time measurement, and can avoid measurement error.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of distance measurement, in particular to a method for measuring and controlling the transmission integral sampling of photons. BACKGROUND

[0002] In the distance measurement method, a pulsed emission source is generally used, and the time interval between the emission pulse and the reception pulse is calculated to obtain the distance value. However, this method has the problems of difficulty in time calculation and difficulty in accurate time measurement, and it is difficult to guarantee the time accuracy of the calculation of the transmission and reception signals. Or, in the general ToF distance measurement, the signal of the sampling point is measured, and the measurement error cannot be eliminated.

[0003] How to design a method for distance measurement to avoid accurate time calculation, and how to avoid time accuracy and eliminate time error through an indirect time measurement method have become urgent problems to be solved at present. SUMMARY

[0004] The purpose of the present application is to provide a distance measurement method which can avoid the problems of high requirement on circuit hardware performance and measurement accuracy caused by time calculation.

[0005] In order to achieve the above-mentioned purpose, the present application provides a distance measurement method, which comprises:

[0006] The echo signal is integrated and sampled, and the time width of the sampling is one quarter of the period of the echo signal. The echo signal is integrated and sampled four times, and the four times of integral sampling form a group. The starting time interval between adjacent integral samples is one quarter of the period. The four times of integral sampling values are D1, D2, D3 and D4, respectively. The flight time t of the photons is calculated by the following formula:

[0007]

[0008] In the formula, T is the period of the periodic echo signal;

[0009] According to the flight time t value, the propagation distance of the photons can be calculated.

[0010] Preferably, the integral sampling values D1, D2, D3 and D4 can be the superposition of the in-phase integral sampling values of the echo signal interval i periods, wherein i≥0 and is a positive integer.

[0011] Preferably, the integral sampling values D1, D2, D3 and D4 can be the integral sampling values of the echo signal n periods and one quarter of a period, respectively, wherein n≥0 and is a positive integer.

[0012] Preferably, the starting time of the integral sampling values D1, D2, D3, D4 is based on the starting time of the transmitted signal, and the starting time interval of the integral sampling values can be the time interval of the adjacent j cycles and one quarter cycle, respectively, wherein j is greater than or equal to 0 and is a positive integer.

[0013] Preferably, the integral sampling values D1, D2, D3, D4 can be the sum of the in-phase integral sampling values of the echo signal interval i cycles, the sum of the integral sampling values of the echo signal n cycles and one quarter cycle, and the sum of the starting time intervals of the integral sampling values based on the starting time of the transmitted signal, and the starting time interval of the integral sampling values can be the time interval of the adjacent j cycles and one quarter cycle, wherein i is greater than or equal to 0 and is a positive integer, n is greater than or equal to 0 and is a positive integer, and j is greater than or equal to 0 and is a positive integer.

[0014] Preferably, m groups of integral sampling can be performed, wherein m is any positive integer.

[0015] Preferably, the value of k can be calculated by the average of the m groups of integral sampling.

[0016] Preferably, the value of k can be calculated by the different groups of integral sampling values.

[0017] Preferably, the integral sampling can be integral sampling after sampling or sampling after integral.

[0018] Preferably, the number of cycles of the echo signal is greater than the number of cycles n of the echo acquisition.

[0019] Preferably, the integral sampling time of the echo signal is determined by a timer.

[0020] Preferably, the calculation of arctan((k+1) / (k-1)) can use any transformation of the trigonometric function.

[0021] Preferably, the integral sampling intervals i in the echo signal can not be equal.

[0022] Preferably, the number of cycles n of the integral sampling in the echo signal can not be equal.

[0023] Preferably, the number of adjacent cycles j of the integral sampling in the echo signal can not be equal.

[0024] Preferably, the measurement system uses the integral sampling method described above to calculate the integral value and the transmission time parameter.

[0025] According to the above technical solution, when receiving the echo signal, the phase is calculated by using the integral sampling method, and the time difference between the transmitted signal and the received signal is indirectly measured, which can effectively avoid the error caused by directly measuring the time and improve the accuracy of distance measurement.

[0026] Other features and advantages of the present application will be illustrated in the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated in and constitute a part of this specification, illustrate embodiments of the present application and serve to explain the principles of the present application, and should not be taken as limiting of the present application. In the drawings:

[0028] Figure 1 is a schematic diagram illustrating integral sampling of a received signal.

[0029] Figure 2 is a schematic diagram illustrating integral sampling interval i.

[0030] Figure 3 is a schematic diagram illustrating integral sampling adjacent period number j.

[0031] Figure 4 is a schematic diagram illustrating integral sampling continuous period number n.

[0032] Figure 5 is a flow chart illustrating a distance calculation method of the present application. DETAILED DESCRIPTION

[0033] The specific embodiments of the present application will be described in detail hereinafter with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and explanatory of the present application and are not intended to limit the present application.

[0034] The present application provides a distance measurement method, which comprises:

[0035] Integral sampling of the echo signal is performed with a time width of one quarter of the period of the echo signal, and four integral samplings of the echo signal are performed to form a group, with a starting time interval of one quarter of the period between adjacent integral samplings. The four integral sampling values are D1, D2, D3 and D4, and the time of flight t of the photon is calculated by the following formula:

[0036]

[0037] In the formula, T is the period of the periodic echo signal.

[0038] The propagation distance of the photon can be calculated according to the time of flight t.

