JP2012118014A - Positional information measuring device, method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance further a power-saving effect by enabling a more accurate determination of whether a position measurement is necessary or unnecessary.SOLUTION: A determination unit 2 for indoor/outdoor changeover is prepared, and an atmospheric temperature is periodically measured first by the determination unit 2 for indoor/outdoor changeover to calculate a temperature variation by applying cosine similarity to temperature information, and a changeover accuracy is calculated by performing a weighted average for the calculated temperature variation. Subsequently, a determination is made whether the calculated changeover accuracy is not less than the threshold, and when the changeover accuracy is determined to be not less than the threshold, a measurement situation transmitting request is transmitted to a position measuring unit 1 to acquire measurement situation information. Whether a positional information measuring section 14 is in a non-measuring state or not is determined based on the acquired measurement situation information, and when the positional information measuring section 14 is determined to be in the non-measuring state, a measurement start trigger is created and transmitted to the position measuring unit 1 so that a positional information measuring operation by the positional information measuring section 14 is reopened.

Description

  The present invention relates to a position information measuring device, method, and program provided in a mobile terminal, for example.

  In recent years, position information is measured using GPS (Global Positioning System) or the like, and services using the measured position information have been activated. In addition, some mobile communication carriers have started services for mobile terminals that constantly measure location information. As described above, the user has a portable terminal equipped with the position information measuring device, so that a social trend of continuously measuring the position of the user for 24 hours 365 days is being made. However, if the position information is constantly measured or measured at a short period, the battery of the position information measuring device, and thus the terminal equipped with this measuring device, increases, resulting in a problem that the operating time of the terminal is shortened. Arise.

  Conventionally, as a technology for power saving of a terminal equipped with a position information measuring device, it is conventionally determined whether the owner of the position information measuring device is in a moving state, and if it is determined to be in a moving state, the power source of the position information measuring device There has been proposed a method of turning on the. For example, in Non-Patent Document 1, when position information measurement becomes impossible, the position measurement operation by the position information measurement device is stopped, and it is estimated whether or not the owner of the terminal is in a moving state using an acceleration sensor. A method is described in which the measuring operation by the position information measuring device is resumed when the mobile device is in a moving state.

Sakamoto et al., “Power Saving Mechanism for Life Log Sensing by Stepwise Switching of Sensor Devices”, IPSJ 72nd National Conference Proceedings (Vol. 3), pp.345346, March 10, 2010.

  However, in the conventional method of turning on the power of the position information measuring device when the owner of the position information measuring device is in a moving state, there arises a situation where it becomes impossible to appropriately cope with the necessity of the position measuring operation. For example, if the user is in an indoor facility or underpass for shopping or commuting, the user is determined to be in a moving state even though the GPS signal from the GPS satellite cannot be received. The power supply of the apparatus is kept ON, and as a result, power is wasted.

  The present invention has been made paying attention to the above circumstances, and the object of the present invention is to provide a position information measuring apparatus, method and method that can further accurately determine whether or not a position measuring operation is necessary and further improve the power saving effect. To provide a program.

  In order to achieve the above object, one aspect of the present invention is to measure the amount of change in air temperature around the mobile device, and based on the measured amount of change in air temperature, the mobile device is indoor and outdoor. Determine the switching timing when moving between. And based on the determination result of this switching timing, the power supply of a position measurement means is controlled so that it may turn on when the said mobile body apparatus exists outdoors.

  By doing so, it becomes possible to accurately determine the switching timing when the mobile device moves between the indoor and the outdoor from the change in the ambient temperature, whereby the mobile device performs the position measurement operation. It is possible to keep the power of the position measuring means off when it is indoors where it is not necessary. For this reason, for example, even when a user who owns a mobile device is moving for shopping or commuting, the position measuring means remains powered off as long as the user moves indoors such as a shopping center or underpass. This makes it possible to reduce wasteful power consumption by the position measuring means.

One aspect of the present invention is also characterized by comprising the following aspects.
In the first aspect, when determining the switching timing, the temperature around the mobile device is measured at a plurality of different timings, and adjacent to each other based on the measured temperature values obtained at these timings. The amount of temperature change between timings is calculated. Then, the switching accuracy is calculated by calculating the weighted average of each temperature change amount between adjacent timings calculated, and the switching timing is determined based on the calculated switching accuracy value.
In this way, when the temperature changes by a predetermined amount or more over a certain time, it is determined that this change is switching between indoor and outdoor. For this reason, the malfunction which misjudges the temporary temperature change by ventilation etc. as indoor / outdoor switching as it is, for example is reduced.

