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US3877666A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for the continuous detection of vehicle position

Assignee: Japan National Railways
•
Filing: 1974-02-07
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Granted: 1975-04-15
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Expires: 1994-02-07
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Abstract

Abstract The present invention relates to a method for the continuous detection of vehicle position, by which the position of a moving railway vehicle can be continuously detected. The vehicle is equipped with a transmitter that can transmit, through an antenna, a high frequency magnetic field at a constant frequency and amplitude. On the group a plurality of induction lines are laid in the travel direction of the vehicle. The induction lines have a plurality of nodal points of transposition at equal intervals in the travel direction of the vehicle. The inter-nodal distance on each induction line is the same and all these induction lines are so laid that the nodal points on each line are staggered by a certain distance from nodal points on the other lines in the travel direction of the vehicle. Thus, if the number of induction lines laid is n, the nodal points on these lines will successively staggered by an inter-nodal distance of 1l(n-1)/n. The antenna on the vehicle and the induction lines on the ground are laid out parallel to each other in the horizontal direction with a predetermined separation from each other so that they are electromagnetically coupled. The signal applied by the vehicle to each of the induction lines is a sine wave with a wavelength equal to twice the internodal distance. The received voltages induced in all the induction lines except one are shifted in phase by 180* X (n-1)/n in the minus and plus directions. Then the induced voltage on the unshifted induction line and n-1 induced voltages phase-shifted in the minus direction are added together, while the induced voltage on the unshifted induction line and n-1 induced voltages phaseshifted in the plus direction are added together. Thus by measuring the phase difference between these two synthetic waves the position of the vehicle can be continuously detected.

Inventors

  • 👤 Eiji Itakura
  • 👤 Toshiaki Sasaki

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 04:20
CPC Classifications
B; B61; B61L; B61L25/00; B61L25/02

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 200 words
A method of continuously detecting the position of a vehicle wherein the vehicle includes means for transmitting a magnetic field of a predetermining frequency and amplitude; and the vehicle travels parallel to a plurality of induction lines, wherein the number of induction lines equals n, each induction line having a plurality of nodal points of transposition, the inter-nodal distance being the same between all the nodal points on all of the induction lines, wherein the nodal points in each induction line are staggered with respect to the nodal points on adjacent induction lines by a distance of (n-l)/n (the distance between nodes), said method comprising the steps of transmitting a signal from the vehicle to the induction lines and thereby inducing a sine wave voltage in each of the induction lines; successively phase shifting said induced signal in each of the induction lines except one by an amount equal to 180* (n-1)/n in both the positive and negative direction; adding all of said positively shifted signals and said non-shifted signal; adding all of said negatively shifted signals and said non-shifted signals; comparing the phase difference of said added signals, the phase difference being indicative of the position of the vehicle.
Claim 2
Independent Claim 200 words
A method of continuously detecting the position of a vehicle wherein the vehicle includes means for transmitting a magnetic field of a predetermining frequency and amplitude; and the vehicle travels parallel to a plurality of induction lines, wherein the number of induction lines equals n, each induction line having a plurality of nodal points of transposition, the inter-nodal distance being the same between all the nodal points on all of the induction lines, wherein the nodal points in each induction line are staggered with respect to the nodal points on adjacent induction lines by a distance of (n-l)/n (the distance between nodes), said method comprising the steps of transmitting a signal from the vehicle to the induction lines and thereby inducing a sine wave voltage in each of the induction lines; successively phase shifting said induced signal in each of the induction lines except one by an amount equal to 180* (n-1)/n in both the positive and negative direction; adding all of said positively shifted signals and said non-shifted signal; adding all of said negatively shifted signals and said non-shifted signals; comparing the phase difference of said added signals, the phase difference being indicative of the position of the vehicle.
Claim 3
Dependent Claim 18 words
The method of claim 1, wherein the wavelength of said transmitted signal is twice the distance between nodes.
Claim 4
Independent Claim 209 words
A method of continuously detecting the position of a vehicle wherein the vehicle includes means for transmitting a magnetic field of a predetermined frequency and amplitude; and the vehicle travels parallel to a plurality of pairs of induction lines, wherein the number of pairs of induction lines equals n, each induction line having a plurality of nodal points of transposition, the inter-nodal distance being the same between all the nodal points on all of the induction lines, wherein the nodal points in each pair of induction lines are staggered with respect to the nodal points on adjacent pairs of induction lines by a distance of (n-1)/n (the distance between nodes), said method comprising the steps of transmitting a signal from the vehicle to the pairs of induction lines and thereby inducing a sine wave voltage in each of the induction lines; rectifying and Adding said induced voltages in each pair of induction lines; generating an ac signal; separately modulating said ac signal with each of said rectified added signals; successively phase-shifting each of said modulated signals except one by 180* (n/n-1); adding said phase shifted and non-shifted signal; comparing the phase of said added signals to said ac signal, the difference being indicative of the position of the vehicle.
Claim 5
Independent Claim 209 words
A method of continuously detecting the position of a vehicle wherein the vehicle includes means for transmitting a magnetic field of a predetermined frequency and amplitude; and the vehicle travels parallel to a plurality of pairs of induction lines, wherein the number of pairs of induction lines equals n, each induction line having a plurality of nodal points of transposition, the inter-nodal distance being the same between all the nodal points on all of the induction lines, wherein the nodal points in each pair of induction lines are staggered with respect to the nodal points on adjacent pairs of induction lines by a distance of (n-1)/n (the distance between nodes), said method comprising the steps of transmitting a signal from the vehicle to the pairs of induction lines and thereby inducing a sine wave voltage in each of the induction lines; rectifying and Adding said induced voltages in each pair of induction lines; generating an ac signal; separately modulating said ac signal with each of said rectified added signals; successively phase-shifting each of said modulated signals except one by 180* (n/n-1); adding said phase shifted and non-shifted signal; comparing the phase of said added signals to said ac signal, the difference being indicative of the position of the vehicle.
Claim 6
Dependent Claim 20 words
The method of claim 3, wherein said modulated signal may be phase shifted in either the positive or negative direction.

References Cited (Backward Citations)

US3740549A Cited
US3786411A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-04-14 1978-10-14 1979-04-15 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-04-14 1982-10-14 1983-04-15 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-04-14 1986-10-14 1987-04-15 $7700.00 Window Closed / Lapsed

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