JP2007003195A - Position detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position detection device capable of acquiring a highly accurate altitude even in a two-dimensional positioning without using a mileage sensor or the like. <P>SOLUTION: This position detection device 1 is equipped with an antenna 2, a GPS receiving processing part 3, a clocking processing part 4, an altitude information storage part 5 and an operation processing part 6. The altitude information storage part 5 stores an altitude map formed by the operation processing part 6. When the GPS receiving processing part performs three-dimensional positioning, the operation processing part 6 updates the altitude map of an area to which the present position belongs in a group of areas by using the longitude, the latitude and/or the altitude of the present position positioned three-dimensionally, and, when the GPS receiving processing part 3 performs two-dimensional positioning, calculates the altitude by using the altitude map of the area to which the present position belongs in the group of areas. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a position detection device for detecting a current position.

  Currently, in various devices such as a car navigation device, a GPS (Global Positioning System) receiver that outputs a current position by receiving radio waves from an artificial satellite is widely used. Such a GPS receiver measures the time required for radio waves respectively transmitted from a plurality of artificial satellites to reach its own device, and the distance from the plurality of artificial satellites to the own device based on these required times. And the current position is calculated based on these distances.

In order for a GPS receiver to perform three-dimensional (longitude, latitude, and altitude) positioning, radio waves from at least four artificial satellites are required. If only radio waves from three artificial satellites can be obtained due to the influence of a building or the like, the GPS receiver can only perform two-dimensional positioning and cannot calculate the altitude.
A GPS navigation device that can determine the position even when the altitude cannot be calculated is known (for example, see Patent Document 1 below).

  The GPS navigation apparatus disclosed in Patent Document 1 includes means for calculating positioning data by receiving GPS satellite radio waves, means for detecting a traveling direction of a vehicle, means for storing map information, and a central processing unit. And altitude calculating means for obtaining altitude data, the altitude calculating means calculates the altitude of the vehicle based on the positioning data obtained from the positioning data calculating means and the position data obtained from the map information, and the altitude data is used as data. The vehicle position is determined based on the altitude data stored in the storage means and when the desired satellite radio wave from the GPS satellite cannot be obtained.

According to this GPS navigation apparatus, even when a desired satellite radio wave from a GPS satellite cannot be obtained, the position of the vehicle can be determined based on altitude data from the data storage means.
However, this GPS navigation apparatus requires means for detecting the traveling direction of the vehicle and means for storing map information. Further, in this GPS navigation device, if the altitude of the automobile changes due to the running of the automobile while the two-dimensional positioning is continued, the error of the altitude data stored in the data storage means becomes large, and the position error becomes large. It gets bigger.

  In order to solve such a problem, the following Patent Document 2 performs three-dimensional positioning based on signals supplied from at least four GPS satellites, stores altitude data of the vehicle, and stores three GPS satellites. Having a GPS receiver that performs two-dimensional positioning using the vehicle altitude data previously stored when a signal is supplied from the vehicle, and using the positioning data of the GPS receiver, Whether the current positioning mode is a three-dimensional positioning mode or a two-dimensional positioning mode in a position detection device that corrects the position of the vehicle obtained based on the vehicle travel distance data and the direction data detected by the direction sensor Based on the determination signal, when it is detected that the 3D positioning mode has been switched to the 2D positioning mode, the calculation of the travel distance is started based on the travel distance data of the vehicle. If the fixed distance is calculated by the distance calculation means and the distance calculation means, the vehicle position data detected by the subsequent two-dimensional positioning data is determined as long as the two-dimensional positioning mode is determined. A position detecting device using a GPS positioning system characterized by having a data selecting means not adopted for correction is described.

  According to this position detection device, it is considered that the accuracy of the altitude data stored in the vehicle is sufficient until the traveling distance after switching from the three-dimensional positioning mode to the two-dimensional positioning mode becomes a certain distance. Therefore, the altitude data is used for correcting the position of the vehicle obtained based on the travel distance data and the direction data of the vehicle detected by the travel distance sensor and the direction sensor. In addition, after the mileage after switching from the 3D positioning mode to the 2D positioning mode becomes a certain distance, it is considered that the accuracy of the altitude data of the previously stored vehicle has become insufficient, This altitude data is not adopted for correcting the vehicle position obtained based on the vehicle travel distance data and the direction data detected by the travel distance sensor and the direction sensor.

