JP2008224249A - Present location positioning device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve more accurate positioning of a present location in a portable navigation device 10 that measures a present location based on the output of a G sensor 15 for a period in which positioning of a present location with a navigation sensor 14 (GPS sensor) is out of working order. <P>SOLUTION: In the device, a detection signal of the navigation sensor 14 is processed by a Kalman filter, white noise in the detection signal is removed, and an optimal estimated acceleration is extracted. The amount of movement is calculated based on the optimal estimated acceleration. A present location predetermined by the navigation sensor 14 in a period of normal positioning is set as a starting point, and thus the present location is measured based on the amount of movement from the starting point. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a current position positioning apparatus and method for interpolating current position positioning based on GPS radio waves.

Patent Document 1 discloses a mobile phone equipped with an acceleration sensor, an azimuth sensor, and an angular velocity sensor in addition to a GPS signal receiver (FIG. 1 of Patent Document 1). In the mobile phone, the current position is measured based on the output of the acceleration sensor or the like during the period in which the current position measurement by GPS is not possible (45 → 46 → 47 in the flowchart of FIG. 6 of Patent Document 1). ).
JP 2004-233058 A

  As will be described later with reference to FIG. 2, the measurement value of the acceleration sensor includes a large amount of white noise due to vehicle vibration on the road surface. Since white noise is distributed over almost the entire frequency range, it is difficult to remove even if a low-pass filter or a high-pass filter is used. In the current position measurement device of Patent Document 1, the output of the acceleration sensor is integrated twice in time to obtain the movement distance. However, because of the whiteness noise included in the measurement value of the acceleration sensor, it is accurate. Therefore, it is difficult to accurately calculate the distance traveled and, therefore, accurately determine the current location.

  An object of the present invention is to provide a current position positioning device and method for improving the accuracy of a current position when positioning the current position based on the output of an acceleration sensor.

  According to the present invention, the output of the acceleration sensor is processed by the Kalman filter to remove white noise in the measurement signal of the acceleration sensor. Then, during a period in which the current position positioning by the GPS radio wave is poor, the movement amount is calculated based on the optimum estimated acceleration output from the Kalman filter, and the current position is determined based on the calculated movement amount.

The present location measurement apparatus of the present invention includes the following components.
First current location means for positioning the current location based on GPS radio waves;
An acceleration sensor that measures acceleration,
A Kalman filter that calculates the optimum estimated acceleration by removing whiteness noise from the measurement signal of the acceleration sensor,
A movement amount calculating means for calculating a movement amount based on the optimum estimated acceleration;
Determining means for determining whether or not the current position measured by the first current position positioning means is appropriate;
In the period in which the determination by the determination unit is negative, the current position is determined based on the amount of movement from the start point with the predetermined current position measured by the first current position measurement unit as the start point during the period in which the determination by the determination unit is positive. 2 current location means.

The present location measurement method of the present invention includes the following steps.
Positioning the current location based on GPS radio waves,
Calculating an optimum estimated acceleration obtained by removing white noise from the measurement signal of the acceleration sensor by a Kalman filter;
Calculating the amount of movement based on the optimum estimated acceleration;
Performing a determination as to whether or not the current location determined based on GPS radio waves is appropriate;
In a period in which the determination is negative, a step of positioning the current location based on a movement amount from the predetermined current location determined based on GPS radio waves in the period in which the determination is positive.

  According to the present invention, the movement amount is calculated based on the optimum estimated acceleration extracted by processing the output of the acceleration sensor by the Kalman filter, and the current position is measured based on the movement amount, so that the current position positioning by the GPS radio wave is difficult. The positioning accuracy of the current location can be improved.

  FIG. 1 is a block diagram of the portable navigation device 10. The portable navigation device 10 has navigation functions such as map display, current location display, and route guidance as its basic functions, and an arithmetic device 11, a display / input unit 12, a storage device as elements for realizing the navigation function 13, a navigation sensor 14, a G sensor 15, a map data holding unit 16, and a power supply unit 17, which are carried by the user.

  The arithmetic unit 11 receives user instruction information from the display / input unit 12 and sends image data to the display / input unit 12. The computing device 11 also performs positioning of the current location based on input signals from the navigation sensor 14 and the G sensor 15. The display / input unit 12 is provided on the front surface of the case of the portable navigation device 10 and includes a plurality of keys as an input unit pressed by the user and an LCD as a display unit for displaying various information to the user.

