JP5637563B2 - Positioning start control method, mobile terminal and program for controlling start of positioning unit - Google Patents

Description

  The present invention relates to a technique for controlling activation of a positioning unit such as a GPS (Global Positioning System) mounted on a mobile terminal.

  Various services based on the current location are provided for mobile terminals such as mobile phones and smartphones. When the mobile terminal always measures the current position, the user who operates the mobile terminal can receive the service in real time. Here, GPS is generally used as a positioning function for the current position. However, the GPS positioning unit mounted on the mobile terminal consumes a relatively large amount of battery power. Therefore, it is preferable from the viewpoint of battery power consumption to reduce the number of times the GPS positioning unit is started as much as possible.

  Conventionally, there is a technique for estimating a three-dimensional movement path using sensor (acceleration sensor, angular velocity sensor, atmospheric sensor, etc.) information in addition to a positioning unit that measures the current position (see, for example, Patent Document 1). According to this technique, a positioning unit is used to estimate a two-dimensional movement path.

  There is also a technique for determining activation of a GPS positioning unit using a body motion detection sensor such as an acceleration sensor or a gyro sensor (see, for example, Patent Document 2). According to this technique, it is determined based on the body motion signal acquired from the sensor whether or not the user's motion state has changed. And only when it determines with having changed, the power supply of a GPS positioning part is turned ON.

  Furthermore, in order to reduce the power consumption of the battery of the mobile terminal, there is a technique for increasing the positioning interval in the GPS positioning unit when it is determined that the mobile terminal is in the “stationary state” (see, for example, Patent Document 3). According to this technique, a control signal transmitted from a base station is always received, and when there is no change in the control signal received from the base station as seen from the mobile terminal, it is determined as “stationary state”.

JP 2002-48589 A Japanese Patent Laid-Open No. 11-132786 JP 2006-153695 A JP 2010-286344 A

  However, according to the technique described in Patent Document 1, since the GPS positioning unit is used for estimating a two-dimensional movement path, it is necessary to start it frequently and regularly. Therefore, reduction of power consumption of the battery of the mobile terminal is not considered.

  Moreover, according to the technique described in Patent Document 2, it is difficult to apply this technique when the body motion detection sensor is in a moving state that easily includes noise, such as in the “electric vehicle riding” state.

  Furthermore, according to the technique described in Patent Document 3, only the “still state” is considered for power consumption, and various movement states such as “walking”, “running”, “boarding an electric vehicle”, and the like are considered. Not done. After all, when moving even a little, the GPS positioning unit needs to be started frequently and regularly.

  Therefore, the present invention provides a positioning activation control method capable of reducing the power consumption of the battery by reducing the number of times the positioning unit is activated as much as possible even in various moving states as well as the “stationary state”, An object is to provide a mobile terminal and a program.

According to the present invention, a positioning activation control method in a mobile terminal including a positioning unit that measures a current position by receiving positioning radio waves, an acceleration sensor, and a wide area communication interface unit that communicates with a base station of a wide area wireless communication network. Because
A first step of setting the flag to “active state”;
If the flag is “activated”, perform the second step,
If the flag is “Hibernate”, perform the third step,
It is executed to repeat the second step and the third step,
The second step is
Based on the acceleration data output from the acceleration sensor, a movement state estimation process is performed to estimate whether the movement state is “stop”, “boarding of electric vehicle”, or “other”,
If the movement state is “stop” or “electric car boarding”, set the flag to “pause”
Start the positioning unit to measure the current position,
The third step is
If the previous movement state is “stop” and there is a step response based on the acceleration sensor, or if the base station identifier obtained by the wide area communication interface unit is changed, the flag is set to “activated state”
Alternatively, if the previous moving state is “boarding an electric vehicle” and there is a step response based on the acceleration sensor, or if the base station identifier acquired by the wide area communication interface unit is not changed, the flag is set to “activated state”. It is characterized by setting to.

According to another embodiment of the positioning activation control method of the present invention,
The mobile terminal is further equipped with a pedometer that detects the step response,
For the third step, it is also preferable to detect the step response with a pedometer.

