JP2008203016A - Personal digital assistant, and control method of portable information terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a personal digital assistant capable of confirming reliability of an output present position. <P>SOLUTION: The personal digital assistant includes a first current position operation part for operating a first current position by receiving a position information signal from a position information satellite (step S42); a second current position operation part for operating a second current position by detecting a moving distance and a moving azimuth (step S46); an operation part selection means for determining whether the first current position operation part can operate the first current position, selecting the first current position operation part in the operable case, and selecting the second current position operation part in the inoperable case (step S43); an error estimation amount operation part for operating an error estimation amount of the second current position, when the second current position operation part is selected by the operation part selection means (step S47-S50); and a current position output part for outputting the second current position and the error estimation amount, when the second current position operation part is selected by the operation part selection means (step S51, S46). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention includes a first current position calculator that receives a position information signal transmitted from a position information satellite and calculates a current position, and a second that calculates a second current position by detecting a moving distance and a moving direction. The present invention relates to a portable information terminal including current position calculation means having a current position calculation unit.

In this type of portable information terminal, positioning means for positioning the current position by satellite navigation, storage means for storing the coordinates and positioning time of the positioning point detected by the positioning means, and data stored in the storage means An estimation unit that estimates a current position based on the display unit and a display unit that draws a map around the current position, the estimation unit obtains a progress vector from data between past positioning points stored in the storage unit; A navigation device is known in which the current position is estimated and displayed on the extension line of the progress vector based on the elapsed time from the latest positioning time (see, for example, Patent Document 1).

In addition, a person who has lost or stolen a mobile wireless terminal can access the Internet network using a personal terminal and enter the phone number and password of the mobile wireless terminal on the loss handling homepage of the mobile phone company. By inputting, the lost processing server searches the position information storage memory for the last detected position of the corresponding portable wireless terminal or reads the communication log from the communication log memory and notifies it on the homepage, and a predetermined fee. There is also known a loss processing system for portable wireless terminals that collects the charges (for example, see Patent Document 2).
JP 2005-291785 A JP 2001-309434 A

However, in the conventional example described in Patent Document 1, the coordinates of the current position and the positioning time detected by the navigation means by the positioning means are stored in the storage means, and the past positioning points stored in the storage means Since the current position is estimated on the extension line of the progress vector based on the elapsed time from the latest positioning time, the current position displayed on the display device is accurate by satellite navigation. There is an unsolved problem that it is impossible to determine whether the current position is the current position or the current position by estimation, and the reliability of the display information cannot be determined.

Further, in the conventional example described in Patent Document 2, a person who has lost or stolen a mobile wireless terminal accesses the Internet network and enters a phone number and a mobile phone company's loss processing homepage. Unresolved issue that the last detected position can be notified on the homepage by entering the password, but it is not possible to determine whether the notified position is an accurate position or not There is.

Therefore, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and an object thereof is to provide a portable information terminal capable of confirming the reliability of the notified current position.

In order to achieve the above object, a portable information terminal according to the first technical means of the present invention receives a position information signal transmitted from a position information satellite and calculates a first current position. The first current position can be calculated by the position calculating unit, the second current position calculating unit that detects the moving distance and moving direction and calculates the second current position, and the first current position calculating unit. Whether or not
When the calculation is possible, the first current position calculation unit is selected, and when the calculation is not possible, the second current position calculation unit is selected, and the calculation unit selection unit selects the second current position calculation unit. When the current position calculation unit is selected, an error estimation amount calculation unit that calculates an error estimation amount of the second current position calculated by the second current position calculation unit; A current position output unit is provided that outputs the second current position and the error estimation amount calculated by the error estimation amount calculation unit when the current position calculation unit is selected.

In the first technical means, for example, a first current position calculation unit configured by a GPS positioning unit,
For example, a second current position calculation unit that performs autonomous positioning calculation is provided, and the second is calculated by the calculation unit selection means.
When the current position calculation unit is selected, the error estimation amount calculation unit calculates the error estimation amount of the second current position, and the calculated error estimation amount together with the second current position is displayed and printed on the current position output unit. Since the output such as information transmission is performed, the reliability of the second current position calculated by the second current position calculation unit can be recognized based on the output error estimation amount.