  The storage device 13 stores a program to be processed by the arithmetic device 11 and temporarily stores calculation data when the program is executed. The navigation sensor 14 receives GPS radio waves and is also called a GPS sensor. The G sensor 15 detects the acceleration of the portable navigation device 10.

  The map data holding unit 16 holds map data and position data necessary when searching for points. The arithmetic unit 11 uses the data in the map data holding unit 16 for calculation such as map drawing and route search. The power supply unit 17 is composed of a rechargeable battery or a replaceable dry battery, and supplies power to each element of the portable navigation device 10.

  Kalman filter processing and learning executed by a program in the arithmetic device 11 will be described with reference to FIGS. 2 to 7, the acceleration Acc is the output of the G sensor 15 when the portable navigation device 10 is brought into the experimental vehicle, and the experimental running of the experimental vehicle is in a stopped state at time = 0, and thereafter The vehicle is accelerated to a predetermined vehicle speed, maintained at the vehicle speed, and finally decelerated and stopped.

  FIG. 2 is a graph showing an example of the time change of the output of the G sensor 15. The measurement value of the G sensor 15 includes a large amount of acceleration caused by the own vehicle vibration, road surface vibration, and the like in addition to the acceleration related to the change in the vehicle speed. In order to obtain an accurate movement distance from the output of the G sensor 15, it is necessary to remove such vibrations. Since these vibrations are white noises distributed over the entire frequency, it is difficult to remove them by extracting a predetermined signal component using a specific frequency transfer function filter.

  Therefore, it is attempted to remove white noise by using an approximate linear algebra as a sequential process. For this calculation, a Kalman filter capable of statistically analyzing environmental variables is excellent. As is well known, the Kalman filter has the following characteristics.

(A) Dynamic characteristics of the system that generates the signal (b) Statistical characteristics of the noise (c) A priori information on the initial value and observation data given from time to time Calculation

  FIG. 3 is a graph in which the output of the G sensor 15 and the estimated value of acceleration obtained by processing the output by the Kalman filter are superimposed. Since FIG. 3 is monochrome, it is difficult to see, but the graph line of the output (= optimum estimated acceleration) of the Kalman filter passes through almost the center of the output waveform of the G sensor 15. The optimum estimated acceleration is obtained by sufficiently removing white noise from the output of the G sensor 15. The Kalman filter process will be described later with reference to FIGS.

  4 is a graph in which the output of the G sensor 15 and the vehicle speed Vel calculated from the vehicle speed pulse are superimposed, and FIG. 5 is a graph in which the output of the acceleration sensor (= optimum estimated acceleration) is further superimposed on the graph in FIG. The portable navigation device 10 is not equipped with a vehicle speed sensor and does not use a vehicle speed sensor. The vehicle speed pulse based on the vehicle speed Vel of FIGS. 4 and 5 uses the output of a vehicle speed sensor that is always provided in the experimental vehicle in which the portable navigation device 10 is brought.

  Although the time derivative of the vehicle speed Vel should coincide with the output of the acceleration, that is, the optimum estimated acceleration, in FIGS. 4 and 5, the initial (acceleration period from the stop state) and the end (to the stop state) of the experimental vehicle in the test run In the deceleration period), the discrepancy between the time derivative of the vehicle speed Vel and the optimum estimated acceleration is conspicuous.

  In order to cope with this, the present location is learned during the acceleration period from the stop state and the deceleration period to the stop state. Since the portable navigation device 10 is not equipped with a vehicle speed sensor, the actual learning in the portable navigation device 10 is to detect the vehicle speed from the time change of the current location detected from the navigation sensor 14 instead of the output of the vehicle speed sensor. Become. Thereby, the correspondence relationship between the actual vehicle speed and the optimum estimated acceleration during the acceleration period from the stop state and the deceleration period from the stop state is determined. The found correspondence relationship is stored in the storage device 13 so as to be appropriately readable as an environment variable.

  FIG. 6 is a graph obtained by superimposing a graph (series of black circles) on the vehicle speed during the acceleration period from the stop state and the deceleration period to the stop state based on the correspondence relationship obtained by learning (black circle series) superimposed on FIG. The vehicle speed (series of black circles) calculated from the optimum estimated acceleration based on the learning result is more consistent with the vehicle speed calculated based on the vehicle speed pulse.

