JP2737243B2 - Mobile navigation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a navigation device for a mobile object that displays the position of a mobile object such as a vehicle on a display together with a map or the like and supports comfortable driving. By applying the self-contained navigation, which is a basic technology, especially in the dead reckoning section, a more accurate traveling direction is obtained, and as a result, more accurate automatic correction of each detection means is performed, and the current position of the moving object is more accurate. More particularly, the present invention relates to a mobile navigation apparatus for detecting and using an angular velocity of a mobile body.

[Conventional technology]

Attempts to determine the trajectory of a moving object have been made for a long time. A method of detecting the position of the vehicle itself using only a sensor is called self-contained navigation. The self-contained navigation is based on the principle that a running locus is obtained from the measured amounts of a distance sensor and a direction sensor mounted on a car, and the current position is known by adding the locus to the starting point. Navigation using only this sensor is particularly called dead reckoning navigation. Dead reckoning is intended to repeat the closing of detecting a moving object orientation θ at that time and minute distance ΔL advanced automobile, the vector addition to the original position P _i-1 for a new position P _i. The relationship between the original position and the new position is approximately determined by, for example, the following equation.

_{X i = X i-1 +} ΔL · cosθ ...... (1) Y i = Y i-1 + ΔL · sinθ ...... (2) orientation and a method of integrating a method and an angular velocity to measure absolute bearing. A geomagnetic sensor is most often used as an absolute compass, but the geomagnetic orientation obtained therefrom is
Due to interference waves, nearby vehicles, geomagnetic declination, inclination, etc., an error of tens of percent often occurs. Further, the vehicle body may be magnetized by a strong disturbing magnetic field such as a magnetic field caused by an inrush current of an electric trajectory.

As an angular velocity sensor, there is a differential odometer for determining a rotation difference between a so-called rate gyro and left and right wheels. An angular velocity sensor (rotation angle sensor) has a property that accuracy is high when traveling for a short distance, but an absolute azimuth error accumulates when traveling for a medium or long distance. An angular velocity sensor (rotation angle sensor) using a differential odometer has effects on tire wear / air pressure, load weight / balance, road bank, and the like. As described above, since the characteristics of the detection data from the sensor change due to the influence of the outside environment of the sensor, the state of the vehicle, and changes with time, some correction is automatically performed to maintain good usability, that is, to continue continuous driving. Need to be done. For this reason, there are many methods for processing (processing) sensor data, providing a plurality of types of sensors, selectively using data from both, correcting driving conditions of the geomagnetic sensor to correct the influence of magnetization, and correcting detection data. Proposed. As an example of the processing (processing) method of the sensor data, for example, Japanese Patent Publication No. 63-52
Some are disclosed in Japanese Patent Application Laid-Open No. 683 and Japanese Patent Application Laid-Open No. 62-85815. In addition, examples of a method for estimating the azimuth with higher accuracy by selectively using data from both by using an absolute azimuth meter and an angular velocity sensor in combination are, for example, Japanese Patent Publication No. 61-51244 and the aforementioned Japanese Patent Application Laid-Open No. 62-85815. Is disclosed in Japanese Unexamined Patent Application Publication No. 2000-205,878. Examples of the method of correcting the geomagnetic sensor data (or correcting the driving conditions of the sensor) to further compensate for the influence of the magnetization include the rotation angle of the vehicle obtained by the angular velocity sensor and the azimuth vector obtained by the geomagnetic sensor. Japanese Patent Application Laid-Open No. 61-269014 discloses a method of calculating a bearing vector fulcrum (center of a bearing circle) after magnetizing a vehicle body from the coordinates of the tip of the vehicle. JP-A-59-104510 and JP-A-59-104510 disclose examples of correcting a terrestrial magnetic azimuth vector fulcrum based on the difference between the azimuth change of the terrestrial magnetism sensor and the azimuth change of the rotation angle sensor, and correcting the angle error of the rotation angle sensor. JP-A-59-218914
Is disclosed in Japanese Unexamined Patent Application Publication No. 2000-205,878. An example of a method of calibrating the mileage sensor focusing on the fact that the reset amount in map matching is largely due to the error of the sensor is a technology announcement; SANE 87-47 (Sumiten, wheel mileage error correction). It should be noted that, as another conventional technique, a moving direction of a moving body is detected by an in-vehicle sensor.
Japanese Patent Application Laid-Open No. 58-151513 discloses an accurate current position or traveling locus which suppresses the influence of magnetic disturbance. Japanese Patent Application Laid-Open No. 58-17 as a compass
Japanese Unexamined Patent Publication (Kokai) No. 57-84310 discloses an apparatus for detecting the direction of a moving object, which is disclosed in Japanese Patent Application Laid-Open No. 313, and further includes a combination of a geomagnetic azimuth detecting apparatus and a rotation angle detecting apparatus.

