CN103644888B - A kind of inertial reference measurement method for detecting bridge deformation - Google Patents

Abstract

The invention discloses a kind of inertial reference measurement method for detecting bridge deformation, for detecting bridge deformation, sedimentation.The method is specially: plan a path on the surface of tested bridge, route marks several reference point, utilizes high-precision GPS information to set up reference data, utilizes inertia system to export and sets up inertial reference; Gather the output of inertia system, the output of mileage gauge, respectively mileage gauge is exported and compensate, test is affected on bridge floor out-of-flatness identify, carry out combination dead reckoning afterwards, complete the test of whole selected track, carry out again closed revising flow process, finally provide tested precise trajectory and extrapolate deformation and the sedimentation of bridge.The present invention is based on inertial navigation system and mileage gauge, GPS combine, utilize three-dimensional inertia measurement mode, realize rapidly, continuously to the measurement of the three-dimensional little dynamic deformation of bridge, not by the restriction of rail and trackless.

Description

A kind of inertial reference measurement method for detecting bridge deformation

Technical field

The invention belongs to inertial technology engineer applied field, concrete, relate to a kind of inertial reference measurement method for detecting bridge deformation.

Background technology

Along with the progress of science and technology and the demand of communications and transportation, many Longspan Bridges arise at the historic moment, and especially suspension bridge is large with its span, beautiful design, save material and enjoy the favor of people, becoming the first-selection of Longspan Bridge.But along with the increase of span, from hundreds of rice to km, owing to lacking necessary monitoring and corresponding maintenance, there is a large amount of bridge damage accident all over the world, caused massive losses to national economy and lives and properties.Therefore, carry out effective monitoring to the bridge security using state for national economy service put into effect, guaranteeing people's life and national wealth safety, is a focus direction of current bridge circle application and research.

Along with people pay attention to increasingly to bridge security problem, be not only that Longspan Bridge builds supervisory system, when young span bridge does not establish corresponding supervisory system yet.Sensing system is the core of supervisory system, and all subsystems of a complete supervisory system are all configured around sensing system.In recent years, Sensor Technology Development is very fast, and especially Fibre Optical Sensor and wireless senser progressively start to apply in engineering.The kind of sensor used from each bridge, be progressively increase, what relate to is wider.The development of satellite remote sensing technology, makes remote sensing technology be widely used in project security monitoring, is especially most widely used in distortion and settlement monitoring.

Instrument at present for bridge deformation monitoring mainly contains: transit, displacement transducer, acceleration transducer and laser testing method.Total powerstation utilizes autoscan method, each measuring point carried out to the continuous sweep of one week, and obtain three-dimensional coordinate, measuring accuracy is higher, but shortcoming to be each measuring point asynchronous and large deformation time can not survey; Displacement transducer is a kind of contact type sensor, and its shortcoming cannot measure and have any problem to lateral displacement measurement for being difficult to the points of proximity; Acceleration transducer, poor for low frequency static displacement identification result, precision is not high.The measuring accuracy of laser testing instrument is higher, but also cannot measure owing to cannot catch luminous point when bridge etc. rocks large.The most emerging high-precision GPS can reach grade measuring accuracy, and shortcoming is necessary long-term measurement and satellite navigation signals is unobstructed.

In existing highway bridge distortion measurement, monitoring, adopt laser tracker, laser scanner, robot measurement, various high-precision GPS receiver, electronic total station, spirit-leveling instrument and various special measurement instrument, adopt one or more surveying instruments to combine, realize high-precision test.The stereo monitoring system be made up of various special monitoring instrument, surveying instrument and air to surface observation instrument, automatic monitoring that bridge is continued and Deformation Prediction can be realized, the feature of this type of metering system is higher, the sustainable monitoring of measuring accuracy, but can only to several measurement, and artificial spanning equipment be very difficult.

Domestic at present have the deformation proposing to adopt inertial technology mode testing engineering, comprises the deformation of the heavy construction such as dam, bridge.Existing inertia test mode mainly adopts some parameters of bidimensional gyro or gyro to measure track three-dimensional separately (in order to survey engineering deformation, when engineering construction, the track that some are fixing can be buried in advance underground, the monitoring in follow-up operation process can be facilitated), start the beginning of inertia measurement.But the metering system of bidimensional is the requirement that can meet plane surveying from demand, but exists and measure defect, cannot the measurement requirement of meeting requirements on three-dimensional solid.

