JP2014062776A - Navigation device, navigation method, and computer program - Google Patents

Abstract

A current position is specified.
A navigation device that provides route guidance to a destination, wherein the route information indicating the route to the destination is acquired, and the position measurement unit that measures the position of the navigation device at a first time. Means for acquiring speed information indicating the moving speed of the navigation device measured using the speed sensor, and position estimating means for estimating the position of the navigation device on the route at the first time based on the route information and the speed information. And a current position specifying means for comparing the position measured by the position measuring means with the position estimated by the position estimating means, and specifying any one position as the current position of the navigation device at the first time; Display means for displaying the current position specified by the current position specifying means.
[Selection] Figure 2

Description

  The present invention relates to a navigation device, a navigation method, and a computer program technology.

  The current position can be measured (hereinafter sometimes referred to as “positioning”) using a satellite positioning system such as GPS (Global Positioning System). However, when GPS is used, the current position cannot be measured at a place where a signal cannot be received from a GPS satellite such as a tunnel. In such a case, the in-vehicle navigation device mounted on the vehicle acquires azimuth information and vehicle speed information from an azimuth sensor and an acceleration sensor provided in the vehicle, and estimates the current position (for example, Patent Document 1).

JP 2011-13381 A

  However, there is a case where the navigation device cannot acquire the direction information from the direction sensor provided in the vehicle. For example, recent mobile computers such as mobile phones and smartphones are equipped with a GPS receiver and can indicate the current position or guide a route to a destination. However, this mobile computer may not be able to acquire azimuth information from an azimuth sensor provided in the vehicle, unlike in-vehicle navigation that is previously installed in the vehicle.

  An object of the present invention is to provide a navigation device, a navigation method, and a computer program that specify a current position with relatively high accuracy.

  Another object of the present invention is to provide a navigation device, a navigation method, and a computer program for estimating the current position even when the current position cannot be measured and direction information cannot be acquired.

  A navigation device that provides route guidance based on a route to a destination according to an embodiment of the present invention, measures a position of the navigation device at a first time, and obtains route information indicating the route to the destination. Position measuring means, means for acquiring speed information indicating the moving speed of the navigation device measured using the speed sensor, and estimating the position of the navigation device on the route at the first time based on the route information and the speed information A position estimation unit, a position measured by the position measurement unit, and a position estimated by the position estimation unit, and a current position that identifies one of the positions as the current position of the navigation device at the first time It has a specifying means and a display means for displaying the current position specified by the current position specifying means.

  According to the present invention, even when the current position cannot be measured and the azimuth cannot be acquired, the current position can be estimated.

  In addition, according to the present invention, it is possible to specify a current position with relatively high accuracy.

1 is a block diagram showing a configuration of a navigation device 1. FIG. 2 is a block diagram illustrating a functional configuration of the navigation device 1. FIG. It is the image figure which plotted the route and the position in each time. It is a conceptual diagram of the process which removes the GPS position and vehicle speed position presumed to be inaccurate. It is a flowchart of the process which the position estimation means 31 estimates the present position. It is a flowchart of the process which calculates a vehicle speed position. It is a conceptual diagram of the 1st method of determining a reference position. It is a flowchart of the 1st method of determining a reference position. It is a conceptual diagram of the 2nd method of determining a reference position. It is a flowchart of the 2nd method of determining a reference position.

  Hereinafter, an embodiment of a navigation device that estimates a current position will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the navigation device 1.

  The navigation apparatus 1 includes a CPU (Central Processing Unit) 12, a memory 13, a GPS module 11, a wireless communication module 17, a storage device 14, an input device 15, a display device 16, and a general-purpose IF (Interface) 18. With. These elements 11 to 18 are connected by a bus 19 capable of bidirectional data communication.

  The CPU 12 reads out a computer program (hereinafter referred to as “program”) held in the storage device 14 and develops it in the memory 13. And CPU12 implement | achieves the various functions mentioned later by reading and executing the program expand | deployed to the memory 13. FIG.

  The storage device 14 holds various programs and data. The storage device 14 is configured by, for example, a flash memory or an HDD (Hard Disk Drive).

