JP4133987B2 - Mobile body position information display device - Google Patents

Description

  The present invention relates to a position information display device, and is preferably applied to a GPS navigation device that displays a current position measured by receiving satellite waves from a plurality of GPS (Global Positioning System) satellites, for example.

  Conventionally, a GPS navigation device is configured by combining a GPS receiver and a navigation device, and the current position of the GPS navigation device itself detected by the GPS receiver is displayed on a map by the navigation device.

  In practice, a GPS receiver obtains positioning information by analyzing satellite waves received from a plurality of (for example, four) GPS satellites via a GPS antenna, and calculates the current position of the GPS navigation device based on the obtained positioning information. The position data indicating the current position is output to the navigation device.

  The navigation device displays a map indicating the periphery of the current position on a monitor such as a liquid crystal display based on position data indicating the current position, and displays a predetermined shape icon indicating the current position, thereby displaying a user on the map. The current position is visually presented.

Here, some GPS receivers have a configuration in which the GPS receiver and the navigation apparatus are wirelessly connected in order to output position data indicating the current position to the navigation apparatus (see, for example, Patent Document 1).
JP 2002-156438 A (2nd page, FIG. 10)

  By the way, the GPS receiver having such a configuration has a configuration in which the GPS receiver and the navigation device are wirelessly connected. Therefore, compared with a wired connection configuration, the wireless communication means is always operated to generate radio waves. Therefore, there is a problem in that a large amount of transmission power is required and the power consumption increases as a whole.

  In particular, in a detachable mobile GPS navigation device, there has been a problem that when the power consumption in the GPS receiver is significantly increased, the use time when being carried is shortened.

  The present invention has been made in view of the above points, and an object of the present invention is to propose a position information display device that can further reduce power consumption with a simple configuration.

In order to solve such a problem, in the present invention, a GPS (Global Positioning System) receiver is connected, and the GPS receiver acquires position information of a mobile body measured based on satellite waves received from a plurality of GPS satellites. The position information is measured based on satellite waves received from a plurality of GPS satellites, a DOP (Dilution Of Precision) value of the positioning data is calculated, and the DOP value is displayed. Receiving means for judging the likelihood of the position information corresponding to the positioning data based on the position information and receiving the position information transmitted from the GPS receiver at time intervals according to the certainty of the position information; and receiving means Display means for displaying a circle of a predetermined diameter surrounding the icon together with an icon of a predetermined shape indicating the current position on the map based on the position information received by the If the accuracy of the location information is higher than the predetermined standard, the time interval when displaying the icon is set to be short according to the reception interval of the location information, and a circle with a small diameter to display the icon is displayed, and the location is displayed. When the accuracy of information is lower than a predetermined standard, a small circle is created by setting a longer time interval for displaying icons according to the location information reception interval and displaying a circle with a larger diameter than a small circle. And a control means for displaying a locus of changes in position information in a state where a large circle is mixed.
As described above, in the mobile object position display device, the display time interval of the icon can be varied in accordance with the reception interval according to the probability of the position information based on the DOP value, and the small circle and the diameter surrounding the icon can be changed. By displaying as a locus of change in position information in a mixed state with a large circle, the diameter surrounding the icon is smaller than when only the icon is displayed during movement where the speed of the moving object changes variously. Since the user can visually check the locus as a mixture of a circle and a circle with a large diameter, it is possible to intuitively recognize whether the position information is high or low and stable. it can.

  According to the present invention, the icon display time interval can be varied in accordance with the reception interval according to the accuracy of position information based on the DOP value, and a small-diameter circle and a large-diameter circle surrounding the icon are provided. Is displayed as a locus of change in position information in a mixed state, so that a circle with a small diameter and a diameter that surrounds the icon is smaller than when only the icon is displayed during movement where the speed of the moving object changes variously. Since the user can visually check the locus as a mixture of large circles, it is possible to intuitively recognize whether the positional information is highly accurate, low or stable, and thus an icon. It is possible to realize a mobile body position information display device that allows the user to intuitively recognize the certainty of the position information indicated by.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Circuit Configuration of GPS Receiver As shown in FIG. 1, a GPS (Global Positioning System) receiver 1 as a position information positioning device is transmitted from a plurality of GPS satellites 2 to 5 existing within a receivable range. The [GHz] band satellite waves S1 to S4 are received via the GPS antenna 6 and the RF (Radio Frequency) unit 7 of the GPS receiving unit 9, and the baseband unit is easy to process by the RF unit 7. Is down-converted to the baseband processing unit 8 as received signals S5 to S8.

