JP2007240167A - Vehicle-mounted travel distance measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle-mounted travel distance measuring apparatus of a simple structure capable of lowering the manufacturing costs of the apparatus and minimizing measurement errors. <P>SOLUTION: The vehicle-mounted travel distance measuring apparatus 1 is provided with a GPS reception part 2 for receiving radio waves from GPS satellites and computing the instantaneous speeds of a vehicle; a recording part 4 for recording the instantaneous speeds of the vehicle computed at the GPS reception part at every prescribe time interval; and a distance computing part (control part 3) for computing a travel distance of the vehicle on the basis of the instantaneous speeds recorded in the recording part and the prescribed time. The instantaneous speeds of the vehicle computed by using radio waves from the GPS satellites are used to perform integration with time intervals at which radio waves from the GPS satellites are acquired to compute the travel distance of the vehicle. Vehicle information including average fuel consumption and the capacity of a fuel tank of the vehicle is inputted from an input part 5 through the use of functions of the apparatus 1. The control part computes a distance which can be traveled. An alarm can be issued from an alarm part 6 when the distance which can be traveled takes on a prescribed value or lower. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-vehicle mileage measuring device, and more particularly to an in-vehicle odometer measuring device using a GPS system built in a radar detector.

  Conventionally, an on-board trip meter (odometer) is used to measure the distance traveled by a vehicle. This trip meter calculates the mileage of the vehicle based on the outer diameter and the rotational speed of the tire.

  However, the trip meter has a problem that when the outer diameter of the tire changes due to wear or the like, the trip meter cannot cope with the change, so that an error occurs in the calculated travel distance.

  Therefore, in order to solve this problem, for example, in Patent Document 1, when the travel distance is obtained using the information from the axle tachometer of the vehicle, it is obtained by the product of the differential value of the wheel rotation speed and the wheel diameter. There has been proposed a vehicle travel distance measuring device that compares the assumed acceleration and the actual acceleration obtained by an acceleration sensor to detect a change in the outer diameter of the wheel and slip and correct the travel distance.

  On the other hand, as a technique for measuring the travel distance of a vehicle using a GPS receiver, Patent Document 2 discloses an orientation sensor that detects the orientation of the vehicle, a vehicle speed sensor that detects vehicle speed pulses, and an orbit around the earth. There has been proposed a vehicle mileage detecting device including a GPS receiving device that receives a radio wave transmitted from a GPS satellite orbiting and detects the position of the vehicle.

JP 2000-206136 A Japanese Unexamined Patent Publication No. 7-306056

  However, in the mileage measuring device described in Patent Document 1, since it is necessary to mount an acceleration sensor or the like that measures the actual acceleration of the vehicle, there is a problem that the structure of the device becomes complicated and the device cost increases. It was.

  Also, the vehicle travel distance detection device described in Patent Document 2 needs to be mounted with a device for detecting a vehicle speed pulse such as a probe device, a pulse coefficient calculation device for calculating a pulse distance coefficient, and the like, so the structure is complicated. In addition, there is a problem that the cost of the apparatus increases.

  Therefore, the present invention has been made in view of the problems in the above-described conventional measuring devices and the like, and has a simple structure, can reduce the manufacturing cost of the device, and minimizes measurement errors. An object of the present invention is to provide an on-vehicle mileage measuring apparatus capable of performing the above.

  In order to solve the above problems, the present invention is an in-vehicle mileage measuring device that receives a radio wave from a GPS satellite and calculates an instantaneous speed of the vehicle, and a vehicle calculated by the GPS receiving unit. A recording unit that records the instantaneous speed of the vehicle at predetermined time intervals, and a distance calculation unit that calculates the travel distance of the vehicle based on the instantaneous speed recorded by the recording unit and the predetermined time. Features.

  According to the present invention, the vehicle travel distance is calculated by the product of the instantaneous speed of the vehicle calculated using the radio wave from the GPS satellite and the time interval from which the radio wave is obtained from the GPS satellite. As described above, it is not necessary to mount a device for detecting vehicle speed pulses such as an acceleration sensor and a probe device, and a pulse coefficient calculation device for calculating a pulse distance coefficient. be able to.

