CN103175529A - Pedestrian inertial positioning system based on indoor magnetic field feature assistance - Google Patents

Abstract

The invention provides a pedestrian inertial positioning system based on indoor magnetic field feature assistance. The system comprises a magnetic field and inertial data obtaining module, a magnetic field positioning module, a pedestrian dead reckoning module, a positioning fusion module and an output module, wherein the magnetic field and inertial data obtaining module is used for acquiring magnetic field, accelerated speed and angular velocity information; the magnetic field positioning module is used for building a magnetic field feature library and carrying out time-frequency analysis on the magnetic field vector sequence in real time to extract the time-frequency feature, and matching with the magnetic field feature library to carry out magnetic field feature positioning; the pedestrian dead reckoning module is used for updating accelerated speed and angular velocity zero offset according to the condition that the step velocity discontinuity is zero during walking, judging the step number and calculating the step length and the direction of each step; the positioning fusion module is used for fusing a magnetic field feature positioning result and a pedestrian dead reckoning inertial positioning result by means of particle filter; and the output module is used for displaying a positioning result on web pages and terminals. The system provided by the invention has the characteristics of being independent from beacon during positioning, low in cost and consumption of positioning terminals, accurate in positioning result and adaptive to environment change.

Description

Based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature

Technical field

The present invention relates to inertial navigation and indoor positioning field, particularly, relate to a kind of based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature.

Background technology

Distributing in the space and pointed to the terrestrial magnetic field of magnetic north by the ground magnetic south.The terrestrial magnetic field is subject to the joint effect of buildings reinforced concrete structure and indoor motor, electrical equipment under indoor environment, form size and Orientation and depart from the abnormal of magnetic field primitively.Even this magnetic field is abnormal also very stable through the several months, can be used as the foundation of location.Present research and patent are used for the location mostly based on the application of robot with Magnetic Field, and during the location pointwise coupling magnetic field data storehouse.Existing indoor positioning scheme has following defective:

1, existing indoor locating system needs the support of beacon.As based on the signal intensity indication (RSSI) of the reception of RFID or Wifi, based on ultrasound wave or all need the support of extra beacon based on the locator meams of ultra broadband, in a lot of situations, important affair knows that first the position of beacon just can position.

2, to obtain the required energy consumption of positioning signal higher for existing indoor locating system.Prior art is obtained locating information with video system and is meaned that energy consumption is higher, can not locate for a long time work in portable equipment.

3, existing positioning equipment cost is higher.Some emerging systems have adopted range sensor, and the first-class equipment cost of the devices such as baroceptor shooting is higher.

Summary of the invention

For defective of the prior art, the purpose of this invention is to provide a kind of based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature.

According to an aspect of the present invention, provide a kind of based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature, comprise: magnetic field and inertial data acquisition module 100, pedestrian's dead reckoning module 101, magnetic field locating module 102, location Fusion Module 103 and output module 104, wherein

Magnetic field and inertial data acquisition module 100 acceleration and the angular velocity information data in order to gather Magnetic Field data and pedestrian;

Pedestrian's dead reckoning module 101 is connected with magnetic field and inertial data acquisition module 100, in order to the step number according to acceleration and angular velocity data judgement pedestrian walking, the step-length in each step and the direction in each step, and extrapolate pedestrian's walking path from the off, obtain inertial position, speed and attitude information;

Magnetic field locating module 102 is connected with pedestrian's dead reckoning module with magnetic field and inertial data acquisition module 100 respectively and is connected, in order to set up the magnetic signature storehouse and to locate the real-time magnetic field feature according to Magnetic Field and inertial position, speed and attitude information;

Location Fusion Module 103 is connected with the magnetic field locating module with pedestrian's dead reckoning module 101 respectively and is connected, and in order to inertial positioning information and magnetic signature locating information are merged, obtains final positioning result, and positioning result is sent to output module 104;

Output module 104 is connected with location Fusion Module 103, in order to receiving positioning result, and positioning result is sent on display device shows.

