CN103743298A - Projectile revolution extraction method based on continuous wave radar - Google Patents

Abstract

The invention relates to a projectile revolution extraction method based on a continuous wave radar, wherein common flying projectiles are tracked and measured by the continuous wave radar, and then an original signal is processed to obtain radial speed data; radar tracking and measuring is performed; micro-Doppler rotational speed signal extraction is performed. The projectile revolution extraction method based on the continuous wave radar is characterized in that a reference signal is established by a radial speed, the extracted original signal is mixed with the reference signal, a rotational speed signal is obtained by demodulation, and rotational speed information is obtained by a micro-Doppler information analysis in a signal phase; the rotational speed signal is fitted and integrated to obtain revolution data. The projectile revolution extraction method based on the continuous wave radar comprises the specific realization steps of: generating a reference signal by the radial speed obtained in step one, performing digital demodulation on the received signal, mixing and then shifting a frequency spectrum to a low-frequency stage, filtering and extracting, then performing a digital spectrum analysis, and then performing projectile rotational speed processing; fitting rotational speed data; extracting a revolution; in this way, the observation time of the radar can be increased, the problem of FFT failure due to spectrum broadening is avoided, and the purpose of weak signal detection and extraction is achieved.

Description

Bullet revolution extracting method based on continuous wave radar

Technical field

The present invention relates to a kind of bullet revolution extracting method based on continuous wave radar, with radar, Flight Projectile is carried out to revolution speed measuring, belong to field of measuring technique.

Background technology

The conventional method of revolution speed measuring is telemetry, optical method etc. both at home and abroad at present.Telemetry is only applicable to telemetry missile, need be on bullet the device such as sensor installation, difficulty is larger, and cost is higher.Optical method requires harsh to weather condition, generally adopt high-speed motion picture camera, and cloth station, in initial trajectory side, needs to be coated with mark on body, and imaging clearly, and therefore operating distance is limited, is only applicable to the revolution speed measuring of certain section of bullet.Radar power is large, and has comprised micro-doppler information in continuous wave radar echo information, by processing, can obtain bullet revolution.

Following article and patent documentation, covered the main background technology in this field substantially.Main contributions and pluses and minuses that we divide several types to introduce document.

Telemetry

The conventional method of telemetering is load sensor on bullet, and telemetered signal is sent to ground telemetering observation station in real time, and this kind of method is only applicable to telemetry missile.For common bullet or dust-shot, be difficult to load sensor device thereon, and on bullet, add after upper sensor, certainly will will affect bullet aeroperformance, and make cost increase.

1. Shen Bo, Wang Zhixing, Chen Hejuan etc. magnetometer tachometer generator experimental study [J]. trajectory journal, 2001,13 (3): 79-83

On the basis of lot of experimental data, with regard to the operation principle of earth magnetism turns counting sensor, carried out experimental study, the rational structure of magnetometer tachometer generator can guarantee all can reliable turns counting in all directions.Advantage is that this sensor can be applied on bullet, and the precision of turns counting is further enhanced.It is more complicated that shortcoming is that Project Realization is got up, and cannot install on dust-shot.

2. Shen Bo, Huang Xiaomao, Wang Zhixing etc. the turns counting sensor technology research [J] based on ground magnetic principle. war industry's journal, 2003,24 (3): 313-315

Set up the Mathematical Modeling that magnetometer tachometer generator produces induced electromotive force in magnetic field equably, derived the theoretically computational methods of induced electromotive force, and the application of earth magnetism turns counting sensor is discussed, the basic structure of magnetometer tachometer generator has been proposed.Shortcoming is that sensor needs miniaturization, has earth magnetism blind zone problem, and is subject to the impact of bullet fine motion.

3. Malaysian's beam. high rotating speed bullet magnetometer/solar azimuth sensor combinations is surveyed attitude positioning method [J]. Institutes Of Technology Of Nanjing's journal, 2013,37 (1): 139-144

Provided magnetometer/solar azimuth sensor nonlinear attitude measurement solution of equations and analysed solution, result of study has certain theory value and engineering significance for high rotating speed projectile attitude measurement problem.Shortcoming is the impact that the certainty of measurement of combination survey attitude positioning method is subject to sensor accuracy, is also subject to the impact of the factors such as geographical position, launch site, earth induction intensity vector, directive, shooting time, ballistic characteristics, airframe material magnetic screen.