  The baseband processing unit 8 obtains each position of the GPS satellites 2 to 5 by performing predetermined demodulation processing or the like on the received signals S5 to S8, and satellites from the GPS satellites 2 to 5 to the GPS receiver 1 Differences in the time at which the waves S1 to S4 arrive are obtained, and the current position of the GPS receiver 1 is measured using these differences.

  The baseband processing unit 8 stores positioning data D5 indicating the current position (latitude, longitude, altitude, etc.) of the GPS receiver 1 in an internal memory (not shown) and a control having a CPU (Central Processing Unit) configuration. Send to unit 10.

  In the baseband processing unit 8, the positioning data D5 indicating the current position of the GPS receiver 1 is calculated at a rate of once per second, and the positioning data D5 is updated each time, The latest positioning data D5 is sent to the control unit 10.

  The control unit 10 supplies power to the GPS receiving unit 9 and the communication processing unit 11 and performs communication control for the communication processing unit 11, and the communication processing unit configured of the positioning data D5 by a Bluetooth module. 11 and an antenna 12 are transmitted to a navigation device (not shown) by short-range wireless transmission.

  Next, two communication control processing procedures (“intermittent communication control processing procedure” and “positioning accuracy” when the control unit 10 of the GPS receiver 1 wirelessly transmits the positioning data D5 to the navigation device via the communication control unit 11. Will be described.

(2) Communication Control Processing Procedure (2-1) Intermittent Communication Control Processing Procedure As shown in FIG. 2, the control unit 10 of the GPS receiver 1 enters from the start step of the routine RT1 and proceeds to step SP1. In step SP1, the controller 10 receives the satellite waves S1 to S4 with the GPS antenna 6 and the GPS receiver 9, and proceeds to the next step SP2.

  In step SP <b> 2, the control unit 10 determines whether or not the current position has been calculated by the baseband processing unit 8 of the GPS receiving unit 9. When the baseband processing unit 8 cannot receive the satellite waves S1 to S4 from the four GPS satellites 2 to 5, and the parameters (reception signals S5 to S8) necessary for performing the positioning calculation are not available, the positioning calculation of the current position is performed. Will not be possible.

  If an affirmative result is obtained in step SP2, this means that the positioning calculation of the current position has been performed because the positioning data D5 has been supplied from the baseband processing unit 8 of the GPS receiving unit 9, and at this time The control unit 10 moves to the next step SP3.

  In step SP3, since the control unit 10 has been able to receive the positioning data D5 from the baseband processing unit 8, the control unit 10 wirelessly transmits the positioning data D5 to the navigation device via the communication processing unit 11, and returns to step SP2. .

  On the other hand, if a negative result is obtained in step SP2, this means that the positioning data D5 has not been supplied from the baseband processing unit 8 of the GPS receiving unit 9, that is, the positioning calculation of the current position has not been performed. At this time, the control unit 10 proceeds to the next step SP4.

  In step SP3, since the control unit 10 could not receive the positioning data D5 from the baseband processing unit 8, it does not wirelessly transmit to the navigation device via the communication processing unit 11, and returns to step SP2. .

  As described above, the control unit 10 wirelessly transmits the positioning data D5 to the navigation device via the communication processing unit 11 only when the positioning calculation of the current position is surely performed once every second, and otherwise. By not performing wireless transmission, the minimum necessary and effective information can be wirelessly transmitted to the navigation device with much lower power consumption than when the positioning data D5 is wirelessly transmitted every second. Has been made.

(2-2) Intermittent Communication Control Processing Procedure As shown in FIG. 3, the control unit 10 of the GPS receiver 1 enters from the start step of the routine RT2 and proceeds to step SP11. In step SP11, the control unit 10 receives the satellite waves S1 to S4 with the GPS antenna 6 and the GPS reception unit 9, and receives the positioning data D5 obtained by the positioning calculation with the baseband processing unit 8, and then proceeds to the next step SP12. Move.

  In step SP12, the control unit 10 determines whether the baseband processing unit 8 of the GPS receiving unit 9 has been able to calculate the current position. If a negative result is obtained here, this means that the positioning data D5 has not been supplied from the baseband processing unit 8 of the GPS receiving unit 9, and the current position has not been calculated. The control unit 10 waits until receiving the positioning data D5 from the baseband processing unit 8.

  On the other hand, if an affirmative result is obtained in step SP12, this means that the positioning calculation of the current position has been performed since the positioning data D5 is supplied from the baseband processing unit 8 of the GPS receiving unit 9. At this time, the control unit 10 proceeds to the next step SP13.

  In step SP13, the control unit 10 determines whether or not the positioning data D5 supplied from the baseband processing unit 8 is a DOP (Dilution Of Precision) value “6” or less.