  However, this position detection device uses positioning data of the GPS receiver for correcting the position of the vehicle obtained based on the travel distance data and the direction data of the vehicle detected by the travel distance sensor and the direction sensor. In other words, the GPS receiver plays an auxiliary role to the mileage sensor and the direction sensor. That is, this position detection device requires a travel distance sensor and an orientation sensor. In addition, this position detection device requires distance calculation means for calculating the travel distance after switching from the three-dimensional positioning mode to the two-dimensional positioning mode.

JP 63-91583 A (first page, FIG. 1) Japanese Patent Laid-Open No. 4-353787 (1st page, FIG. 1)

  Therefore, in view of the above points, the present invention provides a position detection device capable of obtaining a high-precision altitude even during two-dimensional positioning without using a travel distance sensor, a direction sensor, a distance calculation means, or the like. For the purpose.

  In order to solve the above-described problems, a position detection device according to the present invention receives a radio wave from an artificial satellite to measure the longitude, latitude, and / or altitude of the current position by GPS (Global Positioning System). When the reception processing unit, the altitude information storage unit that records a data structure including a group of recording areas for storing information about the altitude of the group of areas, and the GPS reception processing unit are performing three-dimensional positioning In addition, the information on the altitude of the area to which the current position belongs in the group of areas is updated using the longitude, latitude, and / or altitude of the current position measured by the GPS reception processing unit, and the positioning is performed by the GPS reception processing unit. The longitude, latitude, and altitude of the current position is output to the outside, and the current position within the group of areas belongs when the GPS reception processing unit performs two-dimensional positioning. An arithmetic processing unit that calculates the altitude using information related to the altitude of the area to be output, and outputs the calculated altitude and the longitude and latitude of the current position measured by the GPS reception processing unit to the outside.

  In this position detection device, each of the group of recording areas stores a first value that is the number of times that the GPS reception processing unit has stayed in the area corresponding to the recording area when the GPS reception processing unit performs three-dimensional positioning. When the first field and the GPS reception processing unit are performing three-dimensional positioning, a second value that is a cumulative total of the altitudes measured by the GPS reception processing unit when staying in the area corresponding to the recording area A second field for storing, and when the GPS processing unit performs two-dimensional positioning, the arithmetic processing unit includes information on an altitude of an area to which the current position of the group belongs. The altitude may be calculated by dividing the second value by the first value of the information related to the altitude of the area.

  In addition, when the GPS processing unit performs three-dimensional positioning, when the arithmetic processing unit performs a three-dimensional positioning, when an error in altitude of the current position measured by the GPS receiving processing unit satisfies a predetermined condition, Information regarding the altitude of the area to which the current position belongs may be updated.

  Further, when each of the group of recording areas is in the area corresponding to the recording area when the GPS reception processing section is performing the three-dimensional positioning, the total of the squares of the altitudes measured by the GPS reception processing section when staying in the area corresponding to the recording area. A third field for storing a third value is further included. When the GPS reception processing unit is performing three-dimensional positioning, the arithmetic processing unit is an area to which the current position of the group belongs. You may make it judge whether the error of the height of the present position measured by the GPS reception process part satisfy | fills predetermined | prescribed conditions using the 1st-3rd value in the information regarding an altitude.

  In addition, when the first value in the information related to the altitude of any one of the group of areas reaches a predetermined threshold, the arithmetic processing unit obtains the second obtained by subdividing the area. A second data structure including a second group of recording areas for storing information about the altitude of each group area is created in the altitude information storage unit, and then the same processing as that performed for the group of areas is performed. You may make it carry out also with respect to 2 groups of areas.

  Each of the group of recording areas further includes a fourth field for storing a pointer, and the arithmetic processing unit corresponds a pointer indicating the second data structure to the corresponding area in the group of recording areas. You may make it write in the 4th field of the recording area to perform.