In the second aspect, when calculating the temperature change amount, the cosine similarity of each temperature measurement value is calculated by expressing the change direction of each temperature measurement value obtained at an adjacent timing by a cosine value. The calculated cosine similarity is used as the temperature change amount between the adjacent timings.
If it does in this way, the temperature change between each timing can be expressed using the parameter | index called cosine similarity. By using the cosine similarity, it is possible to detect a fine change as a smaller value and a large change as a larger value. Therefore, the influence of noise caused by the accuracy of the temperature sensor and the surrounding environment can be reduced.

  In the third aspect, the position measurement unit has a measurement situation determination function that determines whether the calculation process of the information indicating the current position is possible or impossible. Then, when controlling the power source of the position measuring means, the power source of the position measuring means is set to OFF when it is determined by the measurement status determining function that the calculation processing of the information indicating the current position is impossible. In the state where the power source of the position measuring unit is set to OFF, the power source of the position measuring unit is set to ON when the switching timing is detected by the switching determination unit.

  In this way, when the signal for position measurement cannot be received, the power of the position measuring means is turned off at that point, and in this state, switching from indoor to outdoor is detected based on the amount of change in ambient temperature. At the time, the position measuring means is turned on. That is, the power-off is controlled by non-detection of the position measurement signal, and the power-on is controlled based on the ambient temperature change. For this reason, it is possible to reliably turn off the power even in a situation where it is difficult to measure changes in the ambient temperature, which makes it possible to control both power off and power on based on the amount of temperature change. The power consumption by the position measuring means can be further effectively reduced.

  That is, according to the present invention, it is possible to more accurately determine whether or not position measurement is necessary, and thereby it is possible to provide a position information measuring device, method, and program capable of further enhancing the power saving effect.

FIG. 3 is a state transition diagram of position information measurement operation used for explaining the principle of the present invention. The figure which shows the example of a detection of the indoor / outdoor switching timing used for description of the principle of this invention. The figure which shows the example of temperature change calculation using cosine similarity used for the principle description of this invention. The block diagram which shows the function structure of the positional infomation measuring apparatus concerning one Embodiment of this invention. The block diagram which shows the more concrete structure of the positional infomation measuring apparatus concerning one Embodiment of this invention. The flowchart which shows the switching process procedure and processing content by the positional information measuring apparatus shown in FIG.4 and FIG.5. The flowchart which shows the procedure of the switching probability calculation process in the switching process procedure shown in FIG. 6, and its processing content. The figure which shows an example of the positional information measured by the positional information measuring apparatus shown in FIG.4 and FIG.5. FIG. 6 is a diagram showing an example of temperature information measured by the position information measuring device shown in FIGS. 4 and 5. The figure which shows an example of the switching probability information calculated by the switching probability calculation process shown in FIG.

[principle]
First, the principle of the present invention will be described.
In general, the majority of timings at which the position information measuring apparatus becomes measurable or not measurable is when moving between indoors and outdoors. Therefore, if this indoor / outdoor switching can be detected, the power control of the position information measuring device can be performed according to the detection result.

  FIG. 1 shows a state transition when the position information measuring apparatus is turned on / off with the timing of switching between indoor and outdoor as a trigger. When the position information measuring device detects a change from the outdoor to the indoor, the position information measuring device regards the position information as being incapable of measurement, and turns off the power supply of the position measuring unit of its own device. Further, when switching from indoor to outdoor is detected in a state where the power supply is off, it is considered that the position information can be measured, and the power supply of the position measurement unit of the own apparatus is turned on.

  In order to realize the above control, it is necessary to detect the indoor / outdoor switching timing. In the present invention, temperature information is used to detect the indoor / outdoor switching. In other words, temperature is one of the features that have a large difference between indoor and outdoor, and when a mobile device equipped with a location information measurement device moves from indoor to outdoor, or from indoor to outdoor, its surroundings There is a noticeable change in temperature. In this invention, this temperature change is utilized.