The portable information terminal according to the second technical means of the present invention includes a first current position calculation unit that receives a position information signal transmitted from a position information satellite and calculates a first current position; A second current position calculation unit for calculating a second current position by detecting a distance and a moving direction; and determining whether the first current position can be calculated by the first current position calculation unit. Selecting the first current position calculation unit when the calculation is possible, and selecting the second current position calculation unit when the calculation is not possible; and the calculation unit selection unit An error estimation amount calculation unit that calculates an error estimation amount of the second current position calculated by the second current position calculation unit when the current position calculation unit is selected, and a current position notification request source When the notification request is received, the second current position is calculated by the calculation unit selection means. A current position transmission unit configured to transmit the second current position and the error estimation amount calculated by the error estimation amount calculation unit to the current position notification request source when a calculation unit is selected; Yes.

In the second technical means, in addition to the first technical means described above, when the current position transmitting unit receives a current position notification request from another device, the second technical position calculated by the second current position calculating unit is used. Since the error estimation amount is transmitted to the current position notification request source together with the current position, the current position notification request source can determine the reliability of the second current position based on the error estimation amount.
Furthermore, in the portable information terminal according to the third technical means of the present invention, in the first or second technical means, the error estimation amount calculation unit is the calculation unit selection unit, and the first current position is calculated. The error estimator is configured to increase in accordance with an increase in elapsed time from the time point when the calculation unit is selected to the state where the second current position calculation unit is selected. It is said.

In the third technical means, the error estimation amount is set in a state where the second current position calculation unit is selected, that is, in the first state.
As the elapsed time from the time when the first current position cannot be measured by the current position calculation unit becomes longer, the estimated error amount increases, and a decrease in reliability can be recognized.
Furthermore, in the portable information terminal according to the fourth technical means of the present invention, in the first or second technical means, the second current position calculation unit has an angular velocity detection unit for detecting at least an angular velocity. Then, the error estimation amount calculation unit is selected from the time when the calculation unit selection means switches from the state in which the first current position calculation unit is selected to the state in which the second current position calculation unit is selected. The error estimator is configured to increase in accordance with an increase in the number of changes in angular velocity detected by the angular velocity detector.

In the fourth technical means, when the second current position calculation unit has an angular velocity detection unit such as a gyro and calculates the second current position, the fluctuation of the angular velocity detected by the angular velocity detection unit. As the number of times increases, the estimated error amount increases, and a decrease in reliability can be recognized.
Still further, in the portable information terminal according to the fifth technical means of the present invention, in the first or second technical means, the second current position calculation unit has at least an acceleration detection unit for detecting acceleration. The error estimation amount calculation unit is the calculation unit selection means, wherein the calculation unit selecting means switches from the state of selecting the first current position calculation unit to the state of selecting the second current position calculation unit. The error estimation amount is increased according to an increase in the number of acceleration fluctuations detected by the acceleration detection unit.

In the fifth technical means, when the second current position calculation unit has an acceleration detection unit and calculates the second current position based on the detected acceleration, the number of acceleration fluctuations is increased. As the error estimate increases, the estimated error amount increases, so that a decrease in reliability can be recognized.
In the portable information terminal according to the sixth technical means of the present invention, in any one of the first to fifth technical means, the second current position calculation unit detects at least acceleration. And the error estimation amount calculation unit is based on the acceleration detected by the acceleration detection unit,
If it is determined whether the user who owns the portable information terminal is walking or moving by means of mobile traffic, and it is determined that the user is walking, the calculation unit selecting means, The error in accordance with an increase in the number of acceleration fluctuations detected by the acceleration detection unit from the time when the state of selecting the first current position calculation unit is switched to the state of selecting the second current position calculation unit. A state in which the estimated amount is increased, and when the user determines that the user is moving by means of mobile traffic, the first current position calculation unit is selected by the calculation unit selection unit The error estimation amount is increased in accordance with an increase in elapsed time from when the second current position calculation unit is switched to a state in which the second current position calculation unit is selected.

In the sixth technical means, since the angular velocity information and the acceleration information change between when the vehicle is moving and when walking, the optimum error estimation amount is calculated by changing the calculation of the error estimation amount according to the change. be able to.
Furthermore, the control method of the portable information terminal according to the seventh technical means of the present invention is a first current position calculation unit that receives a position information signal transmitted from a position information satellite and calculates a first current position. A second current position calculation unit that calculates a second current position by detecting a movement distance and a movement direction;
And determining whether or not the first current position calculation unit can calculate the first current position, and when the calculation is possible, the first current position calculation unit determines whether the first current position can be calculated. When a current position calculation unit is selected, a calculation unit selection step of selecting the second current position calculation unit when the calculation is not possible, and a second current position calculation unit selected in the calculation unit selection step, An error estimation amount calculation step of calculating an error estimation amount of the second current position calculated by the second current position calculation unit; and when the second current position calculation unit is selected in the calculation unit selection step, A current position output step for outputting the second current position and the estimated error amount calculated in the estimated error amount calculation step.