According to another embodiment of the positioning activation control method of the present invention,
The positioning unit can set multiple positioning intervals,
For the first step, set the positioning interval to “short”
Regarding the second step, when the estimated moving state is “stop” and “boarding the electric vehicle”, the positioning interval is set to “long”, and the reliability of the moving state estimation result in the moving state estimation process is high. It is also preferable to set the flag to the “pause state” only when it is determined that.

According to the present invention, a mobile terminal having a positioning unit that measures a current position by receiving positioning radio waves, an acceleration sensor, and a wide area communication interface unit that receives a base station identifier from a base station of a wide area wireless communication network. There,
Based on acceleration data output from the acceleration sensor, a movement state estimation means for estimating a movement state of any one of “stop”, “electric vehicle boarding”, and “others”;
Positioning activation control means for controlling the “activation state” and “rest state” of the positioning unit,
Positioning start control means
A first step of setting the flag to “active state”;
If the flag is “activated”, perform the second step,
If the flag is “Hibernate”, perform the third step,
It is executed to repeat the second step and the third step,
The second step is
Obtain the estimated movement state from the movement state estimation means,
If the movement state is “stop” or “electric car boarding”, set the flag to “pause”
Start the positioning unit to measure the current position,
The third step is
If the previous movement state is “stop” and there is a step response based on the acceleration sensor, or if the base station identifier obtained by the wide area communication interface unit is changed, the flag is set to “activated state”
Alternatively, if the previous moving state is “boarding an electric vehicle” and there is a step response based on the acceleration sensor, or if the base station identifier acquired by the wide area communication interface unit is not changed, the flag is set to “activated state”. It is characterized by setting to.

According to the present invention, a mobile terminal having a positioning unit that measures a current position by receiving positioning radio waves, an acceleration sensor, and a wide area communication interface unit that receives a base station identifier from a base station of a wide area wireless communication network. A program for executing an installed computer to control the activation of the positioning unit,
A first step of setting the flag to “active state”;
If the flag is “activated”, perform the second step,
If the flag is “Hibernate”, perform the third step,
It is executed to repeat the second step and the third step,
The second step is
Based on the acceleration data output from the acceleration sensor, a movement state estimation process is performed to estimate whether the movement state is “stop”, “boarding of electric vehicle”, or “other”,
If the movement state is “stop” or “electric car boarding”, set the flag to “pause”
Start the positioning unit to measure the current position,
The third step is
If the previous movement state is “stop” and there is a step response based on the acceleration sensor, or if the base station identifier obtained by the wide area communication interface unit is changed, the flag is set to “activated state”
Alternatively, if the previous moving state is “boarding an electric vehicle” and there is a step response based on the acceleration sensor, or if the base station identifier acquired by the wide area communication interface unit is not changed, the flag is set to “activated state”. The computer is executed so as to be set to

  According to the positioning activation control method, the mobile terminal, and the program of the present invention, the power consumption of the battery is reduced by reducing the number of times the positioning unit is activated as much as possible even in various movement states as well as the “stationary state”. Can be reduced.

It is a function block diagram of the mobile terminal in this invention. It is a flowchart showing the process of the positioning starting control part of the mobile terminal in this invention. FIG. 3 is a flowchart of another embodiment in the activated state with respect to FIG. It is explanatory drawing which derives | leads-out a power spectrum from acceleration data. It is explanatory drawing which derives | leads-out the 1st probability model of a power spectrum. It is explanatory drawing which derives | leads-out the 2nd probability model in consideration of the confidence interval. It is explanatory drawing which derives | leads-out a confidence interval.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a functional configuration diagram of a mobile terminal according to the present invention.

  A mobile terminal 1 such as a mobile phone or a smartphone is carried by a user and moves with the user. According to FIG. 1, the mobile terminal 1 includes a positioning unit 101 that measures the current position, a wide area communication interface unit 102, and an acceleration sensor 103. It is also preferable to mount a pedometer 104.

  The positioning unit 101 receives the positioning radio wave from the GPS satellite 2 to calculate and output the latitude / longitude information of the current position.

  The wide area communication interface unit 102 has, for example, a cellular phone communication function and receives a control signal (including a base station identifier) transmitted from the base station.

  The acceleration sensor 103 is an inertial sensor for measuring acceleration, and can detect a change in velocity per unit time (acceleration of a DC component). The triaxial acceleration sensor is mounted on a general mobile phone. A user who has a mobile phone vibrates his / her body while walking to detect a change in the speed of vertical / horizontal motion.