Summary of the invention

For above defect or the Improvement requirement of prior art, the invention provides a kind of inertial reference measurement method for detecting bridge deformation, its object is to the restriction not by rail and trackless, realize rapidly, continuously to the measurement of the three-dimensional little dynamic deformation of bridge, solve equipment erection difficulty in existing highway bridge distortion measurement thus, by deformation among a small circle, the technical matters of bridge rail-free restriction.

For detecting an inertial reference measurement method for bridge deformation, comprise the following steps:

Measurement environment builds step:

Prepare to measure dolly, inertial navigation system installed by measurement dolly, a mileage gauge laid respectively by four wheels measuring dolly;

Reference data establishment step:

At the two ends of bridge to be measured, selected two reference points, locate latitude, longitude and the height above sea level of determining two reference points by GPS; Set up surving coordinate system using one of them reference point as initial point, another reference point is positioned in the coordinate axis of coordinate system; At the surperficial planned trajectory route of bridge to be measured, make the path of planning must through two reference points; The latitude of reference point, longitude and altitude information is utilized to set up inertia system test benchmark, and using the world, northeast reason coordinate system as inertial navigation coordinate system;

Mileage measuring process:

Start measurement dolly to run along path planning, at present sample period t _i-t _i-1, obtain the mileage increment information that four mileage gauges export, wheel deformation error compensation carried out to mileage increment information, then consider that wheel hanging merges four mileage increment informations after compensation, obtain present sample period t _i-t _i-1measure the true mileage increment Delta L of dolly _i;

Inertial navigation step:

Enable inertial navigation system, at current sample time t _iobtain and measure the attitude angle of dolly in navigational coordinate system

Integrated navigation step:

Note odometer coordinate is m system, and inertial navigation coordinate is b system, and the conversion cosine battle array that b is tied to m system is

Note mileage increment Delta L _ibeing projected as of m system ${\mathrm{\ΔL}}_i^m={\left[\begin{array}{ccc}0& \mathrm{\Δ}{L}_i& 0\end{array}\right]}^T,$ Subscript T represents transposition; Mileage increment is obtained by ordinate transform being projected as of b system and then obtain mileage increment Delta L _iin the projection that navigation coordinate is fastened t _ithe attitude angle of moment measurement dolly;

Calculate current sample time t _imeasure the position coordinates of dolly under navigational coordinate system p _i-1for last sampling instant t _i-1measure the position coordinates of dolly under navigational coordinate system;

Carry out to measuring the position coordinates of dolly under navigational coordinate system the bridge floor track that integration obtains under navigational coordinate system, and then obtained the bridge floor track under surving coordinate system by ordinate transform;

Deformation determination step:

Bridge floor track under surving coordinate system and benchmark bridge floor track are compared, determines to detect bridge deformation situation.

Further, in described mileage measuring process to the specific implementation that mileage increment information carries out wheel deformation error compensation be: make present sample period t _i-t _i-1the mileage increment that mileage gauge exports is L _i, wheel error compensation is carried out to it and obtains effective mileage increment wherein, δ K _dfor mileage gauge calibration factor error, W ₀to jolt the stochastic error caused for measuring dolly.

Further, consider in described mileage measuring process that wheel hanging to the specific implementation that four mileage increment informations after compensation merge is:

By test car off-front wheel, the near front wheel, left rear wheel, off hind wheel odometer at present sample period t _i-t _i-1output mileage increment be designated as Δ L respectively _a, Δ L _b, Δ L _c, Δ L _d, Δ L _ifor the true mileage increment after fusion;

As Δ L _c≤ Δ L _d, show that car body turns left, now Δ L _y=Δ L _a;

As Δ L _a< Δ L _b, show that off-front wheel occurs unsettled, now Δ L _y=Δ L _b* Δ L _d/ Δ L _c, Δ L _c≠ 0;

Work as L _c> L _dtime, car body is turned right, now:

1. L is worked as _a≤ L _btime,

If L _b-L _a> L _c-L _d, then off-front wheel is unsettled, now Δ L _y=Δ L _b* Δ L _d/ Δ L _c, Δ L _c≠ 0;

If Δ L _b-Δ L _a≤ Δ L _c-Δ L _d, then without wheel hanging, now Δ L _y=Δ L _a;

2. L is worked as _a> L _btime, then the near front wheel is unsettled, now Δ L _y=Δ L _a.

Further, the true mileage increment of the measurement dolly of measurement little car kilometer increment to the present sample period also gathered in conjunction with the history samples period carries out linear interpolation smoothing processing, to eliminate the vibration interference that bridge pavement out-of-flatness causes.