Optical method

Optical method generally adopts the continuous photographic subjects of high-speed motion picture camera, and requires imaging clearly.The method is subject to weather condition impact, and optical device operating distance is near, is therefore only applicable to the test of bullet initial segment revolution.And need on body, be coated with visible marking, so that distinguish.

1. Li Yin, Pan Baoqing, Zhang Hongwei. Measuring Method of Low Rotate Speed of Flying Missile research [J]. Huabei Polytechnical College measuring technology journal, 2002,16 (1): 32-35

Adopt separate unit slit camera to ground flat fire guided missile the slow-speed of revolution measures the method for processing, provided certainty of measurement and the scope of application of the method in guided missile test of low rotating speed, when velocity of rotation is greater than 2.5 revolutions per seconds, can utilize single device to carry out tachometric survey completely, when velocity of rotation is less than 2.5 revolutions per seconds, should adopt two station translocations.The method has simple to operate, and without the advantage that changes body structure, weak point needs interpretation exactly.

2. full bright, leaf Yutang, Wu Yunfeng etc. the synchronous sensor-based system [J] of High-Speed Rotating Mirror Camera tachometric survey. light laser and the particle beams, 2006,18 (1): 11-14

Adopt the striped formula High-Speed Rotating Mirror Camera velocity sensor of the method development can in the situation that not affecting the normal work of camera, obtain in real time the rotating speed of tilting mirror.Its advantage is to obtain more accurately compared with the corresponding temporal information of the event in short distance, can effectively improve the performance of high-speed target time parameter measurement system.The application of this system will increase the accuracy that High-Speed Rotating Mirror Camera is analyzed transient event greatly, promotes the overall performance of camera.

Peng can, Peng Nianxiang, Chen Yanhong. a kind of rotating speed measurement method [J] based on video processing technique. computing technique and automation, 2010,29 (1): 76-79,94

A kind of novel rotating speed measuring method based on video processing technique is proposed, it adopts PC and USB camera, by VFW software kit, the video of article for rotation is converted into several continuous rest images, the rotation angle that then converts constantly adjacent two interframe of accumulative total by hough is in the hope of mean speed.The method has that antijamming capability is strong, cost performance is high, system architecture is simple, be easy to the features such as multichannel is integrated.Shortcoming is to only limit to measure motor speed, is difficult to be applied in bullet tachometric survey.

4. Guo Jingjing, Zhao Xuwen, Li Min etc. the Novel speed sensor [J] based on line array CCD. photoelectron laser, 2012,23 (8): 1478-1481

A kind of speed probe based on line array CCD is proposed.The reflection of the particular design striped in rotating shaft is fixed in utilization, and rotational transform is become to translation, utilizes the advantage of CCD at micrometric displacement school procuratorial organ face, then in conjunction with highly sensitive PIN pipe as tick lables.Advantage is that the noncontact, the real-time that have realized in low speed and high-speed range are measured.Shortcoming is only applicable to the fields such as instrument and meter, accurate manufacture and Industry Control, cannot be applied in bullet tachometric survey.

Radar

The method of utilizing radar to carry out revolution speed measuring is the extraction based on to rotating speed, at present there are no this class document and patent.Can analyze by common bullet (not cutting does not load telemetering pickup yet) the micro-doppler information that radar is obtained, obtain fine motion data, but generally only limit to theory analysis or l-G simulation test, not carry out engineering practice.

1. Liu Wei builds, Chen Jianwen. Ballistic Missile Targets fine motion signature analysis and parameter extraction [J]. and radar institute of air force journal, 2009,23 (3): 175-177,186

3 kinds of common fine motions of Ballistic Missile Targets have been studied: swing, spin and coning, by every kind of corresponding micro-doppler of fine motion is analyzed, obtained the frequency content under corresponding fine motion.Shortcoming is that echo-signal is more complicated in compound fine motion situation, cannot effectively extract compound fine motion parameter.

