Position estimating method based on plural position information different in accuracy and measuring time, system, program and recording medium for recording program

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a position estimation method, a system, a program, and a recording medium on which a program is recorded, which is necessary for uniformly handling a plurality of position information having different accuracy.

【0002】

[Conventional technology]

In recent years, various location information acquisition devices such as GPS, mobile phones, PHS, and ID tags that can be carried by humans have been developed. Users are now able to use them to receive services such as displaying their location on a map and searching for restaurants near them.

【0003】

However, in general, the area that can be used by the location information acquisition device is limited. For example, well-GPS used in car navigation systems, are widely used as small positional information acquisition device of measurement errors but that, GPS is it is not possible to obtain position information in such underground mall for use only outdoors .. At this time, if it is possible to combine another type of location information acquisition device such as PHS that can be used in the underground mall, the location information can be obtained at any place. Furthermore, since PHS can be used on the ground, it is possible to obtain a plurality of position information such as GPS and PHS position information on the ground. If a plurality of types of position information are obtained at the same time, more accurate position information can be obtained by comparing or combining the position information.

【0004】

A method of obtaining highly accurate position information using a plurality of position information acquisition devices has been proposed. In the method of improving the accuracy by using a plurality of single type position information acquisition devices, for example, JP-A-6-265626 and JP-A-8-240653 improve the GPS position information accuracy based on the information from multiple satellites. The method is described. Further, a method for improving accuracy by using different types of position information acquisition devices is proposed in Japanese Patent No. 2562678 "Self-position expression device". It detects its own current position data by different types of position information devices and at the same time detects an error, and improves accuracy by selecting the data with the smallest error.

【0005】

In these conventional techniques, the accuracy of the position information at a certain point in time, such as the current position, is limited, and the handling of the position information after a certain time has passed from the position information acquisition time is not described. .. Regarding the handling of the elapsed time from the location information acquisition time to the present, Japanese Patent Application Laid-Open No. 2000-132797 deals with the handling by setting an expiration date for the acquired location information and not selecting the expired one. According to this method, the expired location information is discarded, and there is a problem that the acquired location information cannot be utilized. In addition, there is a problem that the acquired location information is not utilized even when the expiration date is set inappropriately. In particular, when the user's location information is continuously acquired at certain time intervals and the movement record is taken, if the next location information cannot be obtained even after the expiration date of the certain location information, the position is recorded in the movement record. An unknown time zone will be created.

【0006】

As a solution to the above problem, the acquisition of location information may be frequent, but the problem of failure to acquire location information due to being in a place where location information cannot be acquired can be considered. In addition, frequent location information acquisition is not realistic because it costs money to acquire location information once by using a mobile phone or PHS.

【0007】

[Problems to be Solved by the Invention]

Generally, the accuracy and acquisition time of the position information acquired from different position information acquisition devices are different. When the frequency of acquiring location information is not frequent, there is a problem that a plurality of location information cannot be simply compared without considering the elapsed time from the location information acquisition time to the present.

【0008】

Consider selecting more accurate information from a plurality of position information. It is not possible to select more accurate information by simply comparing based only on the novelty of the position information or the measurement error. For example, if you compare the position information 1 hour ago with an error of several cm and the position information 1 minute ago with an error of 10 m, it is the former if you select with the accuracy of the position information, but the position information acquisition time is very recent. It may be better to select the latter location information from. Also, if you compare the position information 11 minutes ago with an error of several cm and the position information 10 minutes ago with an error of 10 m, it is the latter if you select it based on the newness of the position information acquisition time, but the acquisition time does not change much, so It may be better to select the former, which has better location information accuracy.

【0009】

The present invention proposes a method, a system, a program, and a recording medium on which a program is recorded, which enables a simple comparison of a plurality of position information in consideration of the elapsed time from the position information acquisition time to the present and an error. .. For a plurality of position information having different acquisition times and measurement errors, if the respective position information and the error at an arbitrary time are known, highly accurate position information can be acquired by comparison. In addition, when taking a movement record, there is no time zone where the position is unknown because the expiration date is not set.

