CN105575166A - Parking condition monitoring method based on geomagnetic disturbance detection by engine - Google Patents

Abstract

The invention belongs to the technical field of information process of intelligent traffic sensors, and specifically relates to a parking condition monitoring method and an apparatus based on geomagnetic disturbance detection by an engine. According to the method, mode recognition of the driving state of a vehicle in a parking space is performed by employing strong disturbance for a geomagnetic field during the starting of the vehicle engine, and the influence on the state detection result of the parking space due to the starting of an engine of a vehicle nearby is reduced.

Description

A kind of dead ship condition monitoring method geomagnetic disturbance detected based on engine

Technical field

The invention belongs to the technical field of information processing of intelligent transportation aspect sensor.In particular to a kind of dead ship condition monitoring method of detecting geomagnetic disturbance based on engine and device.

Background technology

Along with the quick growth of China's economy, the recoverable amount of automobile also increases sharply, and especially in city, automobile quantity is increased sharply, and cause parking stall quantity nervous, the problem of parking difficulty becomes increasingly conspicuous.Storing cycle problem has become the key factor affecting urban transportation, and subject matter is as follows: stop nowhere, road occupying violating the regulations, unattended, security administration etc.And these problems are often out in the cold, make city fall into chaos can't bear situation.

At present a lot of parking lot or parking stall also rest on the labor management stage, and completely by manually checking parking stall, manual record access time, manual toll collection, and in large-scale parking lot or meet peak period, manual type management is often unable to do what one wishes.Manual toll collection is short of management supervision again, is easy to the situation that arbitrary imposition of fees occurs.Therefore excavate parking resource, the intellectuality parking supervisory systems set up based on the large data platform of city management is extremely urgent, in smart city construction from now on, have wide prospect.

Dead ship condition detection scheme main in the market has: ground induction coil, ultrasound wave, infrared induction and video detection etc.Ground induction coil due to construction not easily, road pavement destroys the shortcoming such as large, difficult in maintenance and cannot be applied to parking lot.Ultrasound wave is more affected by environment, and stability is not enough, often causes accuracy of detection to reduce because of the sensitivity decrease of probe.Infrared induction is affected by environment equally, and particularly the headlight of automobile and the light and shade change in parking lot often can cause flase drop.Ultrasound wave and infraredly cannot be applied to open parking ground.The accuracy of detection that video detects is current still not high, and cost is higher.

For the dead ship condition monitoring method of geomagnetic sensor mode, because its physical characteristics is very easy to the interference being subject to adjacent parking stall vehicle, the data detected are the magnetic field intensity after all vehicle joint effects of periphery in fact, the magnetic field intensity that such magnetic field intensity and single parking stall vehicle affect is obviously distinguishing, do vehicle detection with such data, the result of acquisition is also inaccurate.

Prior art attempts to solve the problem by introducing other car interference value, but remains and judge to have car/disturb without car and other car based on geomagnetic data change thresholding.Problem is not solved at all.Find after tested, other car has started in launch process very large to earth magnetic effect, is easy to interfere with the numerical value of geomagnetic sensor thus causes judgement to make mistakes.

Summary of the invention

The object of the invention is for the deficiencies in the prior art, propose a kind of dead ship condition monitoring method of geomagnetic disturbance being detected based on engine and device.Strong jamming to terrestrial magnetic field when the method utilizes automobile transmitter to start, carries out pattern-recognition to vehicle travel condition on parking stall, thus reduces the impact because other car engine starts this parking space state testing result.

The technical solution adopted for the present invention to solve the technical problems comprises the steps:

First initialization system, measures the geomagnetic data of Magnetic Sensor installation site, current position point under ideal is without car state.Namely measure geomagnetic data value under current environment and be averaged, to obtain background magnetic field value (x ₀y ₀z ₀), it can be expressed as:

$x_0=\frac{1}{N_1}\underset{i=1}{\overset{N_1}{\Σ}}x\left(i\right),y_0=\frac{1}{N_1}\underset{i=1}{\overset{N_1}{\Σ}}y\left(i\right),z_0=\frac{1}{N_1}\underset{i=1}{\overset{N_1}{\Σ}}z\left(i\right)$

Wherein (x, y, z) measures the geomagnetic data obtained, N ₁for for average sampled point number, can 10 ~ 100 be got.Using the geomagnetic data of these data as desirable background environment.Ideal refers on position to be detected without car state and surrounding is all be in without car state.