2. Shang Jianyu, Zhang Xiaoming, Huang Jianlin. conventional ammunition tachometric survey Time-Frequency Analysis Method research [J]. sensing technology journal, 2012,25 (7): 951-956

Propose a kind of " sliding window " Chirp-z mapping algorithm for extracting the frequency of Magnetic Sensor output signal, and then obtain bullet rotary speed information.By by itself and other Time-Frequency Analysis Method comparison, show that its precision when extracting bullet rotating speed is the highest, and it is difficult for affected by noise.Advantage is that Signal-to-Noise is larger, and the precision of this Algorithm Analysis signal is higher.Shortcoming is when in signal, noise energy is larger, need suitably widen the width of " sliding window ", by sacrificing portion of time resolution ratio, exchanges frequency resolution for.

3. Lee east is big, and sieve is met, Zhang Qun etc. and in radar network, rolling target micro-Doppler effect is analyzed and three-dimensional fine motion feature extraction [J]. air force engineering college journal (natural science edition), 2012,13 (3): 45-49,90

Analyze and verified that target fine motion characteristic 3 D is extracted in the realization in radar network, in the radar network proposing, the three-dimensional fine motion information extracting method of target has feasibility, can be for special objective identification provides more accurate and abundant characteristic information, for evaluating objects micro-Doppler effect in radar network provides theoretical foundation.Shortcoming is to have multiple radars target to be measured from different visual angles simultaneously, and Project Realization gets up to acquire a certain degree of difficulty.

4.Victor?C.Chen.Radar?Micro-Doppler?Signatures-Principle?and?Applications[J].Radar?Science?and?Technology,2012,10(3):231-240

The micro-doppler signal characteristic of target shows as different complex frequency modulation, and it is produced by target component, and during with associating, m-Doppler frequency domain is described, and can disclose the characteristic of target uniqueness.Introduce basic principle and the application of radar micro-Doppler effect, describe the micro-doppler signal characteristic from rigid body and non-rigid body.Shortcoming is not carry out engineering practice.

Summary of the invention

The object of the invention is to propose a kind of common bullet revolution extracting method based on continuous wave radar, common bullet herein refers to not cutting at the bottom of bullet, also do not load telemetering pickup, optical method and telemetry cannot obtain common Flight Projectile revolution under more remote condition; The rotating-speed modulation signal of the common bullet that radar obtains is very faint, adopt conventional method cannot obtain tach signal, and this method is by obtaining tach signal to technological means such as primary signal extraction, digital demodulation, time frequency analysis, then according to bullet rotating speed, be this mathematical relationship of derivative of revolution, rotating speed integration is obtained to revolution; So both can increase the observing time of radar, avoid again the FFT Problem of Failure that causes because of video stretching, reach the object of feeble signal detection and extraction.

Technical scheme of the present invention is achieved in that the bullet revolution extracting method based on continuous wave radar, adopts the common Flight Projectile of continuous wave radar tracking measurement, then adopts primary signal is processed, and obtains radial velocity data;

Step 1: radar tracking is measured;

Radar is erected at weapon pack proceeds posterolateral, and Flight Projectile is carried out to tracking measurement, records radar return sampled signal; Sampled signal is made to analysis of spectrum, obtain radial velocity v _r.

Step 2: micro-doppler tach signal extracts;

Tach signal is included in micro-doppler signal, extract revolution, should be first rotational speed extraction out; The rotating-speed modulation signal of not cutting bullet is very faint, directly adopt ultra long FFT processing to increase the radar monitoring time, can not effectively improve tach signal signal to noise ratio, its reason is the lengthening along with observing time, the variation of bullet radial velocity makes Doppler frequency spectrum broadening, FFT handling failure, therefore cannot extract tach signal; It is characterized in that: by radial velocity, set up reference signal, by primary signal and its mixing after extracting, demodulation obtains tach signal, by micro-doppler information analysis in signal phase, draws rotary speed information; Then to rotary speed data carry out matching, integration obtains revolution data; Specific implementation step is as follows: the radial velocity generating reference signal that utilizes step 1 to obtain, carry out to received signal digital demodulation, after mixing, frequency spectrum shift is arrived to low-frequency range, carry out carrying out digital spectral analysis after filtering extraction again, radar echo signal can be characterized by:

$S_r\left(t\right)=\underset{m=-k}{\overset{k}{\mathrm{\Σ}}}{C}_m\left(t\right)\cos \left[2\mathrm{\π}(f_d+m{f}_r)t\right]+n\left(t\right)$

In formula, C _m(t) be the amplitude of sideband signals; f _dbullet Doppler frequency, f=2v _r/ λ, λ radar wavelength; f _rit is bullet rotating speed; N (t) is noise; M is frequency component exponent number, has given up the side frequency component higher than k time here;

By orthogonal double channels, signal is become to analytic signal (not considering noise n (t) herein) as follows:

$S_0\left(t\right)=\underset{m=-k}{\overset{k}{\mathrm{\Σ}}}{C}_m\left(t\right)e^{j2\mathrm{\πm}{f}_{r}t}$

By echo-signal S (t) and reference signal

carry out digital mixing, can obtain tach signal:

$S\left(t\right)=\underset{m=-k}{\overset{k}{\mathrm{\Σ}}}{C}_m\left(t\right)e^{j2\mathrm{\π}(f_d+m{f}_r)t}$

Step 3: bullet rotating speed processing;

Micro-doppler frequency is the instantaneous frequency of doppler echo signal after mixing, and instantaneous frequency is the derivative of signal phase to the time.After mixing, the spectrum component in signal is mf _r(m=-k ,-k+1, Λ, 0, Λ, k-1, k), frequency component is moved low frequency from high frequency, by short time discrete Fourier transform, can calculate f _r, i.e. rotating speed.

Step 4: rotary speed data matching;

Rotary speed data is made to multinomial least square fitting, obtains fitting function and be:

$f\left(t\right)=\underset{i=0}{\overset{P}{\mathrm{\Σ}}}{a}_i{t}^i$

In formula, P is multinomial exponent number, a _i(i=0,1, Λ, P) is coefficient.

Step 5: revolution extracts;

To f (t) integration, can obtain revolution expression formula:

$F\left(t\right)={\∫}_{t_0}^{t}f\left(\mathrm{\τ}\right)\mathrm{d\τ}=\underset{i=0}{\overset{P}{\mathrm{\Σ}}}\frac{a_i{t}^{i+1}}{i+1}+C$

In formula, t ₀for revolution is from 0 counting initial time, generally there is F (t ₀)=0, now $C=-\underset{i=0}{\overset{P}{\mathrm{\Σ}}}\frac{a_i{t_0}^{i+1}}{i+1}.$

Good effect of the present invention is to have utilized the bullet rotary speed information comprising in continuous wave radar micro-doppler echo information, according to bullet rotating speed, is this mathematical relationship of derivative of revolution, and rotating speed integration is obtained to revolution; Its acquired information speed is fast, is not subject to the impact of external environment, and need not increase multiple radars and target is measured from different visual angles simultaneously; The revolution that is applicable to the common bullets such as bullet, shell and rocket projectile extracts, and not be used in bullet bottom cutting.

Accompanying drawing explanation

Fig. 1 is radar working cloth station schematic diagram.

Fig. 2 is rotational speed extraction flow process.

Fig. 3 is radial velocity waterfall figure.

Fig. 4 is harmonic wave modulation spectrum figure.

Fig. 5 is rotating speed fitting result chart.

Fig. 6 is matching residual error scatter diagram.

Fig. 7 is revolution data and curves figure.

The specific embodiment

Below in conjunction with specific embodiment, the present invention will be further described, and the bullet in described example is not cutting all, and general implementation step is as follows:

Step 1: radar tracking is measured;

As shown in Figure 1, in O-XYZ rectangular coordinate system, radar is erected at weapon pack proceeds posterolateral (laterally approximately 10 meters to the right, longitudinally approximately 30 meters to the rear), and certain Flight Projectile is carried out to tracking measurement, records radar return sampled signal; Fig. 2 is rotational speed extraction overall flow.First read original file data, after the processing such as short time discrete Fourier transform, spectrum peak search, obtain radar radial velocity v _r, Fig. 3 is radar return spectrogram, can see speed and rotating speed frequency spectrum.

