Navigation system using angular rate sensor

• US 4,882,689 A
• Filed: 02/09/1988
• Issued: 11/21/1989
• Est. Priority Date: 02/10/1987
• Status: Expired due to Term

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Aoki, Yoshihito
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/154,028
• Time in Patent Office: 651 Days
• Field of Search: 364/443, 364/444, 364/449, 73/178 R, 342/450, 342/451, 340/988, 340/990, 340/995
• US Class Current: 701/209
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30

Abstract

In a navigation system by which vehicle travel locations are detected by an angular rate sensor and a distance sensor and the detected vehicle travel locations are corrected so as to be displayed along a map road, when a detected vehicle travel angle exceeds a predetermined value under the condition that the vehicle is out of a route judge area set at each branch point, an abnormal travel is detected and alarmed while displaying an abnormal vehicle location. Further, when a travel route change cannot be determined after the vehicle has passed through the set route judge area, an abnormal location is also displayed and alarmed.

Claims

1. A navigation system for displaying travel locations of a vehicle on a displayed map, comprising:

(a) means for detecting vehicle travel angle;

(b) means for detecting vehicle travel distance;

(c) means coupled to said vehicle travel angle detecting means and said vehicle travel distance detecting means for calculating vehicle locations on the basis of the detected vehicle travel angles and distances;

(d) means for storing map information data including branch points;

(e) means coupled to said map information data storing means for setting a route judge area at each branch point to determine a route along which the vehicle travels from a branch point;

(f) means coupled to said vehicle distance detecting means said map storing means and said route judge area setting means, for determining vehicle passing into the set route judge area (JE) when a distance (Lc) between a current vehicle location (Pa) and a succeeding branch Point (P₁) becomes shorter than a first predetermined distance and vehicle passing through the set route judge area when a distance (MM) between a position (Pa), at which vehicle enters the set route judge area, and a current vehicle location (Pc) becomes longer than a second predetermined distance;

(g) means coupled to said vehicle travel angle detecting means and said route judge area pass determining means for determining a travel route at each branch point by comparing a travel angle detected by said travel angle detecting means with map data stored in said map data storing means when the vehicle has passed through the set route judge area;

(h) means coupled to said vehicle location calculating means and said travel route determining means, for correcting said calculated vehicle locations (Pn) so as to be located along a road on a displayed map in accordance with expressions;

(i) means coupled to said vehicle location correcting means and said route judge area pass determining means for detecting an abnormal travel when a detected vehicle travel angle exceeds a predetermined angle under the condition that said route judge area pass determining means determines that the vehicle is out of the set route judge area;

(j) means coupled to said abnormal travel detecting means for storing a current vehicle travel location and generating an alarm signal when said abnormal travel detecting means detects said abnormal travel; and

(k) means coupled to said location storing and alarm generating means and said map data storing means for displaying a map stored in said map information data storing means, vehicle locations calculated by said calculating means and corrected by said location correcting means, the stored vehicle located at which the abnormal travel is detected and abnormal vehicle locations deviated from a map route.

2. The navigation system as set forth in claim 1, wherein when said travel route determining means cannot detect a travel route change after said route judge area pass determining means detects that the vehicle has passed through the set route judge area, said location storing and alarm generating means stores a current abnormal location and generates said alarm signal.

3. A method of displaying travel locations of a vehicle along a displayed map, which comprises the following steps of:

(a) detecting vehicle travel angles;

(b) detecting vehicle travel distances;

(c) calculating vehicle locations on the basis of said detected vehicle travel angles and distances;

(d) storing map information data including branch points;

(e) setting a route judge area at each branch point to determine a route along which the vehicle travels from a branch point;

(f) determining vehicle passing into the set route judge area on the basis of a distance between a current vehicle location and a succeeding branch point and vehicle passing through the set route judge area on the basis of a travel distance from a position at which the vehicle enters the route judge area and said current vehicle location;

(g) determining a travel route by comparing a detected travel angle with the stored map data when the vehicle has passed through the set route judge area;

(h) correcting said calculating vehicle locations so as to be located along a road on a displayed map in accordance with expressions;

(i) detecting an abnormal travel when a detected vehicle travel angle exceeds a predetermined angle under the condition that the vehicle is out of the set route judge area;

(j) storing a current vehicle travel location, and generating an alarm signal when said abnormal travel is detected; and

(k) displaying a stored map, the calculated and corrected vehicle locations, a detected abnormal travel location, and abnormal vehicle locations deviated from a map route simultaneously.

4. The method of displaying travel locations of a vehicle as set forth in claim 3, which further comprises the following steps of:

storing a current abnormal location and generating an abnormal signal when a travel route change cannot be detected after the vehicle has passed through the set route judge area.