JP4459017B2 - Moving body position calculating apparatus and calculating method - Google Patents

Description

  The present invention relates to a GPS receiver used in a navigation device or a navigation system, and more particularly to correction of travel angle data in the GPS receiver.

  The navigation device detects the current position of the host vehicle using a GPS receiver. The display shows the map data around the vehicle position, and the vehicle position mark is displayed on the map, and the screen is scrolled according to the change of the vehicle position so that the road and the map are guided. It has become.

  A GPS receiver measures the position of a vehicle based on radio waves received from a plurality of GPS satellites. However, the positioning accuracy is extremely excellent. However, when the vehicle travels in a high-rise building street or the like, multipath may occur or the number of positioning satellites may fluctuate, which may reduce the reliability of positioning data. In order to improve such problems, the following proposals have been made.

  Japanese Patent Application Laid-Open No. 2004-228561 is a navigation device that is independent of GPS movement vectors at a plurality of measurement points indicating the traveling direction and speed of the vehicle by the GPS navigation means and a plurality of corresponding measurement points indicating the traveling direction and speed of the vehicle by the self-contained navigation means. The reliability of the data detected by the GPS navigation means is determined based on the difference between a plurality of difference data indicating the difference between the movement vectors.

  Patent Document 2 calculates the predicted range and predicted displacement from the previous positioning state in the correction of the positioning data of the navigation system. If the current positioning position is within the predicted range, the positioning position difference is added to the previously determined position. If the position is determined and is not within the prediction range, the current position is determined by adding the predicted displacement to the previously determined position, and the influence when the positioning position fluctuates relatively large, such as multipath, is reduced. is there.

JP 2002-323551 A JP-A-8-313278

  In high-rise buildings with poor positioning environment, speed / advance angle data may be output as abnormal values. For this reason, as shown in FIG. 9, the movement prediction range E at the current positioning (T seconds) is determined from the speed and the advance angle data at the previous positioning (T-1 seconds). A movement vector indicating a change in the coordinate position of the moving body is calculated based on received radio waves from a plurality of GPS satellites. The magnitude of the movement vector is represented by velocity data, and the direction is represented by angular velocity data or traveling angle data (angular velocity data multiplied by unit time). That is, the movement prediction range E is a range between the maximum travel angle θmax and the minimum travel angle θmin centered on the previous predicted position P, and the maximum movable distance Dmax and the minimum movable distance from the previous predicted position P. It is the range of Dmin. If the speed / advance angle data at the time of positioning this time is within the movement prediction range E, it is determined that the data is reliable, and if it is not within the movement prediction range E, it is determined as an abnormal value. The movement prediction range E is estimated using a function of predicted speed / angular speed shown in FIG. The abscissa indicates the velocity, the ordinate indicates the angular velocity, and a 3σ function is derived from the measured values of the velocity and angular velocity. This 3σ defines the boundary of the movement prediction range E.

  When the T-second movement vector S measured this time deviates from the movement prediction range E as shown in FIG. 9, it is determined that the angular velocity or the advance angle data is abnormal, and the movement prediction range E falls within the movement prediction range E. In other words, correction is performed so that the maximum traveling angle θmax, which is the upper limit of the movement prediction range E, is drawn.

  However, since the advance angle (angular velocity) data is corrected using one angle prediction function shown in FIG. 10, it may not be appropriately corrected depending on the traveling state of the vehicle. For example, as shown in FIG. 11 (a), when there is an abrupt left turn in the actual vehicle travel W1 (when the angle change is abrupt), a predicted position P by the GPS receiver (indicated by Δ in the figure). Position) cannot follow the actual travel position well, or when there is travel W2 in the straight section as shown in FIG. 11B, the linearity of the predicted position P may be lost. .

  Accordingly, an object of the present invention is to solve the above-described conventional problems and to provide a position calculation device and a calculation method that can accurately calculate the position of the moving body according to the traveling state of the moving body.

  A position calculation device according to the present invention is a device that measures the speed and angular velocity of a moving body based on a received radio wave from a positioning satellite and calculates the position of the moving body from the positioning result, and defines the relationship between the speed and the angular velocity. A prediction range setting means for setting a prediction range of the angular velocity based on the angle prediction function to be performed, and determining whether or not the measured angular velocity data is within the prediction range. If the angular velocity data is outside the prediction range, the angular velocity An angular velocity data correction unit that corrects the angular velocity data so that the data is within the prediction range, and a prediction range variable that determines the traveling state of the moving body and varies the angle prediction function of the prediction range setting unit according to the determination result. Means.