【0010】

[Means for solving problems]

According to the position estimation method of the present invention, a plurality of types of position information having different accuracy and measurement time are acquired for a certain moving body, and the accuracy of each of the plurality of types of position information having different accuracy and measurement time at an arbitrary time. Is estimated, and the estimated accuracy of each of a plurality of types of position information having different accuracy and measurement time at an arbitrary time is compared, and the most accurate position information is selected.

【0011】

According to another embodiment of the position estimation method of the present invention, it is also preferable to display the estimated accuracy at an arbitrary time on the map with the position information of the moving body and its accuracy as an error range.

【0012】

According to another embodiment of the position estimation method of the present invention, a plurality of error ranges are derived by using a plurality of estimated accuracy and position information at an arbitrary time, and the position is estimated by the overlapping portion of the error ranges. It is also preferable.

【0013】

According to another embodiment of the position estimation method of the present invention, the accuracy of the position information at an arbitrary time is estimated by using the moving speed of the moving body, and the moving speed of the moving body is the own speed of the moving body. Whether to receive from the moving body, calculate the moving speed from the displacement of two position information with a time difference, or receive the number of steps taken by the person who owns the moving body from the moving body and calculate the moving speed from that number of steps. Or, it is also preferable to estimate the moving speed from the location obtained by the scheduler that manages the location of the moving object.

【0014】

According to another embodiment of the position estimation method of the present invention, the accuracy of the position information of the moving body is estimated based on the position information acquisition method of the moving body or based on the position of the moving body. Is also preferable.

【0015】

According to the position estimation system of the present invention, there is a means for acquiring a plurality of types of position information having different accuracy and measurement time for a certain moving body, and an arbitrary time for each of the plurality of types of position information having different accuracy and measurement time. It has a means for estimating the accuracy in the above, and a means for selecting the most accurate position information by comparing the estimated accuracy of each of a plurality of types of position information having different accuracy and measurement time at an arbitrary time.

【0016】

According to another embodiment of the position estimation system of the present invention, it is also preferable to further have a means for displaying the estimated accuracy at an arbitrary time on the map with the position information of the moving body and the accuracy as an error range.

【0017】

According to another embodiment of the position estimation system of the present invention, the means for estimating the accuracy derives a plurality of error ranges by using a plurality of estimated accuracy and position information at an arbitrary time, and the error range of the error range is derived. It is also preferable to estimate the position by the overlapping portion.

【0018】

According to another embodiment of the position estimation system of the present invention, the means for estimating the accuracy is estimated by using the moving speed of the moving body, and the moving speed of the moving body is the own speed of the moving body from the moving body. Receive, calculate the movement speed from the displacement of two position information with a time difference, receive the number of steps taken by the person who owns the moving body from the moving body and calculate the moving speed from that number of steps, or move It is also preferable to estimate the movement speed from the location obtained by the scheduler that manages the location of the body.

【0019】

According to another embodiment of the position estimation system of the present invention, it is also preferable that the means for estimating the accuracy estimates the accuracy based on the position information acquisition method of the moving body or based on the position of the moving body.

【0020】

According to the recording medium on which the position estimation program of the present invention is recorded, a means for acquiring a plurality of types of position information having different accuracy and measurement time and a plurality of types of position information having different accuracy and measurement time for a certain moving body. A computer as a means for estimating the accuracy at each arbitrary time and a means for selecting the most accurate position information by comparing the estimated accuracy of each of a plurality of types of position information having different accuracy and measurement time at an arbitrary time. Is what makes it work.

【0021】

According to another embodiment of the recording medium on which the position estimation program of the present invention is recorded, a means for displaying the estimated accuracy at an arbitrary time on the map with the position information of the moving object and the accuracy as an error range is further provided. It is also preferable to have the computer function to have.

【0022】

According to another embodiment of the recording medium on which the position estimation program of the present invention is recorded, the means for estimating the accuracy derives a plurality of error ranges by using a plurality of estimated accuracy and position information at an arbitrary time. It is also preferable to make the computer function so as to estimate the position by the overlapping portion of the error range.

