阅读说明：本技术 一种激光多普勒测速仪数据反演方法 (Data retrieval method for laser Doppler velocimeter ) 是由 郝歌扬 吴国俊 吕沛 杨钰城 吕小鹏 于 2019-10-12 设计创作，主要内容包括：本发明提出一种激光多普勒测速仪数据反演方法,解决了激光多普勒测速仪数据处理时存在的时间分辨率固定,速度测量精度较低的问题。该方法包括以下步骤：1)参数设置；2)获取数据；3)计算带通滤波器的参数；4)数据处理；5)获取标记位；6)判断标记位Flag1的状态；7)计算N1；8)判断m与N1的大小关系；9)对数据进行截取；10)获取f_max；11)将结果放入数组f_max1(m)中；12)判断标记位Flag2的状态；13)计算剩余数据所需的窗口滑动次数N2；14)判断计数位n与N2的关系；15)获取f_max；16)将输出结果放入数组f_max2(n)中；17)数据整合；18)计算运动速度。(The invention provides a data inversion method of a laser Doppler velocimeter, which solves the problems of fixed time resolution and lower speed measurement precision during data processing of the laser Doppler velocimeter. The method comprises the following steps: 1) setting parameters; 2) acquiring data; 3) calculating parameters of the band-pass filter; 4) processing data; 5) acquiring a mark bit; 6) judging the state of a Flag bit 1; 7) calculating N1; 8) judging the size relationship between m and N1; 9) intercepting the data; 10) acquiring f _ max; 11) put the result into the array f _ max1 (m); 12) judging the state of a Flag bit 2; 13) calculating the window sliding times N2 required by the residual data; 14) judging the relation between the counting bit N and N2; 15) acquiring f _ max; 16) putting the output result into an array f _ max2 (n); 17) integrating data; 18) the movement speed is calculated.)

1. A data inversion method of a laser Doppler velocimeter is characterized by comprising the following steps:

1) setting parameters;

setting time resolution delta T1 when the laser Doppler velocimeter is used for carrying out speed calculation when the measured object is uniformly accelerated or moves at a uniform speed;

setting time resolution delta T2 when the laser Doppler velocimeter is used for calculating the speed when the object to be measured becomes accelerated;

setting the range of the speed of movement of the object to be measured, i.e. the maximum speed v of the object to be measured_maxAnd minimum velocity v_min；

2) The laser Doppler velocimeter starts to collect data to obtain the motion state data of the measured object;

3) according to v in step 1)_maxAnd v_minCalculating parameters of the band-pass filter;

the passband cutoff frequency of the bandpass filter is:

the stopband cutoff frequency of the bandpass filter is:

wherein, λ is the laser wavelength used by the laser doppler velocimeter;

4) filtering and removing noise of the data acquired in the step 2);

5) positioning a motion starting point of the data processed in the step 4) to obtain a Flag1 and a Flag;

6) judging the state of the Flag1, if Flag1 is not 1, ending the calculation, and outputting 'the object to be measured does not move'; if yes, executing step 7);

7) according to the time resolution delta T1, the sampling frequency fs and the sampling time T of the laser Doppler velocimeter and the total number of points N0 of data collected by the laser Doppler velocimeter, calculating the total sliding times N1 of the intercepting window, and making the counting bit m equal to 1, wherein the calculation formula of the total sliding times N1 of the intercepting window is as follows:

N₀＝fs×T

8) judging the size relationship between m and N1, and if m is not more than N1, executing step 9); if the data is not true, integrating the data to obtain a spectrum peak measurement result of the whole data, wherein the total data length L is equal to m, the spectrum peak search result f _ max (1: m) is equal to f _ max1, and executing the step 18);

9) intercepting the data processed in the step 4), intercepting the data with the duration delta T1, and putting the data into a temporary array temp (m);

10) acquiring the frequency f _ max corresponding to the maximum amplitude of each frequency point in the temporary array temp (m) spectrum distribution;

11) putting the result of the step 10) into an array f _ max1(m), wherein the counting bit m is m +1, and the intercepting window slides backwards by delta T1;

12) calculating and judging the state of the Flag 2;

if Flag2 is not 1, returning to step 8), and judging the relationship between m and N1 again; if Flag2 is true, then step 13) is executed;