  Each of the second group of recording areas further includes a fifth field for storing the time when the recording area was updated, and the arithmetic processing unit is one of the second group of recording areas. When the recording area is updated, the updated time is stored in the fifth field of the recording area, and the second data structure is deleted when all the recording areas of the second group have not been updated for a predetermined time. You may make it do.

  Further, when the number of stays outside the group of areas reaches a predetermined second threshold, the arithmetic processing unit may perform a process of creating the data structure again.

The best mode for carrying out the present invention will be described below with reference to the drawings. In addition, the same referential mark is attached | subjected to the same component and description is abbreviate | omitted.
FIG. 1 is a diagram showing an outline of a position detection apparatus according to an embodiment of the present invention. As shown in FIG. 1, the position detection device 1 includes an antenna 2, a GPS (Global Positioning System) reception processing unit 3, a time measurement processing unit 4, an altitude information storage unit 5, and a calculation processing unit 6. To do.

  The GPS reception processing unit 3 performs two-dimensional positioning or three-dimensional positioning by receiving radio waves from an artificial satellite (GPS satellite) via the antenna 2. The GPS reception processing unit 3 performs two-dimensional positioning when receiving radio waves from three artificial satellites. The GPS reception processing unit 3 outputs the longitude and latitude of the current position and the current time to the arithmetic processing unit 6 during two-dimensional positioning. Further, the GPS reception processing unit 3 performs three-dimensional positioning when receiving radio waves from four or more artificial satellites. The GPS reception processing unit 3 outputs the longitude, latitude, altitude, and current time of the current position to the arithmetic processing unit 6 at the time of three-dimensional positioning. In the present embodiment, it is assumed that the GPS reception processing unit 3 operates at a predetermined interval.

  The timekeeping processing unit 4 is an RTC (Real Time Clock) or the like that always receives the power from the battery and keeps the time. The time counted by the time measuring unit 4 is appropriately corrected (overwritten) by the arithmetic processing unit 6 with the time output from the GPS reception processing unit 3.

  The altitude information storage unit 5 is a recording medium for storing altitude information (hereinafter referred to as “altitude map”) created by the arithmetic processing unit 6. This altitude map will be described in detail later. The altitude information storage unit 5 may be a non-volatile recording medium (for example, EEPROM) or a volatile recording medium (for example, RAM) that is supplied with backup power from a battery. Also good.

  The arithmetic processing unit 6 creates an altitude map based on the data output from the GPS reception processing unit 3 and stores it in the altitude information storage unit 5. In addition, the arithmetic processing unit 6 is based on the data output from the GPS reception processing unit 3 and / or the altitude map, in the NMEA (National Marine Electronics Association) -0183 format including the current position (longitude and latitude) and the current altitude. The packet is output to the external device. The arithmetic processing unit 6 can be composed of a CPU and firmware (program).

Next, the operation of the position detection device 1 will be described.
FIG. 2 is a flowchart showing the operation of the arithmetic processing unit 6 at the initial time (for example, when the position detection device 1 is first turned on or reset).

  First, the arithmetic processing unit 6 acquires an initial position (step S11). As the initial position, for example, a position measured by the GPS reception processing unit 3 at the initial time may be used, or a position specified by the user via an external device or the like (for example, the user's home position). It may be used. Further, the acquired initial position may be stored in the altitude information storage unit 5.

  Next, the arithmetic processing unit 6 is an altitude map (hereinafter referred to as “wide area map”) that stores information regarding altitudes of a plurality of areas (in the present embodiment, four areas) surrounding the initial position. Or “detail level 0 map”) is created and written into the altitude information storage unit 5 (step S12).

  FIG. 3 is a diagram illustrating an example of a wide area map. In this embodiment, since the four areas surround the initial position, the wide area map has four records respectively corresponding to the four areas as shown in FIG. Each of these four records is a map coordinate (in this embodiment, “0” to “3”) that is a number assigned to each area, and the number of times of staying in each area (an arithmetic processing unit 6 described later) The number of stays (initial value is “0”), the total altitude 1 (the initial value is “0”), the sum of the altitudes obtained when staying in each area, staying in each area Cumulative altitude 2 (initial value is “0”) which is the sum of the squares of altitudes obtained at times, stay count, cumulative altitude 1 and update time which is the time when cumulative altitude 2 is updated, and pointer (initial The value has a field for storing "null").