【0023】

According to another embodiment of the recording medium on which the position estimation program of the present invention is recorded, the means for estimating the accuracy is estimated using the moving speed of the moving body, and the moving speed of the moving body is the self of the moving body. Whether to receive the speed from the moving body, calculate the moving speed from the displacement of two position information with a time difference, or receive the number of steps taken by the person who owns the moving body and calculate the moving speed from that number of steps. Alternatively, it is also preferable to make the computer function to estimate the moving speed from the location obtained by the scheduler that manages the location of the moving object.

【0024】

According to another embodiment of the recording medium on which the position estimation program of the present invention is recorded, the means for estimating the accuracy estimates the accuracy based on the position information acquisition method of the moving body or based on the position of the moving body. It is also preferable to make the computer function as such.

【0025】

According to the position estimation program of the present invention, there is a means for acquiring a plurality of types of position information having different accuracy and measurement time for a certain moving body, and an arbitrary time for each of the plurality of types of position information having different accuracy and measurement time. The computer functions as a means for estimating the accuracy in the above and as a means for selecting the most accurate position information by comparing the estimated accuracy of each of a plurality of types of position information having different accuracy and measurement time at an arbitrary time. is there.

【0026】

According to another embodiment of the position estimation program of the present invention, the computer is further provided with a means for displaying the estimated accuracy at an arbitrary time on the map with the position information of the moving body and the accuracy as an error range. It is also preferable to make it work.

【0027】

According to another embodiment of the position estimation program of the present invention, the means for estimating the accuracy derives a plurality of error ranges by using a plurality of estimated accuracy and position information at an arbitrary time, and the error range of the error range is derived. It is also preferable to make the computer function to estimate the position by the overlap.

【0028】

According to another embodiment of the position estimation program of the present invention, the means for estimating the accuracy is estimated by using the moving speed of the moving body, and the moving speed of the moving body is the own speed of the moving body from the moving body. Receive, calculate the moving speed from the displacement of two position information with a time difference, receive the number of steps taken by the person who owns the moving body and calculate the moving speed from that number of steps, or the existence of the moving body It is also preferable to make the computer function to estimate the moving speed from the location obtained by the scheduler that manages the location.

【0029】

According to another embodiment of the position estimation program of the present invention, the means for estimating the accuracy functions the computer to estimate the accuracy based on the position information acquisition method of the moving body or based on the position of the moving body. It is also preferable to let it.

【0030】

In the present invention, it is possible to simply compare a plurality of position information by considering an error in consideration of the elapsed time from the position information acquisition time to the present. From the position information acquired at a certain time, the position information at an arbitrary time and its accuracy are estimated.

【0031】

Hereinafter, the means of the present invention will be specifically described.

【0032】

In order to estimate the position information and its error at an arbitrary time, an "estimation error" that increases as the time from the position information acquisition time elapses is set. The estimation error at the position information acquisition time is equal to the measurement error of the position information acquisition device.

【0033】

As a method of knowing the measurement error of the position information acquisition device, since the measurement error differs depending on the position information acquisition device, it may be set for each type of the position information acquisition device. Also, in the case of PHS, the error differs depending on the installation interval of the base station or the installation density. Therefore, the error may be set by referring to the installation interval and installation density of the base stations in the area from the acquired position information.

【0034】

From the user's position information and measurement error, the user's position at the time of acquiring the position information can be represented by an area. If this is represented on a map, a circle can be drawn with the measurement error as the radius centered on the position of the position information at the user's position information acquisition time as shown in FIG. This circle will be called the error circle. At the position information acquisition time, the user indicates that the user exists at least within the error circle (shaded part in FIG. 1). For example, if the measurement error is 10 m, it can be considered that the user exists within a circle with a radius of 10 m centered on the point of the position information, and there is an advantage that the position of the user can be confirmed at a glance.