13) starting from the corresponding data when m is m-1, intercepting the residual data by adopting delta T2, calculating the window sliding times N2 required by the residual data, and making the counting bit N be 1, wherein the calculation formula of N2 is as follows:

14) judging the relation between the counting bit N and N2, if N is not more than N2, executing step 15), and if not, executing step 17);

15) acquiring the frequency f _ max corresponding to the maximum amplitude point of each frequency point in the residual data spectrum distribution;

16) putting the output result of the step 15) into an array f _ max2(n), wherein the counting bit n is n +1, and the intercepting window slides backwards by delta T2;

17) integrating the data in f _ max1(m) and f _ max2 (n); firstly, creating a null array f _ max, wherein the number of array columns is 1, and the number of rows is m + n; placing the data within f _ max1(m) at the first m of the f _ max array; placing the data within f _ max2(n) at the m +1 to m + n of the f _ max array;

18) calculating the moving speed v of the measured object according to f _ max,

2. the laser doppler velocimeter data inversion method according to claim 1, characterized in that: the step 5) specifically comprises the following steps,

5.1) reading the data in the step 4) and obtaining the time t when the data start to be collected₀；

5.2) minimum Doppler frequency difference omega₀Is the passband cut-off frequency f of a bandpass filter_passThe calculation formula is as follows:

ω₀＝f_pass(5)

calculating the total point number N of the data collected by the laser Doppler velocimeter₀The calculation formula is as follows:

N₀＝fs×T

wherein fs is the sampling frequency of the laser Doppler velocimeter, and T is the sampling time;

5.3) initializing temporary count bits i and j and temporary Flag bits Flag1, Flag1, and Flag2, and setting i ═ j to 1, Flag1 to 1, and Flag1 to Flag2 to 0;

5.4) putting the data read in the step 5.1) into an Array1, performing fast Fourier transform on the Array1 to obtain the frequency spectrum distribution of the data, finding the frequency point frequency with the maximum frequency spectrum amplitude in the frequency spectrum distribution, and recording the frequency point frequency as f 1;

5.5) determining f1 and ω₀The size relationship of (1): if f 1-omega₀If the value is less than 0, the object to be measured is in a static state or the movement speed is less than the lower speed limit of the laser Doppler velocimeter, so that Flag1 is made to be 0, and Flag1 and Flag are directly output; if f 1-omega₀If the value is more than or equal to 0, executing the step 5.6);

5.6) dividing the Array1 into two groups, wherein the first group of data is put into an Array Temp1, and the second group of data is put into an Array Temp 2;

5.7) carrying out fast Fourier transform on the Temp1 logarithm group to obtain the frequency spectrum distribution of the Temp1 logarithm group, finding the frequency of the frequency point with the maximum frequency spectrum amplitude in the frequency spectrum distribution, and recording the frequency as f 2;

5.8) determining f2 and ω₀The size relationship of (1): if f2 < omega₀Setting the Array Temp2 to the Array1, setting the counting position i to 2, and returning to step 5.6); if f2 is more than or equal to omega₀Then step 5.9) is executed;

5.9) calculating flag bit 1, wherein the calculation formula is as follows:

5.10) make Array2 ═ Array Temp 1;

5.11) the Array2 is divided into two parts, the first part of data is put into the Array Temp3, and the second part of data is put into the Array Temp 4;

5.12) carrying out fast Fourier transform on the Temp4 logarithm group to obtain the frequency spectrum distribution of the Temp4 logarithm group, finding the frequency of the frequency point with the maximum frequency spectrum amplitude in the frequency spectrum distribution, and recording the frequency as f 4;

5.13) judgment of f4- ω₀And ω₀The size relationship of (1): if f 4-omega₀＜ω₀Let the Array Temp3 be the Array2 and the count bit j be j +1, return to step 5.11); if f 4-omega₀≥ω₀Then step 5.14) is executed;

5.14) calculating flag2, wherein the calculation formula is as follows:

5.15) calculating a flag bit flag of a final motion starting point, wherein the calculation formula is as follows:

flag＝flag₁+flag₂(8)

5.16) outputs Flag1 and Flag.