  FIG. 7 is a graph obtained by superimposing the travel distance graph calculated on the basis of the output of the Kalman filter in consideration of learning with FIG. The travel distance in the graph of FIG. 7 is not the vehicle speed obtained by integrating the output of the Kalman filter (= optimum estimated acceleration) as it is during the acceleration period from the stop state and the deceleration period to the stop state, but the correspondence between the learned optimum estimated acceleration and the vehicle speed. The vehicle speed calculated from the optimum estimated acceleration based on the relationship is adopted, and the vehicle speed is calculated based on the adopted vehicle speed. Further, the travel distance in the other period in the graph of FIG. 7 is calculated based on the adopted vehicle speed by adopting the vehicle speed calculated by integrating the output (= optimum estimated acceleration) of the Kalman filter as it is. Thus, when the travel distance is calculated based on the vehicle speed in each period, a travel distance close to the actual travel distance can be calculated from the optimum estimated acceleration as shown in the travel distance graph of FIG.

  The portable navigation device 10 presents the current location determined based on the GPS radio wave to the user as the current location during a period when the navigation sensor 14 normally receives the GPS radio wave and the current location based on the GPS radio wave is appropriate.

  On the other hand, there is a period in which GPS radio waves are weak, or GPS radio waves from three or more GPS satellites cannot be secured, and it is difficult to determine the current location using GPS radio waves. The current location based on is incorrect. The portable navigation device 10 calculates the current location based on the movement amount obtained from the optimum estimated acceleration output from the Kalman filter from the current starting point, starting from the current location that was determined to be appropriate last time during the inappropriate period.

  Furthermore, the portable navigation device 10 is stored as an environmental variable in the acceleration period from the stop state and the deceleration period to the stop state during the inappropriate period when the portable navigation device 10 is brought into the vehicle by the user. Based on the learning data, the vehicle speed corresponding to the optimum estimated acceleration as the output of the Kalman filter is obtained, the travel distance is calculated based on the vehicle speed, and the current location is finally calculated.

  FIG. 8 shows various equations used in the Kalman filter. FIG. 9 shows the meanings and values of the matrices that appear in the Kalman filter formulas shown in the various equations of FIG. System noise and observation noise in the Kalman filter will be described. The observation error is an error included in the sensor. System noise refers to noise that is not included in the observation error in the entire system, such as calculation rounding error and model error. Since these should be strictly real errors, they can be examined and applied in advance. However, it is often difficult to obtain an error in a practically satisfactory manner. For example, the error may be calculated from a system identification method using an adaptive filter.

  A specific example of the Kalman filter processing will be described. For example, the following equation (1) is assumed.

y _k = Σ _{i = 1} ⁿ a _i (k) exp (jω _i t _k ) + v _k (1). However, k = 0, 1, 2,...

y _k , v _k and a _i (k) are observation signals, observation noises, and time-varying components at time t _k = kΔT (ΔT is a sampling interval), respectively, and are defined by complex numbers. ω _i is an angular frequency of the time-varying component a _i (k), and j (j ² = −1) is an imaginary unit. Further, v _k is a stationary complex Gaussian white noise with an average value of zero and a variance σ _v ² .

The output of the G sensor 15 is converted into a digital signal by an A / D converter (not shown) and supplied to the arithmetic unit 11 as a detection signal. The arithmetic unit 11 can execute a Kalman filter process. The Kalman filter is executed by a program in the computing device 11, and sets the detection signal as an observed value y _k, observed value y _k is, as represented by equation (1), specifies the number of n which varies arbitrarily ( Consider the case where n is an arbitrary integer) and is represented by the sum of the complex amplitude a _i (k) and the observed noise v _k, and the complex amplitude a _i of each frequency component ω _i from the observed value y _k. A Kalman filter process for estimating (k) is executed. Then, based on the complex amplitude a _i (k) of each frequency component ω _i , the calculation of the equation (1) is performed to calculate the optimum estimated acceleration, and the optimum estimated acceleration is integrated twice in time to travel distance Ask for.

In the Kalman filter process, white noise in the signal supplied to the movement amount calculation means 34 can be removed by estimating the complex amplitude a _i (k) of each frequency component ω _i from the observed value y _k .