【0035】

Next, consider the condition that maximizes the error that can be estimated after an arbitrary time has elapsed since the location information was acquired. As shown in FIG. 2, when the user is on the error circle at the time of acquiring the position information (time is 0), the measurement error is the maximum. Given the position of the user after an arbitrary amount of time (assumed to be time t), the user either moves in any direction or stands still on the error circle. The maximum error occurs when the user moves away from the center of the error circle on a straight line connecting the positions on the error circle at time 0. The distance from the center at that time is called the estimation error, and a circle with the estimation error as the radius is drawn and called the estimation error circle. It is considered that the user α at time t exists within the estimation error circle (shaded part in FIG. 2). The estimation error is the sum of the measurement error of the position information acquisition device and the movement distance of the user from the position information acquisition time to an arbitrary time later. It can be considered that as the time from the position information acquisition time elapses, the estimation error, that is, the radius of the estimation error circle increases, and the area in which the user exists expands. By doing so, there is an advantage that the estimated position of the user can be easily confirmed. At this time, if a plurality of estimation error circles are used as shown in FIG. 3, there is a high possibility that the user is present in the overlapping portion of the plurality of estimation error circles, that is, the shaded area in FIG. 3, and the position estimation is more accurate. Is possible.

【0036】

If the curve showing how the estimation error increases is called the estimation error curve, it will be as shown in Fig. 4. The estimation error depends on how the user moves. As described above, if the moving speed of the user is known, the magnitude of the estimation error can be known, so a means for acquiring the moving speed of the user is required. For example, the moving speed may be calculated from the displacement of two position information having a time difference. Also, when the user is a worker in the factory and moves only on foot, the estimation error curve is as shown in Fig. 5a. The slope of the estimation error curve is the same as the user's maximum moving speed.

【0037】

Assuming that the user walks at a speed of 4 km / h, the estimation error increases at 4 km / h. Since the estimation error does not become small, the slope of the estimation error curve takes 0 or a positive value. Only this condition should be satisfied, and then the estimation error curve should be determined from the movement condition of the user. Also, when the user is in a car and traveling at a speed of 60 km / h, the slope of the estimation error curve becomes steep as shown in Fig. 5b.

【0038】

One way to determine the user's movement conditions is to set the user's movement status. Further, the moving speed of the user may be measured by the method described below. As a moving speed acquisition means, it is conceivable that the user notifies the system side of the moving speed. It is conceivable that the user inputs his / her movement speed to the device through the location information acquisition device and notifies the system side. For example, if the user knows his / her walking speed, he / she may notify the walking speed together with the position information. It is also conceivable to attach a speed detector to the user and acquire the moving speed of the user together with the position information. For example, when the user moves by car, it is conceivable to acquire the moving speed of the car at the same time as acquiring the position information. This can be achieved by obtaining the moving speed information from the speedometer of the automobile. At this time, if the moving speed of the automobile is 60 km / h, the estimation error becomes large at 60 km / h. Also, when the user knows that he / she is walking, he / she can measure how many steps he / she has walked per unit time by attaching a pedometer (registered trademark) to the user, and can calculate the moving speed by multiplying the stride length. This movement speed may be acquired at the same time as the acquisition.

【0039】

In addition, when the user works in-house in the morning and travels in the afternoon, the slope of the estimation error curve in the morning is 4 km / h, and in the afternoon it is 60 km / h, so it can be linked with the scheduler. Good. The slope of the estimation error curve determined in this way does not have to be linear as shown in FIG.

【0040】

If the estimation error is set, the position information and the error at an arbitrary time can be obtained. As a result, position information from a plurality of different types of position information acquisition devices acquired at different times can be compared simply by an error at an arbitrary time, and highly accurate position information can be easily selected. It will be possible.

【0041】

Further, if a plurality of position information and accuracy at an arbitrary time can be estimated, if an estimation error circle is drawn, there is a high possibility that the user is in the overlapping portion, and it is possible to obtain more accurate position information.