  Further, the position calculation method according to the present invention is a method of measuring the speed and angular velocity of a moving body based on a received radio wave from a positioning satellite, and calculating the position of the moving body from the positioning result. A first step of selecting a corresponding angular prediction function, setting a prediction range of angular velocity based on the selected angular prediction function, and a second step of determining whether or not the measured angular velocity data falls within the prediction range And a third step of correcting the angular velocity data so as to be within the prediction range when the angular velocity data is outside the prediction range.

  According to the position detection device of the present invention, the angular velocity prediction range is selected by selecting a corresponding angle prediction function from a plurality of angle prediction functions according to the traveling state of the moving body, so that the angular velocity prediction range is variable. The angular velocity can be corrected based on the predicted range. As a result, the accuracy of the calculated predicted position of the moving body can be improved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out a position calculation apparatus according to the present invention will be described in detail below with reference to the drawings. The position calculation device according to the present invention is preferably implemented in a GPS receiver used in a navigation device or a navigation system.

  FIG. 1 is a block diagram showing a configuration of a GPS receiver according to an embodiment of the present invention. In the figure, a GPS receiver 1 includes an antenna 10, an RF receiver 12, a positioning calculation unit 14, a movement prediction range setting unit 16, a movement prediction range variable unit 18, a positioning data correction unit 20, an angle prediction function storage unit 22, And a position calculation unit 24.

  The GPS signal emitted from the GPS satellite includes almanac data including orbit information related to the GPS satellite, ephemeris data including accurate orbit information of each satellite and time information when the signal is emitted, and these are encoded in a predetermined format. Has been. The GPS signal is received by the RF receiver 12 via the antenna 10, and the decoded result is output to the positioning calculator 14.

  The positioning calculation unit 14 calculates the velocity and angular velocity of the moving body based on the decoded GPS signal. The velocity data is a change in the distance of the moving body, and the angular velocity data is a change in the azimuth or angle of the moving body. Preferably, the velocity data and the angular velocity data are calculated at regular intervals (for example, 1 second). Further, the traveling angle data of the moving object is calculated by multiplying the angular velocity data by the unit time. The advance angle data is defined as an angle when measuring clockwise from north as a reference (0 degree).

  The movement prediction range setting unit 16 receives the speed data and the angular velocity data from the positioning calculation unit 14, and sets the movement prediction range E as shown in FIG. The movement prediction range E is set based on the velocity data and angular velocity data at the previous positioning (T-1 second). The movement prediction range E is used to determine whether or not the angular velocity data at the current positioning (T seconds) is an abnormal value. In the present embodiment, the movement prediction range E is varied according to an instruction from the movement prediction range variable unit 18 as will be described later.

  The movement prediction range variable unit 18 determines the traveling state of the vehicle, and gives an instruction to change the movement prediction range to the movement prediction range setting unit 16 based on the determination result. Preferably, the movement prediction range variable unit 18 determines whether or not the vehicle is traveling straight from the angle change of the vehicle. As a preferable condition, it is determined whether or not the angle change of the vehicle for the past 2 seconds is 15 degrees or more. If the angle change is 15 degrees or more, it is determined that the vehicle is traveling in a curve (including right and left turns). When the angle is less than 15 degrees, it is determined that the vehicle is traveling straight or straight. The angle change is calculated using the angular velocity data from the positioning calculation unit 14.

  The positioning data correction unit 20 determines whether or not the current positioning (T) speed data and angular velocity data are included in the movement prediction range. When the angular velocity data is not included in the movement prediction range, a correction that attracts the angular velocity data to the upper limit or the lower limit of the movement prediction range is performed. Note that the speed data is also corrected so as to be closer to the upper limit or the lower limit if it is outside the movement prediction range.

The angle prediction function storage unit 22 stores an angle prediction function defined from the relationship between the actually measured speed and the angular speed. In this embodiment, two angle prediction functions corresponding to the traveling state of the vehicle are provided. As shown in FIGS. 2 (a) and 2 (b), a straight angle prediction function used when the vehicle is traveling straight and a curve angle prediction function used when the vehicle is traveling on a curve such as a right or left turn or a curve. I have. The straight angle prediction function defines the function of σ represented by the mathematical expressions (1) and (2) from the speed and the measured value of the angular speed. Equation (1) shows the speed and positive angular velocity, and Equation (2) shows the relationship between the velocity and negative angular velocity.