3. The laser doppler velocimeter data inversion method according to claim 2, characterized in that: the step 10) specifically comprises the following steps,

10.1) reading an array temp (m);

10.2) carrying out fast Fourier transform on the logarithm group temp (m) to obtain the frequency spectrum distribution of the logarithm group temp (m), and solving the average value of the amplitude of each frequency point, which is recorded as A₀；

10.3) comparing the amplitude A _ f of each frequency point with 8 times A₀If the amplitude A _ f of a frequency point is less than 8A₀If A _ f is 0; if the amplitude A _ f of a certain frequency point is more than or equal to 8A₀If not, A _ f is equal to A _ f;

10.4) searching the frequency f _ max corresponding to the maximum amplitude of each frequency point in the frequency spectrum distribution;

10.5) output f _ max.

4. The laser doppler velocimeter data inversion method according to claim 3, characterized in that: in step 12), the calculation of Flag2 specifically includes the following steps,

12.1) read two adjacent values in the f _ max1 array, f _ max1(m) and f _ max1 (m-1);

12.2) the calculation formula for calculating the decision condition ξ is:

12.3) judging the state of m, and if m is more than 0, executing a step 12.4); if m >0 is not true, let Flag2 be 0, and output Flag 2;

12.4) judging the states of f _ max (m) and f _ max (m-1) and ξ, if f _ max (m) and f _ max (m-1) are equal to or more than ξ, making Flag2 equal to 1 and outputting Flag2, and if f _ max (m) and f _ max (m-1) are not equal to or more than ξ, making Flag2 equal to 0 and outputting Flag 2.

5. The laser doppler velocimeter data inversion method according to claim 4, characterized in that: step 15) specifically comprises

15.1) putting the data in the step 13) into an array temp (m), and reading the array temp (m);

15.2) carrying out FFT on the logarithmic arrays temp (m) to obtain the frequency spectrum distribution, and solving the average value of the amplitude of each frequency point, which is recorded as A₀；

15.3) comparing the amplitude A _ f of each frequency point with 8 times A₀If the amplitude A _ f of a frequency point is less than 8A₀If yes, let A _ f be 0; if the amplitude A _ f of a frequency point is less than 8A₀If the result is not true, let A _ f be A _ f;

15.4) searching the frequency f _ max corresponding to the maximum amplitude of each frequency point in the frequency spectrum distribution;

15.5) outputs the running result f _ max.

6. The data inversion method of the laser doppler velocimeter according to any one of claims 1 to 5, characterized in that: the time resolution Δ T1 in step 1) was 100 us.

7. The laser doppler velocimeter data inversion method according to claim 6, characterized in that: the time resolution Δ T2 in step 1) was 2 us.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that: the computer program when executed by a processor implements the steps of the method of any one of claims 1 to 7.

9. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein: the processor, when executing the program, performs the steps of the method of any of claims 1 to 7.

Technical Field

The invention relates to the field of laser Doppler velocity and acceleration measurement, in particular to a data retrieval method for a laser Doppler velocimeter.

Background

The laser Doppler velocity measurement technology is a high-precision non-contact velocity measurement technology based on the optical Doppler effect and is widely applied to various fields. The structure of a typical laser doppler velocimeter is shown in fig. 1, wherein laser emitted by the laser passes through a front lens L₁The light beam is divided into two paths by a beam splitter, one path of reflected light irradiates an object, and the other path of transmitted light irradiates a reflector M₁A surface. Scattered light from the surface of the object to be measured and the beam M₁The two light beams reflected from the surface are reflected by the light beam M₂Reflected by the collimating mirror L₂And collimating and receiving by a detector, wherein the frequency of light scattered back by the measured object is changed due to the fact that the measured object is in a moving state, and the frequency of the light and the other light form a beat frequency on the surface of the detector.

If defined by M₁The reflected light is reference light with a frequency of the output frequency omega of the laser₁Defining the light scattered from the surface of the measured object as signal light, and changing the frequency of the signal light into omega due to Doppler effect₂＝ω₁+2u/λ, where u is the velocity of the object being measured and λ is the wavelength of the output light, the intensity of the two beams can be expressed as:

wherein E is₁Denotes the amplitude of the reference light, t denotes time,indicating the phase of the reference light, E₂Which represents the amplitude of the signal light and,

indicating the phase of the signal light;

according to the interference formula of the light, the interference light intensity of the two beams of light can be expressed as:

due to the square law effect of the photodiode, only the frequency is ω₁-ω₂When the output frequency of the laser is fixed, the frequency of the interference fringe is only related to the speed of the object moving, so that the interference signal received by the photodiode is collected by the digital signal collection system, the doppler frequency difference of the interference signal is calculated by the data processing system, and then the moving speed of the object to be measured is:

at present, data processing of the laser Doppler velocimeter only adopts one step length for data processing, and when complex motion states of variable acceleration, constant speed and uniform acceleration are measured, the time resolution of data processing is fixed and can not be changed, so that the precision of speed measurement at the moment of speed abrupt change is low.