  For example, the ambient temperature of a mobile device equipped with a position information measurement device is periodically detected and stored using a temperature sensor, and switching between indoors and outdoors occurs when the change in the stored memory changes significantly. It is determined that With this change in temperature as a parameter, a value indicating the certainty of the switching timing inside and outside is defined as “switching accuracy” here, and the higher this value, the higher the probability that switching between indoors and outdoors has occurred. The time when the switching accuracy exceeds a certain threshold is determined as the timing at which switching between indoor and outdoor occurs, and if the power of the position measuring means is off at this time, the power is turned on.

  FIG. 2 is a diagram illustrating an example of timing for determining indoor / outdoor switching. The vertical axis represents “switching accuracy” and the horizontal axis represents “time”, and the switching accuracy is calculated at each time when indoor / outdoor switching is determined. It is determined that the indoor / outdoor has been switched at a time when the switching accuracy exceeds a certain threshold, and if the value is equal to or greater than the threshold, it is not determined that the indoor / outdoor has switched. That is, it is determined only when the switching accuracy has changed from less than the threshold value to more than the threshold value. Therefore, in the example of FIG. 2, only three places indicated by circles are regarded as indoor / outdoor switching timing.

  For calculating the switching accuracy at time t, the amount of change in temperature from time t to t-n is used. Time t-n indicates a time before sampling n times from time t. For example, assuming that the temperature measurement cycle is 1 minute, if n = 4, the time t-n is 4 minutes before the time t. Note that the value of n is designated in advance.

In the present invention, the amount of change in temperature is detected between each adjacent time in the period from time t to tn, and a weighted average value of each detected amount of change in temperature is calculated. The switching accuracy at t. The switching accuracy deg (t) at time t is var (k) where the change in temperature at time k (change from k-1 to k) is var (k), and the weight applied to the change in temperature at time k is ωk. Can be represented by the following formula.

  Further, in the present invention, a method applying cosine similarity is used to calculate the amount of change (var (k)) at the time k. The cosine similarity is a technique for calculating the similarity between two data using a cosine value. That is, it is a cosine cos θ of an angle θ formed by two vectors, and the closeness of the vector directions is used as an index of similarity. The cosine similarity takes a value in the range of −1 to 1, and the closer to 1, the two data are considered to be similar. By using cosine similarity, it is possible to express fine changes as smaller values and large changes as larger values. Therefore, there is an advantage that the influence of noise caused by the accuracy of the temperature sensor and the surrounding environment can be reduced.

For example, it is assumed that the temperature from time t-4 to t has changed as shown in FIG. At this time, if the angle formed between the temperature at time k-1 and the temperature at time k is θk, the angles θt-4 and θt-3 formed by the temperatures detected at each adjacent time from time t-4 to t , Θt-2, and θt-1 are as shown in FIG. Therefore, the similarity sim (t) between the temperature at time t and the temperature at time t-1 can be expressed by the following equation.
sim (t) = cos (θt-1)

When the angle θ as shown in FIG. 3 is taken, the range of values that θ can take is −π / 2 to π / 2. For this reason, the range of values that the similarity sim (t) can take is 0 to 1. The value to be calculated is a change amount, and “similar” is equivalent to “no change”. From the above two, if the change amount is obtained by subtracting 1 from the similarity sim (t), a value closer to 0 is obtained as the change is smaller, and a value closer to 1 is obtained as the change is greater. Therefore, the amount of change var (t) at time t can be expressed by the following equation.
var (t) = 1-sim (t)

  Since the range of values that the change amount var (k) can take at time k is from 0 to 1, the range of values that the weight value ωk can take is also set from 0 to 1. Then, the range of values that the switching accuracy deg (t) can take at time t 1 is also from 0 to 1. Therefore, it can be determined that the possibility of switching between indoors and outdoors decreases as deg (t) approaches 0, and the possibility that switching between indoors and outdoors increases as it approaches 1 is determined.

  As described above, it is possible to calculate the switching accuracy by using the change amount of the temperature, and to determine the indoor / outdoor switching timing using the calculated switching accuracy. Then, by using the determined indoor / outdoor switching timing, the power source of the position measuring means is controlled, so that further power saving of the position measuring means can be achieved.

[Embodiment]
Embodiments according to the present invention will be described below with reference to the drawings.
(Device configuration)
FIG. 4 is a block diagram showing a functional configuration of the position information measuring apparatus according to one embodiment of the present invention.
The position information measuring device is mounted on a portable terminal such as a mobile phone, a smart phone, or an electronic book terminal, and includes a position measuring unit 1 and an indoor / outdoor switching determination unit 2.