  The GPS module 11 receives a GPS signal from a GPS satellite 3 that is a satellite positioning system, and measures the current position based on information included in the GPS signal. The GPS module 11 generates GPS information 101 including measurement time, current position (longitude and latitude), and the like. The GPS module 11 notifies the CPU 12 of the generated GPS information 101. When the GPS module 11 cannot receive a GPS signal, the GPS module 11 may notify the CPU 12 to that effect.

  The wireless communication module 17 controls transmission / reception of wireless signals. The wireless communication module 17 receives a wireless signal and transmits information included in the wireless signal to the CPU 12 or transmits information transmitted from the CPU 12 on the wireless signal. The wireless communication module 17 is a module compliant with, for example, the WiFi standard or the MIT-2000 standard. The wireless communication module 17 transmits / receives data related to navigation processing to / from the server 5 through the network 90, for example.

  The display device 16 displays the image information transmitted from the CPU 12. The display device 16 is configured by, for example, a liquid crystal display or an organic EL display.

  The input device 15 converts an operation from the user into an input signal and transmits it to the CPU 12. The input device 15 is configured by, for example, a physical button or a touch panel display.

  The general-purpose IF 18 is an IF for connecting the navigation device 1 and an external device. Various external devices are connected to the general-purpose IF 18. In this embodiment, the external device is a vehicle 7. The CPU 12 can transmit and receive signals to and from the vehicle 7 through the general-purpose IF 18 and a predetermined IF 91 provided in the vehicle 7. For example, the general-purpose IF 18 may be a proprietary IF or an IF that conforms to the USB (Universal Serial Bus) standard. For example, the navigation apparatus 1 acquires the vehicle speed information 102 (see FIG. 2) from the vehicle speed sensor mounted on the vehicle 7 through the general-purpose IF 18 and the predetermined IF 91.

  FIG. 2 is a block diagram showing a functional configuration of the navigation device 1. These functions are realized by executing predetermined programs in the CPU 12.

  The navigation device 1 includes GPS information acquisition means 35, vehicle speed information acquisition means 36, route information acquisition means 37, map information acquisition means 38, position estimation means 31, and reference position determination means 33.

  The GPS information acquisition unit 35 acquires GPS information 101 from the GPS module 11. As described above, the GPS information 101 includes information on the measurement time and the current position (longitude and latitude). Hereinafter, the position specified from the GPS information 101 is referred to as a GPS position. When the GPS module 11 cannot receive a GPS signal, the GPS information acquisition unit 35 acquires a notification to that effect. Note that the current position may be measured by a method other than GPS. For example, the current position may be measured by using radio waves from a WiFi access point or using radio waves from a mobile phone base station.

  The vehicle speed information acquisition unit 36 acquires the vehicle speed information 102 from, for example, a vehicle speed sensor mounted on the vehicle 7. The vehicle speed information 102 includes information indicating the speed of the vehicle 7 at a certain time. Since the navigation device 1 moves with the vehicle 7, the moving speed of the navigation device 1 is equal to the speed of the vehicle 7.

  The route information acquisition unit 37 acquires the route information 103 from the departure place to the destination, for example, from the server 5 via the wireless communication module 17. The route information 103 includes, for example, information indicating a route connecting from the departure place to the destination, which is generated by a predetermined route search engine. The information indicating the route may be constituted by, for example, a continuous road link from the departure place to the destination. Instead of acquiring the route information 103 from the server 5, the navigation device 1 may have a route search engine, and the route information 103 may be calculated inside the navigation device 1.

  The map information acquisition means 38 acquires the map information 104 of a predetermined area from the server 5, for example, via the wireless communication module 17. The map information 104 includes, for example, information such as a map image, road link configuration, and POI (Point Of Interest). Instead of acquiring the map information 104 from the server 5, the map information 104 is stored in the storage device 14 of the navigation apparatus 1, and the map information acquisition unit 38 stores the map information of a predetermined area from the storage device 14. 104 may be acquired.

  The display processing unit 39 generates an image and causes the display device 16 to display the image. For example, the display processing unit 39 generates an image in which the route to the destination and the current position are superimposed on the road map image, and displays the image on the display device 16.