In addition, the curve angle prediction function defines a 3σ function represented by Equations (3) and (4) based on the actually measured values of speed and angle. The measured values in FIG. 2 (b) are obtained by focusing on data obtained when the vehicle travels on a curve such as turning left or right.

  Statistically, since the angular velocity or traveling angle during straight running tends to be smaller than the angular velocity or traveling angle during curve traveling, the angle prediction function for straight traveling is more than that for curves so that it matches. Is also defined as σ (<3σ) so that the predicted angle becomes small.

  The position calculation unit 24 calculates the predicted position of the vehicle at the current positioning (T) based on the output from the positioning data correction unit 20. That is, if the velocity data and the angular velocity data measured this time are within the movement prediction range, the position becomes the predicted position. On the other hand, when the angular velocity data is corrected, a position specified by the angular velocity data and the velocity data attracted to the upper limit or lower limit value of the movement prediction range becomes the predicted position. The position calculation unit 24 outputs the predicted position to, for example, the navigation control unit side.

  Next, the operation of the GPS receiver of this embodiment will be described with reference to the flowchart of FIG. The positioning calculation unit 14 acquires the velocity and angular velocity data at T-1 seconds (step S101). The movement prediction range variable unit 18 determines whether or not the angle change from the past 2 seconds (for example, T-3 seconds to T-1 seconds) of the vehicle is 15 degrees or more (step S102). The determination result is transmitted to the movement prediction range setting unit 16.

  The movement prediction range setting unit 16 reads the corresponding angle prediction function from the angle prediction function storage unit 22 based on the determination result. As described above, if the angle change is 15 degrees or more, the curve angle prediction function shown in FIG. 2B is selected (step S103), and if it is less than 15 degrees, it is shown in FIG. A straight angle prediction function is selected (step S104). The movement prediction range setting unit 16 sets a movement prediction range for determining the positioning data at the current positioning (T seconds) using the selected angle prediction function (step S105).

  Next, velocity data and angular velocity data for T seconds are calculated by the positioning calculation unit 14 and output to the movement prediction range variable unit 18, the movement prediction range setting unit 16, and the positioning data correction unit 20 (step S106). The positioning data correction unit 20 determines whether the angular velocity data at T seconds is included in the range that can be taken by the angular velocity data at the time of T seconds (step S107). For example, when a straight angle prediction function is selected, if the speed at T seconds is 40 km, the angular velocity prediction range is ± 5 degrees, and the angular velocity at T seconds is within a prediction range of ± 5 degrees. It is determined whether or not to enter.

  When the angular velocity data is within the movement prediction range, the positioning data correction unit 20 adopts the angular velocity data at T seconds as correct (step S108). On the other hand, when the angular velocity data is out of the movement prediction range, the angular velocity data at T seconds is corrected closer to the upper limit value or lower limit value of the movement prediction range (step S109). The position calculation unit 24 determines a predicted position at T seconds based on the velocity and angular velocity data output from the positioning data correction unit 20 (step S110).

  FIGS. 4A and 4B show predicted positions (indicated by Δ in the figure) calculated from the GPS receiver when actually traveling in a high-rise building street. FIG. 4 (a) shows a predicted position when a single angle prediction function according to the conventional method is used. In the range indicated by H, the predicted position does not follow that linearity even though the traveling is linear, and linearity is achieved. Lost to meander. FIG. 4B shows the predicted position when using the straight angle prediction function according to the present embodiment, and it is understood that a substantially straight predicted position is calculated in the same range indicated by H. .

  As described above, the angle prediction function suitable for the driving state is selected and the movement prediction range is set according to the driving state of the vehicle, that is, whether the vehicle is traveling straight or curved, thereby improving the accuracy of the predicted position. Can do.

  Next, a second embodiment of the present invention will be described. In the calculation of the predicted position using the GPS receiver, an abnormal angle may be continuously output during a high-speed straight line in an extremely rare case. Temporarily, when using the criteria for determination of the running state in the first embodiment, the angle change becomes 15 degrees or more due to the continuous abnormal angle, and although it is straight running, it is mistaken for the curve. An angle prediction function may be selected.

  FIG. 5 shows an example in which the angular velocity (advance angle) is erroneously corrected by the angle prediction function for curves during high-speed traveling. In this example, the vehicle is traveling at a speed of 50 to 60 km per hour, and the calculated predicted position coordinates are deviated from the actual traveling position by about 100 to 1 km.

  The second embodiment focuses on the fact that the positioning position of the GPS receiver is very large when there are consecutive angular anomalies during high-speed driving, and the distance between the previous and current GPS points. X If the speed per hour is equal to or greater than a certain threshold value, it is determined that the angle change is abnormal, and correction is performed to adopt the previous advance angle as it is.

