CN114501312A - An indoor positioning method and system integrating WIFI and PDR positioning technology - Google Patents

Abstract

The invention discloses an indoor positioning method and system fusing WIFI and PDR positioning technologies, wherein the method comprises the following steps: acquiring a WIFI positioning result of the target to be measured at an initial time t0, and using the WIFI positioning result as an initial position of a PDR positioning technology; acquiring sensor data from t0 to an intermediate time t1, acquiring a PDR positioning result of t1, and acquiring a WIFI positioning result of t 1; judging whether the error between the PDR positioning result and the WIFI positioning result of t1 exceeds a preset threshold value or not; if yes, acquiring sensor data from t0 to the termination time tr to obtain a PDR positioning result of tr; if not, resetting the position corresponding to the WIFI positioning result of t1 as the initial position of the PDR positioning technology, and acquiring sensor data from t1 to tr to obtain a PDR positioning result of tr. By the technical scheme, the indoor positioning precision and stability are improved, and the indoor positioning cost is reduced.

Description

An indoor positioning method and system integrating WIFI and PDR positioning technology

technical field

The invention relates to the technical field of indoor positioning, in particular to an indoor positioning method integrating WIFI and PDR positioning technologies and an indoor positioning system integrating WIFI and PDR positioning technologies.

Background technique

With the popularization of smart phones and the development of mobile Internet, wireless positioning technology has greatly facilitated people's lives. In the outdoor environment, GPS can provide global users with low-cost, high-precision navigation information, but due to the occlusion of buildings and the complexity of the indoor environment, the satellite navigation system cannot be well used indoors. In recent years, people's demand for indoor positioning services has greatly increased, and the positioning technology of large indoor places such as shopping malls, hospitals, and banks is still in the research stage, and large-scale use cannot be guaranteed. Therefore, without the assistance of additional equipment, indoor positioning technology has become a research hotspot. The positioning accuracy of the existing infrared, RFID and other positioning technologies is general, and it is necessary to lay a signal receiving device with high precision in the positioning environment in advance, and there are also high requirements for the placement of the signal receiving device. While positioning technologies such as ultrasound and ultra-wideband have high positioning accuracy, the cost of positioning devices is too high to facilitate technology promotion.

WIFI-based indoor positioning is an indoor positioning technology based on wireless signals. It is one of the most widely used methods. It has low requirements on infrastructure, low cost and no need to install additional equipment. Due to the volatility and the complexity of the indoor environment, the positioning target will be disturbed to a certain extent during the positioning process. WIFI positioning usually uses the following two models for positioning: the first is to use the distance model, calculate the distance from the signal strength through the corresponding model formula, and use the trilateral intersection to calculate the coordinates of the to-be-determined point; the second is to use the location fingerprint model, which is determined by The signal strength received on the to-be-determined point is matched with the known points in the location fingerprint database, and the coordinates are calculated using the fingerprint matching algorithm. The location fingerprint location algorithm is simpler than the distance propagation model, but requires a large amount of fingerprint data to be collected in advance.

On the other hand, inertial navigation systems based on inertial sensors (MEMS, Micro-ElectroMechanical System) are also developing rapidly. Today, ordinary smartphones have various built-in sensors (accelerometers, gyroscopes, etc.). Pedestrian dead reckoning PDR (Pedestrain Dead Reckoning) based on inertial sensor is one of the commonly used inertial navigation technologies. Compared with positioning technology based on wireless signals, the advantage of this technology is that mobile terminals are generally equipped with motion sensors such as gyroscopes, acceleration sensors, electronic compasses, etc. Environmental impact, high stability and high advantages. However, since the electronic compass is easily disturbed by the environment, the heading angle will be deviated, and the gait judgment error and step length estimation error will lead to the walking distance error. Effectively eliminating the accumulated error becomes the key to solving the problem.

On the whole, there is an asynchronous feedback problem in the timing of the positioning results of WIFI and PDR. Due to the large error of the WIFI signal and the accumulated error of the PDR positioning, the positioning results will be inaccurate.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention provides an indoor positioning method that integrates WIFI and PDR positioning technologies. Through the integration of WIFI positioning technology and PDR positioning technology, a positioning error threshold judgment method is adopted to solve the asynchronous feedback of the two positioning technologies in time sequence. At the same time, the positioning results of the two positioning technologies at the same time are mutually corrected, which improves the accuracy and stability of indoor positioning and reduces the cost of indoor positioning.