In the seventh technical means, it is possible to obtain the same effects as those of the first technical means described above.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment when the present invention is applied to a portable information terminal.
In the figure, 1 is a mobile phone having a navigation function, PDA (Personal Digital Assis).
The portable information terminal 1 includes a CPU 2 and an arithmetic processing unit 4 including a clock unit 3 for calculating the current time.

The arithmetic processing unit 4 receives a position information signal transmitted from a position information satellite 6 received by a GPS (Global Positioning System) receiving unit 5 and detects the number of steps for performing an autonomous positioning calculation. Detection signals of the acceleration sensor 7 and the angular velocity sensor 8 such as a gyro for detecting a two-dimensional angular velocity in the horizontal direction for detecting the azimuth are AD converters 9 and 1, respectively.
0 is input.

The arithmetic processing unit 4 includes a mobile phone control processing program that performs a mobile phone function, a navigation processing program that performs navigation display, and a GPS positioning calculation that performs GPS positioning calculation based on the position information signal received by the GPS receiving unit 5. ROM for storing various processing programs to be executed by the CPU 2 of the arithmetic processing unit 4 such as an autonomous positioning calculation program, an autonomous positioning arithmetic program for performing autonomous positioning calculation, and an RA for storing data required in the arithmetic process of the arithmetic processing unit 4
M12 is connected. The ROM 11 also stores an error estimation amount calculation storage table that indicates the relationship between the elapsed time from the time when the first current position is calculated in the GPS positioning process used in the error estimation amount calculation process described later and the error estimation amount. is doing. As shown in FIG. 2, this error estimation amount calculation storage table takes the elapsed time from the elapsed time when the first current position is calculated on the horizontal axis, the error estimated amount E on the vertical axis, and the elapsed time. The characteristic line L1 is set so that the error estimation amount E increases as the length increases.

Further, the arithmetic processing unit 4 is an RF that performs wireless communication with a nearby base station using a mobile phone function.
A transmission / reception unit 13 is connected, and a display unit 14 composed of, for example, a liquid crystal display for displaying navigation display information, predetermined menu information, e-mail information and the like calculated by the arithmetic processing unit 4 is connected. Yes.
Furthermore, a key input unit 15, a microphone 16, a speaker 17, and a vibration motor 18 are connected to the arithmetic processing unit 4.

In the arithmetic processing unit 4, the CPU 2 performs a mobile phone control process (not shown) for performing voice transmission / reception processing and e-mail transmission / reception processing similar to those of a normal mobile phone, GPS positioning calculation processing as a first current position calculation unit, and A navigation process that activates an autonomous positioning calculation process as a second current position calculation unit and performs navigation display, and a calculation of the first current position in the GPS positioning calculation process when a position information transmission request is received from the outside The GPS positioning calculation process and the autonomous positioning calculation process are selected, and when the autonomous positioning calculation process is selected, the second current position calculated by the autonomous positioning calculation process is selected. At least a position information transmission process for calculating an error estimation amount and transmitting it together with the second current position is executed.

The navigation process executed by the CPU 2 is started when the start of the navigation process is selected on a menu screen (not shown). As shown in FIG. 3, first, in step S1, the second positioning process of the RAM 12 is performed by the autonomous positioning calculation process. The second current position stored in the current position storage area is read as the current position, and then the process proceeds to step S2 to generate navigation display information based on the read current position and the map information in the vicinity thereof, In step S3, the generated navigation display information is supplied to and displayed on the display unit 14, and then, in step S4, it is determined whether or not the end of the navigation process is selected on a menu screen (not shown). When the end of the process is not selected, the step S
Returning to 1, when the end of the navigation process is selected, the process proceeds to step S5, where G
After stopping the PS positioning calculation process and the autonomous positioning calculation process, the navigation process is terminated.