  The position estimation means 31 estimates the current position from a plurality of current position candidates. The position estimation unit 31 estimates the current position from, for example, the GPS position obtained from the GPS information 101 and the position obtained from the vehicle speed information 102 and the route information 103 (hereinafter referred to as “vehicle speed position”). When the GPS information 101 can be acquired, the position estimating unit 31 may adopt the GPS position obtained from the GPS information 101 as the current position. When the GPS information 101 cannot be acquired, the position estimation unit 31 may adopt the vehicle speed position obtained from the vehicle speed information 102 and the route information 103 as the current position. The position estimation unit 31 may correct the GPS position by performing a map matching process using the map information 104 when obtaining the GPS position from the GPS information 101. Hereinafter, further description will be given with reference to the drawings.

  FIG. 3 is an image diagram in which the route and the current position at each time are plotted.

In FIG. 3, a tunnel 202 and a branch 212 exist on the route 301 to the destination. FIG. 3 shows a position P _n (t _n ) at each time t _n (n is a positive integer). That is, the position P _n indicates the position at the time t _n .

A general road 201 can receive GPS signals. Therefore, the position estimation means 31 estimates positions P _{1 to} P ₃ and P _{7 to} P _{10 based} on the GPS position.

Within the tunnel 202, GPS signals cannot be received. Therefore, the position estimation means 31 estimates the positions P _{4 to} P _{6 based} on the vehicle speed position. Next, a method for calculating the position P ₅ using vehicle position.

The position estimation unit 31 periodically acquires the vehicle speed through the vehicle speed information acquisition unit 36. And the position estimation means 31 uses the vehicle speed periodically acquired from the time t ₁ of the reference position P ₁ (P _s ) to the current time t ₅ , between the time t ₁ and the current time t _5. Average vehicle speed V _ave is calculated. Details of the reference position will be described later.

The position estimation unit 31 calculates the moving distance _{L a} from the time _{t 1} to time _{t 5.} That is, L _a = V _ave (t ₅ −t ₁ ) is obtained. The position estimating means 31, from a position _{P 1} at time _{t 1,} the position moved by the movement distance _{L a} along the route, the vehicle speed position Pv ₅ at time _{t 5.} Then, because it can not receive a GPS signal at time _{t 5,} the position estimation means 31 adopts the speed position Pv _5, the current position _{P 5.}

That is, if a route is refracted or bent in the middle as shown in FIG. 3, the vehicle speed position Pv ₅ is not a point where you move linearly moving distance L _a from the position P _1, the route from the position P ₁ along a point that has moved the movement distance L _a and.

  Thereby, even if the navigation apparatus 1 does not use direction information from a direction sensor (gyro sensor) or the like mounted on the vehicle 7, it is possible to estimate the current position in a place where a GPS signal cannot be received.

Further, as described below, the position estimating means 31 may estimate the position in the tunnel based on the GPS position without using the vehicle speed. For example, in FIG. 3, it is assumed that the positions P ₁ (t ₁ ), P ₂ (t ₂ ), and P ₃ (t ₃ ) are all GPS positions specified by the GPS signal. In this case, the position estimation means 31 uses the moving distance L _b from the reference position P ₁ to the GPS position P ₃ near the tunnel entrance via the GPS position P ₂ , from time t ₁ to time t ₃ . The average speed _Vb is calculated. That is, V _b = L _b / (t ₃ −t ₁ ) is calculated. And the position estimation means 31 estimates the present position of the own vehicle in the tunnel which cannot receive a GPS signal using this average speed _Vb . For example, the position estimation means 31 estimates the current position of the vehicle in the tunnel, assuming that the average speed _Vb is continued in the tunnel. That is, when the current time and _{t 5,} the position estimating means 31 calculates the moving distance _L c = _{V b} × from GPS position _{P 3 (t 5 -t 3)} . The position estimating means 31, the GPS position _{P 3,} the position moved by the movement distance _{L c} along the route, and the position Px ₅ at the current time _{t 5.} The position estimation unit 31 adopts the position Px _5, the current position _{P 5.}

  Thereby, the navigation apparatus 1 can estimate the present position in the place which cannot receive a GPS signal, without using vehicle speed information.