  FIG. 4 is a diagram showing an initial position on the ground surface and four areas surrounding the initial position. In this embodiment, the map coordinate of the northeast area of the initial position is 0, the map coordinate of the northwest area of the initial position is 1, the map coordinate of the southeast area of the initial position is 2, and the map of the southwest area of the initial position is Let the coordinates be 3. In this embodiment, the initial position is assumed to be included in the area of map coordinate 0.

In the present embodiment, the east-west range of the entire four areas surrounding the initial position is referred to as a wide area of interest east-west range, and the north-south range of the entire four areas surrounding the initial position is referred to as a wide area of interest north-south range. Shall be called. In addition, the length (distance) of the wide area of interest region east-west range is referred to as the wide area of interest region east-west distance, and the length (distance) of the wide area of interest region north-south range is referred to as the wide area of interest region north-south distance. The longitude and latitude of the wide area of interest east-west range and the wide area of interest north-south range, the wide area of interest area east-west distance, and the wide area of interest area north-south distance may be stored in the altitude information storage unit 5 as parameters.
In the present embodiment, the wide area of interest east-west distance and the wide area of interest north-south distance are assumed to be equal, and hereinafter referred to as “wide area of interest region distance”.

In FIG. 4, when the x direction is the east-west direction (the east direction is a positive direction and the west direction is a negative direction) between the longitude of the initial position and the east-west range of the wide area of interest,
(Initial position longitude)
= (Longitude at the east end of the east-west range of the wide area of interest-Longitude of the west end of the east-west area of the wide area of interest) / 2
... (1)
Is established. In addition, if the y direction is the north-south direction (north direction is the positive direction and south direction is the negative direction) between the latitude of the initial position and the wide area of interest north-south range,
(Latitude of initial position)
= (Latitude at the northern end of the wide area of interest)-2
... (2)
Is established.

As will be described in detail later, each area is subdivided into four areas when the number of stays reaches a predetermined threshold (hereinafter referred to as a “detailed area generation determination threshold”). Then, an altitude map (hereinafter referred to as “detail level 1 map”), which is a table for storing information on altitudes of the four subdivided areas, is newly created in the altitude information storage unit 5. The pointer in the record corresponding to the area in which the number of stays in the four areas surrounding the initial position of the four records in the wide area map has reached the detailed area generation determination threshold is changed from null to the detailed level 1 map. Is updated to the start address of.
Note that the four areas at the detailed level 1 are further subdivided when the number of stays reaches the detailed area generation determination threshold.

  FIG. 5 is a diagram illustrating an example of a wide area map and a detail level 1 map. FIG. 5 shows an example of the wide area map and the detailed level 1 map when the area corresponding to the map coordinate 0 among the four areas surrounding the initial position is subdivided.

The initial value of the stay count field in each record of the detailed level 1 map is “0”. After the detail level 1 map is created, the value of each field in the map coordinate 0 record in the wide area map (detail level 0 map) is not updated. In addition, the total number of stays in the area of map coordinate 0 of detail level 1 is
(Total number of stays in the area of map coordinates 0 in detail level 1)
= (Number of stays at map coordinate 0 at detail level 0) x (detailed area generation determination threshold)
+ (Value in the number of stays field in the record at map coordinate 0 of detail level 1)
... (3)
Can be obtained. The total number of stays in the area of the map coordinates 1 to 3 at the detailed level 1 can be obtained in the same manner.

The initial value of the cumulative altitude 1 field in each record of the detailed level 1 map is “0”, and the initial value of the cumulative altitude 2 field in each record of the detailed level 1 map is also “0”. The total altitude 1 of the detailed level 1 map is
(Total level 1 of map coordinates 0 of detail level 1)
= (Cumulative altitude 1 of map coordinates 0 at detail level 0) x (detailed area generation determination threshold)
+ (Cumulative altitude 1 field value in the record of map coordinate 0 of detail level 1)
... (4)
Can be obtained. The total cumulative altitude 1 and the total cumulative altitude 2 of the area of the map coordinates 1 to 3 at the detailed level 1 can be obtained in the same manner.