First, the position measurement unit 1 includes an input / output interface unit 11, a storage unit 12, a timer unit 13, a position information measurement unit 14, and a measurement control unit 15.
The input / output interface unit 11 transmits / receives control data necessary for implementing the present invention to / from the indoor / outdoor switching determination unit 2. The control data to be transmitted / received includes a measurement status transmission request, measurement status information returned in response to the transmission request, and a measurement start trigger. The timer unit 13 generates a position information measurement start trigger at a predetermined measurement cycle and supplies the position information measurement start trigger to the position information measurement unit 14 described later. The storage unit 12 is used to store the position information measured by the position information measurement unit 14.

  The position information measurement unit 14 performs a position information measurement process each time a position information measurement start trigger is given from the timer unit 13. The position information measurement process receives a GPS signal transmitted from a GPS satellite and calculates the latitude / longitude of the current position based on the received GPS signal, and measures the calculated latitude / longitude. The position information is generated by adding the time, and the position information is stored in the storage unit 12.

The measurement control unit 15 has the following processing functions.
(1) The measurement status information is periodically received from the position information measurement unit 14 to determine whether the position information measurement apparatus is in a state where position measurement is possible or impossible. And the process which gives the timer stop trigger with respect to the timer part 13 when it determines with being impossible, and stops the production | generation process of a position information measurement start trigger.
(2) When the measurement status transmission request transmitted from the indoor / outdoor switching determination unit 2 is received by the input / output interface unit 11, the current measurement status information acquired from the position information measurement unit 14 is used as the input / output interface unit 11. To return to the indoor / outdoor switching determination unit 2 from
(3) When the measurement start trigger transmitted from the indoor / outdoor switching determination unit 2 is received by the input / output interface unit 11, the timer unit 13 is given a timer start trigger to restart the generation process of the position information measurement start trigger Processing to be performed.

Next, the indoor / outdoor switching determination unit 2 includes an input / output interface unit 21, a storage unit 22, a timer unit 23, a temperature measurement unit 24, and an indoor / outdoor switching determination unit 25.
The input / output interface unit 21 transmits / receives the above-described measurement status transmission request, measurement status information, and measurement start trigger to / from the position measurement unit 1. The timer unit 23 generates a measurement start trigger at a preset temperature measurement cycle and supplies it to the temperature sensor 24, and also generates a determination start trigger set to an integral multiple of the temperature measurement cycle to generate an indoor / outdoor switching determination unit 25. To give.

  The temperature measurement unit 24 measures the ambient temperature every time a measurement start trigger is given from the timer unit 23, generates temperature information in which the measurement time is added to the measured temperature data, and stores the temperature information in the storage unit 22. Process. The storage unit 22 is used for storing the temperature information generated by the temperature measurement unit 24.

The indoor / outdoor switching determination unit 25 has the following processing functions.
(1) Every time a determination start trigger is given from the timer unit 23, temperature information stored in a sampling period designated in advance before the current determination time is read from the storage unit 22. Then, a process of calculating a temperature change amount by applying cosine similarity to the read temperature information, and calculating a switching accuracy at the current determination time based on the calculated temperature change amount.
(2) By comparing the calculated switching accuracy with a preset threshold value, it is determined whether the switching accuracy is equal to or higher than the threshold value. As a result of this determination, when it is determined that the threshold value is equal to or greater than the threshold value, a measurement status transmission request is transmitted from the input / output interface unit 21 to the position measurement unit 1, and measurement status information is acquired from the position measurement unit 1. Then, it is determined whether or not the position information measurement unit 14 is in a non-measurement state based on the acquired measurement status information, and when it is determined as a non-measurement state, a measurement start trigger is generated. Is transmitted from the input / output interface unit 21 to the position measurement unit 1.

FIG. 5 is a block diagram showing a specific configuration for realizing the functions of the position information measuring apparatus described above.
The position information measurement unit 1 includes a central processing unit (CPU; Control Processing Unit). A program memory 113, a data memory 114, an input / output interface 115, a timer interface 116, and a CPU 112 are connected to the CPU 111 via a bus 112. A GPS receiver 118 equipped with an antenna 119 is connected.