Disclosure of Invention

The invention provides a data inversion method of a laser Doppler velocimeter, aiming at solving the problems that the time resolution is fixed and the speed measurement precision at the time of speed jump is low when the laser Doppler velocimeter processes data.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a data inversion method of a laser Doppler velocimeter comprises the following steps:

1) setting parameters;

setting time resolution delta T1 when the laser Doppler velocimeter is used for carrying out speed calculation when the measured object is uniformly accelerated or moves at a uniform speed;

setting time resolution delta T2 when the laser Doppler velocimeter is used for calculating the speed when the object to be measured becomes accelerated;

setting the range of the speed of movement of the object to be measured, i.e. the maximum speed v of the object to be measured_maxAnd minimum velocity v_min；

2) The laser Doppler velocimeter starts to collect data to obtain the motion state data of the measured object;

3) according to v in step 1)_maxAnd v_minCalculating parameters of the band-pass filter;

the passband cutoff frequency of the bandpass filter is:

the stopband cutoff frequency of the bandpass filter is:

wherein, λ is the laser wavelength used by the laser doppler velocimeter;

4) filtering and removing noise of the data acquired in the step 2);

5) positioning a motion starting point of the data processed in the step 4) to obtain a Flag1 and a Flag;

6) judging the state of the Flag1, if Flag1 is not 1, ending the calculation, and outputting 'the object to be measured does not move'; if yes, executing step 7);

7) according to the time resolution delta T1, the sampling frequency fs and the sampling time T of the laser Doppler velocimeter and the total number of points N0 of data collected by the laser Doppler velocimeter, calculating the total sliding times N1 of the intercepting window, and making the counting bit m equal to 1, wherein the calculation formula of the total sliding times N1 of the intercepting window is as follows:

N₀＝fs×T

8) judging the size relationship between m and N1, and if m is not more than N1, executing step 9); if the data is not true, integrating the data to obtain a spectrum peak measurement result of the whole data, wherein the total data length L is equal to m, the spectrum peak search result f _ max (1: m) is equal to f _ max1, and executing the step 18);

9) intercepting the data processed in the step 4), intercepting the data with the duration delta T1, and putting the data into a temporary array temp (m);

10) acquiring the frequency f _ max corresponding to the maximum amplitude of each frequency point in the temporary array temp (m) spectrum distribution;

11) putting the result of the step 10) into an array f _ max1(m), wherein the counting bit m is m +1, and the intercepting window slides backwards by delta T1;

12) calculating and judging the state of the Flag 2;

if Flag2 is not 1, returning to step 8), and judging the relationship between m and N1 again; if Flag2 is true, then step 13) is executed;

13) starting from the corresponding data when m is m-1, intercepting the residual data by adopting delta T2, calculating the window sliding times N2 required by the residual data, and making the counting bit N be 1, wherein the calculation formula of N2 is as follows:

14) judging the relation between the counting bit N and N2, if N is not more than N2, executing step 15), and if not, executing step 17);

15) acquiring the frequency f _ max corresponding to the maximum amplitude point of each frequency point in the residual data spectrum distribution;

16) putting the output result of the step 15) into an array f _ max2(n), wherein the counting bit n is n +1, and the intercepting window slides backwards by delta T2;

17) integrating the data in f _ max1(m) and f _ max2 (n); firstly, creating a null array f _ max, wherein the number of array columns is 1, and the number of rows is m + n; placing the data within f _ max1(m) at the first m of the f _ max array; placing the data within f _ max2(n) at the m +1 to m + n of the f _ max array;

18) calculating the moving speed v of the measured object according to f _ max,

further, the step 5) specifically comprises the following steps,

5.1) readingThe data in the step 4) is obtained, and the time t when the data start to be collected is obtained₀；