[Problems to be solved by the invention]

However, even those using conventional angular velocity detecting means, which are expected to have relatively high accuracy, are vulnerable to various disturbances that may enter the angular velocity detected by the angular velocity detecting means. Therefore, there has been a problem that an abnormal value is occasionally detected, and as a result, it is impossible to expect to obtain an accurate azimuth and an accurate position at any time.

The present invention has been made in order to solve the above problems, for example, in the case of using a differential odometer as an angular velocity detection means, such as when a disturbance due to one of the wheels slipped, An object of the present invention is to provide a navigation device for a mobile object capable of improving the accuracy of the angular velocity and thus the azimuth and position calculations by minimizing the adverse effects of unexpected disturbances to the angular velocity detecting means. And

[Means for solving the problem]

A moving object navigation device according to the present invention includes a speed detecting means for detecting a traveling speed of the moving object, an angular velocity detecting means for detecting an angular velocity of the turning of the moving object, and a traveling speed detected by at least the speed detecting means. Angular velocity determining means for calculating and determining the angular velocity ω of the moving body from a range of centrifugal force that can occur in normal running based on the velocity V and the angular velocity φ detected by the angular velocity detecting means, and an absolute azimuth detecting the absolute surrounding of the moving body Detecting means; and surrounding operation means for calculating the direction Ω at which the moving body is facing based on at least the angular velocity ω of the moving body determined by the angular velocity determining means and the absolute azimuth θ detected by the absolute azimuth detecting means; Moving body position calculating means for subtracting the current position of the moving body based on the speed V and the direction Ω.

(Operation)

In the present invention, the angular velocity determining means may execute predetermined arithmetic processing based on at least the traveling speed of the moving object detected by the traveling speed detecting means and the angular velocity detected by the angular velocity detecting means, and output the corrected angular velocity. it can.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. The drawing is a block diagram of a navigation device for a mobile object according to the present invention.
In the figure, reference numeral 1 denotes a speed detecting means for detecting a traveling speed of a moving body, and is constituted by, for example, a vehicle speed sensor, a counter controlled by a computer, and a computer with a program. Numeral 2 is an angular velocity detecting means for detecting the angular velocity of the turning of the moving body. For example, two angular velocity sensors attached to the left and right wheels of the moving body, two counters controlled by a computer, and a computer program. It is configured. Numeral 3 is a characteristic means of the present invention, which is an angular velocity determining means for calculating and determining the angular velocity of the moving object based on the detected value of the traveling speed of the moving object and the detected value of the angular velocity, and is constituted by a computer program. I have. Numeral 4 denotes an absolute azimuth detecting means for detecting the absolute azimuth of the moving object, such as a fluxgate type geomagnetic azimuth sensor and an A / D converter for converting an analog signal output of the sensor into a digital signal. It is configured. 5 calculates the direction Ω of the moving body based on the angular velocity of the moving body determined by the angular velocity determining means, the traveling speed detected by the speed detecting means, and the absolute azimuth θ of the moving body detected by the absolute azimuth detecting means 4. The azimuth calculating means is constituted by a computer program. Numeral 6 is a moving body position calculating means for calculating the current position of the moving body based on at least the bearing Ω and the traveling speed V detected by the speed detecting means, which is constituted by a computer program. Provided to

Next, the operation of the navigation apparatus for a mobile object according to the present invention will be described.

Each time the moving body travels for a certain period of time, the speed detecting means 1 detects how much distance the vehicle has traveled, that is, at what traveling speed V it is traveling. The angular velocity detecting means 2 detects how much angle the moving body has turned at regular time intervals, that is, how much angular velocity φ has turned. The angular velocity determining means 3 which is a characteristic means of the present invention is based on the traveling speed V of the moving body detected by the speed detecting means 1, and when V <K, φ = 1 / r × V (3) V> In the case of K, φ = F / m × 1 / V (4) where K is a value about the maximum traveling speed at which the moving body can turn while maintaining the substantially minimum turning radius, r is a value about the minimum turning radius, F is a value about the maximum centrifugal force that the moving body can endure in normal running, m is a value about the mass of the moving body, and the absolute value of the function Φ is calculated according to a predetermined computer program. The absolute value of the angular velocity φ detected by the detecting means 2 is compared with the absolute value of the angular velocity φ, and when the absolute value of the angular velocity φ exceeds that value, the moving body angular velocity ω is calculated using the absolute value of the function φ as the upper limit. Absolute azimuth detecting means 4 detects the absolute azimuth of the mobile object facing the mobile object. The azimuth calculating means 5 calculates the azimuth Ω of the moving object based on at least the angular velocity ω and the absolute azimuth θ detected by the absolute azimuth detecting means 4. The moving body position calculating means 6 calculates and outputs the position of the moving body based on the azimuth Ω of the moving body detected by the azimuth calculating means 5 and the traveling speed V of the moving body detected by the speed detecting means 1.