【0042】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the position information estimation method of the present invention will be described in detail with reference to one of the realized examples, the action history recording system as an example. In this action history recording system, it is possible to acquire the position information of a plurality of users having different types of position information acquisition devices and record the position. This action history recording system compares the position information acquired by an arbitrary position information acquisition device with the position information acquired by another type of position information acquisition device, and obtains the most accurate position information at an arbitrary time. It has a function to display on the position display unit. First, the case of handling the position information of the user α having the position information acquisition devices A1 and A2, the user β having the position information acquisition device B, and the user γ having the position information acquisition device C will be described as follows.

【0043】

FIG. 7 is a functional block configuration diagram of the action history recording system. 7-1, 7-2, 7-3, 7-4 are different types of location information acquisition devices that can acquire location information, and 7-5 receives location information and measurement error notified from the location information acquisition device. It is a location information receiving unit.

【0044】

Hereinafter, the user α will be mainly described. User α has two location information acquisition devices, but the location information acquisition device is not limited to two, and any number of location information acquisition devices can be used in 7-5 location information receivers. Can be connected with. Here, as an example, two location information acquisition devices for the user α, for a total of four cases, will be described.

【0045】

7-6 is an error calculation unit that calculates the estimation error from the position information received in 7-5, 7-7 is an error comparison unit that compares errors, and 7-8 is a more accurate position from multiple position information. Information is stored in the position information calculation unit, 7-9 is the position display unit that displays the current position, 7-10 is the user information recording unit that stores the user's information, and 7-11 is the latest position record that records the latest position of the user. Section 7-12 is a history recording section that records the user's action history. 7-13, 7-14, and 7-15 are movement speed acquisition devices that detect the movement speeds of users α, β, and γ. 7-16 is a control unit that controls the entire action history recording system.

【0046】

Hereinafter, the operation of this action history recording system will be described step by step. Immediately after the system is started, through the flow of FIG. 8, as initial values, "not measured" is recorded in the latest position display unit of users α, β, and γ, and "unmeasured" is recorded in the position information of the latest position recording unit. No history is recorded in the history recording unit.

【0047】

The subsequent operation will be described with reference to FIG. From the position information acquisition devices of 7-2, 7-3, and 7-4, the position information such as the user name and the latitude and longitude of the user and the measurement error are notified to the 7-5 position information receiving unit non-simultaneously. .. When the location information is notified in 9-2, which user's location information is determined in 9-3 and 9-4. In 9-3, the case where it is determined to be the position information of the user α will be described below as an example.

【0048】

Determine if the latest position of user α needs to be updated in 9-5. If necessary, display the latest position information in the user α column of the 7-10 position display section in 9-8, overwrite the latest position in the 7-11 latest position recording section in 9-11, and record 9-14. In 7-12, the latest position is added and recorded in the history recording section. As shown in Tables 1 and 2, what is recorded in the latest position recording unit and history recording unit in 9-11 and 9-14 is the user name, position information, acquisition time, and estimation error curve.

【0049】

[table 1]

<img file="JP2002257564A_D0001.tif" />【0050】

[Table 2]

<img file="JP2002257564A_D0002.tif" />【0051】

The condition judgment in 9-5, 9-6, and 9-7 in FIG. 9 will be described in FIG. 10 by taking the process in 9-5 as an example. 9-5 is the case of user α, but 9-6 and 9-7 are the cases of user β and γ, respectively, and these are the same judgments. It is assumed that the position information of the user α is notified from the 7-1 position information acquisition device A1 in 10-2. This position information is called position information 1 for the sake of simplicity. In 10-3, it is judged whether it is the first location information notification after startup, and if this is the first notification, it will be updated in 10-7. When it is not the first time, comparison with the latest location information (called location information 2) is performed. First, in 10-4, the estimation error function of user α is called from the user information recording unit. The subsequent processing is the same regardless of whether the location information acquisition device that has notified the location information 2 is the 7-1 location information acquisition device A1 or the 7-2 location information acquisition device A2.

【0052】

Here, as an example, it is assumed that the measurement error of the position information acquisition device used for acquiring the position information of the user α changes depending on the position of the user α. Further, the movement speed of the user α will be described by taking as an example the case where the movement speed is notified by the movement speed acquisition device A (7-13 in FIG. 7) used to acquire the position information of the user α.