As shown in FIG. 4, the GPS positioning calculation process executed by the CPU 2 is executed as a timer interruption process at predetermined time intervals. First, in step S11, it is determined whether or not an initial state at the time of power-on is determined. If it is in the initial state when the power is turned on, the process proceeds to step S12 to set a positioning calculation start time for receiving the position information signal transmitted from the position information satellite 6 and starting the GPS positioning calculation, and then to step S15. If the current time is not the positioning calculation start time set in step S12, the process proceeds to step S14 if the current time is not the positioning calculation start time. After the transition, the GPS positioning flag F1 is set to “0”, the timer interrupt process is terminated, the routine returns to the predetermined main program, and the positioning calculation start time is reached. The Rutoki proceeds to step S15.

In this step S15, a GPS reception command for performing a reception processing operation for receiving a position information signal transmitted from the position information satellite 6 is output to the GPS receiver 5, and then in step S16.
To determine whether or not a position information signal has been input from the GPS receiver 5, and if no position information signal has been input, the process proceeds to step S17 to count the number of times the position information signal has not been received. The count value N is incremented, and then the process proceeds to step S18 to determine whether or not the non-reception count value N has reached a predetermined value Ns. If N <Ns, the process returns to step S16, where N ≧ Ns. If there is, the process proceeds to step S19, the GPS positioning flag F1 is set to “0”, and the timer interrupt process is terminated.

If the determination result in step S16 is that the position information signal is input from the GPS receiver 5, the process proceeds to step S20, where the first latitude and longitude coordinates represented by the position information signal are displayed. The current position P1 is calculated, and the positioning time T1 is calculated. Then, the process proceeds to step S21, and the calculated first current position P1 and positioning time T1 are updated to the first current position information storage area formed in the RAM 12. Memorize, then move to step S22 and GPS
After the positioning flag F1 is set to “1”, the timer interrupt process is terminated and the process returns to a predetermined main program.

The GPS positioning calculation processing and GPS reception unit 5 in FIG. 4 corresponds to the first current position calculation unit.
Further, as shown in FIG. 5, the autonomous positioning calculation process is executed as a timer interrupt process at predetermined time intervals. First, immediately after the GPS positioning flag F1 is switched from “0” to “1” in step S31. If it is immediately after the GPS positioning flag F1 is switched from “0” to “1”, the process proceeds to step S32 and is stored in the first current position storage area of the RAM 12. The first current position P1 is read, and this is used as the second current position P2 in the RAM 12
Updated to the second current position storage area formed in step S33, and then the process proceeds to step S33.
If the positioning flag F1 is not immediately after switching from “0” to “1”, the process directly goes to step S3.
3

In this step S33, the angular velocity θv detected by the angular velocity sensor 8 is read, and then the process proceeds to step S34 to integrate the angular velocity θv to calculate the azimuth θ, and then the process proceeds to step S35.
In this step S35, the vertical acceleration G detected by the acceleration sensor 7 is read, and then the process proceeds to step S36 to calculate the number of steps P from the change pattern of the vertical acceleration G, and then the process proceeds to step S37 to obtain the calculated number of steps P. The moving distance L is calculated by multiplying the preset stride W, and then the process proceeds to step S38, where the calculated azimuth θ and moving distance L and the second current position storage area of the RAM 12 are stored. A new second current position P2 is calculated based on the current position P2, and this is updated and stored in the second current position storage area of the RAM 12, and then the timer interrupt process is terminated and the predetermined main program is executed. Return.

The autonomous positioning calculation process and the vertical acceleration sensor 7 and the angular velocity sensor 8 in FIG. 5 correspond to the second current position calculation unit.
Further, as shown in FIG. 6, the position information transmission process executed by the CPU 2 is executed as a timer interruption process at predetermined time intervals. First, in step S41, whether an e-mail including a position information transmission request command has been received. When the e-mail containing the position information transmission request command is not received, the timer interruption process is terminated as it is, and the process returns to the predetermined main program. When the e-mail including the position information request command is received The process proceeds to step S42.

In this step S42, the above-described GPS positioning calculation process of FIG. 4 is started, the GPS receiving unit 5 is activated, the position information signal is received from the position information satellite 6, and the positioning calculation based on the position information signal is performed. Go to calculate the first current position P1, and then move to step S43 to determine whether or not the first current position P1 has been calculated in the GPS positioning calculation processing of step S42, the first current position When P1 is calculated, the process proceeds to step S44, and the calculated first current position P1 is written in an e-mail reply mail including the received position information transmission request command, and then the process proceeds to step S45 to return a reply mail. , The timer interrupt process is terminated and the process returns to a predetermined main program.