  FIG. 6 is a diagram illustrating an initial position on the ground surface, four areas surrounding the initial position, and four areas obtained by subdividing areas corresponding to map coordinates 0 out of the four areas surrounding the initial position. It is assumed that the center positions of all four areas of detail level 1 are included in the area of map coordinates 0 of detail level 1.

The distance in the east-west direction and the north-south direction (hereinafter referred to as “basic distance”) of the four areas of detailed level 1 is as follows:
(Basic distance)
= (Wide area of interest distance) >> (detail level value) (5)
Can be obtained. Note that “>>” is a right shift operation, where the basic distance of detail level 1 is c, the wide region of interest distance is b, and the value of the detail level is a, the above equation (5) is
c = b ÷ 2 ^a (6)
Is equivalent to

  Note that, as described above, each of the four areas of detail level 1 is further subdivided into four areas (detail level 2) when the number of stays exceeds a predetermined number of times. Also in this case, the basic distance at the detail level 2 can be obtained using the above formula (5) or (6).

When x direction is east-west direction (east direction is positive direction, west direction is negative direction)
(Detail range 1 x range)
= {(Wide area of interest in x direction east-west range) >> (value of detail level)} / 2
... (7)
Is established. Similarly, when the y direction is north-south direction (north direction is positive direction and south direction is negative direction)
(Detail range 1 y-direction range)
= {(Wide area of interest in y direction north-south range) >> (value of detail level)} / 2
... (8)
Is established.

Using the above values, the longitudes of the center positions (see FIG. 6) of all the four areas of the detail level 1 obtained by subdividing the area of the map coordinate 0 of the detail level 0 are
(Longitude of center position)
= (Longitude of initial position) + (range in the x direction of detail level 1) (9)
It becomes. In addition, the latitudes of the center positions of the four areas of detail level 1 that are subdivided areas of map coordinates 0 of detail level 0 are
(Latitude of center position)
= (Latitude of initial position) + (range in the y direction of detail level 1) (10)
It becomes.

In addition, the longitudes of the center positions of the four areas of detail level 1 that are subdivided areas of map coordinates 1 of detail level 0 are
(Longitude of center position)
= (Longitude of initial position)-(range in the x direction of detail level 1) (11)
It becomes. In addition, the latitudes of the central positions of the four areas of detail level 1 that are subdivided areas of map coordinates 1 of detail level 0 are
(Latitude of the center position of detail level 1)
= (Latitude of initial position) + (range in the y direction of detail level 1) (12)
It becomes.

In addition, the longitudes of the center positions of the four areas of detail level 1 that are subdivided areas of map coordinates 2 of detail level 0 are
(Longitude of center position)
= (Longitude of initial position) + (range of detail level 1 in x direction) (13)
It becomes. In addition, the latitudes of the central positions of the four areas of detail level 1 that are subdivided areas of map coordinates 2 of detail level 0 are
(Latitude of the center position of detail level 1)
= (Latitude of initial position)-(range in the y direction of detail level 1) (14)
It becomes.

In addition, the longitudes of the center positions of the four areas of detail level 1 that are subdivided areas of map coordinates 3 of detail level 0 are
(Longitude of center position)
= (Longitude of initial position)-(range in the x direction of detail level 1) (15)
It becomes. In addition, the latitudes of the center positions of the four areas of detail level 1 that are subdivided areas of map coordinates 3 of detail level 0 are
(Latitude of the center position of detail level 1)
= (Latitude of initial position)-(range in the y direction of detail level 1) (16)
It becomes.

  Even when the four areas of the detail level 1 are further subdivided (detail level 2), the center position can be obtained using the above equations (7) to (16).

  FIG. 7 is a flowchart showing an operation performed by the arithmetic processing unit 6 at predetermined intervals. The interval value may be stored as a parameter in the altitude information storage unit 5. In the present embodiment, this interval is the same as the operation interval of the GPS reception processing unit 3, and the arithmetic processing unit 6 and the GPS reception processing unit 3 operate in synchronization.