【0053】

For user α, when the latest position information is recorded in 9-11, Table 3 stored in the 7-6 error calculation unit is read out. Read the measurement error from the user's position information.

【0054】

[Table 3]

<img file="JP2002257564A_D0003.tif" />【0055】

As shown in Table 3, the measurement error can be read by inputting the position. Next, the 7-13 movement speed acquisition device A notifies the movement speed of the user α, so that the estimation error curve is calculated and recorded. The estimation error curve may be selected by the operator or may be selected according to the schedule. The estimated error curve of user α in the database of Table 1 is described as type (a), which shows one estimated error curve as shown in FIG. 3, for example.

【0056】

The selection of the estimation error curve that matches the latest position information (position information 2) is performed in 10-4 of Fig. 10. In 10-5, the estimation error of position information 2 is calculated from the time (time 1) when the estimation error curve and position information 2 are acquired by the 7-6 error calculation unit. Since the estimation error of position information 1 is equal to the measurement error, the measurement error of position information 1 and the estimation error of position information 2 are compared in 10-6 by the 7-7 error comparison unit. When the estimation error of the position information 2 is large, it is considered that the accuracy of the position information 1 is higher, so the position information 1 is selected and updated in 10-7. When the measurement error of the position information 1 is larger, it is considered that the accuracy of the position information 2 is higher, so the process ends without updating as it is.

【0057】

So far, we have described a method of comparing a plurality of position information and selecting a more accurate position information. As described with reference to FIG. 3, the action history recording system can be similarly constructed by using a method of obtaining more accurate position information by combining a plurality of position information. For this purpose, the estimation error circle 1 of the position information 1 and the estimation error circle 2 of the position information 2 are drawn as shown in FIG. 11, and the estimation error circle 1 of the position information 1 and the estimation error circle 2 of the position information 2 are overlapped. It is necessary that there is a part, and the overlapping part is presumed to be highly accurate position information. Specifically, the comparison between the position information 1 and the position information 2 in 10-6 may be changed to a method of estimating the position information by the combination of the position information 1 and the position information 2. As shown in FIG. 11, if the xy coordinates are taken appropriately, the area inside the estimation error circles 1 and 2 is expressed by the following equation.

【0058】

Estimated error circle 1: (x-a1)²+ (Y-b1)²&lt;r1²Estimated error circle 2: (x-a2)²+ (y-b2)²&lt;r2² 【0059】

By solving these equations at the same time, the overlapping part of the estimated error circle 1 and the estimated error circle 2 in the shaded area in FIG. 11 can be found. Therefore, more accurate position information can be obtained from the position information 1 and the position information 2. If the estimated error circle 1 and the estimated error circle 2 do not overlap, the comparison may be performed by the above method.

【0060】

[Effect of the invention]

As described in detail above, according to the present invention, it is possible to simply compare a plurality of position information in consideration of the elapsed time and the error from the position information acquisition time to the present. As a result, highly accurate position information can be acquired. In addition, when acquiring a movement record, there is no chance that a time zone of unknown position will be created because the expiration date is not set.

[Simple explanation of drawings]

[Figure 1]

This is a display screen showing the user's position in an area at time t0 (at the time of acquiring position information).

[Figure 2]

This is a display screen showing the position of the user at time t1 as an area.

[Fig. 3]

This is a display screen in which position estimation based on a plurality of estimation error circles is represented by an area.

[Fig. 4]

It is a graph which shows the relationship between the estimation error and time.

[Fig. 5a]

It is a graph of FIG. 4 at the time of walking.

[Fig. 5b]

It is a graph of Fig. 4 when moving by car.

[Fig. 6]

It is another embodiment of the graph of FIG.

[Fig. 7]

It is a block diagram of an action history recording system.

[Fig. 8]

It is a flowchart at the time of starting the action history recording system.

[Fig. 9]

It is a flowchart at the time of starting the action history recording system.

[Fig. 10]

It is a flowchart at the time of updating the latest position of the action history recording system.

[Fig. 11]

It is a display screen by the position information estimation method of this invention.