Further, also carry out error correction to the bridge floor track under surving coordinate system, specific implementation is:

In described surving coordinate system, make the three-dimensional coordinate of planned trajectory route start for (0,0,0), the three-dimensional coordinate of terminal is (Xf, 0,0); The starting point three-dimensional coordinate that bridge floor track under navigational coordinate system is transformed under reference frame is (Xa, Ya, Za), and terminal three-dimensional coordinate is (Xb, Yb, Zb); The bridge floor track three-dimensional coordinate revised under pre-test coordinate system is expressed as (Sx, Sy, Sz);

Determine X to Ratio for error modification Kx=Xf/(Xb-Xa), Ratio for error modification Ky=(the Yb-Ya)/Xf of Y-direction, Ratio for error modification Kz=(the Zb-Za)/Xf of Z-direction;

The bridge floor track under three correction factor correction surving coordinate systems is adopted to obtain revised bridge floor track $(\tilde{S}x,\tilde{S}y,\tilde{S}z),\tilde{S}x=\mathrm{Kx}\&CenterDot;\mathrm{Sx},\tilde{S}y=\mathrm{Ky}\&CenterDot;\mathrm{Sy},\tilde{S}z=\mathrm{Kz}\&CenterDot;\mathrm{Sz}.$

Compared with prior art, Advantageous Effects of the present invention is embodied in:

(1) the present invention adopts high-precision GPS information to set up reference data and utilizes inertia system to set up inertial reference, combines inertia combined navigation technology and closed measuring technique, measuring accuracy is effectively promoted.

(2) wheel deformation error compensation is carried out to mileage increment information, and consider that wheel hanging carries out effective integration to four mileage increment informations after compensation, improve measuring accuracy.

(3) the true mileage increment of the measurement dolly of measurement little car kilometer increment to the present sample period gathered in conjunction with the history samples period carries out linear interpolation smoothing processing, to eliminate the vibration interference that bridge pavement out-of-flatness causes.

(4) adopt closed modification method, error correction is carried out to the bridge floor track under surving coordinate system, further increases precision.

In sum, owing to the present invention is based on inertial navigation system and mileage gauge, GPS combine, can rapidly, continuously to the measurement of bridge three-dimensional deformation, and not by path planning, do not affect by pavement behavior, bridge miniature deformation can be met and measure requirement.

Accompanying drawing explanation

Fig. 1 is that inertial reference measures bridge settlement method flow diagram;

Fig. 2 is reference data and path planning schematic diagram;

Fig. 3 sets up inertial reference schematic flow sheet;

Fig. 4 is mileage gauge information fault tolerance processing flow chart;

Fig. 5 is the program flow diagram of software change rate filtering part;

Fig. 6 is inertia system and mileage dead reckoning and integrated navigation computing method process flow diagram.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.In addition, if below in described each embodiment of the present invention involved technical characteristic do not form conflict each other and just can mutually combine.

Measuring detection bridge deformation mode based on inertial reference is rely on inertia system hardware platform, fundamental measurement unit is counted with inertial navigation system, mileage, gps signal is auxiliary, wherein inertial navigation system, mileage gauge are arranged on and measure on dolly, are arranged in inertial navigation system and acquisition system based on the system software tested.The present invention includes utilize high-precision GPS information to set up reference data, utilize inertia system to set up inertial reference, with the dead reckoning of the auxiliary mileage gauge of inertial navigation system, the fault-tolerant processing of error is caused on the distortion of car body wheel and idle running, affect that test identifies for bridge floor out-of-flatness, dead reckoning data are closed a few part such as to revise and form.Its inertial reference measurement bridge settlement method flow and block diagram are as shown in Figure 1.

Describe in detail below in conjunction with accompanying drawing.

The first step, measurement environment build step.

Prepare to measure dolly, inertial navigation system installed by measurement dolly, a mileage gauge laid respectively by four wheels measuring dolly; The first step: set up reference data.

Second step, reference data establishment step.

At the two ends of measured bridge, selected two fixing benchmark, utilize high-precision GPS to determine the latitude of these 2 reference points, longitude and height above sea level, positioning precision is 2cm.These 2 reference points are utilized to set up surving coordinate system afterwards.One of them reference point is positioned at the initial point of coordinate system, and another reference point is positioned in the X-axis of coordinate system, and coordinate axis Y points on the left of X-axis along local level, and Z axis and X, Y-axis form left-handed coordinate system.