  The pedometer 104 is also an inertial sensor for measuring the number of steps, and detects vertical vibrations of the body during walking. The detection methods are roughly classified into “pendulum type” and “acceleration sensor type”. In the “pendulum type”, a spring with a pendulum attached is fixed inside the main body, the spring expands and contracts in response to vertical vibration during walking, and the pendulum attached to the spring vibrates. In the case of the “acceleration sensor type”, the acceleration sensor 103 described above can be used. By comparing the measured acceleration data with previously stored acceleration data during walking, it is determined whether the vibration is during walking or otherwise.

  According to FIG. 1, the mobile terminal 1 further includes a positioning activation control unit 111, a movement state estimation unit 112, and an application unit 113. These functional components are realized by executing a program that causes a computer mounted on the mobile terminal to function. The application unit 113 provides various services to the user who operates the mobile terminal 1 based on the current position information output from the positioning unit 101.

<Positioning start control unit 111>
FIG. 2 is a flowchart showing the processing of the positioning activation control unit of the mobile terminal according to the present invention.

(S200) It has a “flag” as an internal variable, and its value has either “activated state” or “hibernated state” for the positioning unit. The initial value is “flag = activated state”.
(S201) The processing with S204 is always repeated.
(S202) If “flag = active state”, S211 to S215 are executed, and if “flag = resting state”, S221 to S226 are executed.

(S211) Based on the acceleration data output from the acceleration sensor, the movement state of “stop” / “boarding of electric vehicle” / “others” is estimated. The moving state State (t) at time t is held, and at least one previous (past) moving state State (t-1) is also held. The movement state estimation process will be specifically described later with reference to FIGS.
(S212) Based on the acceleration data from the acceleration sensor, a movement state estimation process is performed to estimate whether the vehicle is “stopped”, “electric vehicle boarding”, or “others”. In the case of “others”, the process proceeds to S215 while keeping “flag = activated state”.
(S213) If the movement state is “stop”, the flag is set to “pause” (State (t) <− pause). Then, the process proceeds to S215.
(S214) If the movement state is “boarding an electric vehicle”, the flag is set to “pause state” (State (t) <− pause state). Then, the process proceeds to S215.
(S215) The positioning unit is activated to determine the current position. The measured current position is output to the application processing unit. Then, the process proceeds to S203.

(S221) The movement state immediately before is set as the current movement state (State (t) <-State (t-1)).

(S222 to S226) Here, three major determinations can be made. Note that FIG. 2 describes the third determination.
(First judgment)
When the previous movement state is “stopped” and the base station identifier acquired by the wide area communication interface unit is changed (S223), the flag is set to “activated state” (S224),
Alternatively, when the previous movement state is “boarding an electric vehicle” and the base station identifier acquired by the wide area communication interface unit is not changed (S225), the flag is set to “activated state” (S226). Then, the process proceeds to S203.
(Second determination)
If the previous movement state is “stop” or “electric vehicle boarding” and there is a step response based on the acceleration sensor (S223, S225), the flag is set to “activated state” (S224, S226). Then, the process proceeds to S203.
(Third determination)
If the previous movement state is “stop” and there is a step response based on the acceleration sensor, or if the base station identifier acquired by the wide area communication interface unit is changed (S223), the flag is set to “active state” Set (S224)
Alternatively, if the previous movement state is “boarding an electric vehicle” and there is a step response based on the acceleration sensor, or the base station identifier acquired by the wide area communication interface unit is not changed (S225), the flag is set to “ “Activation state” is set (S226). Then, the process proceeds to S203.

About S222-S226 mentioned above, it acts as follows.
(1) When the movement state is “stop” / “ride on electric vehicle”
Move the positioning unit from `` activated '' to `` hibernated ''
The movement is monitored by a functional unit (wide area communication interface or walking response) other than the positioning unit,
When the movement is detected, the positioning unit is shifted from the “pause state” to the “activated state”.
As a result, the number of times the positioning unit is activated is reduced as much as possible, and the power consumption of the battery in the mobile terminal is reduced.
(2) If the movement status is “Other”,
The positioning unit is shifted from the “resting state” to the “starting state”.
This immediately activates the positioning unit and newly updates the current position.