A method for estimating the complex amplitude a _i (k) of each frequency component ω _i using the Kalman filter will be described. When the output signal of the G sensor 15 is represented by (1) as described above, the frequency ω _i represents the detection frequency. In estimating the time-varying spectrum by the Kalman filter, the time variation of the time-varying component a _i (k) is linearly approximated as in the following equation (2).

{A _i (k + 1) −a _i (k)} / ΔT = {a _i (k) −a _i (k−1)} / ΔT + w _i (k) ′ (2)

However, w _i (k) ′ represents a time derivative of w _i (k). The slope of the change of the time-varying component a _i (k) at time t _k-1 is substantially equal to the slope at time t _k , and w _i (k) ′ is an approximation error at that time. At this time, {a _i (k)} is expressed by a secondary AR model of the following equation (3).

a _i (k + 1) = 2 a _i (k) −a _i (k−1) + w _i (k) (3). However, w _i (k) = ΔTw _i (k) ′.

  By using the expression (3), the expression (1) can be expressed by the following expression (4).

a _i (k) = 2 a _i (k−1) −a _i (k−2) + w _i (k) (4)

Here, it is assumed that {w _i (k)} is a stationary complex Gaussian white noise having an average of 0, a variance average of 0, and a variance σ _w ² and independent of {v _k }. Next, {w _i (k)} is treated as system noise, and the observation signal {y _k } is transformed to the basic equation consisting of the following state equation (5) and observation equation (6) by modifying equation (4). Can be represented by a system.

x _{k + 1} = Fx _k + Aw _k (5)

y _{k + 1} = H _k x _k + v _k (6). However, k = 0, 1, 2,.

Equations (5) and (6) correspond to the state equation and observation equation of FIG. Thereafter, the complex amplitude a _i (k) of each frequency component ω _i can be estimated from the detection signal (observed value) y _k of the G sensor 15 by a known solution. Then, by substituting the estimated complex amplitude a _i (k) into the equation (1), the optimum estimated acceleration can be calculated, and the optimum estimated acceleration is integrated twice in time to obtain the travel distance.

  FIG. 10 is a block diagram of the current location device 30. An example of the current location device 30 is the portable navigation device 10 of FIG. The current position measurement device 30 is not limited to a portable type, and may be a car navigation device that is attached to a console of a vehicle. When the current location device 30 is a portable type such as the portable navigation device 10, it is appropriately brought into the vehicle by the user and used. Further, the current position measurement device 30 may be incorporated in a mobile phone, a PDA, and a notebook PC, not as a navigation device alone.

  The current location device 30 includes a first current location device 31, an acceleration sensor 32, a Kalman filter 33, a movement amount calculator 34, a determination device 35, and a second current location device 36. The current location device 30 preferably includes a learning unit 40. The functions of the Kalman filter 33, the movement amount calculation means 34, the determination means 35, the second current location positioning means 36, and the learning means 40 are executed by a program in the arithmetic device 11 in the portable navigation device 10.

  The first current location positioning means 31 measures the current location based on GPS radio waves. The acceleration sensor 32 measures acceleration. The Kalman filter 33 calculates an optimum estimated acceleration obtained by removing white noise from the measurement signal of the acceleration sensor 32. The movement amount calculation means 34 calculates a movement amount based on the optimum estimated acceleration.

  The determination means 35 determines whether or not the current position measured by the first current position positioning means 31 is appropriate. In the period in which the determination by the determination means 35 is negative, the second current position positioning means 36 starts from the predetermined current position measured by the first current position positioning means 31 during the period in which the determination by the determination means 35 is positive. Position the current location based on the amount of movement from the starting point.

  A specific example of the first current location means 31 is the G sensor 15 (FIG. 1). The number of acceleration sensors 32 equipped in the current position measurement device 30 is not limited to one. When the current position measurement device 30 is a portable type carried by the user, the current position measurement device 30 is typically equipped with a total of three acceleration sensors 32, one in each of the three axis directions. When the current location device 30 is a car navigation device, the current location device 30 is typically equipped with two acceleration sensors 32, one in each of two axial directions in the horizontal plane.

  When there is one acceleration sensor 32 in each of the three axis directions, the movement direction at each time point can be detected, and the movement amount in the vertical direction can also be detected. The current location device 30 can detect an absolute movement direction (for example, an angle of the movement direction with respect to the north direction) if it is equipped with a direction sensor (geomagnetic sensor). The movement amount calculated by the movement amount calculating means 34 is preferably calculated by calculating each movement amount in each axial direction of the three orthogonal axes or each movement amount in each axial direction of the two orthogonal axes in the plane to obtain the second current position measurement. The means 36 calculates the current location based on each movement amount in each axial direction.