  Even if the position estimation unit 31 can acquire the GPS information 101, if the distance between the GPS position and the vehicle speed position at the same time (positional deviation) is greater than a predetermined distance, the GPS position at this time And the vehicle speed position may be removed so that the current position is not specified. This is because the correct current position cannot be estimated because it is impossible to determine which of the GPS position and the vehicle speed position is correct. Alternatively, any position that is considered more likely may be set as the current position. Hereinafter, further description will be given with reference to the drawings.

  FIG. 4 is a conceptual diagram of a process for removing a GPS position and a vehicle speed position with low accuracy.

Position estimating means 31, for example, the distance between the GPS position Pg _n and the vehicle speed position Pv _n at the predetermined time _{t n} is greater than the predetermined distance _{Δe 1 (| Pg n -Pv n} |> Δe 1) It is determined whether or not. Here, when | Pg _n −Pv _n |> Δe ₁ is satisfied, the position estimation unit 31 removes the GPS position and the vehicle speed position at this time.

In FIG. 4, for example, any each GPS position _Pg 4 _{~Pg 6} shown, which deviates significantly from the vehicle speed position _Pv 4 _{~Pv 6.} Therefore, the position estimation means 31 removes the GPS positions Pg _{4 to} Pg ₆ and the vehicle speed positions Pv _{4 to} Pv ₆ (see region 320). In this case, the current position _P 4 to P ₆ at time _t 4 ~t ₆ is not output.

  Thereby, it is possible to prevent the current position with low accuracy from being displayed. In addition, it is possible to prevent a current position with low accuracy from adversely affecting subsequent calculation of the current position.

  In addition, the position estimation unit 31 may set any one of the GPS position and the vehicle speed position that is considered to be more likely as the current position. For example, the position estimation unit 31 may set the GPS position as the current position when the GPS position is not greatly deviated from the route, and may set the vehicle speed position as the current position when the GPS position is greatly deviated from the route.

  FIG. 5 is a flowchart of processing for estimating the current position by the position estimating means 31.

Position estimating means 31 calculates the vehicle speed position Pv _n at time _{t n} (S101). Details of this calculation method will be described later.

  The position estimation unit 31 tries to acquire the GPS information 101 through the GPS information acquisition unit 35 (S102). And the position estimation means 31 determines whether the GPS information 101 was able to be acquired (S103).

  First, a case where the GPS information 101 cannot be acquired in step S103 (S103: NO) will be described. In this case, the position estimation means 31 determines whether or not the time during which the GPS information 101 cannot be acquired continues for a predetermined time or more (S110).

  If the time during which the GPS information 101 cannot be acquired does not continue for a predetermined time or longer (S110: NO), the position estimating unit 31 proceeds to step S121.

If the time can not be acquired GPS information 101 is followed by more than a predetermined time (S110: YES), the position estimation means 31 adopts the speed position Pv _n, the current position _{P n} at the time _{t n} (S 111), step S120 Proceed to

Next, the case where the GPS information 101 can be acquired in step S103 (S103: YES) will be described. In this case, the position estimation means 31 calculates the GPS position Pg _n at time _{t n} (S104).

Then, the position estimating means 31 determines whether or not | GPS position Pg _n −vehicle speed position Pv _n | <Δe ₁ is satisfied (S105). That is, the position estimating unit 31 determines that the GPS position Pg _n and the vehicle speed position Pv _n is not an abnormal value.

| GPS position Pg _n - speed position _Pv n | <If .DELTA.e ₁ is not satisfied (S105: NO), the position estimating means 31, to remove the GPS position Pg _n and the vehicle speed position Pv _n (S106), the step S121 move on.

| GPS position Pg _n - speed position _Pv n | <If .DELTA.e ₁ is satisfied (S105: YES), the position estimating means 31, the GPS position Pg _n, adopted to the current position _{P n} at the time _{t n} (S107 ), The process proceeds to step S120.

In step S120, the position estimation means 31 outputs the current position _{P n} at time _{t n} (S120). For example, the current position P _n output here is displayed on the navigation screen. Then, the position estimation means 31 adds 1 to n (n ← n + 1) (S121), and returns to step S101. That is, the process from step S101 is repeated at the next time tn _{+ 1} .