(S203) It is determined whether the current movement state is the previous movement state in the next iteration (State (t-1) <-State (t)).
(S204) Then, the process proceeds to S201.

  FIG. 3 is a flowchart of another embodiment in the activated state with respect to FIG.

(S200) The positioning time interval Interval is set to “short” as an initial value. Interval is set with at least two of “long” and “short”. “Interval = long” is, for example, about 15 minutes. Further, “Interval = short” is, for example, about 5 minutes.

(S211) Based on the acceleration data output from the acceleration sensor, the movement state of “stop” / “boarding of electric vehicle” / “others” is estimated. Here, not only the moving state but also the reliability “high” and “low” in the moving state are derived. The reliability will be specifically described later with reference to FIG.

(S212) The estimation result of the moving state is “stop, reliability: high”, “stop, reliability: low”, “electric vehicle boarding, reliability: high”, “electric vehicle boarding, reliability: low”, “other” It is determined whether it is.

(S2131) When it is determined that the estimation result of the moving state is “stop, reliability: high”, the positioning time interval is set to Interval = “long”.
(S2132) Then, the flag is set to “pause state” (State (t) <− pause state), and the process proceeds to S2151.
(S2133) When it is determined that the estimation result of the movement state is “stop, reliability: low”, the time interval of positioning is set to Interval = “long”, and the process proceeds to S2151.

(S2141) When it is determined that the estimation result of the moving state is “electric vehicle, reliability: high”, the positioning time interval is set to Interval = “long”.
(S2142) Then, the flag is set to “pause state” (State (t) <− pause state), and the process proceeds to S2151.
(S2143) When it is determined that the estimation result of the moving state is “electric vehicle, reliability: low”, the time interval of positioning is set to Interval = “long”, and the process proceeds to S2151.

(S2150) When it is determined that the estimation result of the movement state is “others”, the positioning time interval is set to Interval = “short”.

(S2151) It is determined whether the elapsed time from the previous positioning is longer than the current positioning interval. If it is shorter, the process proceeds to S203.
(S215) If the elapsed time from the previous positioning is longer than the current positioning interval Interval, the positioning unit is activated to measure the current position. The measured current position is output to the application processing unit. Then, the process proceeds to S203.
As described above, the number of times the positioning unit is started can be reduced as much as possible by setting the positioning time interval to “long / short” as well as “starting / stopping” the positioning unit.

<Movement state estimation unit 112>
The movement state estimation unit 112 uses the acceleration data output from the acceleration sensor to estimate which movement state among the n (n ≧ 2) movement states. Examples of the moving state include “stop”, “walking”, “running”, “bicycle boarding”, “train boarding”, “car boarding”, and “bus boarding”. According to the present invention, the movement states of at least “stop”, “electric vehicle boarding”, and “others” are estimated.
"Stop"
"Electric car boarding" = "Train boarding""Automobileboarding""Busboarding"
"Others" = "Walking""Running""Bicycleboarding"
In addition, about a movement state estimation process, it is an existing technique (for example, refer patent document 4).

[Calculation of features]
FIG. 4 is an explanatory diagram for deriving a power spectrum from acceleration data.

First, time-series acceleration data output from the acceleration sensor is divided into a plurality of frames (unit sections). Then, each frame is divided into smaller sub-sections (groups). A power spectrum is calculated from the acceleration data included in each small section by FFT (Fast Fourier Transform). According to this technique, the time series change of the power spectrum of the acceleration data is used to estimate the movement state. By “Fourier transform”, it is possible to extract how many frequency components are included in the acceleration data. When “N = the number of small sections”, the number of calculations is proportional to N ² , but by using “Fast Fourier Transform”, the number of calculations is proportional to N · logN.

[Construction of first probability model of power spectrum using teacher data]
FIG. 5 is an explanatory diagram for deriving a first probability model of a power spectrum.

  Next, a teacher data group to which a correct moving state label is assigned is prepared. The teacher data group includes a power spectrum (feature amount) in a correct movement state.