[0039] In a most preferred embodiment of the present application,

[0040] as shown in the formula. Figure 1 Integral sampling of the echo signal is performed with a time width of one quarter of the period of the echo signal, and four integral samplings of the echo signal are performed to form a group, with a starting time interval of one quarter of the period between adjacent integral samplings. The four integral sampling values are D1, D2, D3 and D4, and the time of flight t of the photon is calculated by the following formula: Figure 1The figure shown in (a) uses Figure 1 Displayed in the form of (b), where i, j, and n are all 0. It can also be displayed as... Figure 2 The form shown is a superposition of quarter-cycle integral samples with i-cycle intervals and in phase (i can be changed at any time during integral sampling), according to... Figure 3 The form shown is an integral sampling at intervals of j periods and a quarter period (j can be changed at any time during integral sampling), according to... Figure 4 The method involves integral sampling over n consecutive periods plus a quarter period (n can be changed at any time during integral sampling). In practice, i, j, and n can be arbitrarily chosen and combined. Here, the number of groups m = 1500, with n taking values ​​of 1, 2, ..., 1500, and intervals i = 0 and j = 0. Based on each group of integral samples, the corresponding k can be calculated, and the average of k over the m groups is taken. The time value t is then calculated based on the phase value obtained from this average k. Figure 5 The flowchart shows that simultaneously with emitting the optical signal, the system begins determining the quarter-cycle time point and performing integral sampling. Four integral samples are grouped together, with the integral sampling time being n cycles plus a quarter cycle. These four integral sample data constitute a set of measurement value k. There are m sets of measurement value k. m Calculate the mean k, and then calculate the time based on this mean. The denominator of this formula corresponds to the angular frequency, which is related to the frequencies of the transmitted signal and the echo integral sampling signal. The numerator is the phase angle of the transmitted and received signals. The distance value can be calculated based on this time t.

[0041] In one specific embodiment of the present invention, the method may further include:

[0042] When the time for the transmitter to emit a signal is greater than the integral sampling period value, different integral sampling periods n, period interval i, and adjacent j periods can be selected, and the values ​​of i, j, and n are arbitrary.

[0043] Repeat the above steps until the integral sampling result k of m groups is obtained. m Then, calculate the mean value at time t.

[0044] Through the above implementation method, the time value between transmission and reception can be calculated by phase calculation, thereby determining the time it takes for a photon to travel through the air and calculating the distance value.

[0045] In one specific embodiment of the present invention, in order to acquire time values, the integration sampling time of the echo signal is determined by a timer during integration sampling.

[0046] This invention calculates the time from the emission of a signal to the receipt of the echo signal by indirectly calculating the phase. This improves the accuracy of distance measurement and avoids errors caused by direct time measurement.

[0047] The preferred embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the specific details of the above-described embodiments. Various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0048] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again by the present application.

[0049] In addition, various different embodiments of the present application can also be combined in any manner, as long as they do not deviate from the idea of the present application, and they should also be considered as disclosed by the present application.

Claims

1. A distance measuring method characterized by: The echo signal is integrated and sampled, and the time width of the sampling is one quarter of the period of the echo signal. The echo signal is integrated and sampled four times, and the four times of integration and sampling form a group. The starting time interval between adjacent integration and sampling is one quarter of the period. The four times of integration and sampling values are D1, D2, D3 and D4, and the time of flight t of the photon is calculated by the following formula: In the formula, T is the period of the periodic echo signal; According to the time of flight t, the propagation distance of the photon can be calculated.

2. The distance measuring method according to claim 1, characterized in that, The integration and sampling values D1, D2, D3 and D4 are the superposition of the in-phase integration and sampling values of the echo signal with an interval of i periods, wherein i≥0 and is a positive integer.

3. The distance measuring method according to claim 1, characterized in that, The integration and sampling values D1, D2, D3 and D4 are the integration and sampling values of the echo signal with n periods and one quarter of the period, wherein n≥0 and is a positive integer.

4. The distance measuring method according to claim 1, characterized by, The starting time of the integration and sampling values D1, D2, D3 and D4 is based on the starting time of the emission signal, and the starting time interval of the integration and sampling values is the time of adjacent j periods and one quarter of the period, wherein j≥0 and is a positive integer.

5. The distance measuring method according to claim 1, characterized in that, The integration and sampling values D1, D2, D3 and D4 are the superposition of the in-phase integration and sampling values of the echo signal with an interval of i periods, or the integration and sampling values of the echo signal with n periods and one quarter of the period, or the starting time of the integration and sampling values is based on the starting time of the emission signal, and the starting time interval of the integration and sampling values is the time of adjacent j periods and one quarter of the period, wherein i≥0 and is a positive integer, n≥0 and is a positive integer, and j≥0 and is a positive integer.

6. The distance measuring method according to claim 1, characterized by, The integration and sampling is performed m times, wherein m is any positive integer.

7. The distance measuring method according to claim 1, characterized by, The value of k is calculated by the average value of the m times of integration and sampling.

8. The distance measuring method according to claim 1, characterized by, The value of k is calculated by the different groups of integration and sampling values.

9. The distance measuring method according to claim 1, characterized by, The integration and sampling is the sampling after integration or the integration after sampling.

10. The distance measuring method according to claim 1, characterized by, The number of periods of the echo signal is greater than the number n of periods of the echo acquisition.

11. The distance measuring method according to claim 1, characterized by, The integration and sampling time of the echo signal is determined by a timer.

12. The distance measuring method according to claim 1, characterized by, The calculation of arctan((k+1) / (k-1)) uses any transformation of the trigonometric function.

13. The distance measuring method according to claim 2, characterized by, The interval i of the integration and sampling in the echo signal is not equal.

14. The distance measuring method according to claim 3, characterized by, The number n of periods of the integration and sampling in the echo signal is not equal.

15. The distance measuring method according to claim 4, characterized by, The number j of adjacent periods of the integration and sampling in the echo signal is not equal.

16. The distance measuring method according to claim 1, characterized by, The distance measurement method uses the integration and sampling method of any one of claims 1-15 to calculate the integration value and the transmission time parameter.

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