If the determination result of step S43 is that the first current position P1 is not calculated, the process proceeds to step S46, the above-described autonomous positioning calculation process is executed to calculate the second current position P2, and then step S47. , The positioning time T1 obtained by positioning the first current position P1 stored in the first current position storage area of the RAM 12 is read, and then the process proceeds to step S48, where the current time calculated by the clock unit 3 is read. The time Tr is read, and then the process proceeds to step S49, and the elapsed time T _L (= Tr−T1) from the time when the previous first current position P1 is calculated by subtracting the positioning time T1 from the current time Tr is calculated. Then, the process proceeds to step S50.

In step S50, the estimated error amount E is calculated by referring to the error estimation amount calculation storage table stored in the ROM 11 based on the elapsed time T _L , and then the process proceeds to step S51 to calculate the calculated first value. The current position P2 of 2 and the estimated error amount E are written in an e-mail reply mail including the received position information transmission request command, and then the process proceeds to step S45.
The position information transmission process in FIG. 6 corresponds to the current position output unit and the current position transmission unit.

Next, the operation of the above embodiment will be described.
When the portable information terminal 1 is turned on, the GPS positioning calculation process shown in FIG. 4 and the autonomous positioning calculation process shown in FIG. 5 are started.
For this reason, the GPS positioning calculation process is in the initial state after the power is turned on.
The start time of PS positioning calculation is set (step S12), and then the GPS receiver 5 receives G
A PS reception command is output, and the GPS reception unit 5 starts reception processing of the position information signal from the position information satellite 6 (step S15).

When the position information signal of the position information satellite 6 is input from the GPS receiving unit 5, the first current position P1 composed of latitude and longitude coordinates is calculated based on the input position information signal, and
GPS positioning time T1 is calculated (step S20), and the calculated first current position P1 and GP
The S positioning time T1 is updated and stored in the first current position information storage area of the RAM 12 (step S2
1) Next, after the GPS positioning flag F1 is set to "1", the timer interrupt process is terminated and the process returns to the predetermined main program.

At this time, the portable information terminal 1 is used indoors, and the position information signal from the position information satellite 6 is
If the position information signal cannot be received by the PS receiver 5 or if the position information signal cannot be received due to a fading phenomenon in the valley of the building group, the position information signal is not input from the GPS receiver 5 to the CPU 2, so the non-reception count value N is incremented. Then, the process waits until the non-reception count value N becomes equal to or larger than a preset setting value Ns.
The GPS positioning flag F1 is reset to “0” to end the timer interrupt process and return to a predetermined main program.

On the other hand, in the autonomous positioning calculation process of FIG. 5, in the GPS positioning calculation process described above, immediately after the GPS positioning flag F1 is inverted from “0” to “1”, it is immediately after the first current position P1 is calculated. Sometimes, the first current position P1 stored in the first current position information storage area of the RAM 12 is read and stored as the second current position in the second current position information storage area of the RAM 12. Then, the timer interrupt process is terminated (step S32).

However, when the GPS positioning flag F1 is not immediately after switching from “0” to “1”, the angular velocity θv detected by the angular velocity sensor 8 is read (step S33), and the angular velocity θv is integrated to calculate the azimuth θ. (Step S34), for example, the vertical acceleration G detected by the acceleration sensor 7 worn on the user's waist is read (Step S35), and then the number of steps P is calculated based on the vertical acceleration G (Step S36). Moving distance L with stride W
(Step S37), the second current position P2 is calculated based on the calculated movement distance L and direction θ, and the calculated second current position P2 is stored in the second current position information storage area of the RAM 12. Update storage is performed (step S38).

As described above, by executing the GPS positioning calculation process of FIG. 4 and the autonomous positioning calculation process of step S5, the first current position P1 and the GPS positioning time T1 are updated every predetermined time, and this GPS positioning is also performed. Until the first current position P1 and the GPS positioning time T1 in the calculation process are updated, the second current position P2 is updated by the azimuth θ and the movement distance L by the autonomous positioning calculation process.

In this state, for example, by executing a predetermined navigation start operation such as displaying a menu screen on the display unit 14 and selecting the start of the navigation process, the CPU 2 starts executing the navigation process of FIG.
In this navigation process, first, the second current position P2 stored in the RAM 12 in the navigation process of FIG. 3 is read as the current position (step S1), and based on the read current position and map information in the vicinity thereof. Navigation display information is generated (step S2),
The generated navigation display information is output to the display unit 14 to perform a navigation display indicating the current position and a nearby map (step S3).