  The program memory 113 stores an input / output control program 1131, a position information calculation program 1132, and a measurement control program 1133. The input / output control program 1131 realizes the functions of the input / output interface unit 11 shown in FIG. 4 by controlling the input / output interface 115. The position information calculation program 1132 calculates the latitude and longitude based on the GPS signal received by the GPS receiver 118, and realizes the function of the position information measurement unit 14 shown in FIG. The measurement control program 1133 implements the function of the measurement control unit 15 shown in FIG.

  The data memory 114 is provided with a position information storage area 1141 in addition to a work storage area and the like. This position information storage area 1141 has the function of the storage unit 12 shown in FIG. The timer interface 116, together with the timer 117, realizes the function of the timer unit 13 shown in FIG.

  The GPS receiver 118 is provided with a power supply switch circuit (not shown). This power supply switch circuit supplies operation power to the GPS receiver 118 only for a certain period of time from when the position information measurement start trigger is generated from the timer 117 until the GPS signal reception operation ends, for example. During the period, power supply to the GPS receiver 118 is cut off.

  On the other hand, the indoor / outdoor switching determination unit 2 also includes a central processing unit (CPU; Control Processing Unit) 211 similar to the position information measurement unit 1, and a program memory 213 and a data memory are connected to the CPU 211 via a bus 212. 214, an input / output interface 215, a timer interface 216, and a temperature sensor 218 are connected.

  The program memory 213 stores an input / output control program 2131, a switching accuracy calculation program 2132, and an indoor / outdoor switching determination program 2133. The input / output control program 2131 realizes the function of the input / output interface unit 21 shown in FIG. 4 by controlling the input / output interface 215. The switching accuracy calculation program 2132 and the indoor / outdoor switching determination program 2133 implement the function of the indoor / outdoor switching determination unit 25 shown in FIG.

  The data memory 214 is provided with a temperature information storage area 2141 and a switching accuracy information storage area 2142 in addition to a work storage area and the like. The temperature information storage area 2141 is used to store temperature information obtained by adding the measurement time to the temperature data measured by the temperature sensor 218. The switching accuracy information storage area 2142 is used to store the switching accuracy calculated by the switching accuracy calculation program 2132. The timer interface 216 implements the function of the timer unit 23 shown in FIG.

(Device operation)
Next, the position information measurement operation by the apparatus configured as described above will be described. FIG. 6 is a flowchart showing the processing procedure and processing contents.
(1) Stop processing of position information measurement operation In the position measurement unit 1 in a state where position measurement is possible, a position information measurement start trigger is generated from the timer unit 13 at intervals of 1 second, for example. Each time this position information measurement start trigger is generated, the GPS receiver 118 performs a GPS signal reception operation, and the latitude and longitude are calculated based on the received GPS signal. Then, data representing the measurement time is added to the calculated latitude / longitude data, and the latitude / longitude data to which the data representing the measurement time is added is stored in the storage unit 12 as position information. FIG. 8 shows an example of position information stored in the storage unit 12.

  Further, the position information measuring unit 14 performs a process of monitoring whether or not the position information can be measured while performing the position information measurement process, and whether or not the position measurement obtained by the monitoring process is possible. The measurement status information indicating is sent to the measurement control unit 15. The measurement control unit 15 determines whether or not the position information measuring device is in a state where the position information can be measured based on the measurement state information. When it is determined that the measurement is impossible, a timer stop trigger is given to the timer unit 13. As a result, the timer unit 13 stops generating the position information measurement start trigger. Therefore, in the position information acquisition unit 14, the power supply to the GPS receiver 118 is subsequently cut off, and the GPS receiver 118 is in a non-operating state in which power is not consumed.

(2) Process for Starting Position Information Measurement Operation In the indoor / outdoor switching determination unit 2, a process of monitoring whether or not the temperature measurement timing has come is performed by the temperature measurement unit 24 in step S11. In this state, when the temperature measurement timing comes, the timer unit 23 generates a measurement start trigger. The generation period of this measurement start trigger is set to 1 second, for example. Each time the measurement start trigger is generated, the temperature measurement unit 24 performs temperature information generation processing in step S12. In this temperature information generation process, the ambient temperature is measured by the temperature sensor 218, and time data at the time of measurement is added to the temperature data obtained by the measurement. The generated temperature information is stored in the storage unit 22 in step S13. FIG. 9 shows an example of temperature information stored in the storage unit 22.