Preferably, magnetic field and inertial data acquisition module 100 are arranged on pedestrian foot, it comprises: three axle magnetometers 1001, three axis accelerometer 1002, three-axis gyroscope 1003 and demarcating module 1004, three axis accelerometer 1002 and three-axis gyroscope 1003 are in order to measure pedestrian foot acceleration at the volley and the angular velocity of various rotations, three-axle magnetic field size in three axle magnetometer 1001 survey sensor coordinate systems, demarcating module 1004 is in order to demarcate and to export acceleration, angular velocity and Magnetic Field.

Preferably, the sample frequency of three axle magnetometers 1001 is not less than 100Hz.

Preferably, pedestrian's dead reckoning module 101 comprises that zero-speed detection module 1011, EKF module 1012 and position and attitude inertia resolve module 1013, the angular velocity information that zero-speed detection module 1011 utilizes magnetic field and inertial data to obtain mould output judges whether foot is in static state, and whether output was the sign of zero-speed at that time, simultaneously zero-speed detection module receiving position and attitude inertia resolve the velocity information of module 1013 outputs, and when zero-speed being detected, the margin of error of speed are passed to EKF module 1012; EKF module 1012 is zero partially as the error state amount take zero-speed brief acceleration and angular velocity, and the output error quantity of state resolves module 1013 to position and attitude inertia, and position and attitude inertia resolve module 1013 and resolves position, speed and attitude information according to acceleration and the angular velocity measurement value output inertia of the error state amount that receives and magnetic field and 100 outputs of inertial data acquisition module.

Preferably, magnetic field locating module 102 comprises: geomagnetism detecting module 1021, magnetic signature storehouse 1022 and earth magnetism characteristic extracting module 1023, geomagnetism detecting module 1021 is resolved attitude according to the inertia that the Magnetic Field of magnetic field and inertial data acquisition module 100 outputs and position and attitude inertia resolve module 1013 outputs, and magnetic vector is rotated in sky, northeast coordinate system; Earth magnetism characteristic extracting module 1023 is sampled to the magnetic field data of earth magnetism detection module output when zero-speed detection module 1011 detects pedestrian's foot motion, extract magnetic signature, and the feature in magnetic signature and magnetic signature storehouse 1022 is mated, then draw the magnetic signature positioning result, i.e. the probability of pedestrian position.

Preferably, after earth magnetism characteristic extracting module 1023 gathers full or 256 data at 128, the sky, northeast in data segment is done to magnetic-field component or magnetic field amplitude discrete Fourier changes and discrete wavelet changes to obtain frequency domain characteristic; Simultaneously, data segment is extracted its temporal signatures through Dynamic Time Warping Dynamic Time Warping and hidden markov models.

Preferably, earth magnetism characteristic extracting module 1023 identifies to extract magnetic signature according to the sky, northeast of earth magnetism detection module 1023 input to the zero-speed of magnetic field and 101 outputs of pedestrian's dead reckoning module.

Preferably, the particle that location Fusion Module 103 adopts the mode of particle filter to simulate some, estimate pedestrian's position by more newly arriving of particle state and weight, it comprises: particle state update module 1031, particle weight update module 1032 and resampling module 1033, and state update module 1031 adds that with every long size and Orientation step by step of pedestrian's dead reckoning module 101 output suitable zero-mean Gaussian error is with the state of new particle more; The pedestrian position that particle weight update module 1032 is used magnetic field locating module output is the weight of new particle more; The number of the resampling module 1033 effective particles of assessment if the number of effective particles order lower than certain threshold value, resamples to guarantee enough the effectively number of particle, is specially:

The particle that reproduction right is great, and the weight of all particles is set to 1/N, after the particle weight was upgraded each time, the weighted mean positioning result of all particles was the positioning result output that location Fusion Module 103 merges.

Preferably, effectively the number of particle is:

$N_{\mathrm{eff}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\frac{1}{{{\mathrm{\ω}}_i}^2},$

Wherein, ω i is the weight of i particle, and N is total number of particles, N _effNumber for effective particle.

Preferably, display device comprises mobile phone, computer and other Portable video display device.