In order to achieve the above purpose, the present invention provides an indoor positioning method integrating WIFI and PDR positioning technology, including:

Step S1, at the starting time t0, the WIFI positioning technology is used to obtain the WIFI positioning result of the target to be measured, and the WIFI positioning result at the starting time is used as the starting position of the PDR positioning technology;

Step S2, acquiring the sensor data from the starting time t0 to the intermediate time t1, and thereby obtaining the intermediate time PDR positioning result based on the PDR positioning technology at the intermediate time t1, and obtaining the intermediate time WIFI positioning result based on the WIFI positioning technology at the intermediate time t1;

Step S3, comparing the error between the PDR positioning result at the intermediate moment and the WIFI positioning result at the intermediate moment, and determining whether the error exceeds a preset threshold;

Step S4, if the error exceeds the preset threshold, then acquire the sensor data from the start time t0 to the end time tr, and obtain the PDR positioning result at the end time based on the PDR positioning technology;

If the error does not exceed the preset threshold, the WIFI positioning result at the middle time is used as the target positioning result at the middle time t1, and the corresponding position is reset to the starting position of the PDR positioning technology, and the data from the middle time t1 to the end time tr is obtained. The sensor data is obtained, and the PDR positioning result at the termination time based on the PDR positioning technology is obtained.

In the above technical solution, preferably, the indoor positioning method integrating WIFI and PDR positioning technology further includes:

Step S5, when the termination time tr still needs to continue positioning, reset the position corresponding to the PDR positioning result at the termination time to the starting position based on the PDR positioning technology, and continue to perform steps S2 to S4.

In the above technical solution, preferably, the specific process of step S3 includes:

Taking the position corresponding to the PDR positioning result at the intermediate time as the center of the circle, and taking the displacement of the target to be measured based on the PDR positioning technology from the starting time t0 to the intermediate time t1 as the radius, a circular range is constructed;

Determine whether the position corresponding to the WIFI positioning result at the intermediate moment is within the circular range;

If the position corresponding to the WIFI positioning result at the intermediate time is within the circular range, it is determined that the error does not exceed the preset threshold; otherwise, the determination error exceeds the preset threshold.

In the above technical solution, preferably, in the steps S1 and S2, the method for obtaining the WIFI positioning result at the starting moment or the WIFI positioning result at the intermediate moment based on the WIFI positioning technology includes the trilateral method, the TOA ranging method, and the TDOA measurement method. Distance method and fingerprint matching algorithm.

In the above technical solution, preferably, the specific steps of using the fingerprint matching algorithm to obtain the WIFI positioning result include:

Offline stage:

Set reference points in the indoor area, and collect WIFI signal strength values for each reference point;

Data preprocessing is performed on the WIFI signal strength value, and a location fingerprint database of the indoor area is established according to the WIFI signal strength value of each reference point;

Online stage:

Collect the WIFI signal of the target to be tested based on WIFI positioning technology, and perform data preprocessing;

The preprocessed WIFI signal of the target to be tested is matched with the location fingerprint database, and the corresponding reference point position estimation result is determined according to the matching result, which is used as the WIFI positioning result of the target to be tested.

In the above technical solution, preferably, a sensor is installed in the object to be measured, and the displacement of the object to be measured is calculated according to the acceleration sensor data according to the acceleration sensor data and the orientation sensor data acquired in real time, and according to the orientation sensor The data determines the heading of the target to be measured;

According to the displacement and heading of the target to be measured, the real-time position of the target to be measured is comprehensively calculated based on the PDR positioning technology, as the PDR positioning result at the current moment.