5.2) minimum Doppler frequency difference omega₀Is the passband cut-off frequency f of a bandpass filter_passThe calculation formula is as follows:

ω₀＝f_pass(5)

calculating the total point number N of the data collected by the laser Doppler velocimeter₀The calculation formula is as follows:

N₀＝fs×T

wherein fs is the sampling frequency of the laser Doppler velocimeter, and T is the sampling time;

5.3) initializing temporary count bits i and j and temporary Flag bits Flag1, Flag1, and Flag2, and setting i ═ j to 1, Flag1 to 1, and Flag1 to Flag2 to 0;

5.4) putting the data read in the step 5.1) into an Array1, performing fast Fourier transform on the Array1 to obtain the frequency spectrum distribution of the data, finding the frequency point frequency with the maximum frequency spectrum amplitude in the frequency spectrum distribution, and recording the frequency point frequency as f 1;

5.5) determining f1 and ω₀The size relationship of (1): if f 1-omega₀If the value is less than 0, the object to be measured is in a static state or the movement speed is less than the lower speed limit of the laser Doppler velocimeter, so that Flag1 is made to be 0, and Flag1 and Flag are directly output; if f 1-omega₀If the value is more than or equal to 0, executing the step 5.6);

5.6) dividing the Array1 into two groups, wherein the first group of data is put into an Array Temp1, and the second group of data is put into an Array Temp 2;

5.7) carrying out fast Fourier transform on the Temp1 logarithm group to obtain the frequency spectrum distribution of the Temp1 logarithm group, finding the frequency of the frequency point with the maximum frequency spectrum amplitude in the frequency spectrum distribution, and recording the frequency as f 2;

5.8) determining f2 and ω₀The size relationship of (1): if f2 < omega₀Setting the Array Temp2 to the Array1, setting the counting position i to 2, and returning to step 5.6); if f2 is more than or equal to omega₀Then step 5.9) is executed;

5.9) calculating flag bit 1, wherein the calculation formula is as follows:

5.10) make Array2 ═ Array Temp 1;

5.11) the Array2 is divided into two parts, the first part of data is put into the Array Temp3, and the second part of data is put into the Array Temp 4;

5.12) carrying out fast Fourier transform on the Temp4 logarithm group to obtain the frequency spectrum distribution of the Temp4 logarithm group, finding the frequency of the frequency point with the maximum frequency spectrum amplitude in the frequency spectrum distribution, and recording the frequency as f 4;

5.13) judgment of f4- ω₀And ω₀The size relationship of (1): if f 4-omega₀＜ω₀Let the Array Temp3 be the Array2 and the count bit j be j +1, return to step 5.11); if f 4-omega₀≥ω₀Then step 5.14) is executed;

5.14) calculating flag2, wherein the calculation formula is as follows:

5.15) calculating a flag bit flag of a final motion starting point, wherein the calculation formula is as follows:

flag＝flag₁+flag₂(8)

5.16) outputs Flag1 and Flag.

Further, the step 10) specifically includes the steps of,

10.1) reading an array temp (m);

10.2) carrying out fast Fourier transform on the logarithm group temp (m) to obtain the frequency spectrum distribution of the logarithm group temp (m), and solving the average value of the amplitude of each frequency point, which is recorded as A₀；

10.3) comparing the amplitude A _ f of each frequency point with 8 times A₀If the amplitude A _ f of a frequency point is less than 8A₀If A _ f is 0; if the amplitude A _ f of a certain frequency point is more than or equal to 8A₀If not, A _ f is equal to A _ f;

10.4) searching the frequency f _ max corresponding to the maximum amplitude of each frequency point in the frequency spectrum distribution;

10.5) output f _ max.

Further, in step 12), the calculation of Flag2 specifically includes the following steps,

12.1) read two adjacent values in the f _ max1 array, f _ max1(m) and f _ max1 (m-1);

12.2) the calculation formula for calculating the decision condition ξ is:

12.3) judging the state of m, and if m is more than 0, executing a step 12.4); if m >0 is not true, let Flag2 be 0, and output Flag 2;

12.4) judging the states of f _ max (m) and f _ max (m-1) and ξ, if f _ max (m) and f _ max (m-1) are equal to or more than ξ, making Flag2 equal to 1 and outputting Flag2, and if f _ max (m) and f _ max (m-1) are not equal to or more than ξ, making Flag2 equal to 0 and outputting Flag 2.