After completing background earth magnetism environment learning, system enters dead ship condition monitoring pattern.Due to very large on the impact of magnetic survey value when motor car engine is started; therefore all experience the process that a geomagnetic data acutely changes when automobile enters parking stall and sail out of parking stall, amplitude of this violent variation to be usually better than after background ground magnetic value and vehicle parking the amplitude of variation between magnetic value.Traditional dead ship condition detection method based on the change of ground magnetic value can not well be screened because contiguous parking stall motor car engine starts caused false-alarm signal.The derivative of the geomagnetic data that the present invention utilizes computation and measurement to obtain identify and mate engine start and flame-out process corresponding geomagnetic data change process, measure the geomagnetic data value obtained when adopting engine start by identifying this process to avoid and carry out dead ship condition detection, avoid the error detection occurred because adjacent parking stall car engine causes.

The derivative calculating the geomagnetic data recorded is continued, that is: in dead ship condition monitoring pattern

$\mathrm{\Δ}x\left(i\right)=\frac{x\left(i\right)-x(i-1)}{T_s},\mathrm{\Δ}y\left(i\right)=\frac{y\left(i\right)-y(i-1)}{T_s},\mathrm{\Δ}z\left(i\right)=\frac{z\left(i\right)-z(i-1)}{T_s}$

Wherein T _sfor geomagnetic data measures interval.

Then judge whether the absolute value of the derivative value calculated is greater than threshold T h ₁, judge the positive pulse/negative pulse of magnetic survey value by this method, to catch this parking stall or adjacent parking stall automobile engine starting/flame-out process.Threshold T h1, for judging the start time of geomagnetic data acute variation, generally can be set to 5 ~ 20.During concrete judgement in the following way:

|Δx(i)|≥Th ₁or|Δy(i)|≥Th ₁or|Δz(i)|≥Th ₁

When measuring the derivative value that obtains and being less than threshold value, illustrating currently does not have motor car engine to start/stop working process or geomagnetic disturbance factor.Because the present invention is for judging parking stall state, certainly existing a motor car engine before one time parking stall state changes and starting/stop working process, namely there is a geomagnetic data acute variation process.And automobile is compared with background magnetic field data from engine start to the geomagnetic data flame-out process and is altered a great deal, if now adopt these data to carry out Parking Stall state-detection, probably have influence on the testing result of this parking space state when adjacent parking stall has associated vehicular engine to start.

When judging that derivative value is greater than thresholding, think current due to car engine or flame-out cause magnetic survey value acute variation, then after this measure the geomagnetic data obtained and shall not be applied to identification to parking space state.Now need to judge the process of motor car engine from starting to stopping working.The present invention carries out pattern-recognition, to reach the impact eliminated engine start and detect dead ship condition by the magnetic survey value of derivative value to engine start/flame-out process recording adjacent two ground magnetic-pulses.

After detecting that magnetic survey value derivative value is greater than thresholding, think and capture a ground magnetic-pulse, then continue to calculate magnetic survey value derivative value.When geomagnetic data derivative absolute value second time is greater than threshold value, carry out pattern-recognition.Specifically, each average being less than geomagnetic data derivative value in time that threshold value terminates from derivative value is greater than threshold value to derivative value is first calculated, that is:

$\mathrm{\Δ}\stackrel{\‾}{x}\left(n\right)=\frac{1}{N_2}\underset{i=n}{\overset{N_2+n}{\Σ}}\mathrm{\Δ}x\left(i\right),\mathrm{\Δ}\stackrel{\‾}{y}\left(n\right)=\frac{1}{N_2}\underset{i=n}{\overset{N_2+n}{\Σ}}\mathrm{\Δ}y\left(i\right),\mathrm{\Δ}\stackrel{\‾}{z}\left(n\right)=\frac{1}{N_2}\underset{i=n}{\overset{N_2+n}{\Σ}}\mathrm{\Δ}z\left(i\right)$

In formula, n is the sampling start time of computation of mean values, N ₂for the number of samples of the current geomagnetic data derivative for computation of mean values.