  FIG. 6 is a flowchart for explaining the operation of correcting the advance angle according to the second embodiment. The positioning data correction unit 20 receives the positioning data at T-1 seconds and T seconds from the positioning calculation unit 14 (step S201). The positioning data includes coordinate position data at T-1 seconds and T seconds before correction, in addition to velocity data and angular velocity data.

  The positioning data correction unit 20 calculates the distance between the two points from the coordinate position data at T-1 seconds and T seconds, and multiplies this distance by the speed per hour at T seconds, and the multiplication value is equal to or greater than the threshold value. It is determined whether or not there is (step S202). As described above, it is considered that the position jump (distance between two points) is large as one of the causes of the angle abnormality. Therefore, when the product of the distance between the two points and the speed is equal to or greater than a predetermined threshold, the angle abnormality Is determined.

  If it is determined that the angle is abnormal, the positioning data correction unit 20 employs angular velocity data at T-1 seconds (step S203). As a result, the previous advance angle or angular velocity is adopted as the current advance angle or angular velocity (T = T−1), and even if an angle abnormality occurs during straight running, the advance angle is corrected in the wrong direction. It is prevented.

  On the other hand, when the multiplication value is smaller than the threshold value, the positioning data correction unit 20 performs the advance angle correction process shown in the first embodiment, assuming that no angle abnormality has occurred (step S204). . Thus, the predicted position at T seconds is determined (step S205).

  FIGS. 7A and 7B show the predicted positions (indicated by Δ in the figure) calculated from the GPS receiver when actually traveling on a high-rise building street. FIG. 7A shows a predicted position calculated by the conventional method. In the range indicated by H, the predicted position does not follow the curve, but is curved even though the vehicle is traveling straight ahead. FIG. 7B shows the predicted position when the advance angle is corrected according to the second embodiment, and it can be seen that the position is almost a linear predicted position in the range indicated by H. As described above, in the second embodiment, it is possible to minimize the influence of the positioning error due to the abnormal angle during high speed traveling.

  FIG. 8 is a diagram showing a configuration when the GPS receiver 1 according to the present invention is applied to an in-vehicle navigation device. The in-vehicle navigation device 100 includes the GPS receiving device 1 described in the first embodiment, a self-contained navigation sensor 110 including a vehicle speed sensor and a gyro sensor, an operation input unit 120 for inputting an instruction from a user, the Internet, etc. A communication control unit 130 that performs network communication and acquires map data and traffic information from a server, a storage unit 140 that stores map data and the like necessary for navigation, an audio output unit 150 that outputs audio from a speaker 152, and a display 162 includes a display control unit 160 for drawing a map and the like, and a navigation control unit 170 for controlling each of these units.

  The navigation control unit 170 receives the predicted position data measured by the GPS receiver 1, reads map data corresponding to the vehicle position from the storage unit 140 based on the predicted position data, and displays the map data on the display 162. At the same time, a mark indicating the position of the vehicle is drawn on the map screen of the display, and the map screen is scrolled as the vehicle moves.

  By applying the GPS receiver of this embodiment to the navigation device, it is possible to suppress the occurrence of positional deviation or position jump of the vehicle on the map screen, and at the time of route guidance or non-route guidance Accurate vehicle position information can be provided to the user.

  In addition, when the position accuracy by the GPS receiver 1 is high, the self-contained navigation sensor is not necessarily used regularly. In addition, the self-contained navigation sensor may be used only when the vehicle is in a position (in a tunnel or underground) where radio waves from GPS satellites cannot be received.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Deformation / change is possible.

  In the first embodiment, two angle prediction functions are used for straight travel and for curves. However, the present invention is not limited to this, and a plurality of angle prediction functions are used so as to cope with more detailed driving conditions. be able to. In addition, the angle prediction function is not necessarily a high-order function, and a function that defines the relationship between the velocity and the angular velocity at a constant ratio (for example, y = αx, α is a constant) for each velocity range ( A plurality may be prepared at 0 to 20 km / h, 20 to 40 km / h.

  The position calculation device and the calculation method according to the present invention can be used for a position detection device such as a GPS reception device, and thus can be used in a navigation device or system for in-vehicle use or ship use.