Further, the step 15) specifically comprises

15.1) putting the data in the step 13) into an array temp (m), and reading the array temp (m);

15.2) carrying out FFT on the logarithmic arrays temp (m) to obtain the frequency spectrum distribution, and solving the average value of the amplitude of each frequency point, which is recorded as A₀；

15.3) comparing the amplitude A _ f of each frequency point with 8 times A₀If the amplitude A _ f of a frequency point is less than 8A₀If yes, let A _ f be 0; if the amplitude A _ f of a frequency point is less than 8A₀If the result is not true, let A _ f be A _ f;

15.4) searching the frequency f _ max corresponding to the maximum amplitude of each frequency point in the frequency spectrum distribution;

15.5) outputs the running result f _ max.

Further, the time resolution Δ T1 in step 1) is 100 us.

Further, the time resolution Δ T2 in step 1) was 2 us.

Meanwhile, the present invention also provides a computer-readable storage medium having stored thereon a computer program which, when being executed by a processor, carries out the steps of the above-mentioned method.

Furthermore, the present invention also provides a computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the program.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention provides a data retrieval method for a digital laser Doppler velocimeter, which is characterized in that a user can set different time resolutions according to the user's own requirements to obtain the movement speed of a measured object under different time precisions, and further obtain the time-speed curve of the measured object under different time precisions.

2. The method can automatically identify the motion state of the measured object, such as a static state, a constant speed state, a variable acceleration state and the like, and adjust the motion parameters in real time according to different motion states, thereby effectively improving the speed and the precision of data inversion.

Drawings

Fig. 1 is a structural diagram of a typical conventional laser doppler velocimeter;

FIG. 2 is a flow chart of a data inversion method of a laser Doppler velocimeter according to the present invention;

FIG. 3 is a flow chart of step 5 of the data inversion method of the laser Doppler velocimeter of the present invention;

FIG. 4 is a flow chart of step 10 of the data inversion method of the laser Doppler velocimeter of the present invention;

fig. 5 is a flowchart of step 12 of the data inversion method of the laser doppler velocimeter of the present invention.

Detailed Description

The invention is described in further detail below with reference to the figures and specific embodiments.

The invention provides a method for inverting original data acquired by a data acquisition system when a digital laser Doppler velocimeter is used for speed measurement. The method is based on the windowed Fourier transform technology, and can invert the digital signals acquired by the laser Doppler velocimeter to obtain the real-time movement speed information of the measured object.

The data retrieval method of the laser Doppler velocimeter provided by the invention specifically comprises the following steps:

1) the user needs to set parameters

Setting time resolution delta T1 when a laser Doppler velocimeter carries out velocity calculation when a measured object is accelerated or moves at a uniform velocity, wherein the parameter represents the length of intercepting data from all collected data each time when velocity inversion is carried out, a user of the parameter can set the parameter according to the requirement of the user, and the length of intercepting data each time is defaulted to be 100us under the condition that the user does not set the parameter;

the time resolution delta T2 of the laser Doppler velocimeter when the object to be measured changes to accelerate movement and carries out speed calculation is set, the parameter indicates that if the object to be measured possibly has obvious acceleration or deceleration movement in the test process, when the time resolution delta T1 is adopted for interception, the speed measurement precision is reduced, therefore, aiming at the acceleration or deceleration process, a smaller time resolution needs to be set to improve the precision of speed inversion, the parameter can be set by a user according to the requirement of the user, and the interception length is 2us each time under the condition that the user does not set;

setting the range of the speed of movement of the object to be measured, i.e. the maximum possible speed v of the object to be measured_maxAnd minimum velocity v_min；

2) The laser Doppler velocimeter starts to collect data to obtain the motion state data of the measured object;

3) according to v in step 1)_maxAnd v_minAnd calculating parameters of the band-pass filter during data preprocessing, wherein the specific calculation method comprises the following steps:

the passband cutoff frequency of the bandpass filter is:

the stopband cutoff frequency of the bandpass filter is:

wherein, λ is the laser wavelength used by the laser doppler velocimeter;

4) filtering and removing noise of the data acquired in the step 2);

