Guidance method and system for an automotive vehicle

Claim 1

A method of guiding an automotive vehicle in accordance with at least three navigational electromagnetic wave signals transmitted from at least three fixed stations, which comprises the following steps: (a) receiving the at least three navigational electromagnetic wave signals synchronously transmitted from the at least three fixed stations; (b) detecting the differences in receive time between at least three navigational electromagnetic wave signals; (c) determining at least two hyperbolas in accordance with the detected difference in receive time between the three navigational electromagnetic wave signals; (d) calculating a point of intersection of the at least two determined hyperbolas to obtain a vehicle position on the basis of navigational electromagnetic wave signals; (e) storing sequencially the vehicle position calculated on the basis of navigational electromagnetic wave signals; (f) detecting vehicle orientation in which the vehicle is travelling; (g) detecting vehicle speed at which the vehicle is travelling; (h) calculating a distance over which the .vehicle has travelled in accordance with the detected vehicle orientation and the detected vehicle speed; (i) adding the distance calculated on the basis of vehicle orientation and vehicle speed to the current stored vehicle position calculated on the basis of navigational electromagnetic wave signals in order to obtain a vehicle position calculated on the basis of vehicle orientation and vehicle speed; (j) detecting the field strengths of the at least three navigational electromagnetic wave signals; (k) comparing the detected field strengths with a predetermined -lower limit; and (1) selecting and displaying the vehicle position calculated on the basis of navigational electromagnetic wave signals when the detected field strengths are all beyond the predetermined lower limit and the vehicle position calculated on the basis of vehicle orientation and vehicle speed when any one of the detected field strengths is below the predetermined lower limit.

Claim 2

A method of guiding an automotive vehicle in accordance with at least three navigational electromagnetic wave signals transmitted from at least three fixed stations, which comprises the following steps: (a) receiving the at least three navigational electromagnetic wave signals synchronously transmitted from the at least three fixed stations; (b) detecting the differences in receive time between at least three navigational electromagnetic wave signals; (c) determining at least two hyperbolas in accordance with the detected difference in receive time between the three navigational electromagnetic wave signals; (d) calculating a point of intersection of the at least two determined hyperbolas to obtain a vehicle position on the basis of navigational electromagnetic wave signals; (e) storing sequencially the vehicle position calculated on the basis of navigational electromagnetic wave signals; (f) detecting vehicle orientation in which the vehicle is travelling; (g) detecting vehicle speed at which the vehicle is travelling; (h) calculating a distance over which the .vehicle has travelled in accordance with the detected vehicle orientation and the detected vehicle speed; (i) adding the distance calculated on the basis of vehicle orientation and vehicle speed to the current stored vehicle position calculated on the basis of navigational electromagnetic wave signals in order to obtain a vehicle position calculated on the basis of vehicle orientation and vehicle speed; (j) detecting the field strengths of the at least three navigational electromagnetic wave signals; (k) comparing the detected field strengths with a predetermined -lower limit; and (1) selecting and displaying the vehicle position calculated on the basis of navigational electromagnetic wave signals when the detected field strengths are all beyond the predetermined lower limit and the vehicle position calculated on the basis of vehicle orientation and vehicle speed when any one of the detected field strengths is below the predetermined lower limit.

Claim 3

A method of guiding an automotive vehicle in accordance with at least three navigational electromagnetic wave signals transmitted from at least three fixed stations, which comprises the following steps: (a) receiving the at least three navigational electromagnetic wave signals synchronously transmitted from the at least three fixed stations; (b) detecting the differences in receive time between at least three navigational electromagnetic wave signals; (c) determining at least two hyperbolas in accordance with the detected difference in receive time between the three navigational electromagnetic wave signals; (d) calculating a point of intersection of the at least two determined hyperbolas to obtain a vehicle position on the basis of navigational electromagnetic wave signals; (e) storing sequencially the vehicle position calculated on the basis of navigational electromagnetic wave signals with a delay; (f) detecting vehicle orientation in which the vehicle is travelling; (g) detecting vehicle speed at which the vehicle is travelling; (h) calculating a distance over which the vehicle has travelled in accordance with the detected vehicle orientation and the detected vehicle speed; (i) adding the distance calculated on the basis of vehicle orientation and vehicle speed to the current stored vehicle position calculated on the basis of navigational electromagnetic wave signals in order to obtain a vehicle position calculated on the basis of vehicle orientation and vehicle speed; . (j) detecting the field strengths of the at least three navigational electromagnetic wave signals; (k) comparing the deteted field strengths with a predetermined lower limit; (1) generating a signal indicative of a vehicle position with a large positive position error on the basis of navigational electromagnetic wave signals when any one of the detected field strengths is below the predetermined lower limit; (m) calculating the vehicle speed according to the generated signal indicative of the vehicle position calculated on the basis of navigational electromagnetic wave signals; (n) comparing the calculated vehicle speed with the detected vehicle speed; and (o) selecting and displaying the vehicle position calculated on the basis of navigational electromagnetic wave signals when the calculated vehicle-speed is roughly equal to the detected vehicle speed and the vehicle position calculated on the basis of vehicle orientation and vehicle speed when the calculated vehicle speed is excessively greater than the detected vehicle speed.