  In the device according to the present invention, the mileage of the vehicle is calculated based on the instantaneous speed and time interval of the vehicle using radio waves from the GPS satellite, but the actual vehicle speed is within a predetermined time interval. Change. However, since the error is offset between the case where the actual vehicle speed is faster and the case where the actual vehicle speed is slower than the calculated instantaneous speed, the measurement error of the travel distance can be minimized.

  In the on-vehicle travel distance measuring device, the recording unit further records the average fuel consumption of the vehicle and the capacity of the fuel tank, and calculates the travelable distance of the vehicle when fuel is injected into the fuel tank. The travelable distance for calculating the travelable distance for each predetermined time interval of the vehicle by subtracting the travel distance of the vehicle calculated by the distance calculation unit at each predetermined time interval from the travelable distance of the vehicle A calculation part can be provided. Thus, the travelable distance for each predetermined time interval of the vehicle can be calculated with a simple configuration.

  The vehicle-mounted travel distance measuring device may include an alarm unit that issues an alarm when the calculated travelable distance is equal to or less than a predetermined value. Thus, with a simple configuration, when the travelable distance of the vehicle becomes short, it is possible to prompt the driver or the like to refuel with good timing.

  The in-vehicle mileage measuring device may include an input unit for inputting vehicle information including an average fuel consumption of the vehicle and a capacity of a fuel tank. Thus, various types of vehicles can be handled.

  As described above, according to the present invention, it is possible to provide an in-vehicle mileage measuring device that has a simple structure, can reduce the manufacturing cost of the device, and can minimize measurement errors. .

  FIG. 1 shows an embodiment of an in-vehicle mileage measuring apparatus according to the present invention. This in-vehicle odometer measuring apparatus (hereinafter abbreviated as “apparatus”) 1 includes a GPS receiver 2 and various kinds of devices. A control unit 3 that performs calculation and controls the entire apparatus 1, a recording unit 4 that records a calculation result of the control unit 3, an input unit 5 for inputting vehicle information and the like, and an alarm unit that issues an alarm 6.

  The GPS receiver 2 calculates the current position, instantaneous speed, and current time of the vehicle based on the GPS signal transmitted from the GPS satellite every second (2 to 10 seconds in the case of the low power consumption mode). Are transmitted to the control unit 3 and the recording unit 4. The instantaneous speed of the vehicle is calculated using radio waves transmitted from GPS satellites and the Doppler effect.

  The control unit 3 includes a CPU (central processing unit), a computer program, and the like, and controls the entire apparatus 1 and performs various arithmetic processes. For example, the travel distance, the travelable distance, and the like are calculated based on data such as the current position and instantaneous speed obtained from the GPS receiver 2.

  The recording unit 4 is configured by a non-volatile memory or the like so that the travel distance data and the like can be retained even when the power is turned off, and records the data transmitted from the receiving unit 2 and the calculation result by the control unit 3.

  The input unit 5 includes a plurality of switch groups, and inputs and sets data such as the average fuel consumption of the vehicle and the capacity of the fuel tank.

  The warning unit 6 issues a warning by voice when the travelable distance becomes a predetermined value or less. The warning by voice can be performed by a buzzer, melody, synthesized voice, etc., and any one of these can be selected in this apparatus.

  Next, the operation of the apparatus 1 according to the present invention will be described with reference to FIG.

  First, the user of the device 1 inputs vehicle information such as the average fuel consumption of the vehicle and the capacity of the fuel tank via the input unit 5. The input information is recorded in the recording unit 4 via the control unit 3.

  While the vehicle is running, the GPS receiver 2 calculates the position, instantaneous speed, and time of the vehicle every second, and outputs the calculated information to the controller 3. The output information is recorded in the recording unit 4 via the control unit 3.