5) positioning a motion starting point of the data processed in the step 4) to obtain a Flag1 and a Flag;

5.1) reading the data in the step 4), and acquiring the time t when the data starts to be acquired by an internal clock of the digital laser Doppler velocimeter₀；

5.2) minimum Doppler frequency difference omega₀Is the passband cut-off frequency f of a bandpass filter_passThe calculation formula is as follows:

ω₀＝f_pass(5)

calculating the total point number N of the data collected by the laser Doppler velocimeter₀The calculation formula is as follows:

N₀＝fs×T

wherein fs is the sampling frequency of the laser Doppler velocimeter, and T is the sampling time;

5.3) initializing temporary count bits i and j and temporary Flag bits Flag1, Flag1, and Flag2, and setting i ═ j to 1, Flag1 to 1, and Flag1 to Flag2 to 0;

5.4) putting the data read in the step 5.1) into an Array1, performing Fast Fourier Transform (FFT) on Array1 to obtain the frequency spectrum distribution of the data, and finding the frequency point frequency with the maximum frequency spectrum amplitude in the frequency spectrum distribution, wherein the frequency point frequency is recorded as f 1;

5.5) determining f1 and ω₀The size relationship of (1): if f 1-omega₀If the value is less than 0, the object to be measured is in a static state or the movement speed is less than the lower speed limit of the laser Doppler velocimeter, so that Flag1 is made to be 0, and Flag1 and Flag are directly output; if f 1-omega₀If the value is more than or equal to 0, executing the step 5.6);

5.6) dividing the Array1 into two groups, wherein the first group of data is put into an Array Temp1, and the second group of data is put into an Array Temp 2;

5.7) carrying out FFT on the array Temp1 to obtain the frequency spectrum distribution of the array Temp1, finding the frequency of the frequency point with the maximum frequency spectrum amplitude in the frequency spectrum distribution, and recording the frequency as f 2;

5.8) determining f2 and ω₀The size relationship of (1): if f2 < omega₀Setting the Array Temp2 to the Array1, setting the counting position i to 2, and returning to step 5.6); if f2 is more than or equal to omega₀Then step 5.9) is executed;

5.9) calculating flag bit 1, wherein the calculation formula is as follows:

5.10) make Array2 ═ Array Temp 1;

5.11) the Array2 is divided into two parts, the first part of data is put into the Array Temp3, and the second part of data is put into the Array Temp 4;

5.12) carrying out FFT on the array Temp4 to obtain the frequency spectrum distribution of the array Temp4, finding the frequency of the frequency point with the maximum frequency spectrum amplitude in the frequency spectrum distribution, and recording the frequency as f 4;

5.13) judgment of f4- ω₀And ω₀The size relationship of (1): if f 4-omega₀＜ω₀Let the Array Temp3 be the Array2 and the count bit j be j +1, return to step 5.11); if f 4-omega₀≥ω₀Then step 5.14) is executed;

5.14) calculating flag2, wherein the calculation formula is as follows:

5.15) calculating a flag bit flag of a final motion starting point, wherein the calculation formula is as follows:

flag＝flag₁+flag₂(8)

5.16) output Flag1 and Flag;

6) judging the state of the Flag bit 1, if Flag1 is not 1, ending the calculation, and outputting text information of 'no movement of the measured object'; if yes, executing step 7);

7) according to the time resolution delta T1, the sampling rate fs and the sampling time T of the laser Doppler velocimeter and the total number N of points of data collected by the laser Doppler velocimeter₀Calculating the total number of times of sliding of the interception window N1, and making the count bit m equal to 1, wherein the calculation formula of the total number of times of sliding of the interception window N1 is as follows:

N₀＝fs×T

8) judging the size relationship between m and N1, and if m is not more than N1, executing step 9); if the data is not true, integrating the data to obtain a spectrum peak measurement result of the whole data, wherein the total data length L is equal to m, the spectrum peak search result f _ max (1: m) is equal to f _ max1, and executing the step 18);

9) intercepting the data processed in the step 4), intercepting the data with the duration delta T1, and putting the data into a temporary array temp (m);

10) acquiring the frequency f _ max corresponding to the maximum amplitude of each frequency point in the temporary array temp (m) spectrum distribution;

10.1) reading an array temp (m);