Selected test trails on measured bridge floor, its track can be arbitrary, but selected track must by reference data two point of above-mentioned foundation, and can pre-establish some monumented points in selected test trails, these monumented points can be arbitrary simultaneously.Set up benchmark and path planning as shown in Figure 2.

There is provided initial longitude and latitude high information by GPS, some parameters that inertial navigation system realizes bookbinding complete autoregistration.On fixed position, car body stops 5min, the static output gathering inertia system, and carries out autoregistration according to the initial parameter of bookbinding, sets up the benchmark of inertia system test.Initial parameter is carried out parameter by host computer and is uploaded.First carry out the coarse alignment of 60s, proceed to fine alignment process after 60s, utilize KALMAN filtering and parameter identification, 5min fine alignment completes, and exports identified parameters, and aim at and terminate, system proceeds to flow of navigation.Set up inertial reference flow process and see Fig. 3.

3rd step: mileage measuring process.

At present sample period t _i-t _i-1, obtain the mileage increment information that four mileage gauges export, wheel deformation error compensation carried out to mileage increment information, then consider that wheel hanging merges four mileage increment informations after compensation, obtain present sample period t _i-t _i-1measure the true mileage increment Delta L of dolly _i.

In this step, measure in bridge floor sedimentation and deformation process utilizing inertial technology, by due to deck conditions, wheel aeration quantity, tire size is changed in tire heating and the factor such as wear condition of tire causes mileage gauge calibration factor to become slowly, be difficult to the real stroke (i.e. mileage gauge calibration factor) determined representated by each pulse, become the principal element of restriction mileage gauge rate accuracy.In order to improve precision, mileage gauge calibration factor being corrected, improving measuring accuracy.

The mathematical model of mileage gauge can be written as:

L _i＝N _pulse.K _d（1）

In formula: L _ifor mileage gauge is at each Δ t time interval (Δ t=t _i+1-t _i) interior measured mileage value; N _pulsefor the umber of pulse produced in each Δ t time interval; K _dfor the calibration factor of mileage gauge.

Can release again:

$L_i=N_{\mathrm{pulse}}.K_d={\tilde{L}}_i(1+\mathrm{\&delta;}{K}_d)+W_0---\left(2\right)$

In formula: for the actual distance that vehicle in each time interval travels; δ K _dfor calibration factor error; W ₀for the stochastic error caused of jolting of vehicle, may be defined as white noise.

According to the known effective mileage increment carrying out wheel error compensation and obtain of formula (2)

In measuring process, the structure due to car body causes in test process, and four wheels exists not coplanar phenomenon, measuring wheel can be caused unsettled, cause this mileage gauge no-output, need to carry out fault-tolerant processing to this row.Mileage gauge information fault tolerance processing flow chart is shown in Fig. 4.

By test car off-front wheel, the near front wheel, left rear wheel, off hind wheel odometer at present sample period t _i-t _i-1output mileage increment be designated as Δ L respectively _a, Δ L _b, Δ L _c, Δ L _d, Δ L _ifor the true mileage increment after fusion;

As Δ L _c≤ Δ L _d, show that car body turns left, now Δ L _y=Δ L _a;

As Δ L _a< Δ L _b, show that off-front wheel occurs unsettled, now Δ L _y=Δ L _b* Δ L _d/ Δ L _c, Δ L _c≠ 0;

Work as L _c> L _dtime, car body is turned right, now:

1. L is worked as _a≤ L _btime,

If L _b-L _a> L _c-L _d, then off-front wheel is unsettled, now Δ L _y=Δ L _b* Δ L _d/ Δ L _c, Δ L _c≠ 0;

If Δ L _b-Δ L _a≤ Δ L _c-Δ L _d, then without wheel hanging, now Δ L _y=Δ L _a.

L _a> L _btime, then the near front wheel is unsettled, now Δ L _y=Δ L _a.

Within the same sampling period, computing machine gathers the pulse number that four mileage gauges export respectively, through type (2) calculates each mileage gauge in each sampling period and exports mileage, then according to above-mentioned mileage gauge information fusion flow process, in each computation period T, judge the rolling of carrier, judge the vacant state of four road mileages, and filter mileage export in undesired signal, by merging the calculating of No. four odometers, final output can be moved real mileage information Δ L by display carriers _y.