  Here, the DOP value is a numerical value that serves as an index of “degradation of accuracy” in the GPS positioning calculation, and is greatly influenced by the arrangement of the GPS satellites 2 to 5. Specifically, the GPS positioning calculation is performed using at least three or more GPS satellites (in this embodiment, a case where four GPS satellites 2 to 5 are used will be described as an example). The DOP value is determined by the satellite arrangement state of three or more GPS satellites 2 to 5 used for the positioning calculation.

  For example, consider a unit sphere centered at an observation point, and a tetrahedron formed by re-arranging the GPS satellites on the spherical surface so that the actual GPS satellites can be seen and connecting the four GPS satellites to each other. The larger the volume of this tetrahedron, the smaller the DOP value and the better the GPS positioning accuracy at that time. Conversely, the smaller the volume of the solid, the larger the DOP value and the worse the GPS positioning accuracy at that time. Represents that.

  That is, the volume of the solid is large, which means that the GPS satellites 2 to 5 used for the positioning calculation are scattered in the sky, and the DOP value is small when such GPS satellites 2 to 5 are arranged. Become the most accurate.

  On the other hand, the small volume of the solid means that the GPS satellites 2 to 5 used for the positioning calculation are not scattered in the sky and are in a state of being offset, so such GPS satellites 2 to 2 In the case of the arrangement of 5, the DOP value becomes large and the accuracy deteriorates.

  In practice, as shown in FIG. 4, in the navigation device, when the current position is indicated on the map in accordance with the positioning data D5 received from the GPS receiver 1, the current position that changes with the passage of time is indicated by an icon P having a predetermined shape. And a circle CIR1 or CIR2.

  Here, the circle CIR1 or CIR2 centering on the icon P is an index indicating the certainty of the current position of the icon P. The circle CIR1 having a larger diameter has a lower accuracy and the circle CIR2 having a smaller diameter has a higher accuracy. Represents.

  That is, when the DOP value is “6” or less, the navigation device displays an icon P indicating the current position at the center of the small circle CIR2, and when the DOP value exceeds “6”, the current value is displayed at the center of the large circle CIR1. An icon P indicating the position is displayed.

  Therefore, the navigation apparatus displays the icon P as a large circle CIR1 or the icon P as a small circle CIR2 in accordance with the change in the DOP value of the positioning data D5.

  If an affirmative result is obtained in step SP13, this indicates that the DOP value is “6” or less and the positioning accuracy indicating the current position is high by the positioning data D5. The process proceeds to step SP14.

  In step SP14, since the DOP value is “6” or less and the positioning accuracy is high, the control unit 10 wirelessly transmits the positioning data D5 to the navigation device every second, and returns to the above-described step SP12.

  On the other hand, if a negative result is obtained in step SP13, this indicates that the DOP value is larger than “6” and the positioning accuracy indicating the current position is low by the positioning data D5. Moves to the next step SP15.

  In step SP15, since the DOP value is larger than “6” and the positioning accuracy is low, the control unit 10 wirelessly transmits the positioning data D5 to the navigation device every 5 seconds, and returns to step SP12 described above.

  In this way, the control unit 10 determines the probability of the positioning data D5 based on the DOP value, and when determining that the positioning accuracy is high, the control unit 10 wirelessly transmits the positioning data D5 to the navigation device every second during the actual positioning calculation. By transmitting, the current position with excellent positioning accuracy can be displayed with a circle CIR2 and an icon P at short time intervals (every second).

  Further, the control unit 10 determines the probability of the positioning data D5 based on the DOP value, and when determining that the positioning accuracy is low, wirelessly transmits the positioning data D5 to the navigation device every 5 seconds instead of every 1 second. The positioning data D5 with low positioning accuracy and low reliability is prevented from being wirelessly transmitted to the navigation device at short time intervals to reduce power consumption.

(3) Operation and Effect In the above configuration, the control unit 10 of the GPS receiver 1 transmits the positioning data D5 via the communication processing unit 11 only when the positioning calculation can be performed by the baseband processing unit 8 of the GPS receiving unit 9. If the positioning data D5 to be transmitted does not exist or the positioning data D5 sent to the control unit 10 is not valid, the wireless transmission is not performed at all. As a result, the positioning data D5 can be wirelessly transmitted effectively with the minimum required power consumption.

  Further, the control unit 10 wirelessly performs the calculation every one second when the baseband processing unit 8 of the GPS receiving unit 9 can perform the positioning calculation and determines that the accuracy of the positioning data D5 is high based on the DOP value. Although it is transmitted, when it is determined that the accuracy of the positioning data D5 is low, the time interval is extended so that it is wirelessly transmitted only once every 5 seconds. The positioning data D5 can be effectively transmitted wirelessly.