Compared with prior art, the present invention has following beneficial effect:

1, the location need to be by beacon or other extra equipment.Because indoor earth magnetism feature is extensive existence, there is not the problem that to layout.

2, the energy consumption cost of each sensor is lower.Except gyrostatic power consumption at several mA, the power consumption of accelerometer and magnetometer be all the uA level other, power consumption is much smaller with respect to other indoor positioning terminals, is fit to the application of portable set.Simultaneously, its cost also more has superiority than other locating terminals.

3, can use and the indoor environment complicated situation, owing to can upgrade the magnetic signature locating information in position fixing process, therefore the change of environment be had adaptability.

Description of drawings

By reading the detailed description of non-limiting example being done with reference to the following drawings, it is more obvious that other features, objects and advantages of the present invention will become:

Fig. 1 is the structure principle chart that the present invention is based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature;

Fig. 2 is the magnetic field of the embodiment of the present invention and the structure principle chart of inertial data acquisition module;

Fig. 3 is the structure principle chart of pedestrian's dead reckoning module of the embodiment of the present invention;

Fig. 4 is the structure principle chart of the magnetic field locating module of the embodiment of the present invention;

Fig. 5 is the process principle figure of setting up the magnetic signature storehouse of the embodiment of the present invention;

Fig. 6 is the structure principle chart of the location Fusion Module of the embodiment of the present invention.

Embodiment

The present invention is described in detail below in conjunction with specific embodiment.Following examples will help those skilled in the art further to understand the present invention, but not limit in any form the present invention.Should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, can also make some distortion and improvement.These all belong to protection scope of the present invention.

See also Fig. 1 to Fig. 6, a kind of based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature, comprising: magnetic field and inertial data acquisition module 100, pedestrian's dead reckoning module 101, magnetic field locating module 102, location Fusion Module 103 and output module 104.

Magnetic field and inertial data acquisition module 100 acceleration and the angular velocity information data in order to gather Magnetic Field data and pedestrian.It is arranged on pedestrian foot, comprise: three axle magnetometers 1001, three axis accelerometer 1002, three-axis gyroscope 1003 and demarcating module 1004, three axis accelerometer 1002 and three-axis gyroscope 1003 are in order to measure pedestrian foot acceleration at the volley and the angular velocity of various rotations, three-axle magnetic field size in three axle magnetometer 1001 survey sensor coordinate systems, demarcating module 1004 is in order to demarcate and to export acceleration, angular velocity and Magnetic Field.

In this example, magnetometer 1001 adopts magnetic compasses, and the gyroscope 1003 that adopts three axles is as turn meter.After demarcating through demarcating module 1004, the measured value of magnetic field and inertial data acquisition module 100 output calibrated acceleration, gyroscope and magnetometers.Because magnetometer needs magnetic interference in testing environment, such as power frequency interference of 50Hz etc., therefore, in the present invention, the sample frequency of three axle magnetometers 1001 of magnetic field and inertial data acquisition module is not less than 100Hz.

Pedestrian's dead reckoning module 101 is connected with magnetic field and inertial data acquisition module 100, in order to the step number according to acceleration and angular velocity data judgement pedestrian walking, the step-length in each step and the direction in each step, and extrapolate pedestrian's walking path from the off, obtain inertial position, speed and attitude information.It comprises zero-speed detection module 1011, and EKF module 1012 and position and attitude inertia resolve module 1013.

Pedestrian's dead reckoning module 101, the inclined to one side margin of error as EKF of degree of will speed up meter and gyroscope zero, and foot's speed is moment of zero to upgrade the margin of error to come compensated acceleration meter and gyrostatic measured value when the people being detected and walk, and calculate position, speed and the attitude information of pedestrian's inertial positioning.