The present invention also proposes an indoor positioning system integrating WIFI and PDR positioning technologies, applying the indoor positioning method integrating WIFI and PDR positioning technologies disclosed in any of the above technical solutions, including:

The starting time positioning module is used to obtain the WIFI positioning result of the target to be measured by using the WIFI positioning technology at the starting time t0, and use the WIFI positioning result at the starting time as the starting position of the PDR positioning technology;

The middle time positioning module is used to obtain the sensor data from the starting time t0 to the middle time t1, and then obtain the middle time PDR positioning result based on the PDR positioning technology at the middle time t1, and obtain the middle time t1 based on the WIFI positioning technology. WIFI positioning result;

A positioning error judgment module, configured to compare the error between the PDR positioning result at the intermediate time and the WIFI positioning result at the intermediate time, and determine whether the error exceeds a preset threshold;

The PDR correction WIFI module is used to obtain the sensor data from the start time t0 to the end time tr when the error exceeds the preset threshold, and obtain the PDR positioning result based on the PDR positioning technology at the end time;

The WIFI reset PDR module is used to use the WIFI positioning result at the intermediate time as the target positioning result at the intermediate time t1 when the error does not exceed the preset threshold, and reset the corresponding position to the starting position of the PDR positioning technology to obtain The sensor data from the intermediate time t1 to the termination time tr is used to obtain the PDR positioning result at the termination time based on the PDR positioning technology.

In the above technical solution, preferably, the indoor positioning system integrating WIFI and PDR positioning technology further includes a recursive reset positioning module, which is used for positioning the PDR positioning result corresponding to the position at the termination time tr when the positioning still needs to be continued. Reset to the starting position based on the PDR positioning technology, and continue to execute the intermediate time positioning module, the positioning error judgment module, the PDR correction WIFI module and the WIFI reset PDR module.

In the above technical solution, preferably, the positioning error judgment module is specifically used for:

Taking the position corresponding to the PDR positioning result at the intermediate time as the center of the circle, and taking the displacement of the target to be measured based on the PDR positioning technology from the starting time t0 to the intermediate time t1 as the radius, a circular range is constructed;

Determine whether the position corresponding to the WIFI positioning result at the intermediate moment is within the circular range;

If the position corresponding to the WIFI positioning result at the intermediate time is within the circular range, it is determined that the error does not exceed the preset threshold; otherwise, the determination error exceeds the preset threshold.

In the above technical solution, preferably, the initial time positioning module and the intermediate time positioning module include an offline stage and an online stage in the process of using the fingerprint matching algorithm to obtain the WIFI positioning result;

Offline stage:

Set reference points in the indoor area, and collect WIFI signal strength values for each reference point;

Data preprocessing is performed on the WIFI signal strength value, and a location fingerprint database of the indoor area is established according to the WIFI signal strength value of each reference point;

Online stage:

Collect the WIFI signal of the target to be tested based on WIFI positioning technology, and perform data preprocessing;

The preprocessed WIFI signal of the target to be tested is matched with the location fingerprint database, and the corresponding reference point position estimation result is determined according to the matching result, which is used as the WIFI positioning result of the target to be tested.

Compared with the prior art, the present invention has the beneficial effects of: integrating the WIFI positioning technology and the PDR positioning technology, and adopting the positioning error threshold judgment method to solve the asynchronous feedback problem of the two positioning technologies in the time sequence, and simultaneously aiming at the two positioning technologies at the same time. The positioning results of the different positioning technologies are mutually corrected, which improves the accuracy and stability of indoor positioning and reduces the cost of indoor positioning.

Description of drawings

1 is a schematic flowchart of an indoor positioning method that integrates WIFI and PDR positioning technologies disclosed in an embodiment of the present invention;

2 is a schematic diagram of a positioning principle of a fingerprint matching algorithm based on a WIFI positioning technology disclosed by an embodiment of the present invention;

FIG. 3 is a schematic block diagram of an indoor positioning system integrating WIFI and PDR positioning technologies disclosed in an embodiment of the present invention.