  Further, in the indoor / outdoor switching determination unit 2 while performing the temperature measurement process, the indoor / outdoor switching determination unit 25 performs a process of monitoring whether or not the switching determination timing has been reached in step S14. In this state, a determination start trigger is generated from the timer unit 23 when the switching determination timing comes. The generation cycle of this determination start trigger is set to 1 minute, for example.

When the determination start trigger is generated, the indoor / outdoor switching determining unit 25 proceeds to step S15, and executes a switching accuracy calculation process as follows. FIG. 7 is a flowchart showing the processing procedure and processing contents.
That is, first, in step S151, the latest n pieces of temperature information stored until the current determination time are read from the storage unit 22. Then, in step S152, the temperature information at the oldest time is selected from the read out n pieces of temperature information, and the measurement information is measured in the temperature information whose measurement time is newer than the selected temperature information and the selected temperature information. The amount of change from the latest temperature information is calculated. At this time, if the temperature change amount at time t is var (t), the temperature change amount var (t) is expressed by the following equation as described in the principle description.
var (t) = 1-cos (θt)

  Here, θt is an angle made up of the currently selected temperature information and the temperature information at the closest time that is newer than the currently selected temperature information among the n pieces of read out temperature information. For example, in FIG. 3, assuming that the currently selected temperature information is the temperature information obtained at time t-4, the temperature at the closest time that is newer than the currently selected temperature information among the latest n pieces of temperature information. The information is time t-3. The angle formed by the two temperature information is θt-4, and the cosine value is the amount of change. The angle is calculated with the horizontal axis representing 1 sampling difference = 1 and the vertical axis representing temperature (Celsius) 1 degree = 1.

  In step S155, the temperature change amount between the currently selected temperature information and the temperature information at the nearest time that is newer than the currently selected temperature information among the read n pieces of temperature information is calculated. In step S156, the indoor / outdoor switching determination unit 25 stores the calculated temperature change amount in the work storage area in the storage unit 22.

  Next, in step S156, the indoor / outdoor switching determination unit 25 selects, as a new selection destination, temperature information that has a new measurement time from the currently selected temperature information out of the n pieces of read temperature information. To do. For example, if the temperature information at time t-4 is selected as described above, the temperature information at time t-3 is selected as a new selection destination. In step S153, it is determined whether or not temperature information whose measurement time is newer than the newly selected temperature information still remains. If there is still temperature information, the process proceeds to step S155, where As in the case of the temperature information at time t-4, the temperature information at the currently selected time t-3 and the temperature information that is currently selected among the n pieces of read out temperature information are closest. The amount of temperature change with the temperature information at time t-2 is calculated. Then, the calculation result is stored in the working storage area in the storage unit 22 in step S156.

  Similarly, in step S156, each time one temperature information is selected from the n pieces of read out temperature information in order from the oldest measurement time, the selected temperature information and one measurement time are determined accordingly. The temperature change amount with the new temperature information is calculated and stored in the work storage area in the storage unit 22.

If it is determined in step S153 that no temperature information whose measurement time is newer than the newly selected temperature information remains, the indoor / outdoor switching determination unit 25 proceeds to step S154. Then, the stored temperature change amounts at the respective times t-4, t-3, t-2, and t-1 are read from the working storage area in the storage unit 22, and calculated at the read times. The weighted average of the measured temperature change amounts is used to calculate the switching accuracy. This switching accuracy is calculated by the following equation.

  When the switching accuracy is calculated, the indoor / outdoor switching determination unit 25 stores the calculation result of the switching accuracy in association with the determination time in the switching accuracy information storage area 2142 in the storage unit 22 in step S16 of FIG. FIG. 10 shows an example of stored data of this switching accuracy.

  When new switching accuracy calculation data is stored in the switching accuracy information storage area 2142, the indoor / outdoor switching determination unit 25 next determines whether or not the switching accuracy calculated this time is equal to or greater than a preset threshold value in step S17. If it is less than the threshold value, the process proceeds to step S20. On the other hand, when the switching accuracy calculated this time is equal to or greater than the threshold value, information on the past switching accuracy whose determination time is closest to the switching accuracy determination time calculated this time, that is, information on the previous switching accuracy is recorded. Read from unit 22. Then, it is determined whether or not the switching accuracy included in the previous switching accuracy information is equal to or less than a threshold value. .