On the other hand, when the portable information terminal 1 is lost or stolen, or when it is desired to know the current position of the owner of the portable information terminal 1, a personal information connected to another portable information terminal 1 or the Internet. An e-mail including a position information transmission request command is transmitted from the computer or the like to the portable information terminal 1 that wants to know the current position.
When this e-mail is received by the portable information terminal 1, in the position information transmission process of FIG.
The GPS positioning calculation process is activated to calculate the first current position P1 (step S42), and when the first current position P1 is calculated, the calculated first current position is written in a reply mail (
Step S44) Next, by sending a reply mail, an accurate current position is obtained by receiving a reply mail in which the first current position is written in the current position transmission request source that is the sender of the e-mail. can do.

On the other hand, if the first current position P1 cannot be calculated when the GPS positioning calculation process is performed in step S42, the second current position P2 is calculated by the autonomous positioning calculation process (
Next, the GPS positioning time T1 of the first current position P1 calculated by the previous GPS positioning calculation process stored in the RAM 12 is read (step S47).
Next, the current time Tr is read from the clock unit 3 (step S48), and the GP is calculated from the current time Tr.
The elapsed time _TL from the previous GPS positioning time T1 is calculated by subtracting the S positioning time T1 (step S49).

Next, an error estimation amount E is calculated with reference to the error estimation amount calculation storage table shown in FIG. 2 stored in the ROM 11 based on the elapsed time T _L (step S50). This error estimation amount E becomes a large value as the elapsed time T _L increases.
Then, the second current position P2 and the error estimation amount E are written in the reply mail (step S51).
Then, by sending a reply mail, the current position transmission requester, which is the sender of the electronic mail, receives the reply mail in which the second current position P2 and the error estimation amount E are written. The current position of the portable information terminal 1 and its error range can be grasped from the current position P2 of 2 and the error estimation amount E, and the reliability of the second current position P2 can be recognized.

Thus, in the above embodiment, when the portable information terminal 1 is turned on,
When the GPS positioning calculation process and the autonomous positioning calculation process are executed, and the user carries the portable information terminal 1 and moves, the GPS positioning calculation process is executed at every predetermined time with the current position changing every moment. Thus, it is possible to calculate an accurate current position, and it is possible to reduce the power consumption of the portable information terminal 1 by reducing the operation of the GPS receiving unit 5 with high power consumption. In addition, by calculating the second current position in the autonomous positioning calculation process after the first current position P1 is calculated in the GPS positioning calculation process until the next calculation of the first current position P1,
The first current position can be corrected, and the current position according to the movement status of the user who has the portable information terminal 1 can be calculated.

Therefore, by starting the navigation process, the display unit 14 is based on the first current position P1 and the second current position P2 calculated by the GPS positioning calculation process and the autonomous positioning calculation process.
A navigation display can be displayed.
Furthermore, when an e-mail containing a current position transmission request command is received from the outside,
When the first current position P1 is calculated by the S positioning calculation process and the position information signal from the position information satellite 6 is received and the first current position P1 can be calculated, the first current position P1 is returned to the reply mail. By writing and transmitting to the current position transmission request source, it is possible to grasp the accurate current position of the portable information terminal 1 that the current position transmission request source wants to know.

However, when the first current position P1 cannot be calculated by the GPS positioning calculation process, the second current position P2 calculated based on the azimuth θ, the number of steps P, and the moving distance L determined by the step length W by the autonomous positioning calculation process is returned as a reply mail. At this time, the first GPS positioning calculation process
An elapsed time _TL from the GPS positioning time T1 calculated from the current position P1 is calculated, and an error estimated amount E is calculated by referring to the error estimated amount calculation storage table based on the elapsed time _TL. Since the error estimated amount E is written in the reply mail together with the second current position and transmitted, the second current position P2 and the error estimated amount E can be grasped by the current position transmission request source. That the portable information terminal 1 is present in the vicinity of the current position P2, and the reliability of the second current position P2 can be recognized.

In the first embodiment, the case where the current position transmission process is performed when an e-mail including the current position transmission request command is received has been described. However, the present embodiment is not limited to this, and the current position transmission request is not limited thereto. When a packet including a command is received, a response packet including the first current position P1 or the second current position P2 and the error estimation amount E is generated and transmitted to the transmission source of the packet. The point is that the first current position P1 or the second current position P2 and the error estimation amount E may be transmitted to the current position transmission request source when a current position transmission request is received from the outside.