Claim 4

A method of guiding an automotive vehicle in accordance with at least three navigational electromagnetic wave signals transmitted from at least three fixed stations, which comprises the following steps: (a) receiving the at least three navigational electromagnetic wave signals synchronously transmitted from the at least three fixed stations; (b) detecting the differences in receive time between at least three navigational electromagnetic wave signals; (c) determining at least two hyperbolas in accordance with the detected difference in receive time between the three navigational electromagnetic wave signals; (d) calculating a point of intersection of the at least two determined hyperbolas to obtain a vehicle position on the basis of navigational electromagnetic wave signals; (e) storing sequencially the vehicle position calculated on the basis of navigational electromagnetic wave signals with a delay; (f) detecting vehicle orientation in which the vehicle is travelling; (g) detecting vehicle speed at which the vehicle is travelling; (h) calculating a distance over which the vehicle has travelled in accordance with the detected vehicle orientation and the detected vehicle speed; (i) adding the distance calculated on the basis of vehicle orientation and vehicle speed to the current stored vehicle position calculated on the basis of navigational electromagnetic wave signals in order to obtain a vehicle position calculated on the basis of vehicle orientation and vehicle speed; . (j) detecting the field strengths of the at least three navigational electromagnetic wave signals; (k) comparing the deteted field strengths with a predetermined lower limit; (1) generating a signal indicative of a vehicle position with a large positive position error on the basis of navigational electromagnetic wave signals when any one of the detected field strengths is below the predetermined lower limit; (m) calculating the vehicle speed according to the generated signal indicative of the vehicle position calculated on the basis of navigational electromagnetic wave signals; (n) comparing the calculated vehicle speed with the detected vehicle speed; and (o) selecting and displaying the vehicle position calculated on the basis of navigational electromagnetic wave signals when the calculated vehicle-speed is roughly equal to the detected vehicle speed and the vehicle position calculated on the basis of vehicle orientation and vehicle speed when the calculated vehicle speed is excessively greater than the detected vehicle speed.

Claim 6

A system of guiding an automotive vehicle in .accordance with at least three navigational electromagnetic wave signals transmitted from at least three fixed stations, which comprises: (a) a receiver for receiving the at least three navigational electromagnetic wave signals synchronously transmitted from the at least three fixed stations and for generating signals corresponding thereto; (b) a position detection unit connected to said receiver for detecting differences in receive time between at least three navigational electromagnetic wave signals, for determining at least two hyperbolas in accordance with the detected difference in receive time between the three navigational wave signals, for calculating a point of intersection of the at least two determined hyperbolas, and for outputting a signal indicative of a vehicle position calculated on the basis of navigational electromagnetic wave signals; (c) a vehicle orientation sensor for detecting vehicle orientation in which the vehicle is travelling and for outputting signals corresponding thereto; (d) a vehicle speed sensor for detecting vehicle speed at which the vehicle is travelling and for outputting signals corresponding thereto; (e) a position calculating unit connected to said vehicle orientation sensor, said speed sensor, and said position detection unit for calculating a distance over which the vehicle has travelled in accordance with the detected vehicle orientation and the detected vehicle speed, for sequencially storing the vehicle position calculated on the basis of navigational wave signals, for adding the distance calculated on the basis of vehicle orientation and vehicle speed to the current stored vehicle position calculated on the basis of navigational electromagnetic wave signals, and for outputting a signal indicative of a vehicle position calculated on the basis of vehicle orientation and vehicle speed; (f) a receive-state detection unit connected to said receiver for detecting field strengths of the at least three navigational electromagnetic wave signals, for comparing the detected field strengths with a predetermined lower limit, and for outputting no signal when the detected field strengths are all beyond the lower limit and an output signal when any one of the detected field strengths is below the lower limit; (g) a selector connected to said position calculating unit, said position detection unit, and said receive-state ditection unit for selecting the signal generated from said position detection unit when said receive-state detection unit outputs no signal and the signal generated from said position calculating unit when said receive-state detection unit outputs an output signal; and (h) a display unit connected to said selector for selectively display the signals generated from said .position detection unit and from said position calculating unit; whereby the vehicle positions are displayed; on the basis of navigational electromagnetic wave signals when the field strengths are all beyond the predetermined lower limit and on the basis of vehicle orientation and vehicle speed when any one of the field strengths is below the predetermined lower limit.