  Subsequently, the indoor / outdoor switching determination unit 25 determines whether the position measurement unit 1 is in a measurement state or a non-measurement state in step S18. This determination process is performed based on the measurement status information sent from the input / output interface unit 21 to the position measurement unit 1 and returned from the position measurement unit 1 in response to this request. As a result of this determination, if it is determined that the measurement state is not measured, a measurement start trigger is generated in step S19, and this measurement start trigger is transmitted from the input / output interface unit 21 to the position measurement unit 1. If the position measurement unit 1 is in the measurement state as a result of the determination, the process proceeds to step S20 without transmitting the measurement start trigger.

  When a measurement start trigger is transmitted from the indoor / outdoor switching determination unit 2 and this measurement start trigger is received by the input / output interface unit 11, the measurement control unit 15 of the position measurement unit 1 sends a timer start trigger to the timer unit 13. give. As a result, the timer unit 13 resumes the position information measurement start trigger generation process. Therefore, the position information measurement unit 14 supplies power to the GPS receiver 118, and thereafter, the position information measurement process is executed at intervals of one second in synchronization with the position information measurement start trigger.

  The indoor / outdoor switching determination unit 2 determines whether or not to turn off the power saving function of position information measurement in step S20. As a result of the determination, if the power saving function is continued, the process returns to step S11, and the process for starting the position information measurement operation in steps S11 to S19 is continued. On the other hand, for example, when the user performs an operation to turn off the power saving function, or the mobile terminal enters an operation state in which the power saving function is not used, an operation that always performs the position information measurement process regardless of indoors or outdoors. Transition to the state.

  As described above in detail, in this embodiment, in addition to the position measurement unit 1, an indoor / outdoor switching determination unit 2 is provided, and the indoor / outdoor switching determination unit 2 first measures the ambient temperature periodically to obtain temperature information. The amount of change in temperature is calculated by applying cosine similarity, and the switching accuracy is calculated by weighted averaging the calculated amount of change in temperature. Subsequently, it is determined whether or not the calculated switching accuracy is equal to or higher than a threshold value. When it is determined that the calculated switching accuracy is equal to or higher than the threshold value, a measurement status transmission request is transmitted to the position measurement unit 1 to acquire measurement status information. Then, based on the acquired measurement status information, it is determined whether or not the position information measurement unit 14 is in the non-measurement state. If it is determined that the position information measurement unit 14 is in the non-measurement state, a measurement start trigger is generated. A start trigger is transmitted to the position measurement unit 1 so that the position information measurement operation by the position information measurement unit 14 is resumed.

  Therefore, when the mobile terminal moves between indoors and outdoors, the switching timing is determined based on the change in ambient temperature, so that the position measurement is performed when the mobile terminal is indoors where it is not necessary to perform the position measurement operation. It becomes possible to keep the power supply of the means off. For this reason, for example, even when a user with a mobile terminal is moving for shopping or commuting, the GPS receiver 118 is kept off when moving indoors such as a shopping center or underpass As a result, wasteful power consumption by the GPS receiver 118 can be reduced and the power saving effect can be enhanced.

  In addition, the switching accuracy is calculated by weighted average of the temperature change amounts respectively obtained at a plurality of measurement times, and the switching timing is determined based on the calculated switching accuracy value. For this reason, when the temperature changes by a predetermined amount or more over a certain time, it can be determined that the change at this time is switching between indoor and outdoor. Therefore, for example, it is possible to prevent a problem that a temporary temperature change caused by, for example, blowing air is erroneously determined as switching between indoors and outdoors.

  Furthermore, when calculating the temperature change amount, cosine similarity is applied to each temperature information obtained at adjacent timings to calculate the temperature change amount represented by the cosine similarity. For this reason, it is possible to represent the temperature change between the respective timings using an index called cosine similarity, whereby a minute change can be detected as a smaller value and a large change as a larger value. Therefore, the influence of noise caused by the accuracy of the temperature sensor and the surrounding environment can be reduced.