  FIG. 6 is a flowchart of a process for calculating the vehicle speed position.

Position estimating means 31 obtains a reference position _{P s,} a reference time _{t s} when located in its reference position _{P s} from the memory 13 (S201).

Position estimating means 31, by using a periodically obtained vehicle speed, it calculates the average vehicle speed _{V ave} of until the current time _{t n} from the reference time _{t s} (S202).

The position estimation unit 31 calculates the movement distance L _a = V _ave (t _n −t _s ) (S203). That is, the position estimation means 31 calculates the moving distance _{L a} to the current time _{t n} from the reference time _{t s.}

Position estimating means 31 from the reference position P _s, and calculates a point where moving the moving distance L _a along the route, the vehicle speed position Pv _n of the point current time t _n (S204), the process ends . Thus, it is possible to calculate the vehicle speed position Pv _n at the current time _{t n.}

  As described above, the position estimation unit 31 calculates the vehicle speed position based on the movement distance from the reference position. Therefore, it is preferable that the reference position is as accurate as possible. Therefore, the navigation device 1 includes reference position determination means 33 that determines a reference position (see FIG. 2). Hereinafter, the reference position determination unit 33 will be described.

  FIG. 7 is a conceptual diagram of a first method for determining the reference position.

  As shown in FIG. 7, for example, after passing through the tunnel 202, the GPS position and the vehicle speed position may deviate greatly. In this case, as described above, it is difficult to determine which of the GPS position and the vehicle speed position is likely. Therefore, as shown in FIG. 4, it is difficult to estimate the current position. Therefore, the reference position determination means 33 determines the reference position by the following first method.

  The reference position determination means 33 according to the first method determines the likelihood of the GPS position by comparing the movement distance calculated from the GPS position and the movement distance calculated from the vehicle speed position at the same time. That is, the reference position determination unit 33 first calculates the movement distance of the GPS position and the movement distance of the vehicle speed position at the same time. Then, the reference position determination unit 33 calculates the difference between the movement distance calculated from the GPS position and the movement distance calculated from the vehicle speed position. Then, the reference position determination unit 33 determines that the GPS position is likely when the state in which the difference is smaller than a predetermined value continues for a predetermined time or more (or a predetermined number of times or more). Then, the reference position determining means 33 determines this GPS position as the reference position. Thereafter, the position estimation means 31 estimates the vehicle speed position from the movement distance from the reference position. Hereinafter, a more detailed description will be given with reference to FIG.

The reference position determination unit 33 calculates the movement distance Lg ₈ = | Pg ₈ −Pg ₇ | from the GPS positions Pg ₇ and Pg _{8 at} time t ₈ . Similarly, the reference position determination unit 33 calculates the movement distance Lv ₈ = | Pv ₈ −Pv ₇ | from the vehicle speed positions Pv ₇ and Pv _{8 at} time t ₈ . Then, the reference position determination unit 33 determines whether or not the difference between Lg ₈ and Lv ₈ is smaller than a predetermined value Δe ₂ (| Lg ₈ −Lv ₈ | <Δe ₂ ). Reference position determining means 33, the same determination even at time _{t 9} and _{t 10.} Here, the reference position determination unit 33 determines that the GPS position Pg is obtained when the difference is smaller than the predetermined value Δe ₂ at any time t ₈ , t ₉ , t ₁₀ (that is, a predetermined time or a predetermined number of times). ₁₀ is determined to be probable, and this Pg ₁₀ is set as a reference position 401 of the subsequent vehicle speed position. That is, the reference position is updated.

  Note that, when there is no large difference between the GPS position and the vehicle speed position, the above determination is always satisfied, so the reference position 401 is updated as needed. In addition, the update of the reference position by the reference position determination unit 33 may be executed only when a large deviation occurs between the GPS position and the vehicle speed position.

  Thereby, even if a large divergence occurs between the GPS position and the vehicle speed position temporarily, the reference position is updated and this divergence is resolved. That is, the accuracy of the vehicle speed position can be increased.

  FIG. 8 is a flowchart of the first method for determining the reference position.

Reference position determining means 33 calculates the vehicle speed position Pv _n at the current time point _{t n} (S301). This process is the same as the process shown in FIG.