Claim 7

A system of guiding an automotive vehicle in .accordance with at least three navigational electromagnetic wave signals transmitted from at least three fixed stations, which comprises: (a) a receiver for receiving the at least three navigational electromagnetic wave signals synchronously transmitted from the at least three fixed stations and for generating signals corresponding thereto; (b) a position detection unit connected to said receiver for detecting differences in receive time between at least three navigational electromagnetic wave signals, for determining at least two hyperbolas in accordance with the detected difference in receive time between the three navigational wave signals, for calculating a point of intersection of the at least two determined hyperbolas, and for outputting a signal indicative of a vehicle position calculated on the basis of navigational electromagnetic wave signals; (c) a vehicle orientation sensor for detecting vehicle orientation in which the vehicle is travelling and for outputting signals corresponding thereto; (d) a vehicle speed sensor for detecting vehicle speed at which the vehicle is travelling and for outputting signals corresponding thereto; (e) a position calculating unit connected to said vehicle orientation sensor, said speed sensor, and said position detection unit for calculating a distance over which the vehicle has travelled in accordance with the detected vehicle orientation and the detected vehicle speed, for sequencially storing the vehicle position calculated on the basis of navigational wave signals, for adding the distance calculated on the basis of vehicle orientation and vehicle speed to the current stored vehicle position calculated on the basis of navigational electromagnetic wave signals, and for outputting a signal indicative of a vehicle position calculated on the basis of vehicle orientation and vehicle speed; (f) a receive-state detection unit connected to said receiver for detecting field strengths of the at least three navigational electromagnetic wave signals, for comparing the detected field strengths with a predetermined lower limit, and for outputting no signal when the detected field strengths are all beyond the lower limit and an output signal when any one of the detected field strengths is below the lower limit; (g) a selector connected to said position calculating unit, said position detection unit, and said receive-state ditection unit for selecting the signal generated from said position detection unit when said receive-state detection unit outputs no signal and the signal generated from said position calculating unit when said receive-state detection unit outputs an output signal; and (h) a display unit connected to said selector for selectively display the signals generated from said .position detection unit and from said position calculating unit; whereby the vehicle positions are displayed; on the basis of navigational electromagnetic wave signals when the field strengths are all beyond the predetermined lower limit and on the basis of vehicle orientation and vehicle speed when any one of the field strengths is below the predetermined lower limit.