  Furthermore, in this embodiment, for example, when the portable terminal enters the indoor state and GPS signals cannot be received, the GPS receiver 118 is turned off at that time, and in this state, the indoor / outdoor switching unit 2 controls the amount of change in the ambient temperature. When the switch from indoor to outdoor is detected, the GPS receiver 118 is powered on. That is, the power-off is controlled according to the non-detection of the GPS signal, and the power-on is controlled based on the ambient temperature change. For this reason, it is possible to reliably turn off the power even in a situation where it is difficult to measure changes in the ambient temperature, which makes it possible to control both power off and power on based on the amount of temperature change. The power consumption by the GPS receiver 118 can be further effectively reduced.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the case where the CPUs 11 and 21 are provided in both the position measurement unit 1 and the indoor / outdoor switching unit 2 has been described as an example, but the processing of both units may be executed by one CPU. Good. The CPU may be replaced by a CPU provided in the mobile terminal.

  In the above-described embodiment, the power-off of the GPS receiver 118 is controlled according to the non-detection of the GPS signal, and the power-on is controlled based on the change in the ambient temperature change amount. Both power off and power on may be controlled based on the temperature change amount.

  In addition, the configuration of the position measurement unit 1 and the indoor / outdoor switching unit 2 and the processing procedure and processing contents thereof can be variously modified and implemented without departing from the gist of the present invention.

  In short, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Position measurement unit, 2 ... Indoor / outdoor switching determination unit, 11, 21 ... Input / output interface unit, 12, 22 ... Storage unit, 13, 23 ... Timer unit, 14 ... Position information measurement unit, 15 ... Measurement control unit, 24 ... Temperature measurement unit, 25 ... Indoor / outdoor switching determination unit, 111, 211 ... CPU, 112,212 ... Bus, 113,213 ... Program memory, 114,214 ... Data memory, 115,215 ... Input / output interface, 116, 216 ... Timer interface, 117,217 ... Timer, 118 ... GPS receiver, 218 ... Temperature sensor, 1131 ... Input / output control program, 1132 ... Position information calculation program, 1141 ... Position information storage area, 2131 ... Input / output control program, 2132: switching accuracy calculation program, 2133: indoor / outdoor switching Determination program, 2141 ... temperature information storage area, 2142 ... switching accuracy information storage area.

Claims (6)

Position measuring means mounted on the mobile device, receiving a signal necessary for position measurement, and calculating information representing the current position of the mobile device based on the received signal;
A switching determination for measuring a change amount of the temperature around the mobile device and determining a switching timing when the mobile device moves between indoor and outdoor based on the measured change amount of the temperature. Means,
And a control unit that controls a power source of the position measurement unit so that the mobile unit is turned on when the mobile device is outdoors based on the determination result of the switching timing by the determination unit. Information measuring device. The switching determination means includes
Means for measuring the temperature around the mobile device at different timings;
Based on the measured temperature values obtained at the plurality of timings, means for calculating the temperature change amount between adjacent timings;
Means for calculating a switching probability by performing a weighted average of each air temperature change amount between the calculated adjacent timings;
2. The position information measuring apparatus according to claim 1, further comprising means for determining a switching timing based on the calculated switching accuracy value.   The means for calculating the temperature change amount calculates a cosine similarity of each temperature measurement value by expressing a change direction of each temperature measurement value obtained at an adjacent timing by a cosine value, and calculates the cosine similarity The position information measuring device according to claim 2, wherein the degree is a temperature change amount between the adjacent timings. The position measuring unit includes a measurement situation determination unit that determines whether the calculation process of information representing the current position is possible or impossible.
The control means includes
Means for setting the power of the position measuring means off when it is determined by the measurement situation determining means that the situation is impossible;
Means for setting the power of the position measuring means on when the switching determination means detects the switching timing in a state where the power of the position measuring means is set to off. The position information measuring device according to claim 1. A step of receiving a signal required for position measurement by a position measuring means mounted on the mobile device and calculating information representing the current position of the mobile device based on the received signal;
Measuring a change in temperature around the mobile device, and determining a switching timing when the mobile device moves between indoors and outdoors based on the measured change in temperature; ,
A position information measuring method comprising: controlling a power source of the position measuring means so that the mobile device is turned on when the mobile device is outdoors based on the determination result of the switching timing. Processing for receiving a signal necessary for position measurement by the position measurement means mounted on the mobile device and calculating information representing the current position of the mobile device based on the received signal;
A process of measuring a change amount of the temperature around the mobile device and determining a switching timing when the mobile device moves between indoor and outdoor based on the measured change amount of the air temperature; ,
A program for causing a computer included in the mobile device to execute processing for controlling the power of the position measurement means so that the mobile device is turned on when the mobile device is outdoors based on the determination result of the switching timing. .

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