  The control unit 3 calculates the travel distance of the vehicle based on the information calculated by the GPS reception unit 2. Specifically, the travel distance of the vehicle is calculated by multiplying the instantaneous speed of the vehicle obtained every second by a predetermined time and accumulating the result. Further, the travelable distance is calculated in advance from the average fuel consumption of the vehicle and the capacity of the fuel tank recorded in the recording unit 4, and the remaining travelable distance and the like are calculated by subtracting the travel distance. The calculated data is recorded in the recording unit 4. If the fuel tank is not filled at the time of refueling, the fuel supply amount is input from the input unit 5, and the control unit 3 calculates the remaining travelable distance and the like based on the input value.

  In addition, when the calculated travelable distance is equal to or less than a predetermined value recorded in the recording unit 4, the control unit 3 instructs the alarm unit 6 to issue an alarm to the outside. As a result, the warning unit 6 can issue a voice warning or the like and prompt the driver to refuel.

  The device 1 uses the radio wave from the GPS satellite to calculate the mileage of the vehicle based on the instantaneous speed of the vehicle calculated by the GPS receiver 2 and a predetermined time interval, but the actual vehicle speed is Change within a predetermined time interval. For this reason, the travel distance obtained by accurately tracking the vehicle is not necessarily calculated.

  Therefore, a comparison test was performed between the instantaneous speed calculated using GPS and the actual vehicle speed. The result is shown in FIG. As shown in the figure, the case where the actual vehicle speed (broken line) is faster and the case where the actual vehicle speed (broken line) is higher than the instantaneous speed (solid line) calculated using GPS appear equally, and the error is canceled out. In the figure, the integrated value of each curve is the travel distance. However, comparing the two, there is no significant difference, and it can be seen that no error that accumulates when used by the driver of the vehicle is accumulated.

  In the above embodiment, the remaining travelable distance is calculated by the control unit 3 and is set as an alarm target from the alarm unit 6, but the amount of fuel used, the remaining amount of fuel, the actual fuel consumption, the total fuel supply amount, Accumulated travel distance, etc. is calculated and recorded in the recording unit 4, or when these values are below or above a predetermined value, an alarm is issued from the alarm unit 6, or on a display unit composed of liquid crystal or the like It can also be configured to display.

  The GPS receiver 2 also calculates the current position of the vehicle based on GPS signals transmitted from GPS satellites every second. In the GPS system, since the moving component in the longitude direction depends on the latitude, it is not easy to calculate the vehicle travel distance using the calculated position data as it is, but the vehicle travel distance calculated by the device 1 It is also possible to calculate and use the vehicle travel distance from the position data by comparing the vehicle travel distance calculated from the position data and grasping the tendency of the error.

It is a block diagram which shows one Embodiment of the vehicle-mounted mileage measuring device concerning this invention. It is an integrated movement distance graph for demonstrating the test example of the vehicle-mounted travel distance measuring device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 In-vehicle mileage measuring device 2 GPS receiving part 3 Control part 4 Recording part 5 Input part 6 Alarm part

Claims (4)

A GPS receiver that receives radio waves from a GPS satellite and calculates the instantaneous speed of the vehicle;
A recording unit for recording the instantaneous speed of the vehicle calculated by the GPS receiving unit at predetermined time intervals;
An in-vehicle travel distance measuring device comprising: a distance calculation section that calculates a travel distance of the vehicle based on the instantaneous speed recorded by the recording section and the predetermined time. In the recording unit, the average fuel consumption of the vehicle and the capacity of the fuel tank are further recorded,
Calculating a travelable distance of the vehicle when fuel is injected into the fuel tank, and subtracting the travel distance of the vehicle calculated by the distance calculation unit at the predetermined time interval from the travelable distance of the vehicle; The in-vehicle travel distance measuring device according to claim 1, further comprising a travelable distance calculation unit that calculates a travelable distance for each predetermined time interval of the vehicle.   The travel distance measuring apparatus according to claim 2, further comprising an alarm unit that issues an alarm when the calculated travelable distance is equal to or less than a predetermined value.   The travel distance measuring device according to claim 1, 2 or 3, further comprising an input unit for inputting vehicle information including an average fuel consumption of the vehicle and a capacity of a fuel tank.

Images