In the figure, the corresponding relationship between each component and the reference sign is:

11. Initial time positioning module, 12. Middle time positioning module, 13. Positioning error judgment module, 14. PDR correction WIFI module, 15. WIFI reset PDR module, 16. Recursive reset positioning module.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

Below in conjunction with accompanying drawing, the present invention is described in further detail:

As shown in FIG. 1, an indoor positioning method integrating WIFI and PDR positioning technology provided according to the present invention includes:

Step S1, at the starting time t0, the WIFI positioning technology is used to obtain the WIFI positioning result of the target to be measured, and the WIFI positioning result at the starting time is used as the starting position of the PDR positioning technology;

Step S2, acquiring the sensor data from the starting time t0 to the intermediate time t1, and thereby obtaining the intermediate time PDR positioning result based on the PDR positioning technology at the intermediate time t1, and obtaining the intermediate time WIFI positioning result based on the WIFI positioning technology at the intermediate time t1;

Step S3, compare the error between the PDR positioning result at the middle moment and the WIFI positioning result at the middle moment, and determine whether the error exceeds a preset threshold Φ;

Step S4, if the error exceeds the preset threshold, then acquire the sensor data from the start time t0 to the end time tr, and obtain the PDR positioning result at the end time based on the PDR positioning technology;

If the error does not exceed the preset threshold, the WIFI positioning result at the middle time is used as the target positioning result at the middle time t1, and the corresponding position is reset to the starting position of the PDR positioning technology, and the sensor data from the middle time t1 to the end time tr is obtained. , and obtain the PDR positioning result at the termination time based on the PDR positioning technology.

In this embodiment, the WIFI positioning technology and the PDR positioning technology are integrated, and the positioning error threshold judgment method is used to solve the asynchronous feedback problem of the two positioning technologies in terms of time sequence, and the positioning results of the two positioning technologies at the same time are compared. The correction improves the accuracy and stability of indoor positioning and reduces the cost of indoor positioning.

Specifically, WIFI positioning usually uses the following two models for positioning: the first is to use the distance model, calculate the distance from the signal strength through the corresponding model formula, and use the trilateral intersection to calculate the coordinates of the to-be-determined point; the second is to apply the location fingerprint The model is matched by the signal strength received on the to-be-determined point and the known points in the location fingerprint database, and the coordinates are calculated using the fingerprint matching algorithm. The location fingerprint location algorithm is simpler than the distance propagation model, but it needs to collect a large number of fingerprints in advance. data.

In this embodiment, preferably, the methods for obtaining the WIFI positioning result at the starting time or the WIFI positioning result at the intermediate time based on the WIFI positioning technology in steps S1 and S2 include trilateral method, TOA ranging method, TDOA ranging method and fingerprinting matching algorithm.

As shown in Figure 2, specifically, the specific steps of using the fingerprint matching algorithm to obtain the WIFI positioning result include:

Offline stage:

Set reference points in the indoor area, and collect WIFI signal strength values for each reference point;

Data preprocessing is performed on the WIFI signal strength value, and the location fingerprint database of the indoor area is established according to the WIFI signal strength value of each reference point;

Online stage:

Collect the WIFI signal of the target to be tested based on WIFI positioning technology, and perform data preprocessing;

The preprocessed WIFI signal of the target to be measured is matched with the location fingerprint database, and the corresponding reference point position estimation result is determined according to the matching result, which is used as the WIFI positioning result of the target to be measured.

In the above embodiment, preferably, a sensor is installed in the target to be measured, the displacement of the target to be measured is calculated according to the acceleration sensor data and the data of the azimuth sensor obtained in real time, and the heading of the target to be measured is determined according to the data of the azimuth sensor;

According to the displacement and heading of the target to be measured, the real-time position of the target to be measured is comprehensively calculated based on the PDR positioning technology as the PDR positioning result at the current moment.

Among them, the sensor data includes the acceleration, magnetic declination and angular velocity when the target object moves. The acceleration data obtains the step length and number of steps of the object holding the mobile terminal, and then obtains the displacement of the mobile terminal; the magnetometer and the gyroscope can carry the traveling direction of the mobile terminal. The sensor data can be collected in real time. Generally, the data is collected through the collection software (the sampling rate is generally 10 to 100 Hz), and the graph is drawn to calculate the target position based on the PDR.

In the above embodiment, preferably, the specific process of step S3 includes:

Taking the position corresponding to the PDR positioning result at the middle time as the center of the circle, and taking the displacement s of the target to be measured based on the PDR positioning technology from the starting time t0 to the middle time t1 as the radius, a circle range is constructed;

Determine whether the corresponding position of the WIFI positioning result at the middle moment is within the circular range;

If the position corresponding to the WIFI positioning result at the middle moment is within the circular range, it is determined that the error does not exceed the preset threshold Φ, Φ=πs ² , otherwise the determination error exceeds the preset threshold Φ.