Always step left foot when the people walks and step again right crus of diaphragm, and so forth.If magnetic field and inertial data acquisition module are arranged on left foot, when the people steps left foot, sensor collects the data of motion; And left foot is almost as you were when stepping right crus of diaphragm, and it is static that sensor detects, and foot motion and static two states when telling walking.The angular velocity information that zero-speed detection module 1011 utilizes magnetic field and inertial data to obtain mould output judges whether foot is in static state, and whether output was the sign of zero-speed at that time, simultaneously zero-speed detection module 1011 receiving positions and attitude inertia resolve the velocity information of module 1013 outputs, and when zero-speed being detected, the margin of error of speed are passed to EKF module 1012.Because the integration of acceleration obtains speed, strategy according to foot's Zero velocity Updating, EKF module 1012 is zero partially as the error state amount take zero-speed brief acceleration and angular velocity, and the output error quantity of state resolves module 1013 to position and attitude inertia, and position and attitude inertia resolve module 1013 and resolves position, speed and attitude information according to acceleration and the angular velocity measurement value output inertia of the error state amount that receives and magnetic field and 100 outputs of inertial data acquisition module.

Magnetic field locating module 102 is connected with pedestrian's dead reckoning module with magnetic field and inertial data acquisition module 100 respectively and is connected, in order to set up the magnetic signature storehouse and to locate the real-time magnetic field feature according to Magnetic Field and inertial position, speed and attitude information.

Magnetic field locating module 102 uses the magnetic signature locating information to position, its sky, northeast that obtains step when motion is to the magnetic vector sequence, and with Dynamic Time Warping and discrete Fourier and discrete wavelet change obtain time domain and frequency domain character come with the magnetic signature storehouse in feature mate and carry out magnetic signature and locate.Specifically comprise: geomagnetism detecting module 1021, magnetic signature storehouse 1022 and earth magnetism characteristic extracting module 1023.

Geomagnetism detecting module 1021 is resolved attitude according to the inertia that the Magnetic Field of magnetic field and inertial data acquisition module 100 outputs and position and attitude inertia resolve module 1013 outputs, and magnetic vector is rotated in sky, northeast coordinate system.Earth magnetism characteristic extracting module 1023 is sampled to the magnetic field data of earth magnetism detection module output when zero-speed detection module 1011 detects pedestrian's foot motion, extract magnetic signature, and the feature in magnetic signature and magnetic signature storehouse 1022 is mated, then draw the magnetic signature positioning result, i.e. the probability of pedestrian position.

The present invention adopts the time-frequency characteristics extracting method based on discrete Fourier changes and discrete wavelet changes, after concrete earth magnetism characteristic extracting module 1023 gathers full or 256 data at 128, the sky, northeast in data segment is done to magnetic-field component or magnetic field amplitude discrete Fourier changes and discrete wavelet changes to obtain frequency domain characteristic; Simultaneously, data segment is extracted its temporal signatures through Dynamic Time Warping Dynamic Time Warping and hidden markov models.

Particularly, the corresponding relation in recording magnetic field feature and place in the magnetic signature storehouse, Fig. 5 is the process flow diagram of setting up the magnetic signature storehouse.Preferably, earth magnetism characteristic extracting module 1023 identifies to extract magnetic signature according to the sky, northeast of earth magnetism detection module 1023 input to the zero-speed of magnetic field and 101 outputs of pedestrian's dead reckoning module.Yet the geographic position at each magnetic signature place can be by the output of pedestrian's dead reckoning module, also can be from the output of other locating modules 105, such as merging locating module 103.Because all there is certain error in existing indoor positioning mode, the structure of Gu Cichangtezhengku is also not necessarily accurate.Use the positioning result of location Fusion Module in the location, can after the precision in Simultaneous Iteration raising magnetic signature storehouse of location.The magnetic signature storehouse can be in use New Characteristics more, not only can improve the precision of location, the variation for environmental magnetic field simultaneously also has better adaptability.

Location Fusion Module 103 is connected with the magnetic field locating module with pedestrian's dead reckoning module 101 respectively and is connected, and in order to inertial positioning information and magnetic signature locating information are merged, obtains final positioning result, and positioning result is sent to output module 104.

The particle that location Fusion Module 103 adopts the mode of particle filter to simulate some, estimate pedestrian's position by more newly arriving of particle state and weight, the inertial positioning result of the concrete pedestrian of use dead reckoning module output is upgraded particle state, the magnetic field positioning result of use magnetic field locating module output is the new particle weight more, and adopts resampling technique guarantee number of effective particles order.It comprises: particle state update module 1031, particle weight update module 1032 and resampling module 1033.