  The Kalman filter 33 may be realized by hardware or a program. An example of a specific process in which the Kalman filter 33 calculates the optimum estimated acceleration from the acceleration signal supplied from the acceleration sensor 32 is as described based on the equations (1) to (6).

  Specifically, the determination means 35 determines whether or not the current position measured by the first current position positioning means 31 is appropriate. (A) At least three (3 are for the current position measurement in the horizontal direction). Whether or not GPS radio waves can be received from GPS satellites, (b) When the current location calculated based on GPS radio waves is collated with map data, the current location is on the sea or on the lake (except when the user is on board) )) Or (c) Assuming that the current location is calculated based on GPS radio waves at regular time intervals, whether the current location calculated this time stays within a common sense distance from the previously calculated current location, etc. Judgment by

  The case where GPS radio waves from GPS satellites cannot be received is, for example, when the current position measurement device 30 is present in a tunnel, underground mall, or building. In the period in which the current location measured by the first current location positioning means 31 is appropriate, the appropriate current location is typically adopted as the official current location, but the current location calculated based on the movement amount is officially used even in this period. It may be adopted as the present location.

  The predetermined current location used as the starting point in the second current location positioning means 36 is typically the current location that is the basis of the last positive determination in the final positive determination period of the determination means 35.

  Preferably, the current location device 30 includes a learning unit 40. The learning means 40 has a vehicle speed based on the optimum estimated acceleration and a vehicle speed based on a change in the current position measured by the first current position measuring means 31 during the vehicle acceleration period from the stop state during the period when the determination of the determination means 35 is positive. Learn the correspondence of. On the other hand, the movement amount calculation unit 34 calculates the movement amount from the optimum estimated acceleration based on the correspondence relationship based on learning during the period in which the determination by the determination unit 35 is negative and the vehicle acceleration period from the stop state. .

  The learning means 40 is also based on the change in the vehicle speed based on the optimum estimated acceleration and the current location measured by the first current location positioning means 31 during the vehicle deceleration period to the stop state during the period when the determination by the determination means 35 is positive. Learn correspondence with vehicle speed. On the other hand, the movement amount calculation means 34 calculates the movement amount from the optimum estimated acceleration based on the correspondence relationship based on learning during the period when the determination by the determination means 35 is negative and during the vehicle deceleration period to the stop state. .

  A specific example of the learning mode of the vehicle acceleration period and the vehicle stop period by the learning unit 40 is as described with reference to FIGS. 4 to 7 for the portable navigation device 10.

  Thus, in the current position positioning device 30, white noise included in the output of the acceleration sensor 32 is removed by the Kalman filter 33, an accurate amount of movement is calculated, and the accuracy of the current position positioning in the current position positioning impossible period based on GPS radio waves is improved. be able to.

  FIG. 11 is a flowchart of the current location method 50. The current location measurement method 50 is executed at regular time intervals, for example. Note that S51 may be anywhere as long as it is before S54. For example, it can be arranged between S53 and S54. Further, S54 may be anywhere after S51, for example, it may be arranged before S52.

  In S51, the current location is determined based on the GPS radio wave. In S52, the optimum estimated acceleration obtained by removing whiteness noise from the measurement signal of the acceleration sensor 32 is calculated by the Kalman filter. In S53, the movement amount is calculated based on the optimum estimated acceleration.

  In S54, it is determined whether or not the current location determined based on GPS radio waves is appropriate. If the determination is positive, the process proceeds to S55, and if not, the process proceeds to S56. In S55, the predetermined current location determined in S51 is set as a starting point, and the current location positioning method 50 is terminated. In S56, the current location is measured based on the movement amount of S53 from the starting point, and the current location positioning method 50 is terminated.

  The processes of S51, S52, S53, and S54 respectively correspond to the functions of the first current position positioning means 31, the Kalman filter 33, the movement amount calculating means 34, and the determining means 35 of the current position positioning device 30 (FIG. 10). Therefore, the specific modes described for the functions of the first current location positioning unit 31 to the determination unit 35 can also be applied as specific modes for the processes of S51 to S54, respectively. Further, the processing of S55 and S56 corresponds to the function of the second current position positioning means 36 of the current position positioning device 30. Therefore, the specific mode described for the function of the second current location positioning means 36 can be applied as a specific mode for the processing of S55 and S56.