  The reference position determination unit 33 tries to acquire the GPS information 101 through the GPS information acquisition unit 35 (S302). Then, the reference position determination unit 33 determines whether or not the GPS information 101 has been acquired (S303).

  When the GPS information 101 cannot be acquired (S303: NO), the reference position determination unit 33 cannot determine the reference position this time, and thus proceeds to step S310.

If you can get the GPS information 101 (S303: YES), the reference position determination unit 33 identifies the GPS position tg _n at time _{t n} (S304).

The reference position determination unit 33 calculates a movement distance Lg _n = | Pg _n −Pg _n−1 | based on the GPS position (S305).

The reference position determination unit 33 calculates a movement distance Lv _n = | Pv _n −Pv _n−1 | based on the vehicle speed position (S306).

The reference position determination unit 33 determines whether or not | Lg _n −Lv _n | <Δe ₂ has continued (or has been established) for a predetermined time (or a predetermined number of times) (S307).

If | Lg _n −Lv _n | <Δe ₂ has not yet continued for a predetermined time (or a predetermined number of times) (S307: NO), the reference position determination unit 33 proceeds to step S310.

| _Lg n _-Lv n | if <.DELTA.e ₃ is continued for a predetermined time (or a predetermined number of times) or more (S307: YES), the reference position determination unit 33 as GPS position Pg _n is approximately correct, this GPS position the pg _n, and the reference position _{P s} (S308), the process proceeds to step S310.

In step S310, the reference position determination unit 33 adds 1 to n (S310), and returns to step S301. That is, the position correcting unit repeats the process from step S301 at the next time t _{n + 1} .

  FIG. 9 is a conceptual diagram of a second method for determining the reference position. In the second method, the reference position is determined by a method different from the first method.

  The reference position determination unit 33 according to the second method determines the likelihood of the GPS position depending on whether or not the GPS position is almost on (along) the route 301. For example, the reference position determination unit 33 determines whether or not the GPS position exists within an area having a predetermined width D centered on the route. Then, the reference position determination unit 33 determines that the GPS position is almost accurate when the GPS position is almost on the route 301 for a predetermined time or more (or a predetermined number of times). Then, the reference position determining means 33 determines this GPS position as the reference position. Thereafter, the position estimation means 31 calculates the vehicle speed position as the movement distance from this reference position. Hereinafter, it will be described in more detail with reference to FIG.

The reference position determination unit 33 determines whether or not the GPS position Pg ₇ exists within the range of the width D with the route 301 as the center. Similarly, the reference position determination unit 33 determines whether the GPS positions Pg ₈ , Pg ₉ , and Pg ₁₀ are also present within the range of the width D with the route 301 as the center. Here, the reference position determining means 33, when any of the GPS positions Pg _{7 to} Pg ₁₀ (that is, continuously four times or more) is present within the range of the width D around the route 301, The GPS position Pg ₁₀ is determined to be probable, and this Pg ₁₀ is set as a reference position 401 for the subsequent speed position. That is, the reference position is updated.

  Note that, when there is no large difference between the GPS position and the vehicle speed position, the above determination is always satisfied, so the reference position 402 is updated as needed. In addition, the update of the reference position by the reference position determination unit 33 may be executed only when a large deviation occurs between the GPS position and the vehicle speed position.

  Thereby, even if a large divergence occurs between the GPS position and the vehicle speed position temporarily, the reference position is updated and this divergence is resolved. That is, the accuracy of the vehicle speed position can be increased.

  FIG. 10 is a flowchart of the second method for determining the reference position.

  The reference position determination unit 33 tries to acquire the GPS information 101 through the GPS information acquisition unit 35 (S401). Then, the reference position determination unit 33 determines whether or not the GPS information 101 has been acquired (S402).

  When the GPS information 101 cannot be acquired (S402: NO), the reference position determination unit 33 cannot determine the reference position this time, and thus proceeds to step S410.

If you can get the GPS information 101 (S402: YES), the reference position determination unit 33 identifies the GPS position tg _n at time _{t n} (S403).

Reference position determining means 33, a state in which the GPS position Pg _n is within the range of width D around the route and determines whether or not the subsequent predetermined time (or a predetermined number of times) or more (S404).