Step 2: micro-doppler tach signal extracts;

The rotating-speed modulation signal of not cutting bullet is very faint, directly adopt ultra long FFT processing to increase the radar monitoring time, can not effectively improve tach signal signal to noise ratio, its reason is the lengthening along with observing time, the variation of bullet radial velocity makes Doppler frequency spectrum broadening, FFT handling failure, therefore cannot extract tach signal.

It is characterized in that: the radial velocity generating reference signal that utilizes step 1 to obtain, carry out to received signal digital demodulation, after mixing, frequency spectrum shift is arrived to low-frequency range, carry out carrying out again digital spectral analysis after filtering extraction, so both can increase the observing time of radar, avoid again the FFT Problem of Failure causing because of video stretching, reached the object of feeble signal detection and extraction.Idiographic flow is shown in Fig. 4.

Radar echo signal can be characterized by:

$S_r\left(t\right)=\underset{m=-k}{\overset{k}{\mathrm{\Σ}}}{C}_m\left(t\right)\cos \left[2\mathrm{\π}(f_d+m{f}_r)t\right]+n\left(t\right)$

In formula, C _m(t) be the amplitude of sideband signals; f _dbullet Doppler frequency, f _d=2v _r/ λ, λ is radar wavelength; f _rit is bullet rotating speed; N (t) is noise; M is frequency component exponent number, has given up the side frequency component higher than k time here.

By orthogonal double channels, signal is become to analytic signal (not considering noise n (t) herein) as follows:

$S_0\left(t\right)=\underset{m=-k}{\overset{k}{\mathrm{\Σ}}}{C}_m\left(t\right)e^{j2\mathrm{\πm}{f}_{r}t}$

By echo-signal S (t) and reference signal

carry out digital mixing, can obtain tach signal:

$S_0\left(t\right)=\underset{m=-k}{\overset{k}{\mathrm{\Σ}}}{C}_m\left(t\right)e^{j2\mathrm{\πm}{f}_{r}t}$

Step 3: bullet rotating speed processing;

Micro-doppler frequency is the instantaneous frequency of doppler echo signal after mixing, and instantaneous frequency is the derivative of signal phase to the time.After mixing, the spectrum component in signal is mf _r(m=-k ,-k+1, Λ, 0, Λ, k-1, k), frequency component is moved low frequency from high frequency, by short time discrete Fourier transform, can calculate f _r, Fig. 4 is that rotating speed is processed harmonic wave waterfall figure, has provided laterally zygomorphic triple-frequency harmonics spectrogram, establishing m subharmonic corresponding data is f _rm, rotating speed is f _rm/ m, in order to improve processing accuracy, need to process multiple harmonic waves, then gets average as tachometer value.

Step 4: rotary speed data matching;

Rotary speed data is made to multinomial least square fitting, obtains fitting function and be:

$f\left(t\right)=\underset{i=0}{\overset{P}{\mathrm{\Σ}}}{a}_i{t}^i$

In formula, P is multinomial exponent number, a _i(i=0,1, Λ, P) is coefficient.Fig. 5, the 6th, rotating speed fitting result chart, in order to be clear that fitting effect, only provides 28-30s data in two seconds.

Step 5: revolution extracts;

To f (t) integration, can obtain revolution expression formula:

$F\left(t\right)={\∫}_{t_0}^{t}f\left(\mathrm{\τ}\right)\mathrm{d\τ}=\underset{i=0}{\overset{P}{\mathrm{\Σ}}}\frac{a_i{t}^{i+1}}{i+1}+C$

In formula, t ₀for revolution is from 0 counting initial time, generally there is F (t ₀)=0, now $C=-\underset{i=0}{\overset{P}{\mathrm{\Σ}}}\frac{a_i{t_0}^{i+1}}{i+1}.$ Fig. 7 was revolution curve map, since 27 seconds countings.