Location Fusion Module 103 merges from the locating information of pedestrian's dead reckoning module 101 with from the locating information of earth magnetism characteristic extracting module 102, and its block diagram as shown in Figure 6.The location Fusion Module adopts the mode of particle filter, namely uses a plurality of particles such as the various possibilities of N simulation pedestrian walking, estimates pedestrian's position by more newly arriving of particle state and weight.The at first initialization of particle filtering blending algorithm generates N particle, and the state of each particle represents a kind of possibility of position, and the weight of particle represents the size of this position possibility.N the particle that initialization generates has the initial position by Gaussian distribution.Upgrade particle state according to the output of pedestrian's dead reckoning module afterwards.Particularly, state update module 1031 adds that with every long size and Orientation step by step of pedestrian's dead reckoning module 101 output suitable zero-mean Gaussian error is with the state position of new particle more; Afterwards, the particle weight update module 1032 pedestrian position weight of new particle more of using magnetic field locating module output; The number of the resampling module 1033 effective particles of assessment

Wherein, wherein, ω i is the weight of i particle, and N is total number of particles, N _effNumber for effective particle.If the number of effective particles order is lower than certain threshold value, need to resample to guarantee enough numbers of effective particle, be specially: the particle that resampling module 1033 reproduction rights are great, and the weight of all particles is set to 1/N, after the particle weight was upgraded each time, the weighted mean positioning result of all particles was the positioning result output that location Fusion Module 103 merges.

Output module 104 is connected with location Fusion Module 103, in order to receiving positioning result, and positioning result is sent on display device shows.Concrete can be presented on webpage positioning result or mobile phone, and on computer and other portable equipments, display device can comprise mobile phone, computer and other Portable video display device.

Above specific embodiments of the invention are described.It will be appreciated that, the present invention is not limited to above-mentioned specific implementations, and those skilled in the art can make various distortion or modification within the scope of the claims, and this does not affect flesh and blood of the present invention.

Claims (10)

1. one kind based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature, it is characterized in that, comprise: magnetic field and inertial data acquisition module (100), pedestrian's dead reckoning module (101), magnetic field locating module (102), location Fusion Module (103) and output module (104), wherein

Described magnetic field and inertial data acquisition module (100) acceleration and the angular velocity information data in order to gather Magnetic Field data and pedestrian;

Described pedestrian's dead reckoning module (101) is connected with described magnetic field and inertial data acquisition module (100), in order to the step number according to described acceleration and angular velocity data judgement pedestrian walking, the step-length in each step and the direction in each step, and extrapolate pedestrian's walking path from the off, obtain position, speed and attitude information that inertia resolves;

Described magnetic field locating module (102) is connected 101 with described magnetic field and inertial data acquisition module (100) with pedestrian's dead reckoning module respectively) be connected, set up the magnetic signature storehouse and locate the real-time magnetic field feature in order to the position, speed and the attitude information that resolve according to described Magnetic Field and inertia;

Described location Fusion Module (103) is connected 102 with described pedestrian's dead reckoning module (101) with the magnetic field locating module respectively) be connected, in order to described inertial positioning information and magnetic signature locating information are merged, obtain final positioning result, and positioning result is sent to described output module (104);

Described output module (104) is connected with described location Fusion Module (103), in order to receiving positioning result, and described positioning result is sent on display device shows.

2. according to claim 1 based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature, it is characterized in that, described magnetic field and inertial data acquisition module (100) are arranged on pedestrian foot, it comprises: three axle magnetometers (1001), three axis accelerometer (1002), three-axis gyroscope (1003) and demarcating module (1004), described three axis accelerometer (1002) and three-axis gyroscope (1003) are in order to measure pedestrian foot acceleration at the volley and the angular velocity of various rotations, three-axle magnetic field size in described three axle magnetometer (1001) survey sensor coordinate systems, described demarcating module (1004) is in order to described acceleration, angular velocity and Magnetic Field are demarcated and are exported.