Next, a description will be given of a problem which the conventional navigation apparatus for a mobile object according to the present invention seeks to eliminate, that is, the most typical action on the wheel slip of the mobile object.

If one of the wheels slips excessively despite the normal running of the moving object, the angular velocity detecting means 2 apparently suddenly turns the moving object because one of the wheels rotates at a high speed for a moment. Such abnormal values are detected. However, V = rΦ until the traveling speed V of the moving body reaches a value K which is about the maximum traveling speed at which the moving body can turn while maintaining a substantially minimum turning radius. It is extremely rare, that is, an abnormal situation, and the centrifugal force when the moving body turns in a normal state must be equal to or less than a substantially constant value regardless of the traveling speed, that is, F = mVΦ
Can be assumed to be constant.
In the case where the abnormally large angular velocity value detected including the error caused by the slip exceeds the above-mentioned angular velocity Φ derived from the relational expression such as centrifugal force, the value is clamped and output with the value as an upper limit. Thereafter, the azimuth calculating means 5 performs the calculation of the geomagnetic azimuth θ detected by the absolute azimuth detecting means 4 at predetermined intervals based on the information on the traveling speed detected by the speed detecting means 1 in the same manner as the conventional one. The degree of disturbance and the degree of disturbance of the azimuth information due to the angular velocity ω determined by the angular velocity determining means 3 are detected. The information is added and the bearing Ω of the moving object is output. The moving body position calculating means 6 performs the same calculation as the conventional formulas (1) and (2) from the obtained azimuth Ω of the moving body, the information on the moving distance obtained from the traveling speed V, and the original position information. The position of the moving object is calculated and displayed on a display together with a road map. In addition,
The above-described processing may be executed only when the moving body is not traveling linearly or during acceleration / deceleration.

〔The invention's effect〕

As described above, according to the present invention, the upper limit is set based on the centrifugal force that can occur according to the traveling speed of the moving object, based on the angular velocity detected by the angular velocity detecting means of the turning of the moving object. It is possible to minimize the instantaneous abnormality, which is the greatest drawback of the angular velocity detecting means that requires high accuracy in a short distance section, thereby obtaining a high-precision azimuth, and thus a high-precision moving object It becomes a navigation device.

[Brief description of the drawings]

The drawings are block diagrams of a navigation apparatus for a mobile object according to an embodiment of the present invention. 1 speed detecting means 2 angular speed detecting means 3 angular speed detecting means 4 absolute azimuth detecting means 5 azimuth calculating means 6 moving object position calculating means

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-109313 (JP, A) JP-A 1-254813 (JP, A) JP-A 2-110378 (JP, A) JP-A 62-108 85815 (JP, A) JP-A-57-84310 (JP, A) JP-A-2-501855 (JP, A) JP-A-2-55114 (JP, U) JP-B-62-46809 (JP, B2) Tokiko Sho 61-51244 (JP, B2)

Claims (2)

(57) [Claims] 1. A speed detecting means for detecting a traveling speed of a moving body, an angular velocity detecting means for detecting an angular velocity of turning of the moving body, and at least a traveling speed V detected by the speed detecting means and the angular velocity. An angular velocity determining means for calculating and determining an angular velocity ω of the moving body from a range of centrifugal force that can occur in normal traveling based on the angular velocity φ detected by the detecting means; an absolute azimuth detecting means for detecting an absolute azimuth of the moving body; Azimuth calculating means for calculating the azimuth Ω facing the moving body based on the angular velocity ω of the moving body determined by the angular velocity determining means and the absolute azimuth θ detected by the absolute azimuth detecting means, and at least the traveling speed V and the azimuth Ω And a moving body position calculating means for subtracting a current position of the moving body based on the moving object. 2. The azimuth calculating means includes: at least a traveling speed V detected by the speed detecting means, an angular velocity ω of the moving body determined by the angular velocity determining means, and an absolute azimuth θ detected by the absolute azimuth detecting means. 2. The navigation system for a mobile object according to claim 1, wherein the heading Ω is calculated.