Then the derivative average phase adduction that adjacent twice earth magnetism impulsive measurement obtains is asked its square value, it can be expressed as:

$\hat{x}=\frac{\mathrm{\Δ}\stackrel{\‾}{x}\left(n_1\right)+\mathrm{\Δ}\stackrel{\‾}{x}\left(n_2\right)}{2},\hat{y}=\frac{\mathrm{\Δ}\stackrel{\‾}{y}\left(n_1\right)+\mathrm{\Δ}\stackrel{\‾}{y}\left(n_2\right)}{2},\hat{z}=\frac{\mathrm{\Δ}\stackrel{\‾}{z}\left(n_1\right)+\mathrm{\Δ}\stackrel{\‾}{z}\left(n_2\right)}{2}$

Then judge whether the square value calculated is less than threshold T h ₂, the calculating of square value and thresholding compare by such as under type:

$({\hat{x}}^2+{\hat{y}}^2+{\hat{z}}^2)\≤{\mathrm{Th}}_2$

Wherein Th ₂for judging magnetic data pulse gate limit value symmetrically, can 20 ~ 50 be set to.

When being less than threshold value, think to start/stop working the ground magnetic-pulse pair that produces due to same vehicle motor a pair.Local magnetic-pulse is to after appearance, and follow-up earth magnetism sampled data may be used for carrying out parking space state detection.Then calculate N ₃the average of secondary earth magnetism sampled data, namely

$\stackrel{\‾}{x}=\frac{1}{N_2}\underset{i=1}{\overset{N_3}{\Σ}}x\left(i\right),\stackrel{\‾}{y}=\frac{1}{N_2}\underset{i=1}{\overset{N_3}{\Σ}}y\left(i\right),\stackrel{\‾}{z}=\frac{1}{N_2}\underset{i=1}{\overset{N_3}{\Σ}}z\left(i\right)$

Wherein N ₃for average length, be set to 10 ~ 50.

Difference between computation of mean values and background value, that is:

$M={(\stackrel{\‾}{x}-x_0)}^2+{(\stackrel{\‾}{y}-y_0)}^2+{(\stackrel{\‾}{z}-z_0)}^2$

Judge whether difference is greater than threshold T h ₃, as being greater than, send parking space state and change information, instruction has car signal.Th ₃can 20 ~ 50 be set to.

Accompanying drawing explanation

Fig. 1 process flow diagram of the present invention.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.

Time synchronization method under a kind of high-speed mobile environment, the method detects geomagnetic disturbance based on engine, and for improving the correct probability that dead ship condition under complex environment detects, the method specifically comprises the steps:

Step (1). system initialization, carries out self study to background magnetic field under without car state.Namely measure geomagnetic data value under current environment and be averaged, to obtain background magnetic field value (x ₀y ₀z ₀), it can be expressed as:

$x_0=\frac{1}{N_1}\underset{i=1}{\overset{N_1}{\Σ}}x\left(i\right),y_0=\frac{1}{N_1}\underset{i=1}{\overset{N_1}{\Σ}}y\left(i\right),z_0=\frac{1}{N_1}\underset{i=1}{\overset{N_1}{\Σ}}z\left(i\right)$

Wherein (x, y, z) measures the geomagnetic data obtained, N ₁for for average sampled point number, can 10 ~ 100 be got.

Step (2). calculate the derivative of the geomagnetic data recorded.It can be expressed as:

$\mathrm{\Δ}x\left(i\right)=\frac{x\left(i\right)-x(i-1)}{T_s},\mathrm{\Δ}y\left(i\right)=\frac{y\left(i\right)-y(i-1)}{T_s},\mathrm{\Δ}z\left(i\right)=\frac{z\left(i\right)-z(i-1)}{T_s}$

Wherein T _sfor geomagnetic data measures interval.