  First, the arithmetic processing unit 6 performs three-dimensional positioning (receives radio waves from four or more artificial satellites) by the GPS reception processing unit 3 or performs two-dimensional positioning (three artificial satellites). It is checked whether a radio wave is received from the satellite (step S21). The arithmetic processing unit 6 moves the process to step S22 when the GPS reception processing unit 3 performs three-dimensional positioning, and performs processing when the GPS reception processing unit 3 performs two-dimensional positioning. To step S30.

When the GPS reception processing unit 3 performs the three-dimensional positioning, the arithmetic processing unit 6 checks whether or not the error of the altitude measured by the three-dimensional positioning satisfies a predetermined condition (step S22). Then, when the three-dimensional positioning altitude error satisfies the predetermined condition, the arithmetic processing unit 6 moves the process to step S23, and when the three-dimensional positioning altitude error does not satisfy the predetermined condition. Moves the process to step S29. Whether or not the error of the altitude measured in three dimensions satisfies a predetermined condition, for example, the value of the total altitude 1 field in the record corresponding to the area to which the current position (the position measured in three dimensions) belongs, Using the value of the altitude 2 field, the value of the stay frequency field, and a threshold (hereinafter referred to as “abnormal altitude removal determination threshold”),



The determination may be made as follows. Here, the abnormal altitude removal determination threshold value may be stored in the altitude information storage unit 5 as a parameter. In addition, the standard deviation obtained from the value of the cumulative altitude 1 field and the value of the cumulative altitude 2 field in the record corresponding to the area to which the current position belongs, whether or not the error of the altitude measured in three dimensions is satisfied. You may make it judge using.

In the above, the area to which the current position belongs can be obtained as follows.
x direction is east-west direction (east direction is positive direction, west direction is negative direction), y direction is north-south direction (north direction is positive direction, south direction is negative direction),
Δx = (positioning longitude) − (area center longitude) (18)
Δy = (Positioning latitude) − (Center latitude in the area) (19)
And If Δx is larger than the basic distance or Δy is larger than the basic distance, it can be determined that the positioning position (current position) is outside the area. Further, when Δx is 0 or more and Δy is 0 or more, it can be determined that the positioning position (current position) is within the area of map coordinate 0. When Δx is smaller than 0 and Δy is 0 or more, it can be determined that the positioning position (current position) is within the area of the map coordinate 1. When Δx is 0 or more and Δy is smaller than 0, it can be determined that the positioning position (current position) is within the area of the map coordinate 2. If none of the above conditions is satisfied, it can be determined that the positioning position (current position) is within the area of the map coordinates 3.

  When it is determined in step S22 that the error of the altitude three-dimensionally measured by the GPS reception processing unit 3 is less than or equal to a certain level, the calculation processing unit 6 counts the number of stays in the record corresponding to the area to which the positioning position (current position) belongs. The field value is incremented (step S23), and the value of the positioning altitude (current altitude) is added to the value of the cumulative altitude 1 field in the record corresponding to the area to which the positioning position (current position) belongs (step S24). The square of the positioning altitude (current altitude) is added to the value of the accumulated altitude 2 field in the record corresponding to the area to which the position (current position) belongs (step S25), and the record corresponding to the area to which the positioning position (current position) belongs The current time is written in the update time field (step S26). As the current time, the time measured by the time measurement processing unit 4 may be used, or the time output from the GPS reception processing unit 3 may be used.

  Next, the arithmetic processing unit 6 checks whether or not the value of the stay count field in the record corresponding to the area to which the current position belongs has reached a threshold value (hereinafter referred to as “detailed area generation determination threshold value”) (Step S S27). If it is determined that the value of the stay count field in the record corresponding to the area to which the current position belongs has reached the detailed area generation determination threshold, the arithmetic processing unit 6 selects the area to which the positioning position (current position) belongs. An altitude map (see FIG. 5) having four records each divided into four areas and corresponding to the new four areas is created in the altitude information storage unit 5 (step S28).

  If the arithmetic processing unit 6 determines that the error of the altitude measured by the GPS reception processing unit 3 in step S22 is not below a certain level, the arithmetic processing unit 6 does not reduce the accuracy of the data in the altitude map. S28 is not executed.

  Then, the arithmetic processing unit 6 outputs the longitude, latitude, and altitude measured three-dimensionally as an NMEA packet to the external device (step S29).