In measuring process, because bridge floor exists uneven, cause testing apparatus to be vibrated, and produce error.In software flow, adopt rate of change ripple filtering algorithm, the interference that the irregular vibration of bridge pavement brings can be overcome, the data error process that the vibration that road pavement out-of-flatness produces causes, adopt the mode of digit rate ripple to propose error.

First bridge floor hollow identification determination error band to be passed through, then to error point assignment again.The method of assignment is setting to 0 a recovery original value.Level and smooth by the nearly step of method of linear interpolation between the starting point and end point of error band.The program flow diagram of software change rate filtering part is shown in Fig. 5.

When equipment is through hollow bridge floor, two secondary travelling wheels and a secondary relocatable measuring wheel by various degree fall into potted road surface.Produce larger vibration, make the horizontal data distortion recorded.Known, not single in the information of each road level parameter.But form one group by multiple, according to these features.Rate of change filtering adopts following methods to carry out rail gap identification: twice adjacent sampled point is subtracted each other.Obtain its increment (with absolute value representation), the maximum difference DY then allowed with double sampling, compares, if be less than DY, then this point is set to 0; If be greater than DY, then think error point, put y0 (y0 value rule of thumb or test draw) at this point.That is:

As y (n)-y (n-1)≤DY, time, then get y (n)=0;

As y (n)-y (n-1) >DY, time, then get y (n)=y0

Then, carried out on average at 5 to 0 and these group data of y0.Its objective is and can be selected by the size changing y0 value to need, using y (n-1) as the starting point of error band; Find the point of y (n+i) >0, y (n+i+1)=0 again, using y (n+i+1) as the end point of error band.

In history continuously multiple (such as 5) sampling period, calculate mileage signal successively to export, according to level and smooth to the nearly step of data by the method for linear interpolation between starting point and end point, eliminate the interference that the irregular vibration of bridge pavement brings, improve measurement accuracy.

4th step, inertial navigation step:

Enable inertial navigation system, obtain at current sample time ti and measure the attitude angle of dolly in navigational coordinate system

5th step, integrated navigation step

In Integrated Navigation Algorithm, dead reckoning algorithm directly uses the attitude matrix of strapdown inertial, therefore dead reckoning algorithm and strapdown inertial have identical attitude, course angle error, along with the attitude of strapdown inertial navitation system (SINS), the increase of course angle error, the positioning precision of dead reckoning will inevitably be affected.In Integrated Navigation Algorithm, estimate the attitude of system, course angle error compensating, improve the measuring precision.

Choosing sky, northeast (ENU) geographic coordinate is inertial navigation coordinate system, is designated as n system, when inertial navigation is installed on year car by certain orientation, thinks that a year car coordinate system is demarcated coordinate system with inertial navigation and overlapped, is designated as b system.Odometer coordinate system is designated as m system, and odometer is at a bit of time Δ t=t _i+1-t _ithe mileage increment Delta L of interior measurement _ibeing write as vector form in the projection of m system is:

${\mathrm{\&Delta;L}}_i^m={\left[\begin{array}{ccc}0& \mathrm{\&Delta;}{L}_i& 0\end{array}\right]}^T---3$

Suppose there is installation deviation angle between m system and b system, be respectively installation deviation angle, course pitching installation deviation angle α _θwith roll installation deviation angle α _γ, the conversion cosine battle array that can be tied to m system from b is:

Thus mileage increment fastening projective representation at b is:

Mileage increment and the α of expression is fastened by the visible b of above formula _γirrelevant, the projection that mileage increment is fastened at navigation coordinate can be obtained further:

$\mathrm{\&Delta;}{L}_i^n=C_b^n\left(i\right)\mathrm{\&Delta;}{L}_i^b---\left(6\right)$

In formula t _ithe attitude matrix in moment.

Calculate current sample time t _imeasure the position coordinates of dolly under navigational coordinate system p _i-1for last sampling instant t _i-1measure the position coordinates of dolly under navigational coordinate system.Position coordinates is expressed as three-dimensional coordinate as the formula (7)

$\begin{array}{c}{X}_i=X_{i-1}+\mathrm{\&Delta;}{L}_{\mathrm{iN}}^n\\ Y_i=Y_{i-1}+\mathrm{\&Delta;}{L}_{\mathrm{iE}}^n\\ Z_i=Z_{i-1}+\mathrm{\&Delta;}{L}_{\mathrm{iU}}^n\end{array}---\left(7\right)$

In formula: X _i, Y _iand Z _irepresent t respectively _imoment measures the component of the position coordinates of dolly under navigational coordinate system in X, Y and Z-direction, with represent respectively at the component of X, Y and Z-direction.