Embodiment 1: certain shell revolution speed measuring

Certain common projectile flying distance is far away, and optics and telemetry all cannot be measured its revolution, and this method can complete revolution speed measuring.Table 1 is the rotary speed data that adopts triple-frequency harmonics to calculate, and table 2 is revolution data.

Table 1 example 1 rotating speed result of calculation

Table 2 example 1 revolution result of calculation

Time (second)	Revolution (turning)
		27.0	0
27.3	41.786
		27.61	84.901
27.92	127.953
		28.23	170.941
28.54	213.867
		28.85	256.73
29.16	299.531
		29.47	342.271
29.78	384.948
		30.09	427.564
30.4	470.12
		30.71	512.614
31.02	555.048
		31.33	597.422
31.64	639.736
		31.95	681.99
32.26	724.184
		32.57	766.319
32.88	808.395
		33.19	850.411
33.5	892.368
		33.81	934.266
34.12	976.103
		34.43	1017.886
34.74	1059.607
		35.05	1101.27
35.36	1142.874
		35.67	1184.419
35.98	1225.905
		36.29	1267.333
36.6	1308.702
		36.91	1350.012
37.22	1391.263

Embodiment 2: certain small-bore bullet revolution speed measuring

Small-bore bullet target is little, cannot load telemetering pickup, when distant, (exceedes 100 meters), and optical device cannot imaging, and this method can complete this type of target revolution speed measuring.Table 3 is tachometric survey results, and table 4 is that bullet goes out the rotary speed data after gun muzzle.

Table 3 example 2 rotating speed result of calculations

0.436	609.102
		0.481	605.388
0.525	602.453
		0.57	599.356
0.615	596.255
		0.659	592.824
0.704	590.06
		0.748	586.918
0.793	584.586
		0.838	580.151
0.882	578.28
		0.927	575.349
0.971	572.573
		1.016	569.23
1.061	567.052
		1.105	564.055
1.15	561.721
		1.194	558.415
1.239	556.097
		1.284	553.285
1.328	550.903
		1.373	547.79
1.417	545.567
		1.462	543.233
1.507	540.688
		1.551	538.448
1.596	535.284
		1.64	533.244
1.685	530.712
		1.73	528.666
1.774	525.71
		1.819	523.328
1.864	521.238
		1.908	518.868
2.101	508.603

Table 4 example 2 revolution result of calculations

Time (second)	Revolution (turning)
		0.00	0
0.05	30.967
		0.11	69.149
0.17	107.044
		0.23	144.657
0.29	181.994
		0.35	219.058
0.41	255.854
		0.47	292.387
0.53	328.659
		0.59	364.676
0.65	400.441
		0.71	435.959
0.77	471.232
		0.83	506.266
0.89	541.062
		0.95	575.626
1.01	609.959
		1.07	644.067
1.13	677.951
		1.19	711.615
1.25	745.062
		1.31	778.296
1.37	811.318
		1.43	844.132
1.49	876.74
		1.55	909.145
1.61	941.35
		1.67	973.357
1.73	1005.167
		1.79	1036.785
1.85	1068.211
		1.91	1099.447
1.97	1130.496
		2.03	1161.36
2.09	1192.04

Embodiment 3: certain rocket projectile revolution speed measuring

Rocket projectile rotating speed is low, and this method also can complete this type of target revolution speed measuring, and table 5 is the rotary speed datas that adopt 16 subharmonic to calculate, and table 6 is revolution data.

Table 5 example 3 rotating speed result of calculations

Table 6 example 3 revolution result of calculations

Time (second)	Revolution (turning)
		35.00	0
35.35	5.607
		35.71	11.386
36.07	17.176
		36.43	22.973
36.79	28.777
		37.15	34.584
37.51	40.394
		37.87	46.204
38.23	52.013
		38.59	57.819
38.95	63.621
		39.31	69.416
39.67	75.205
		40.03	80.985
40.39	86.756
		40.75	92.516
41.11	98.265
		41.47	104.001
41.83	109.724
		42.19	115.434
42.55	121.129
		42.91	126.809
43.27	132.473
		43.63	138.123
43.99	143.756
		44.35	149.373
44.71	154.975
		45.07	160.561
45.43	166.13
		45.79	171.685
46.15	177.224
		46.51	182.748
46.87	188.259
		47.23	193.700
47.59	199.239
		47.95	204.711