  Then, a first probability model of the acceleration sensor representing the moving state is constructed. This probability model is constructed by clustering teacher data in all moving states. For clustering, an X-Means method is used. According to the clustering of the K-means method, it is necessary to fix the number of clusters K in advance. On the other hand, the X-Means method is an extension of the K-means method, and can estimate the optimum number of clusters according to data. According to the X-means method, the K-means method is recursively executed with K = 2. The BIC (Bayes information criterion) or AIC (Akaike information criterion) is compared before and after the cluster division, and the division is continued until the value does not improve.

  Here, according to the present method, as an index different from BIC or the like, for each cluster, it is determined whether or not the re-division is to be executed while referring to the deviation of the distribution of the movement state label of the teacher data. Calculate cluster size and number of clusters. After the end of clustering, “average power spectrum” and “label distribution of teacher data” are calculated for each cluster, and set as the first probability model.

  The first probabilistic model described above is insufficient for estimating the movement state with high accuracy and causes deterioration in estimation accuracy. This is because each moving state has an unreliable interval in which it is difficult to distinguish between a confidence interval (frame) in which a power spectrum peculiar to the moving state appears and a zone in another moving state. .

  Therefore, the reliability of the section is evaluated, and the estimation accuracy is improved by using the estimation result of only the section with high reliability (hereinafter referred to as “key frame”). This reliability can be expressed by the probability table described above.

[Construction of second probability model of reliability using teacher data]
FIG. 6 is an explanatory diagram for deriving a second probability model considering the confidence interval.

  According to FIG. 6, the power spectrum and the nearest cluster corresponding to each small section are searched, and the probability table is set as the movement state probability of the small section. This is executed for all the small sections in the frame, and the average value of the moving state probabilities (hereinafter referred to as “average probability table”) is calculated.

  For example, referring to the average probability table in FIG. 6, “running: 50%” and “walking: 40%” are shown, and it is difficult to distinguish between “running” and “walking”. However, if this average probability table appears in the “running” state but has characteristics that do not appear in the “walking” state, this average probability table is a reliable “running” state. It can be said that. It is assumed that in the “running” state, movements close to walking are often mixed, but in the “walking” state, movements close to running are rarely mixed.

  Therefore, a second probability model of reliability is constructed using the teacher data described above and the first probability model of the power spectrum. An average probability table for the frame is calculated using the first probability model. This is executed for all frames and all moving states. The average probability table and the set of moving state labels calculated in this way are used as a population, and the average probability table is clustered. Thus, a second probability model of reliability is constructed. Also for this clustering, for each cluster, it is determined whether or not to perform re-division while referring to the deviation of the distribution of the movement state label of the teacher data, and an appropriate cluster size and number of clusters are calculated.

After the end of clustering, an average probability table is calculated for each cluster, and a moving state A having the maximum probability is derived. Moreover, the most frequently appearing movement state B is derived from the movement state label of the teacher data. Then, both movement states are compared.
A = B cluster (average probability table) = reliable cluster A ≠ B cluster (average probability table) = unreliable cluster In this way, a “reliability flag” is assigned to each cluster. Build a reliability probability model.

[Estimation of moving state]
The movement state is estimated using the first probability model and the second probability model described above. As in FIG. 4, the measured acceleration data is divided into frames and small sections, and a power spectrum for each small section is calculated. For each power spectrum, the nearest probability cluster is searched with reference to the first probability model of the power spectrum. The probability table possessed by the nearest neighbor cluster is set as the movement state probability of the small section, and the average value (average probability table) of the movement state probabilities of all the small sections belonging to the frame is obtained.

  FIG. 7 is an explanatory diagram for deriving a confidence interval.

  Next, a cluster having the calculated average probability table and the nearest average probability table is searched with reference to the second probability model of reliability. The reliability is determined with reference to the “reliability flag” of the cluster. If only the confidence interval is referenced and it is in the same movement state, the interval between the two frames is set as the confidence interval (key frame) of the movement state.

  As described above in detail, according to the positioning activation control method, the mobile terminal, and the program of the present invention, the number of times the positioning unit is activated is reduced as much as possible not only in the “stationary state” but also in various movement states. By doing so, the power consumption of the battery can be reduced.