  On the other hand, when the GPS reception processing unit 3 is performing two-dimensional positioning, since the altitude is not output from the GPS reception processing unit 3, the arithmetic processing unit 6 calculates the altitude (step S30). Specifically, the arithmetic processing unit 6 divides the value of the cumulative altitude 1 field in the record corresponding to the area to which the positioning position (current position) belongs by the value of the stay count field, thereby determining the positioning position (current position). The average value of altitudes that have been three-dimensionally measured in the past in the area to which the

  Then, the arithmetic processing unit 6 outputs the longitude and latitude obtained by the two-dimensional positioning and the altitude calculated in step S30 to the external device as an NMEA packet (step S31).

  Note that the arithmetic processing unit 6 performs the processing shown in FIG. 7 on the four new areas obtained by subdivision in step S28 after the next interval.

  FIG. 8 is a flowchart illustrating an operation performed by the arithmetic processing unit 6 at a predetermined time (for example, when the position detection device 1 is activated).

First, the arithmetic processing unit 6 detects an altitude map that has not been updated for a predetermined time (step S31). This is, for example, for all four records (current time)-(update time in each record)-(time when the power was turned off)
> (Altitude Map Deletion Threshold) (20)
It may be detected depending on whether or not. As the current time, the time measured by the time measurement processing unit 4 may be used, or the time output from the GPS reception processing unit 3 may be used. Further, the time during which the power is off may be calculated using the difference between the current time and the time output by the GPS reception processing unit 3 immediately before the power is turned off. It is also possible to use the time that was spent.

  Next, the arithmetic processing unit 6 deletes the altitude map searched in step S41 and releases the recording area (garbage collection) (step S42).

  In addition, when the user's life sphere of the position detection device 1 is temporarily changed (for example, travel) or completely changed (for example, moving), the current position moves out of the wide area of interest. The altitude map cannot be updated. In such a case, the number of stays outside the wide area of interest is recorded as auxiliary information. When the position detection device 1 is activated, the positioning position at the time of activation is outside the wide area of interest, and the number of stays outside the wide area of interest reaches a predetermined threshold (referred to as “out of wide area of interest movement determination threshold”). In addition, it may be determined that a move or the like has occurred, and a process of creating a wide area map (see FIG. 3) again (see FIG. 2) may be performed. If the number of stays outside the wide area of interest has not reached the threshold for determining movement outside the wide area of interest, it is determined that the trip is a trip, etc. It is good also to continue.

  As described above, according to the present embodiment, when the GPS reception processing unit 3 performs three-dimensional positioning, information in the wide area map (see FIG. 3) in the altitude information storage unit 5 is updated. . Thereby, when the GPS reception processing unit 3 performs two-dimensional positioning, the altitude can be calculated using information in the wide area map in the altitude information storage unit 5.

  Even if the GPS reception processing unit 3 performs three-dimensional positioning, if the error in the information output by the GPS reception processing unit 3 is not below a certain level, Information is not updated. Thereby, since the accuracy of the information in the wide area map in the altitude information storage unit 5 can be maintained, the accuracy of altitude calculated when the GPS reception processing unit 3 is performing two-dimensional positioning can be increased. it can.

  In addition, when the number of stays in each area reaches a predetermined threshold, the area is divided into four new areas, and an altitude map having four records respectively corresponding to the four new areas is displayed as an altitude information storage unit. 5 (see FIG. 5). Thereby, the altitude of the frequently visited place can be calculated with higher accuracy.

  Further, by deleting an altitude map that has not been updated for a predetermined time, the storage capacity of the altitude information storage unit 5 can be used effectively.

  Further, when the number of stays outside the wide area reaches a predetermined threshold, the wide area map can be recreated. Thereby, even when a user moves, etc., it can respond.

  The present invention can be used in a position detection device that detects a current position. This position detection device can be used in a car navigation device or the like.