Step (3). judge whether the absolute value of the derivative value calculated is greater than threshold T h ₁, as otherwise go to step 6.Wherein threshold T h ₁can 5 ~ 20 be set to, when specifically judging in the following way:

|Δx(i)|≥Th ₁or|Δy(i)|≥Th ₁or|Δz(i)|≥Th ₁

Step (4). store geomagnetic data derivative value;

Step (5). geomagnetic data derivative record mark is set, goes to step 2;

Step (6). judge whether geomagnetic data derivative record mark is arranged, as otherwise go to step 2;

Step (7). calculate the average of the derivative value of record and store, its average can calculate by such as under type:

$\mathrm{\Δ}\stackrel{\‾}{x}\left(n\right)=\frac{1}{N_2}\underset{i=n}{\overset{N_2+n}{\Σ}}\mathrm{\Δ}x\left(i\right),\mathrm{\Δ}\stackrel{\‾}{y}\left(n\right)=\frac{1}{N_2}\underset{i=n}{\overset{N_2+n}{\Σ}}\mathrm{\Δ}y\left(i\right),\mathrm{\Δ}\stackrel{\‾}{z}\left(n\right)=\frac{1}{N_2}\underset{i=n}{\overset{N_2+n}{\Σ}}\mathrm{\Δ}z\left(i\right)$

Wherein N ₂for the number of samples of the geomagnetic data of current storage.

Step (8). judge whether geomagnetic data pulse mark is arranged, as arranged, then goes to step 10;

Step (9). geomagnetic data pulse mark is set, and goes to step 2;

Step (10). the derivative value average phase adduction of current derivative value average and storage is asked its square value, and it can be expressed as:

$\hat{x}=\frac{\mathrm{\Δ}\stackrel{\‾}{x}\left(n_1\right)+\mathrm{\Δ}\stackrel{\‾}{x}\left(n_2\right)}{2},\hat{y}=\frac{\mathrm{\Δ}\stackrel{\‾}{y}\left(n_1\right)+\mathrm{\Δ}\stackrel{\‾}{y}\left(n_2\right)}{2},\hat{z}=\frac{\mathrm{\Δ}\stackrel{\‾}{z}\left(n_1\right)+\mathrm{\Δ}\stackrel{\‾}{z}\left(n_2\right)}{2}$

Step (11). judge whether the square value calculated is less than threshold T h ₂, as otherwise go to step 2.The calculating of square value and thresholding compare by such as under type:

$({\hat{x}}^2+{\hat{y}}^2+{\hat{z}}^2)\≤{\mathrm{Th}}_2$

Wherein Th ₂for judging magnetic data pulse gate limit value symmetrically, can 20 ~ 50 be set to.

Step (12). calculate N ₃the average of secondary earth magnetism sampled data, namely

$\stackrel{\‾}{x}=\frac{1}{N_2}\underset{i=1}{\overset{N_3}{\Σ}}x\left(i\right),\stackrel{\‾}{y}=\frac{1}{N_2}\underset{i=1}{\overset{N_3}{\Σ}}y\left(i\right),\stackrel{\‾}{z}=\frac{1}{N_2}\underset{i=1}{\overset{N_3}{\Σ}}z\left(i\right)$

Step (13). the difference between computation of mean values and background value, that is:

$M={(\stackrel{\‾}{x}-x_0)}^2+{(\stackrel{\‾}{y}-y_0)}^2+{(\stackrel{\‾}{z}-z_0)}^2$

Step (14). judge whether difference is greater than threshold T h ₃, as otherwise remove have car mark and go to step 16;

Step (15). be provided with car mark;

Step (16). remove geomagnetic data record mark;

Step (17). remove geomagnetic data pulse mark, go to step 2.

Claims (1)

1., based on the dead ship condition monitoring method that engine detects geomagnetic disturbance, it is characterized in that comprising the following steps:

Step (1): system initialization, carries out self study to background magnetic field under without car state, namely measures geomagnetic data value under current environment and is averaged, to obtain background magnetic field value (x ₀y ₀z ₀), it is expressed as:

$x_0=\frac{1}{N_1}\underset{i=1}{\overset{N_1}{\Σ}}x\left(i\right),y_0=\frac{1}{N_1}\underset{i=1}{\overset{N_1}{\Σ}}y\left(i\right),z_0=\frac{1}{N_1}\underset{i=1}{\overset{N_1}{\Σ}}z\left(i\right)$

Wherein (x, y, z) measures the geomagnetic data obtained, N ₁for for average sampled point number, get 10 ~ 100;