10.2) carrying out FFT on the pairs of temp (m) to obtain the frequency spectrum distribution, and solving the average value of the amplitude of each frequency point, which is recorded as A₀；

10.3) comparing the amplitude A _ f of each frequency point with 8 times A₀If the amplitude A _ f of a frequency point is less than 8A₀If yes, let A _ f be 0; if the amplitude A _ f of a frequency point is less than 8A₀If the result is not true, let A _ f be A _ f;

10.4) searching the frequency f _ max corresponding to the maximum amplitude of each frequency point in the frequency spectrum distribution;

10.5) outputting an operation result f _ max;

11) putting the result of the step 10) into an array f _ max1(m), wherein the counting bit m is m +1, and the intercepting window slides backwards by delta T1;

12) calculating and judging the state of the Flag 2;

judging the state of Flag2, if Flag2 is not 1, jumping to step 8), and judging the relationship between m and N1 again; if Flag2 is true, then step 13) is executed;

calculating Flag2 specifically includes the following steps,

12.1) read two adjacent values in the f _ max1 array, f _ max1(m) and f _ max1 (m-1);

12.2) calculating a decision condition ξ, when the acceleration of the object to be measured is > 10g, the motion state of the object to be measured is considered to be changed, so the calculation formula ξ is:

12.3) judging the state of m, and if m is more than 0, executing a step 12.4); if m >0 is not satisfied, making Flag2 equal to 0 and outputting Flag 2;

12.4) judging the states of f _ max (m) -f _ max (m-1) and ξ, if f _ max (m) -f _ max (m-1) ≧ ξ is established, making Flag2 equal to 1 and outputting Flag2, if f _ max (m) -f _ max (m-1) ≧ ξ is not established, making Flag2 equal to 0 and outputting Flag 2;

13) if Flag2 is true, it indicates that there is acceleration or deceleration motion with large acceleration in the test process of the object to be tested, so it needs to adopt finer time resolution Δ T2 to intercept the residual data, adopt Δ T2 to re-intercept the residual data according to the value of m in step 12), and calculate the window sliding number N2 required by the residual data, and let the counting bit N be 1, the calculation formula of N2 is:

14) judging the relation between the counting bit N and N2, if N is not more than N2, executing step 15), and if not, executing step 17);

15) acquiring the frequency f _ max corresponding to the maximum amplitude point of each frequency point in the residual data spectrum distribution;

15.1) putting the data in the step 13) into an array temp (m), and reading the array temp (m); (the array referred to at this time means the remaining array in step 13)

15.2) carrying out FFT on the logarithmic arrays temp (m) to obtain the frequency spectrum distribution, and solving the average value of the amplitude of each frequency point, which is recorded as A₀；

15.3) comparing the amplitude A _ f of each frequency point with 8 times A₀If the amplitude A _ f of a frequency point is less than 8A₀If yes, let A _ f be 0; if the amplitude A _ f of a frequency point is less than 8A₀If the result is not true, let A _ f be A _ f;

15.4) searching the frequency f _ max corresponding to the maximum amplitude of each frequency point in the frequency spectrum distribution;

15.5) outputting an operation result f _ max;

16) putting the output result of the step 15) into an array f _ max2(n), wherein the counting bit n is n +1, and the intercepting window slides backwards by delta T2;

17) integrating the data in f _ max1(m) and f _ max2 (n);

firstly, creating a null array f _ max, wherein the number of array columns is 1, and the number of rows is m + n; placing the data in f _ max1(m) in the first m of the f _ max array, and placing the data in f _ max2(n) in the m +1 to m + n of the f _ max array;

18) calculating the moving speed v of the measured object according to f _ max,

the embodiment of the invention also provides a computer readable storage medium for storing a program, and the program realizes the steps of the data inversion method of the laser Doppler velocimeter when being executed. In some possible embodiments, the various aspects of the invention may also be implemented in the form of a program product comprising program code means for causing a terminal device to carry out the steps according to the various exemplary embodiments of the invention described in the method part above of the description, when said program product is run on the terminal device.

A program product for implementing the above method, which may employ a portable compact disc read only memory (CD-ROM) and include program code, may be run on a terminal device, a computer device, such as a personal computer. However, the program product of the present invention is not limited in this regard and, in the present document, a readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The program product may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.