Claims (1)

1. the bullet revolution extracting method based on continuous wave radar, adopts the common Flight Projectile of continuous wave radar tracking measurement, then adopts primary signal is processed, and obtains radial velocity data;

Step 1: radar tracking is measured;

Radar is erected at weapon pack proceeds posterolateral, and Flight Projectile is carried out to tracking measurement, records radar return sampled signal; Sampled signal is made to analysis of spectrum, obtain radial velocity v _r;

Step 2: micro-doppler tach signal extracts;

Tach signal is included in micro-doppler signal, extract revolution, should be first rotational speed extraction out; The rotating-speed modulation signal of not cutting bullet is very faint, directly adopt ultra long FFT processing to increase the radar monitoring time, can not effectively improve tach signal signal to noise ratio, its reason is the lengthening along with observing time, the variation of bullet radial velocity makes Doppler frequency spectrum broadening, FFT handling failure, therefore cannot extract tach signal; It is characterized in that: by radial velocity, set up reference signal, by primary signal and its mixing after extracting, demodulation obtains tach signal, by micro-doppler information analysis in signal phase, draws rotary speed information; Then to rotary speed data carry out matching, integration obtains revolution data; Specific implementation step is as follows: the radial velocity generating reference signal that utilizes step 1 to obtain, carry out to received signal digital demodulation, after mixing, frequency spectrum shift is arrived to low-frequency range, carry out carrying out digital spectral analysis after filtering extraction again, radar echo signal can be characterized by:

$S_r\left(t\right)=\underset{m=-k}{\overset{k}{\mathrm{\Σ}}}{C}_m\left(t\right)\cos \left[2\mathrm{\π}(f_d+m{f}_r)t\right]+n\left(t\right)$ In formula, C _m(t) be the amplitude of sideband signals; f _dbullet Doppler frequency, f _d=2v _r/ λ, λ is radar wavelength; f _rit is bullet rotating speed; N (t) is noise; M is frequency component exponent number, has given up the side frequency component higher than k time here;

By orthogonal double channels, signal is become to analytic signal (not considering noise n (t) herein) as follows:

$S_0\left(t\right)=\underset{m=-k}{\overset{k}{\mathrm{\Σ}}}{C}_m\left(t\right)e^{j2\mathrm{\πm}{f}_{r}t}$

By echo-signal S (t) and reference signal

carry out digital mixing, can obtain tach signal:

$S\left(t\right)=\underset{m=-k}{\overset{k}{\mathrm{\Σ}}}{C}_m\left(t\right)e^{j2\mathrm{\π}(f_d+m{f}_r)t}$

Step 3: bullet rotating speed processing;

Micro-doppler frequency is the instantaneous frequency of doppler echo signal after mixing, and instantaneous frequency is the derivative of signal phase to the time;

After mixing, the spectrum component in signal is

Mf _r(m=-k ,-k+1, Λ, 0, Λ, k-1, k) frequency component is moved low frequency from high frequency, by short time discrete Fourier transform, can calculate f _r, i.e. rotating speed;

Step 4: rotary speed data matching;

Rotary speed data is made to multinomial least square fitting, obtains fitting function and be:

$f\left(t\right)=\underset{i=0}{\overset{P}{\mathrm{\Σ}}}{a}_i{t}^i$

In formula, P is multinomial exponent number, a _i(i=0,1, Λ, P) is coefficient;

Step 5: revolution extracts;

To f (t) integration, can obtain revolution expression formula:

$F\left(t\right)={\∫}_{t_0}^{t}f\left(\mathrm{\τ}\right)\mathrm{d\τ}=\underset{i=0}{\overset{P}{\mathrm{\Σ}}}\frac{a_i{t}^{i+1}}{i+1}+C$

In formula, t ₀for revolution is from 0 counting initial time, generally there is F (t ₀)=0, now $C=-\underset{i=0}{\overset{P}{\mathrm{\Σ}}}\frac{a_i{t_0}^{i+1}}{i+1}.$

Images