In the above embodiment, if the error result exceeds the threshold, the sensor data from the start time t0 to the end time tr is obtained, and the PDR positioning result obtained based on the PDR positioning technology at the end time is used as the target positioning result at time tr.

If the error result does not exceed the threshold, take the positioning result based on WIFI at the intermediate time t1 as the positioning result of the target to be measured at this time, reset the positioning result to the starting position of the PDR positioning technology, and obtain the intermediate time t1 to the termination time tr According to the sensor data, the PDR positioning result at the termination time obtained based on the data based on the PDR positioning technology is used as the positioning result of the target to be measured at the time tr.

In this embodiment, in the PDR positioning technology, the current position state is related to the information of the previous position, and this recursive relationship will cause its error to accumulate over time, so when the error is within the threshold range Φ, the WIFI positioning technology The positioning result is used to reset the positioning starting position of the PDR positioning technology, which can effectively eliminate the PDR positioning error caused by time accumulation. When the error exceeds the threshold Φ, the relatively accurate positioning results of the PDR positioning technology can be used to compensate for the inaccurate positioning caused by the interference of the WIFI signal, which plays a role in mutual correction.

In the above embodiment, preferably, the indoor positioning method integrating WIFI and PDR positioning technology further includes:

Step S5, when the positioning still needs to be continued at the termination time tr, reset the position corresponding to the PDR positioning result at the termination time to a new starting position based on the PDR positioning technology, and return to re-execute steps S2 to S4.

When it is not necessary to continue the positioning at the termination time tr, the positioning result of the PDR at the termination time obtained in step S4 is directly used as the positioning result of the target to be measured, and the positioning is ended.

As shown in FIG. 3 , the present invention also proposes an indoor positioning system integrating WIFI and PDR positioning technologies, applying the indoor positioning method integrating WIFI and PDR positioning technologies disclosed in any of the above embodiments, including:

The starting time positioning module 11 is used for obtaining the WIFI positioning result of the target to be measured by using the WIFI positioning technology at the starting time t0, and using the WIFI positioning result at the starting time as the starting position of the PDR positioning technology;

The intermediate time positioning module 12 is used to obtain the sensor data from the starting time t0 to the intermediate time t1, and thereby obtain the intermediate time PDR positioning result based on the PDR positioning technology at the intermediate time t1, and obtain the intermediate time t1 based on the WIFI positioning technology. Time WIFI positioning results;

The positioning error judgment module 13 is used to compare the error between the PDR positioning result at the middle moment and the WIFI positioning result at the middle moment, and judge whether the error exceeds a preset threshold;

The PDR correction WIFI module 14 is used to acquire the sensor data from the start time t0 to the end time tr when the error exceeds the preset threshold, and thereby obtain the PDR positioning result based on the PDR positioning technology at the end time;

The WIFI reset PDR module 15 is used to use the WIFI positioning result at the intermediate time as the target positioning result at the intermediate time t1 when the error does not exceed the preset threshold, and reset the corresponding position to the starting position of the PDR positioning technology, and obtain the intermediate position. The sensor data from the time t1 to the termination time tr is used to obtain the PDR positioning result at the termination time based on the PDR positioning technology.

In this embodiment, the WIFI positioning technology and the PDR positioning technology are integrated, and the positioning error threshold judgment method is used to solve the asynchronous feedback problem of the two positioning technologies in terms of time sequence, and the positioning results of the two positioning technologies at the same time are compared. The correction improves the accuracy and stability of indoor positioning and reduces the cost of indoor positioning.

In the above-mentioned embodiment, preferably, the initial time positioning module 11 and the intermediate time positioning module 12 include an offline stage and an online stage in the process of using the fingerprint matching algorithm to obtain the WIFI positioning result;

Offline stage:

Set reference points in the indoor area, and collect WIFI signal strength values for each reference point;

Data preprocessing is performed on the WIFI signal strength value, and the location fingerprint database of the indoor area is established according to the WIFI signal strength value of each reference point;

Online stage:

Collect the WIFI signal of the target to be tested based on WIFI positioning technology, and perform data preprocessing;

The preprocessed WIFI signal of the target to be measured is matched with the location fingerprint database, and the corresponding reference point position estimation result is determined according to the matching result, which is used as the WIFI positioning result of the target to be measured.