It is a block diagram which shows the structure of the GPS receiver which concerns on the Example of this invention. The angle prediction function used in the present embodiment is shown. FIG. 2 (a) is a straight traveling function, and FIG. 2 (b) is a curve function. It is a flowchart explaining the operation | movement of a present Example. FIG. 4A shows the predicted position calculated by the conventional method, and FIG. 4B shows the predicted position calculated by the present embodiment. It is a figure which shows the example which correct | amended angular velocity (advance angle) by the angle prediction function for curves accidentally at the time of high-speed driving | running | working. It is a flowchart explaining the operation | movement of a 2nd Example. FIG. 7A shows the predicted position calculated by the conventional method, and FIG. 7B shows the predicted position calculated by the second embodiment. It is a block diagram which shows the structure of the navigation apparatus with which the GPS apparatus of a present Example is provided. It is a figure explaining a movement prediction range. It is a figure which shows the conventional angle prediction function. It is a figure explaining the subject of the conventional advance angle correction.

Explanation of symbols

1: GPS receiver 10: Antenna 12: RF receiver 14: Positioning calculator 16: Movement prediction range setting unit 18: Movement prediction range variable unit 20: Positioning data correction unit 22: Angle prediction function storage unit 24: Position calculation unit

Claims (6)

A position calculation device that measures the position of a moving body based on a received radio wave from a positioning satellite and calculates the speed and angular velocity of the moving body based on the positioned position,
A prediction range setting means for setting a prediction range of angular velocity based on an angle prediction function that defines the relationship between the velocity and the angular velocity;
Angular velocity data correction means for determining whether or not the angular velocity data measured this time is within the prediction range, and correcting the angular velocity data so that the angular velocity data is within the prediction range when the angular velocity data is outside the prediction range When,
A prediction range variable means for determining a traveling state of the mobile body and varying an angle prediction function of the prediction range setting means according to the determination result ;
The predictive range variable means determines a straight traveling state when the angle change of the moving body is smaller than a certain value based on the angular velocity at the time of the previous positioning, and determines a curved traveling state when the angular change is equal to or greater than a certain value,
The prediction range setting means sets a first prediction range by a first angle prediction function when it is determined that the vehicle is in a straight traveling state, and performs a second prediction by a second angle prediction function when it is determined that the vehicle is in a curve traveling state. Set a range, the first prediction range is narrower than the second prediction range,
Position calculation device. The prediction range setting means includes a storage unit that stores first and second angle prediction functions, and the prediction range setting means corresponds to the first corresponding to the determination result of the straight running state or the curved running state . Alternatively, the position calculation device according to claim 1, wherein the second angle prediction function is selected, and the angular velocity prediction range is set based on the selected angle prediction function. The position calculation device further determines whether or not a multiplication value of the moving distance of the moving body from the previous positioning (T-1) to the current positioning (T) and the velocity data at the current positioning (T) is greater than or equal to a threshold value. If it is equal to or greater than the threshold, the angular velocity data at the previous positioning (T-1) is used as the angular velocity data at the current positioning (T), and if it is smaller than the threshold, the angular velocity data based on the prediction range having a determination means for correcting the position calculating apparatus according to claim 1 or 2. A position calculation device according to any one of claims 1 to 3 ,
Display control means for displaying the current position of the moving body on the display based on the position information calculated by the position calculating device and displaying a road map around the current position;
Navigation control means for executing a navigation function;
A navigation device. A position calculation method for measuring a position of a moving body based on a received radio wave from a positioning satellite and calculating a speed and an angular velocity of the moving body based on the positioned position,
Obtaining the angular velocity at the time of the previous positioning;
A step of determining a straight traveling state when the angle change of the moving body is smaller than a certain value based on the angular velocity at the time of the previous positioning, and a curve traveling state when exceeding a certain value;
When it is determined that the vehicle is traveling in a straight line, the first prediction range is set by the first angle prediction function, and when it is determined that the vehicle is traveling in a curve, the second prediction range that is wider than the first prediction range by the second angle prediction function. Setting the forecast range;
A step of positioning the angular velocity data to determine whether or not to enter the first or second expected range this,
When the angular velocity data is out of the first or second expected range, and correcting the angular velocity data such that the first or the second expected range,
A position calculation method comprising: The position calculation method further determines whether the product of the moving distance of the moving body from the previous positioning (T-1) to the current positioning (T) and the velocity data at the current positioning (T) is greater than or equal to a threshold value. If it is equal to or greater than the threshold, the angular velocity at the previous positioning (T-1) is set as the angular velocity at the current positioning (T). If it is smaller than the threshold, the angular velocity is within the first or second prediction range. The position calculation method according to claim 5, wherein the correction of the angular velocity data based thereon is performed .

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