Step (2): the derivative calculating the geomagnetic data recorded, it can be expressed as:

$\mathrm{\Δ}x\left(i\right)=\frac{x\left(i\right)-x\left(i-1\right)}{T_s},\mathrm{\Δ}y\left(i\right)=\frac{y\left(i\right)-y\left(i-1\right)}{T_s},\mathrm{\Δ}z\left(i\right)=\frac{z\left(i\right)-z\left(i-1\right)}{T_s}$

Wherein T _sfor geomagnetic data measures interval;

Step (3): judge whether the absolute value of the derivative value calculated is greater than threshold T h ₁, as otherwise go to step 6;

Wherein threshold T h ₁value gets 5 ~ 20, when specifically judging in the following way:

|Δx(i)|≥Th ₁or|Δy(i)|≥Th ₁or|Δz(i)|≥Th ₁

Step (4): store geomagnetic data derivative value;

Step (5): geomagnetic data derivative record mark is set, goes to step 2;

Step (6): judge whether geomagnetic data derivative record mark is arranged, as otherwise go to step 2;

Step (7): calculate the average of the derivative value of record and store, its average such as under type calculates:

$\mathrm{\Δ}\stackrel{\‾}{x}\left(n\right)=\frac{1}{N_2}\underset{i=n}{\overset{N_2+n}{\Σ}}\mathrm{\Δ}x\left(i\right),\mathrm{\Δ}\stackrel{\‾}{y}\left(n\right)=\frac{1}{N_2}\underset{i=n}{\overset{N_2+n}{\Σ}}\mathrm{\Δ}y\left(i\right),\mathrm{\Δ}\stackrel{\‾}{z}\left(n\right)=\frac{1}{N_2}\underset{i=n}{\overset{N_2+n}{\Σ}}\mathrm{\Δ}z\left(i\right)$

Wherein N ₂for the number of samples of the geomagnetic data of current storage;

Step (8): judge whether geomagnetic data pulse mark is arranged, as arranged, then goes to step 10;

Step (9): geomagnetic data pulse mark is set, and goes to step 2;

Step (10): the derivative value average phase adduction of current derivative value average and storage is asked its square value, and it can be expressed as:

$\hat{x}=\frac{\mathrm{\Δ}\stackrel{\‾}{x}\left(n_1\right)+\mathrm{\Δ}\stackrel{\‾}{x}\left(n_2\right)}{2},\hat{y}=\frac{\mathrm{\Δ}\stackrel{\‾}{y}\left(n_1\right)+\mathrm{\Δ}\stackrel{\‾}{y}\left(n_2\right)}{2},\hat{z}=\frac{\mathrm{\Δ}\stackrel{\‾}{z}\left(n_1\right)+\mathrm{\Δ}\stackrel{\‾}{z}\left(n_2\right)}{2}$

Step (11): judge whether the square value calculated is less than threshold T h ₂, as otherwise go to step 2; The calculating of square value and thresholding compare by such as under type:

$({\hat{x}}^2+{\hat{y}}^2+{\hat{z}}^2)\≤{\mathrm{Th}}_2$

Wherein Th ₂for judging magnetic data pulse gate limit value symmetrically, can 20 ~ 50 be set to;

Step (12): calculate N ₃the average of secondary earth magnetism sampled data, namely

$\stackrel{\‾}{x}=\frac{1}{N_2}\underset{i=1}{\overset{N_3}{\Σ}}x\left(i\right),\stackrel{\‾}{y}=\frac{1}{N_2}\underset{i=1}{\overset{N_3}{\Σ}}y\left(i\right),\stackrel{\‾}{z}=\frac{1}{N_2}\underset{i=1}{\overset{N_3}{\Σ}}z\left(i\right)$

Step (13): the difference between computation of mean values and background value, that is:

$M={(\stackrel{\‾}{x}-x_0)}^2+{(\stackrel{\‾}{y}-y_0)}^2+{(\stackrel{\‾}{z}-z_0)}^2$

Step (14): judge whether difference is greater than threshold T h ₃, as otherwise remove have car mark and go to step 16;

Step (15): be provided with car mark;

Step (16): remove geomagnetic data record mark;

Step (17): remove geomagnetic data pulse mark, go to step 2.