In the first embodiment, the case where the error estimation amount E is calculated only when there is a request for transmitting the current position from the outside has been described. However, the present invention is not limited to this. When the second current position P2 calculated by the positioning calculation process is adopted, an error estimation amount E is calculated at the same time and is included in the navigation display information and displayed in a specific area of the display unit 14. In this case, the user can grasp the reliability of the navigation display.

Further, in the first embodiment, the case where the error estimation amount E is calculated based on the elapsed time T _L from the GPS positioning time T1 when the first current position P1 is calculated by the GPS positioning calculation processing has been described. However, the present invention is not limited to this, and the error estimation amount E is calculated as the number of changes in the vertical angular velocity G detected by the vertical acceleration sensor 7 increases as shown in FIG. As shown in FIG. 8, a storage table for increasing the error estimation amount E according to the number of changes in the angular velocity θv detected by the angular velocity sensor 8, or a cumulative value of the vertical acceleration G or the angular velocity θv, as shown in FIG. It is possible to use a storage table that increases the error estimation amount E in accordance with the increase in.

Furthermore, in the above-described embodiment, the case where there is one type of error estimation amount calculation storage table has been described. However, the present invention is not limited to this, and the CPU 2 executes the storage table selection process shown in FIG. It may be. In this storage table selection process, first, in step S61, the vertical acceleration G detected by the vertical acceleration sensor 7 is read, and then in step S61.
The process moves to 62 and Fourier transform is performed on the read vertical acceleration G to calculate a power spectrum distribution. Then, the process moves to Step S63, and the portable information terminal 1 is changed based on the pattern of the vertical acceleration G and the power spectrum distribution. It is determined whether the possessed user is walking or riding on a moving transportation means such as an automobile or a railroad, and if the user is walking, the process proceeds to step S64 to calculate an error estimation amount. As the storage table, a storage table in which the error estimation amount E increases as the number of changes in the vertical acceleration G shown in FIG. 7 or a storage table in which the error estimation amount E increases as the cumulative value of the vertical acceleration G increases is shown. When the process is completed after the selection and the user is on the moving transportation means, the process proceeds to step S65, and the GPS positioning time T1 at which the first current position shown in FIG. Error estimated amount E is the process ends select the memory table which increases according to an increase in the elapsed time et. According to this storage table selection process, the optimum error estimation amount E can be calculated according to the user's moving method.

Incidentally, in step S63, in order to determine the time of walking and the time of getting on the transportation means based on the vertical acceleration G, the pattern of the vertical acceleration G during walking is as shown in FIG. 10 (a). Since a vibration is input to the vertical acceleration sensor 7 sometimes, a large amplitude continues for a predetermined time every time it lands, and the power spectrum distribution obtained by Fourier transforming the vertical acceleration G is 0.5 Hz to as shown in FIG. Although a peak is observed in the range of 2 Hz, when the vehicle is in a car, the vertical angular velocity G detected by the vertical acceleration sensor 7 is such that the vertical acceleration G is always as shown in FIG. As shown in FIG. 11B, only white noise is observed in the power spectrum distribution obtained by Fourier transform of the vertical acceleration G, which fluctuates with a relatively small amplitude.

Therefore, it can be determined from the pattern of the vertical acceleration G and the power spectrum distribution whether the vehicle is moving while walking.

It is a block diagram which shows one Embodiment of this invention. It is a characteristic diagram which shows the memory table for error estimation amount calculation. It is a flowchart which shows an example of the navigation processing procedure performed with CPU. It is a flowchart which shows an example of the GPS positioning calculation processing procedure performed with CPU. It is a flowchart which shows an example of the autonomous positioning calculation processing procedure performed with CPU. It is a flowchart which shows an example of the position information transmission process procedure performed with CPU. It is a characteristic diagram which shows the other example of the memory table for error estimation amount calculation. It is a characteristic diagram which shows the further another example of the memory table for error estimation amount calculation. It is a flowchart which shows an example of the storage table selection processing procedure performed with CPU. It is explanatory drawing which shows the vertical acceleration pattern and power spectrum distribution at the time of a walk. It is explanatory drawing which shows the vertical acceleration pattern at the time of movement with a motor vehicle etc., and power spectrum distribution.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Portable information terminal, 2 ... CPU, 3 ... Clock part, 4 ... Arithmetic processing part, 5 ... GPS receiving part,
6 ... Position information satellite, 7 ... Vertical acceleration sensor, 8 ... Angular velocity sensor, 11 ... ROM, 12 ... R
AM, 14 ... display section