  Various changes, modifications, and omissions of the above-described various embodiments of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

DESCRIPTION OF SYMBOLS 1 Mobile terminal 101 Positioning part 102 Wide area communication interface part 103 Acceleration sensor 104 Pedometer 111 Positioning starting control part 112 Moving state estimation part 113 Application part

Claims (5)

A positioning activation control method in a mobile terminal having a positioning unit that measures a current position by receiving positioning radio waves, an acceleration sensor, and a wide area communication interface unit that communicates with a base station of a wide area wireless communication network,
A first step of setting the flag to “active state”;
If the flag is “activated”, execute the second step;
If the flag is “Hibernate”, perform the third step;
It is executed to repeat the second step and the third step,
The second step is
Based on the acceleration data output from the acceleration sensor, a movement state estimation process is performed for estimating whether the movement state is “stop”, “boarding of electric vehicle”, or “other”,
If the movement state is "stop""electric car boarding", the flag is set to "pause"
Starts the positioning unit to measure the current position,
The third step is
If the previous moving state is “stop” and there is a step response based on the acceleration sensor, or if the base station identifier obtained by the wide area communication interface unit is changed, the flag is set to “activated state”. Set,
Alternatively, if the previous movement state is “boarding an electric vehicle” and there is a step response based on the acceleration sensor, or if the base station identifier acquired by the wide area communication interface unit is not changed, the flag is set to “ A positioning activation control method, characterized by being set to “activation state”. The mobile terminal is further equipped with a pedometer for detecting a step response,
The positioning activation control method according to claim 1 , wherein a step response is detected by the pedometer in the third step. The positioning unit can set a plurality of positioning intervals,
For the first step, set the positioning interval to “short”
Regarding the second step, when the estimated movement state is “stop” and “boarding of an electric vehicle”, the positioning interval is set to “long” and the reliability of the estimation result of the movement state in the movement state estimation process is set. 3. The positioning activation control method according to claim 1, wherein the flag is set to “pause” only when it is determined that the value is high. A mobile terminal having a positioning unit that measures a current position by receiving positioning radio waves, an acceleration sensor, and a wide area communication interface unit that receives a base station identifier from a base station of a wide area wireless communication network,
Based on acceleration data output from the acceleration sensor, a movement state estimation means for estimating a movement state of any one of “stop”, “electric vehicle boarding”, and “others”;
Positioning start control means for controlling the "starting state""restingstate" of the positioning unit,
The positioning activation control means includes
A first step of setting the flag to “active state”;
If the flag is “activated”, execute the second step;
If the flag is “Hibernate”, perform the third step;
It is executed to repeat the second step and the third step,
The second step is
Obtaining the estimated movement state from the movement state estimation means,
If the movement state is "stop""electric car boarding", the flag is set to "pause"
Starts the positioning unit to measure the current position,
The third step is
If the previous moving state is “stop” and there is a step response based on the acceleration sensor, or if the base station identifier obtained by the wide area communication interface unit is changed, the flag is set to “activated state”. Set,
Alternatively, if the previous movement state is “boarding an electric vehicle” and there is a step response based on the acceleration sensor, or if the base station identifier acquired by the wide area communication interface unit is not changed, the flag is set to “ A mobile terminal characterized in that it is set to an “active state”. A computer mounted on a mobile terminal having a positioning unit that measures a current position by receiving positioning radio waves, an acceleration sensor, and a wide area communication interface unit that receives a base station identifier from a base station of a wide area wireless communication network, A program to be executed to control the activation of the positioning unit,
A first step of setting the flag to “active state”;
If the flag is “activated”, execute the second step;
If the flag is “Hibernate”, perform the third step;
It is executed to repeat the second step and the third step,
The second step is
Based on the acceleration data output from the acceleration sensor, a movement state estimation process is performed for estimating whether the movement state is “stop”, “boarding of electric vehicle”, or “other”,
If the movement state is "stop""electric car boarding", the flag is set to "pause"
Starts the positioning unit to measure the current position,
The third step is
If the previous moving state is “stop” and there is a step response based on the acceleration sensor, or if the base station identifier obtained by the wide area communication interface unit is changed, the flag is set to “activated state”. Set,
Alternatively, if the previous movement state is “boarding an electric vehicle” and there is a step response based on the acceleration sensor, or if the base station identifier acquired by the wide area communication interface unit is not changed, the flag is set to “ A program that causes a computer to execute so as to be set to "startup state".

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