  In this case, in the navigation device, when the accuracy of the positioning data D5 is high, the circle CIR2 and the icon P are updated and displayed on the map of the display unit every second, and when the accuracy of the positioning data D5 is low, the map of the display unit is displayed. The circle CIR1 and the icon P are updated and displayed every 5 seconds.

  Therefore, the navigation device can allow the user to visually recognize the accuracy of the positioning accuracy visually through the size of the circle CIR1 or CIR2 displayed on the display unit of the navigation device, and the time when the icon P is updated. Through the interval, it is possible to intuitively recognize the certainty of the current position indicated by the currently displayed icon P.

  According to the above configuration, the control unit 10 of the GPS receiver 1 can control the wireless communication of the positioning data D5 by the communication processing unit 11 according to the detection result of the positioning data D5. Compared with the case where the positioning data D5 is always wirelessly transmitted via the processing unit 11, the power consumption can be significantly reduced.

(4) Other Embodiments In the above-described embodiment, the communication processing unit 11 is used only when the positioning calculation is reliably performed once every second in the intermittent communication control processing procedure (FIG. 2) of the routine RT1. In the above description, the positioning data D5 is wirelessly transmitted to the navigation device via the wireless communication system, and wireless transmission is not performed at other times. However, the present invention is not limited to this, and the positioning calculation is surely performed once every second. Even if it is possible, the current position does not change when the data contents of the previous positioning data D5 and the current positioning data D5 do not change, so it is determined that the positioning data D5 is not worth wireless transmission. Wireless transmission may not be performed. In this case, the control unit 10 can prevent repeated transmission of the positioning data D5 having the same content, and can further reduce power consumption.

  Further, in the above-described embodiment, it is determined that the positioning accuracy is high when the DOP value of the positioning data D5 as the position information is “6” or less, and the positioning accuracy is low when the DOP value is greater than “6”. However, the present invention is not limited to this, and the accuracy of the positioning data D5 may be determined based on other various DOP values.

  Furthermore, in the above-described embodiment, the time interval for wirelessly transmitting the positioning data D5 to the navigation device via the communication processing unit 11 according to the DOP value is set to two types, every 1 second and every 5 seconds. Although cases have been described, the present invention is not limited to this, and a plurality of types may be set at arbitrary time intervals.

  Furthermore, in the above-described embodiment, the case where the short-distance wireless communication is performed using the Bluetooth module by the communication processing unit 11 as the communication means has been described, but the present invention is not limited to this, and the IEEE (Institute of Electrical) and Electronics Engineers) 802.11a, b, g, etc. communication means compliant with wireless LAN (Local Area Network) specifications may be used.

  The position information display device of the present invention can be applied to, for example, an application that allows a user to intuitively recognize the positioning accuracy when position information is measured and displayed on a map.

It is a rough-line block diagram which shows the circuit structure of the GPS receiver in this invention. It is a flowchart which shows an intermittent communication control processing procedure. It is a flowchart which shows the intermittent communication control processing procedure according to positioning accuracy. It is a basic diagram with which it uses for description of the difference of positioning accuracy and a communication interval.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... GPS receiver, 2-5 ... GPS satellite, 8 ... Baseband process part, 10 ... Control part, 11 ... Communication process part.

Claims (1)

A mobile body position information display device that is connected to a GPS (Global Positioning System) receiver and acquires and displays position information of a mobile body measured based on satellite waves received from a plurality of GPS satellites by the GPS receiver. And
Positioning the position information based on satellite waves received from the plurality of GPS satellites, calculating a DOP (Dilution Of Precision) value of the positioning data, and the position information corresponding to the positioning data based on the DOP value determining the likelihood of a receiving means for receiving the location information made a to be transmitted at time intervals corresponding to the certainty of the positional information from the GPS receiver,
Display means for displaying an icon of a predetermined shape indicating a current position on a map based on the position information received by the receiving means;
When the accuracy of the position information is higher than a predetermined reference based on the DOP value, a time interval for displaying the icon is set to be short in accordance with the reception interval of the position information and the icon is enclosed When a circle with a small diameter is displayed and the accuracy of the position information is lower than a predetermined reference, the time interval for displaying the icon is set to be longer than the reception interval of the position information, and the circle is smaller than the small circle. by also displaying the large diameter circle, vehicle location information, characterized in that it comprises a control means for displaying the trajectory of the change in the position information in a state of being mixed with large circle the small circles and the Display device.

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