In the above embodiment, preferably, the positioning error judgment module 13 is specifically used for:

Taking the position corresponding to the PDR positioning result at the middle time as the center of the circle, and taking the displacement of the target to be measured based on the PDR positioning technology from the starting time t0 to the middle time t1 as the radius, a circle range is constructed;

Determine whether the corresponding position of the WIFI positioning result at the middle moment is within the circular range;

If the position corresponding to the WIFI positioning result at the middle moment is within the circular range, it is determined that the error does not exceed the preset threshold; otherwise, the determination error exceeds the preset threshold.

In the above embodiment, preferably, the indoor positioning system integrating WIFI and PDR positioning technology further includes a recursive reset positioning module 16, which is used to reset the position corresponding to the PDR positioning result at the termination time when the positioning still needs to be continued at the termination time tr. Set as the starting position based on the PDR positioning technology, and continue to execute the intermediate time positioning module 12 , the positioning error judgment module 13 , the PDR correction WIFI module 14 and the WIFI reset PDR module 15 .

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. An indoor positioning method fusing WIFI and PDR positioning technologies is characterized by comprising the following steps:

step S1, acquiring a WIFI positioning result of the target to be detected by adopting a WIFI positioning technology at the starting time t0, and taking the WIFI positioning result at the starting time as the starting position of a PDR positioning technology;

step S2, acquiring sensor data from a starting time t0 to an intermediate time t1, acquiring an intermediate time PDR positioning result of the intermediate time t1 based on a PDR positioning technology, and acquiring an intermediate time WIFI positioning result of the intermediate time t1 based on a WIFI positioning technology;

step S3, comparing the error between the intermediate moment PDR positioning result and the intermediate moment WIFI positioning result, and judging whether the error exceeds a preset threshold value;

step S4, if the error exceeds the preset threshold, acquiring sensor data from the starting time t0 to the ending time tr, and accordingly obtaining a PDR positioning result at the ending time based on the PDR positioning technology;

and if the error does not exceed the preset threshold, taking the intermediate WIFI positioning result as a target positioning result of the intermediate time t1, resetting the corresponding position to the initial position of the PDR positioning technology, acquiring sensor data from the intermediate time t1 to the end time tr, and thus obtaining an end time PDR positioning result based on the PDR positioning technology.

2. The indoor positioning method fusing WIFI and PDR positioning technologies as claimed in claim 1, further comprising:

step S5, when the ending time tr still needs to continue positioning, resetting the position corresponding to the ending time PDR positioning result to the starting position based on the PDR positioning technology, and continuing to execute steps S2 to S4.

3. The indoor positioning method fusing WIFI and PDR positioning technologies as claimed in claim 1, wherein the specific process of step S3 includes:

constructing a circular range by taking the corresponding position of the PDR positioning result at the middle moment as a circle center and taking the displacement of the target to be measured from the starting moment t0 to the middle moment t1 based on the PDR positioning technology as a radius;

judging whether the position corresponding to the WIFI positioning result at the middle moment is within the circular range or not;

and if the position corresponding to the WIFI positioning result at the middle moment is within the circular range, judging that the error does not exceed a preset threshold value, otherwise, judging that the error exceeds the preset threshold value.

4. The indoor positioning method integrating WIFI and PDR positioning technologies as claimed in claim 1, wherein the method for obtaining the start moment WIFI positioning result or the middle moment WIFI positioning result based on WIFI positioning technology in steps S1 and S2 includes trilateration, TOA ranging, TDOA ranging and fingerprint matching algorithm.

5. The indoor positioning method fusing WIFI and PDR positioning technologies as claimed in claim 4, wherein the specific step of obtaining a WIFI positioning result by using the fingerprint matching algorithm comprises:

an off-line stage:

setting reference points in an indoor area, and collecting a WIFI signal intensity value for each reference point;

data preprocessing is carried out on the WIFI signal intensity value, and a position fingerprint database of the indoor area is established according to the WIFI signal intensity value of each reference point;

an online stage:

acquiring a WIFI signal of a target to be detected based on a WIFI positioning technology, and preprocessing data;

and matching the preprocessed WIFI signal of the target to be detected with the position fingerprint database, determining a corresponding reference point position estimation result according to the matching result, and using the reference point position estimation result as a WIFI positioning result of the target to be detected.