Integration is carried out to the position coordinates of measurement dolly under navigational coordinate system and obtains bridge floor track to be measured, and obtain the bridge floor track under surving coordinate system by coordinate conversion.

Inertia system and mileage dead reckoning and integrated navigation computational algorithm process flow diagram are shown in Fig. 6.

6th step: adopt Closed-cycle correction.

In described surving coordinate system, make the three-dimensional coordinate of planned trajectory route start for (0,0,0), the three-dimensional coordinate of terminal is (Xf, 0,0); The starting point three-dimensional coordinate that bridge floor track under navigational coordinate system is transformed under reference frame is (Xa, Ya, Za), and terminal three-dimensional coordinate is (Xb, Yb, Zb); The bridge floor track three-dimensional coordinate revised under pre-test coordinate system is expressed as (Sx, Sy, Sz)

Determine X to Ratio for error modification Kx=Xf/(Xb-Xa), Ratio for error modification Ky=(the Yb-Ya)/Xf of Y-direction, Ratio for error modification Kz=(the Zb-Za)/Xf of Z-direction;

The bridge floor track under three correction factor correction surving coordinate systems is adopted to obtain revised bridge floor track $(\tilde{S}x,\tilde{S}y,\tilde{S}z),\tilde{S}x=\mathrm{Kx}\&CenterDot;\mathrm{Sx},\tilde{S}y=\mathrm{Ky}\&CenterDot;\mathrm{Sy},\tilde{S}z=\mathrm{Kz}\&CenterDot;\mathrm{Sz}.$

Through the closed data revised, its precision can improve an order of magnitude on the basis of original dead reckoning, and can improve two orders of magnitude than the result of inertial navigation, these data can characterize the deformed state of bridge pavement.Carry out repeatedly repeated test according to above-mentioned aspect, or compare with reference point, the deformation of bridge can be obtained.

7th step, deformation determination step.

Bridge floor track under surving coordinate system and benchmark bridge floor track are compared, determines to detect bridge deformation situation.

In system work process, the output of system acquisition mileage gauge, fault-tolerant, filtering, export the mileage under m system, can obtain mileage export three-dimensional data by formula 3.Simultaneous computer gathers the output of three optical fibre gyros and three quartz flexible accelerometers, and compensate and revision through instrumental error, hypercomplex number is resolved, and exports one group of attitude matrix parameter, and export attitude angle within 4 employing cycles.The attitude information calculated by formula 5,6 and mileage information merge, and utilize the mode of dead reckoning, are engraved in the displacement information under navigation coordinate when exporting each, carry out integration by formula (7), can extrapolate the track on whole measured road surface.Three-dimensional track information after resolving exports by computing machine in real time, saves as a data file simultaneously, after testing, provides and carry out Closed-cycle correction, provide output accuracy.

Those skilled in the art will readily understand; the foregoing is only preferred embodiment of the present invention; not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (3)

1. for detecting an inertial reference measurement method for bridge deformation, it is characterized in that, comprising the following steps:

Measurement environment builds step:

Prepare to measure dolly, inertial navigation system installed by measurement dolly, a mileage gauge laid respectively by four wheels measuring dolly;

Reference data establishment step:

At the two ends of bridge to be measured, selected two reference points, locate latitude, longitude and the height above sea level of determining two reference points by GPS; Set up surving coordinate system using one of them reference point as initial point, another reference point is positioned in the coordinate axis of coordinate system; At the surperficial planned trajectory route of bridge to be measured, make the path of planning must through two reference points; The latitude of reference point, longitude and altitude information is utilized to set up inertia system test benchmark, and using the world, northeast reason coordinate system as inertial navigation coordinate system;

Mileage measuring process:

Start measurement dolly to run along path planning, at present sample period t _i-t _i-1, obtain the mileage increment information that four mileage gauges export, wheel deformation error compensation carried out to mileage increment information, then consider that wheel hanging merges four mileage increment informations after compensation, obtain present sample period t _i-t _i-1measure the true mileage increment Delta L of dolly _i;

Inertial navigation step:

Enable inertial navigation system, at current sample time t _iobtain and measure the attitude angle of dolly in navigational coordinate system

Integrated navigation step:

Note odometer coordinate is m system, and inertial navigation coordinate is b system, and the conversion cosine battle array that b is tied to m system is

Note mileage increment Delta L _ibeing projected as of m system ${\mathrm{\&Delta;L}}_i^m={\left[\begin{array}{ccc}0& {\mathrm{\&Delta;L}}_i& 0\end{array}\right]}^T,$ Subscript T represents transposition; Mileage increment is obtained by ordinate transform being projected as of b system and then obtain mileage increment Delta L _iin the projection that navigation coordinate is fastened t _ithe attitude angle of moment measurement dolly;

Calculate current sample time t _imeasure the position coordinates of dolly under navigational coordinate system p _i-1for last sampling instant t _i-1measure the position coordinates of dolly under navigational coordinate system;

Carry out to measuring the position coordinates of dolly under navigational coordinate system the bridge floor track that integration obtains under navigational coordinate system, and then obtained the bridge floor track under surving coordinate system by ordinate transform;

Deformation determination step:

Bridge floor track under surving coordinate system and benchmark bridge floor track are compared, determines to detect bridge deformation situation;

In described mileage measuring process to the specific implementation that mileage increment information carries out wheel deformation error compensation be: make present sample period t _i-t _i-1the mileage increment that mileage gauge exports is L _i, wheel error compensation is carried out to it and obtains effective mileage increment wherein, δ K _dfor mileage gauge calibration factor error, W ₀to jolt the stochastic error caused for measuring dolly;

Consider in described mileage measuring process that wheel hanging to the specific implementation that four mileage increment informations after compensation merge is:

By test car off-front wheel, the near front wheel, left rear wheel, off hind wheel odometer at present sample period t _i-t _i-1output mileage increment be designated as Δ L respectively _a, Δ L _b, Δ L _c, Δ L _d, Δ L _ifor the true mileage increment after fusion;

As Δ L _c≤ Δ L _d, show that car body turns left, now Δ L _i=Δ L _a;

As Δ L _a< Δ L _b, show that off-front wheel occurs unsettled, now Δ L _i=Δ L _b* Δ L _d/ Δ L _c, Δ L _c≠ 0;

Work as L _c> L _dtime, car body is turned right, now:

1. L is worked as _a≤ L _btime,

If L _b-L _a> L _c-L _d, then off-front wheel is unsettled, now Δ L _i=Δ L _b* Δ L _d/ Δ L _c, Δ L _c≠ 0;

If Δ L _b-Δ L _a≤ Δ L _c-Δ L _d, then without wheel hanging, now Δ L _i=Δ L _a;

2. L is worked as _a> L _btime, then the near front wheel is unsettled, now Δ L _i=Δ L _a.

2. the inertial reference measurement method for detecting bridge deformation according to claim 1, it is characterized in that, the true mileage increment of the measurement dolly of measurement little car kilometer increment to the present sample period also gathered in conjunction with the history samples period carries out linear interpolation smoothing processing, to eliminate the vibration interference that bridge pavement out-of-flatness causes.

3. the inertial reference measurement method for detecting bridge deformation according to claim 1, is characterized in that, also carry out error correction to the bridge floor track under surving coordinate system, specific implementation is:

In described surving coordinate system, make the three-dimensional coordinate of planned trajectory route start for (0,0,0), the three-dimensional coordinate of terminal is (Xf, 0,0); The starting point three-dimensional coordinate that bridge floor track under navigational coordinate system is transformed under reference frame is (Xa, Ya, Za), and terminal three-dimensional coordinate is (Xb, Yb, Zb); The bridge floor track three-dimensional coordinate revised under pre-test coordinate system is expressed as (Sx, Sy, Sz);

Determine X to Ratio for error modification Kx=Xf/ (Xb-Xa), Ratio for error modification Ky=(the Yb-Ya)/Xf of Y-direction, Ratio for error modification Kz=(the Zb-Za)/Xf of Z-direction;

The bridge floor track under three correction factor correction surving coordinate systems is adopted to obtain revised bridge floor track $(\tilde{S}x,\tilde{S}y,\tilde{S}z),\tilde{S}x=Kx\&CenterDot;Sx,\tilde{S}y=Ky\&CenterDot;Sy,\tilde{S}z=Kz\&CenterDot;Sz.$