Claim 8

A system of guiding an automotive vehicle in accordance with at least three navigational electromagnetic, wave signals transmitted from at least three fixed stations, which comprises: (a) a receiver for receiving the at least three navigational electromagnetic wave signals synchronously transmitted from the at least three fixed stations, for comparing the received field strengths with a predetermined lower limit, and for generating received and compared signals corresponding thereto; (b) a position detection unit connected to said receiver for detecting differences in receive time between at least three navigational electromagnetic wave signals, for determining at least two hyperbolas in accordance with the detected difference in receive time between the three navigational wave signals, for calculating a point of intersection of the at least two determined hyperbolas, for outputting a signal indicative of a vehicle position calculated on the basis of navigational wave signals when field strengths of navigational electromagnetic wave signals are all beyond a predetermined lower limit and an error signal indicative of a vehicle position with a large positive error when any one of the detected field strengths is below the predetermined lower limit; (c) a vehicle orientation sensor for detecting vehicle orientation in which the vehicle is travelling and for outputting signals corresponding thereto; (d) a vehicle speed sensor for detecting vehicle speed at which the vehicle is travelling and for outputting signals corresponding thereto; (e) a delay memory connected to said position detection unit for outputting the signal from said position detection unit with a delay; (f) a position calculating unit connected to said vehicle orientation sensor, said vehicle speed sensor, and said delay memory, for calculating a distance over which the vehicle has travelled in accordance with the detected vehicle orientation and the detected vehicle speed, for sequencially storing the delayed signal from said position detection unit, for adding the distance calculated on the basis of vehicle orientation and vehicle speed to the current stored vehicle position calculated on the basis of navigational electromagnetic wave signals, and for outputting a signal indicative of a vehicle position calculated on the basis of vehicle orientation and vehicle speed; (g) a speed calculating unit connected to said position detection unit for calculating the vehicle speed according to the generated signal indicative of the vehicle position calculated on the basis of navigational electromagnetic wave signals; (h) a comparator connected to said position calculating unit and said speed calculating unit for comparing the calculated vehicle speed with the detected vehicle speed and for outputting no signal when the calculated vehicle speed is roughly equal to the detected vehicle speed and an output' signal when the calculated vehicle speed is excessively greater than the detected vehicle speed; (i) a selector connected to said position calculating unit, said position detection unit, and said comparator for selecting the signal generated from said position detection unit when said comparator outputs no signal and the signal generated from said position calculating unit when said comparator outputs an output signal; (j) a display unit connected to said selector for selectively display the signals generated from said position detection unit and from said position calculating unit; whereby the vehicle positions are displayed on the basis of navigational electromagnetic wave signals when .the field strengths are all beyond the predetermined lower limit and on the basis of vehicle orientation and vehicle speed when any one of the field strengths is below the predetermined lower limit.

Claim 9

A system of guiding an automotive vehicle in accordance with at least three navigational electromagnetic, wave signals transmitted from at least three fixed stations, which comprises: (a) a receiver for receiving the at least three navigational electromagnetic wave signals synchronously transmitted from the at least three fixed stations, for comparing the received field strengths with a predetermined lower limit, and for generating received and compared signals corresponding thereto; (b) a position detection unit connected to said receiver for detecting differences in receive time between at least three navigational electromagnetic wave signals, for determining at least two hyperbolas in accordance with the detected difference in receive time between the three navigational wave signals, for calculating a point of intersection of the at least two determined hyperbolas, for outputting a signal indicative of a vehicle position calculated on the basis of navigational wave signals when field strengths of navigational electromagnetic wave signals are all beyond a predetermined lower limit and an error signal indicative of a vehicle position with a large positive error when any one of the detected field strengths is below the predetermined lower limit; (c) a vehicle orientation sensor for detecting vehicle orientation in which the vehicle is travelling and for outputting signals corresponding thereto; (d) a vehicle speed sensor for detecting vehicle speed at which the vehicle is travelling and for outputting signals corresponding thereto; (e) a delay memory connected to said position detection unit for outputting the signal from said position detection unit with a delay; (f) a position calculating unit connected to said vehicle orientation sensor, said vehicle speed sensor, and said delay memory, for calculating a distance over which the vehicle has travelled in accordance with the detected vehicle orientation and the detected vehicle speed, for sequencially storing the delayed signal from said position detection unit, for adding the distance calculated on the basis of vehicle orientation and vehicle speed to the current stored vehicle position calculated on the basis of navigational electromagnetic wave signals, and for outputting a signal indicative of a vehicle position calculated on the basis of vehicle orientation and vehicle speed; (g) a speed calculating unit connected to said position detection unit for calculating the vehicle speed according to the generated signal indicative of the vehicle position calculated on the basis of navigational electromagnetic wave signals; (h) a comparator connected to said position calculating unit and said speed calculating unit for comparing the calculated vehicle speed with the detected vehicle speed and for outputting no signal when the calculated vehicle speed is roughly equal to the detected vehicle speed and an output' signal when the calculated vehicle speed is excessively greater than the detected vehicle speed; (i) a selector connected to said position calculating unit, said position detection unit, and said comparator for selecting the signal generated from said position detection unit when said comparator outputs no signal and the signal generated from said position calculating unit when said comparator outputs an output signal; (j) a display unit connected to said selector for selectively display the signals generated from said position detection unit and from said position calculating unit; whereby the vehicle positions are displayed on the basis of navigational electromagnetic wave signals when .the field strengths are all beyond the predetermined lower limit and on the basis of vehicle orientation and vehicle speed when any one of the field strengths is below the predetermined lower limit.