  A step or routine corresponding to the learning means 40 of the current position positioning device 30 can be added to the current position positioning method 50. When this step or the routine is added, in S56, the movement amount is calculated from the optimum estimated acceleration based on the correspondence relationship based on learning during the acceleration period from the stop state and / or the vehicle deceleration period from the stop state. It will be.

  Although the present invention has been described with respect to the best mode, the present invention is not limited to this, and each constituent element in the best mode can be modified and embodied without departing from the gist of the invention. Various inventions can be formed by a convenient combination of a plurality of constituent elements disclosed in the best mode. The invention disclosed in this specification includes those obtained by deleting some constituent elements from all the constituent elements shown in the best mode or combining the constituent elements according to different best modes.

It is a block diagram of a portable navigation device. It is a graph which shows the example of a time change of the output of G sensor. It is the graph which superimposed the output value of G sensor, and the estimated value of the acceleration obtained by processing this output by a Kalman filter. It is the graph which piled up the output of G sensor, and the vehicle speed computed from the vehicle speed pulse. 5 is a graph in which the output of the acceleration sensor is further superimposed on the graph of FIG.

FIG. 6 is a graph obtained by superimposing the graph calculated from the optimum estimated acceleration on the basis of the correspondence relationship obtained by learning the vehicle speed during the acceleration period from the stop state and the deceleration period from the stop state to FIG. 5. FIG. 7 is a graph obtained by superimposing the travel distance graph calculated based on the output of the Kalman filter in consideration of learning on FIG. 6. It is a figure which shows the various equations used with a Kalman filter. It is a figure which shows the meaning and value of the matrix which appear in the numerical formula of the Kalman filter shown in the various equations of FIG. It is a block diagram of a current location device. It is a flowchart of a current location positioning method.

Explanation of symbols

30: Current location positioning device, 31: First current location positioning means, 32: Acceleration sensor, 33: Kalman filter, 34: Movement amount calculation means, 35: Determination means, 36: Second current location positioning means, 40: Learning means, 50: Current location positioning method.

Claims (4)

First current location means for positioning the current location based on GPS radio waves;
An acceleration sensor that measures acceleration,
A Kalman filter that calculates the optimum estimated acceleration by removing whiteness noise from the measurement signal of the acceleration sensor,
A movement amount calculating means for calculating a movement amount based on the optimum estimated acceleration;
Determining means for determining whether or not the current position measured by the first current position positioning means is appropriate;
In the period in which the determination by the determination unit is negative, the current location is determined based on the amount of movement from the start point, starting from the predetermined current location measured by the first current location measurement unit during the period in which the determination by the determination unit is positive. A second current location means for positioning
A current location positioning device characterized by comprising: Correspondence relationship between the vehicle speed based on the optimum estimated acceleration and the vehicle speed based on the change of the current location measured by the first current location positioning means during a period in which the determination by the determination means is positive and the vehicle acceleration period from the stop state. Learning means to learn,
The movement amount calculation means for calculating the movement amount from the optimum estimated acceleration based on a correspondence relationship based on learning during a period in which the determination by the determination means is negative and the vehicle acceleration period from the stop state,
The present location measuring device according to claim 1, further comprising: A correspondence relationship between a vehicle speed based on the optimum estimated acceleration and a vehicle speed based on a change in the current position measured by the first current position positioning means during a period in which the determination by the determination means is positive and the vehicle is decelerated to a stop state. Learning means to learn,
The movement amount calculating means for calculating the movement amount from the optimum estimated acceleration based on the correspondence relationship based on learning during the period in which the determination by the determination means is negative and the vehicle deceleration period to the stop state,
The present location locating device according to claim 1 or 2 characterized by things. Positioning the current location based on GPS radio waves,
Calculating an optimum estimated acceleration obtained by removing white noise from the measurement signal of the acceleration sensor by a Kalman filter;
Calculating the amount of movement based on the optimum estimated acceleration;
Performing a determination as to whether or not the current location determined based on GPS radio waves is appropriate;
In the period in which the determination is negative, the step of positioning the current location based on the amount of movement from the start point, starting from a predetermined current location determined based on GPS radio waves during the period in which the determination is positive;
A current location positioning method characterized by comprising:

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