6. The indoor positioning method integrating WIFI and PDR positioning technologies as claimed in claim 1, wherein a sensor is installed in the target to be measured, the displacement of the target to be measured is calculated according to acceleration sensor data and orientation sensor data acquired in real time, and the course of the target to be measured is determined according to the orientation sensor data;

and comprehensively calculating the real-time position of the target to be detected based on a PDR positioning technology according to the displacement and the course of the target to be detected, and taking the real-time position as a PDR positioning result at the current moment.

7. An indoor positioning system fusing WIFI and PDR positioning technologies, wherein the indoor positioning method fusing WIFI and PDR positioning technologies as claimed in any one of claims 1 to 6 is applied, and comprises the following steps:

the starting time positioning module is used for acquiring a WIFI positioning result of the target to be detected by adopting a WIFI positioning technology at a starting time t0, and taking the starting time WIFI positioning result as a starting position of a PDR positioning technology;

the middle time positioning module is used for acquiring sensor data from a starting time t0 to a middle time t1, acquiring a middle time PDR positioning result of a middle time t1 based on a PDR positioning technology, and acquiring a middle time WIFI positioning result of a middle time t1 based on a WIFI positioning technology;

the positioning error judgment module is used for comparing an error between the middle moment PDR positioning result and the middle moment WIFI positioning result and judging whether the error exceeds a preset threshold value or not;

the PDR correction WIFI module is used for acquiring sensor data from a starting time t0 to an ending time tr when the error exceeds a preset threshold value, and accordingly, a PDR positioning result at the ending time based on the PDR positioning technology is obtained;

and the WIFI resetting PDR module is used for taking the middle moment WIFI positioning result as a target positioning result of a middle moment t1 when the error does not exceed a preset threshold, resetting the corresponding position to the initial position of the PDR positioning technology, acquiring sensor data from the middle moment t1 to the end moment tr, and thus obtaining an end moment PDR positioning result based on the PDR positioning technology.

8. The indoor positioning system integrating WIFI and PDR positioning technologies as claimed in claim 7, further comprising a recursive reset positioning module, configured to reset the location corresponding to the PDR positioning result at the termination time to a starting location based on the PDR positioning technology when the location still needs to be continued at the termination time tr, and continue to execute the middle time positioning module, the positioning error determination module, the PDR calibration WIFI module, and the WIFI reset PDR module.

9. The indoor positioning system fusing WIFI and PDR positioning technologies as claimed in claim 7, wherein said positioning error determination module is specifically configured to:

constructing a circular range by taking the corresponding position of the PDR positioning result at the middle moment as a circle center and taking the displacement of the target to be measured from the starting moment t0 to the middle moment t1 based on the PDR positioning technology as a radius;

judging whether the position corresponding to the WIFI positioning result at the middle moment is within the circular range or not;

and if the position corresponding to the WIFI positioning result at the middle moment is within the circular range, judging that the error does not exceed a preset threshold value, otherwise, judging that the error exceeds the preset threshold value.

10. The indoor positioning system integrating WIFI and PDR positioning technologies as recited in claim 7, wherein said start time positioning module and said intermediate time positioning module comprise an offline stage and an online stage in the process of obtaining WIFI positioning results using fingerprint matching algorithm;

an off-line stage:

setting reference points in an indoor area, and collecting a WIFI signal intensity value for each reference point;

data preprocessing is carried out on the WIFI signal intensity value, and a position fingerprint database of the indoor area is established according to the WIFI signal intensity value of each reference point;

an online stage:

acquiring a WIFI signal of a target to be detected based on a WIFI positioning technology, and performing data preprocessing;

and matching the preprocessed WIFI signal of the target to be detected with the position fingerprint database, determining a corresponding reference point position estimation result according to the matching result, and using the reference point position estimation result as a WIFI positioning result of the target to be detected.

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