3. pedestrian's inertial positioning system of assisting based on indoor magnetic signature according to claim 2, is characterized in that, the sample frequency of described three axle magnetometers (1001) is not less than 100Hz.

4. according to claim 1 based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature, it is characterized in that, described pedestrian's dead reckoning module (101) comprises zero-speed detection module (1011), EKF module (1012), and position and attitude inertia resolve module (1013), the angular velocity information that described zero-speed detection module (1011) utilizes magnetic field and inertial data to obtain mould output judges whether foot is in static state, and whether output was the sign of zero-speed at that time, zero-speed detection module (1011) receiving position and attitude inertia resolve the velocity information of module (1013) output simultaneously, and when zero-speed being detected, the margin of error of speed is passed to EKF module (1012), EKF module (1012) is zero partially as the error state amount take zero-speed brief acceleration and angular velocity, and output error quantity of state to described position and attitude inertia resolves module (1013), and described position and attitude inertia resolve module (1013) and resolves position, speed and attitude information according to acceleration and the angular velocity measurement value output inertia of the error state amount that receives and magnetic field and inertial data acquisition module (100) output.

5. according to claim 1 based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature, it is characterized in that, described magnetic field locating module (102) comprising: geomagnetism detecting module (1021), magnetic signature storehouse (1022) and earth magnetism characteristic extracting module (1023), described geomagnetism detecting module (1021) is resolved attitude according to the inertia that the Magnetic Field of described magnetic field and inertial data acquisition module (100) output and position and attitude inertia resolve module (1013) output, magnetic vector is rotated in sky, northeast coordinate system, described earth magnetism characteristic extracting module (1023) is sampled to the magnetic field data of described geomagnetism detecting module output when described zero-speed detection module (1011) detects pedestrian's foot motion, extract magnetic signature, and the feature in magnetic signature and magnetic signature storehouse (1022) is mated, then draw the magnetic signature positioning result, i.e. the probability of pedestrian position.

6. according to claim 5 based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature, it is characterized in that, after described earth magnetism characteristic extracting module (1023) gathers full or 256 data at 128, the sky, northeast in data segment is done to magnetic-field component or magnetic field amplitude discrete Fourier changes and discrete wavelet changes to obtain frequency domain characteristic; Simultaneously, data segment is extracted its temporal signatures through Dynamic Time Warping and hidden markov models.

7. according to claim 5 based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature, it is characterized in that, described earth magnetism characteristic extracting module (1023) identifies to extract magnetic signature according to the sky, northeast of described geomagnetism detecting module (1023) input to the zero-speed of magnetic field and pedestrian's dead reckoning module (101) output.

8. according to claim 1 based on the auxiliary pedestrian's inertial positioning system of indoor magnetic signature, it is characterized in that, the particle that described location Fusion Module (103) adopts the mode of particle filter to simulate some, estimate pedestrian's position by more newly arriving of particle state and weight, it comprises: particle state update module (1031), particle weight update module (1032) and resampling module (1033), described state update module (1031) adds that with every long size and Orientation step by step of described pedestrian's dead reckoning module (101) output suitable zero-mean Gaussian error is with the state of new particle more, the pedestrian position that described particle weight update module (1032) is used magnetic field locating module output is the weight of new particle more, the number of the effective particle of described resampling module (1033) assessment if the number of effective particles order lower than certain threshold value, resamples to guarantee enough the effectively number of particle, is specially:

The particle that reproduction right is great, and the weight of all particles is set to 1/N, after the particle weight was upgraded each time, the weighted mean positioning result of all particles was the positioning result output that location Fusion Module (103) merges.

9. pedestrian's inertial positioning system of assisting based on indoor magnetic signature according to claim 8, is characterized in that, the number of described effective particle is:

$N_{\mathrm{eff}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\frac{1}{{{\mathrm{\ω}}_i}^2},$

Wherein, ω i is the weight of i particle, and N is total number of particles, N _effNumber for effective particle.

10. pedestrian's inertial positioning system of assisting based on indoor magnetic signature according to claim 1, is characterized in that, described display device comprises mobile phone, computer and other Portable video display device.

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