The block diagram which shows the position detection apparatus which concerns on one Embodiment of this invention. The flowchart which shows the operation | movement at the time of the initial stage of the position detection apparatus 1 of FIG. The figure which shows the example of the altitude map recorded on the altitude information storage part 5 of FIG. The figure which shows the area represented by the altitude map of FIG. The figure which shows the example of the altitude map recorded on the altitude information storage part 5 of FIG. The figure which shows the area represented by the altitude map of FIG. The flowchart which shows the operation | movement for every predetermined interval of the position detection apparatus 1 of FIG. The flowchart which shows the operation | movement at the time of starting of the position detection apparatus 1 of FIG.

Explanation of symbols

  1 position detection device, 2 antenna, 3 GPS reception processing unit, 4 timing processing unit, 5 altitude information storage unit, 6 arithmetic processing unit

Claims (8)

A GPS (Global Positioning System) reception processing unit for positioning the longitude, latitude, and / or altitude of the current position by receiving radio waves from an artificial satellite;
An altitude information storage unit for recording a data structure including a group of recording areas for respectively storing information about the altitude of the group of areas;
When the GPS reception processing unit is performing three-dimensional positioning, information on the altitude of the area to which the current position of the group of areas belongs is the longitude, latitude, and the current position measured by the GPS reception processing unit. When updating using the altitude, outputting the longitude, latitude, and altitude of the current position measured by the GPS reception processing unit to the outside, and the GPS reception processing unit performing two-dimensional positioning In addition, the altitude is calculated using information about the altitude of the area to which the current position of the group belongs, and the calculated altitude and the longitude and latitude of the current position measured by the GPS reception processing unit are output to the outside. An arithmetic processing unit;
A position detection apparatus comprising: Each of the group of recording areas is
A first field for storing a first value that is the number of times the GPS reception processing unit has stayed in an area corresponding to the recording area when performing the three-dimensional positioning;
When the GPS reception processing unit is performing three-dimensional positioning, a second value that is a cumulative total of altitudes measured by the GPS reception processing unit when staying in an area corresponding to the recording area is stored. A second field;
Including
The arithmetic processing unit is
When the GPS reception processing unit is performing two-dimensional positioning, the second value in the information related to the altitude of the area to which the current position of the group of areas belongs is included in the information related to the altitude in the area. The position detection device according to claim 1, wherein the altitude is calculated by dividing by the first value. The arithmetic processing unit is
When the GPS reception processing unit is performing three-dimensional positioning, when an error in altitude of the current position measured by the GPS reception processing unit satisfies a predetermined condition, the current position in the group of areas is The position detection device according to claim 1, wherein information relating to an altitude of an area to which the information belongs is updated. Each of the group of recording areas is
When the GPS reception processing unit is performing three-dimensional positioning, a third value that is the cumulative sum of the squares of the altitudes measured by the GPS reception processing unit when staying in the area corresponding to the recording area is stored. A third field for further comprising:
The arithmetic processing unit is
When the GPS reception processing unit performs three-dimensional positioning, the GPS reception is performed using the first to third values in the information about the altitude of the area to which the current position of the group of areas belongs. The position detection apparatus according to claim 3, wherein it is determined whether an error in altitude of the current position measured by the processing unit satisfies the predetermined condition. The arithmetic processing unit is
The altitude of the second group of areas obtained by subdividing the area when the first value of the information related to the altitude of any one of the group of areas reaches a predetermined threshold. A second data structure including a second group of recording areas for storing information relating to each of the second group is created in the altitude information storage unit, and then processing similar to that performed for the group of areas is performed in the second group. The position detection apparatus according to any one of claims 1 to 4, which is also performed on the area. Each of the group of recording areas is
A fourth field for storing a pointer;
The arithmetic processing unit is
6. The position detecting device according to claim 5, wherein a pointer indicating the second data structure is written in the fourth field of the recording area corresponding to the area of the group of recording areas. Each of the recording areas of the second group is
A fifth field for storing the time when the recording area was updated;
The arithmetic processing unit is
When any one of the recording areas of the second group of recording areas is updated, the updated time is stored in the fifth field of the recording area, and all of the recording areas of the second group have a predetermined time. The position detection device according to claim 6, wherein the second data structure is deleted when it has not been updated. The arithmetic processing unit is
The position detection device according to any one of claims 1 to 7, wherein when the number of stays outside the group of areas reaches a predetermined second threshold value, a process of creating the data structure again is performed. .