If the state where the GPS position Pg _n is within the range of width D around the root does not continue yet predetermined time (or a predetermined number of times) or more (S404: NO), the reference position determination unit 33, the process proceeds to step S410 .

If the state where the GPS position Pg _n is within the range of width D around the route is continued for a predetermined time (or a predetermined number of times) or more (S404: YES), the reference position determination unit 33, GPS position Pg _n is as is almost accurate, the GPS position Pg _n, and the reference position _{P s} (S405), the process proceeds to step S410.

In step S410, the reference position determination unit 33 adds 1 to n (S410), and returns to step S401. That is, the position correcting unit repeats the process from step S401 at the next time t _{n + 1} .

  The above-described embodiments of the present invention are examples for explaining the present invention, and are not intended to limit the scope of the present invention only to those embodiments. Those skilled in the art can implement the present invention in various other modes without departing from the gist of the present invention.

The method determines whether substantially riding (in line) to the GPS position Pg _n is on the route may be other than the above. For example, distance extending perpendicularly to route GPS position Pg _n, may be determined by whether or not smaller than the threshold value.

DESCRIPTION OF SYMBOLS 1 ... Navigation apparatus 31 ... Position estimation means 33 ... Reference | standard position determination means 101 ... GPS information 102 ... Vehicle speed information 103 ... Route information 104 ... Map information

Claims (8)

A navigation device that provides route guidance based on a route to a destination,
Means for obtaining route information indicating a route to the destination;
Position measuring means for measuring the position of the navigation device at a first time;
Means for acquiring speed information indicating the moving speed of the navigation device, measured using a speed sensor;
Position estimating means for estimating a position on the route at the first time of the navigation device based on the route information and the speed information;
The current position specifying means for comparing the position measured by the position measuring means with the position estimated by the position estimating means and specifying any one position as the current position of the navigation device at the first time. When,
A navigation device comprising display means for displaying the current position specified by the current position specifying means.
The navigation apparatus according to claim 1, wherein the current position specifying means specifies the position estimated by the position estimating means as the current position when the position measuring means cannot measure the position of the navigation device.
The current position specifying means, when the position measuring means can measure the position of the navigation device, the distance between the position measured by the position measuring means and the position estimated by the position estimating means is a predetermined value 3. The navigation device according to claim 1, wherein a position measured by the position measurement unit is specified as the current position when the distance is smaller than the predetermined value.
The current position specifying means, when the position measuring means can measure the position of the navigation device, the distance between the position measured by the position measuring means and the position estimated by the position estimating means is a predetermined value The position measured by the position measuring means is not specified as the current position when the distance is not smaller than the predetermined value. The navigation device described.
The position estimating means uses a position on the route of the navigation device at a second time before the first time as a reference position, and on the route at the first time based on the route information and the speed information. The navigation device according to any one of claims 1 to 4, wherein the position is estimated.
The position estimating means is based on a position moved from the reference position along the route indicated by the route information at a speed indicated by the speed information from the second time to the first time. The navigation device according to claim 5, wherein a position on the route at the first time is estimated.
A navigation method by a navigation device that provides route guidance based on a route to a destination,
Obtain route information indicating the route to the destination,
Measuring the position of the navigation device at a first time by a predetermined position measuring means;
Obtaining speed information indicating the moving speed of the navigation device measured using a speed sensor;
Based on the route information and the speed information, estimate a position on the route at the first time of the navigation device,
Comparing the position measured by the position measuring means with the estimated position, and specifying one of the positions as the current position at the first time;
A navigation method for displaying the specified current position.
A computer program for a navigation device that provides route guidance based on a route to a destination, and when executed on the navigation device,
Obtain route information indicating the route to the destination,
Obtaining position information indicating the position of the navigation device at a first time measured by a predetermined position measuring means;
Obtaining speed information indicating the moving speed of the navigation device measured using a speed sensor;
Based on the route information and the speed information, estimate a position on the route at the first time of the navigation device,
Comparing the position measured by the position measuring means with the estimated position, and specifying one of the positions as the current position at the first time;
A computer program that causes the navigation device to display the specified current position on a display unit.

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