Claims (7)

A first current position calculation unit that receives a position information signal transmitted from a position information satellite and calculates a first current position;
A second current position calculation unit that detects a movement distance and a movement direction and calculates a second current position;
When it is determined whether the first current position can be calculated by the first current position calculation unit, and when the calculation is possible, the first current position calculation unit is selected, and when the calculation is not possible Calculating unit selecting means for selecting the second current position calculating unit;
An error estimation amount calculation unit that calculates an error estimation amount of the second current position calculated by the second current position calculation unit when the second current position calculation unit is selected by the calculation unit selection unit;
A current position output unit that outputs the second current position and the error estimation amount calculated by the error estimation amount calculation unit when the second current position calculation unit is selected by the calculation unit selection unit; A portable information terminal characterized by that. A first current position calculation unit that receives a position information signal transmitted from a position information satellite and calculates a first current position;
A second current position calculation unit that detects a movement distance and a movement direction and calculates a second current position;
When it is determined whether the first current position can be calculated by the first current position calculation unit, and when the calculation is possible, the first current position calculation unit is selected, and when the calculation is not possible Calculating unit selecting means for selecting the second current position calculating unit;
An error estimation amount calculation unit that calculates an error estimation amount of the second current position calculated by the second current position calculation unit when the second current position calculation unit is selected by the calculation unit selection unit;
When the current position notification request is received from the current position notification request source, the calculation unit selecting means
A current position transmitter that transmits the second current position and the error estimated amount calculated by the error estimated amount calculator to the current position notification request source when the current position calculator is selected. A portable information terminal characterized by The estimated error amount calculation unit is an elapsed time from when the calculation unit selection unit switches from the state in which the first current position calculation unit is selected to the state in which the second current position calculation unit is selected. The portable information terminal according to claim 1, wherein the estimated error amount is increased in accordance with an increase in the mobile information terminal. The second current position calculation unit includes an angular velocity detection unit that detects at least an angular velocity, and the error estimation amount calculation unit selects the first current position calculation unit by the calculation unit selection unit. The error estimator is configured to increase in accordance with an increase in the number of changes in angular velocity detected by the angular velocity detector from the time when the state is switched to a state in which the second current position calculator is selected. The portable information terminal according to claim 1 or 2. The second current position calculation unit includes an acceleration detection unit that detects at least acceleration, and the error estimation amount calculation unit selects the first current position calculation unit by the calculation unit selection unit. The error estimator is configured to increase in accordance with an increase in the number of acceleration fluctuations detected by the acceleration detector from the time when the state is switched to a state in which the second current position calculator is selected. The portable information terminal according to claim 1 or 2. The second current position calculation unit includes an acceleration detection unit that detects at least acceleration,
The error estimator calculating unit determines whether the user who owns the portable information terminal is walking or moving by means of mobile traffic based on the acceleration detected by the acceleration detecting unit,
When it is determined that the user is walking, the calculation unit selection unit switches from the state in which the first current position calculation unit is selected to the state in which the second current position calculation unit is selected. Configured to increase the error estimation amount according to an increase in the number of acceleration fluctuations detected by the acceleration detection unit from the time point,
When it is determined that the user is moving by means of mobile traffic, the second current position calculation unit is changed from the state in which the calculation unit selection unit selects the first current position calculation unit. The portable information terminal according to claim 1 or 2, wherein the error estimation amount is increased in accordance with an increase in elapsed time from the time of switching to the selection state. A first current position calculator for calculating a first current position by receiving a position information signal transmitted from a position information satellite; and a second for calculating a second current position by detecting a moving distance and a moving direction. A current position calculation unit, and a portable information terminal control method comprising:
When it is determined whether the first current position can be calculated by the first current position calculation unit, and when the calculation is possible, the first current position calculation unit is selected, and when the calculation is not possible A calculation unit selection step of selecting the second current position calculation unit;
An error estimation amount calculation step of calculating an error estimation amount of the second current position calculated by the second current position calculation unit when the second current position calculation unit is selected in the calculation unit selection step;
A current position output step of outputting the second current position and the error estimated amount calculated in the error estimated amount calculating step when the second current position calculating unit is selected in the calculating unit selecting step; A method for controlling a portable information terminal.

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