Information system for informing users of a public transport network about waiting times at stops in the network

• US 6,253,148 B1
• Filed: 07/01/1998
• Issued: 06/26/2001
• Est. Priority Date: 07/04/1997
• Status: Expired due to Fees

• Current Assignee: Jean-Claude Decaux
• Original Assignee: Jean-Claude Decaux
• Inventors: Decaux, Jean-Claude, Le Gars, Jacques
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): To, Tuan C
• Application Number:
  US09/114,236
• Time in Patent Office: 1,091 Days
• Field of Search: 701/204, 364/436, 364/443, 455/31.2
• US Class Current: 701/204
• CPC Class Codes: G08G 1/123 indicating the position of vehicles, e.g. scheduled vehicles; Managing passenger vehicles circulating according to a fixed timetable, e.g. buses, trains, tramstransmission of navigation instructions to vehicles G08G1/0968

Abstract

An information system for informing users of a bus network about waiting times for buses at stops in the network. The system includes a system for locating buses coupled to a central point which broadcasts said positions at successive instants θ to receivers adapted to calculate waiting times for the buses on the basis of their positions, which positions reach the receivers after a certain average length of “transit” time T. In order to ensure that calculated waiting times as are accurate as possible, the central computer point broadcasts to the receivers estimated positions that the buses are expected to occupy at instant θ+T.

Claims

1. An information system for informing users of a public transport network about waiting times for public transport vehicles at stops of the network, the information system comprising:

electronic information devices each provided with an interface for informing users about waiting times for public transport vehicles, each of said information devices being adapted to determine the waiting times for said public transport vehicles on the basis of successive positions of said public transport vehicles;

a central computer point adapted to broadcast repetitively to the information devices new positions for the public transport vehicles, said broadcasting beginning at successive broadcast instants θ and

said positions reaching the information devices after a certain average transit time T has elapsed from each broadcast instant θ

; and

a locating system adapted to locate the public transport vehicles and to send data to the central computer point representing the position xi(ti) of each public transport vehicle in association with the instant ti at which the vehicle was located;

wherein the central computer point is adapted;

prior to each broadcast instant θ

, to estimate the position xi(θ

+T) that each public transport vehicle is expected to have at instant θ

+T, as a function of the prior positions of the public transport vehicles; and

then, at the broadcast instant θ

, to transmit said estimates xi(θ

+T) to the information devices as the new positions of the public transport vehicles.

2. An information system according to claim 1, in which at least some of the information devices are portable receiver appliances for receiving one-way radio paging, with the positions of the public transport vehicles being broadcast to said information devices by radio.

3. An information system according to claim 1, in which the public transport vehicles are buses.

4. An information system according to claim 1, in which the central computer point is adapted to estimate the position which each public transport vehicle is expected to have at instant θ

+T by calculating a distance Li that said vehicle will normally travel between instants ti and θ

+T, using the formula;

5. An information system according to claim 4, in which, when the most recently known position of said public transport vehicle is not at a stop in the public transport network, the central computer point is adapted to calculate the estimated speed Vi of each public transport vehicle as being an average speed travelled by said public transport vehicle.

6. An information system according to claim 4, in which, when the position of said public transport vehicle as identified by the locating system has been at the same stop for a length of time greater than a predetermined first duration, the central computer point is adapted to calculate the estimated speed Vi of each public transport vehicle as being a past average speed of said public transport vehicle.

7. An information system according to claim 4, in which, when the last known position of the public transport vehicle is for the first time at a stop of the public transport network, the central computer point is adapted to calculate the estimated speed Vi of each public transport vehicle as being equal to zero during a second predetermined duration, followed, after said second predetermined duration has elapsed, by Vi, where Vi is a past average speed of the public transport vehicle in question.

8. An information system according to anyone of claims 5-7, in which said past average speed is calculated over a period having a duration of less than 1 min.

9. An information system according to anyone of claims 5-7, in which said past average speed is an average speed calculated over a period of duration less than 5 min, multiplied by a correction factor lying in the range 1.1 to 1.5.

10. An information system according to anyone of claims 5-7, in which said past speed is the most recent non-zero speed of the public transport vehicle calculated between two successive located positions of said vehicle.

11. An information system according to claim 1, in which the central computer system is adapted to determine whether each public transport vehicle is at a stop of the public transport network if the most recent position is at a distance from said stop which is less than a certain limit value lying in the range of 10 m to 50 m.

12. An information system according to claim 1, in which the positions of the public transport vehicles at instant q+T are estimated by the central computer point as a function of at least one parameter other than the data received from the locating system, the central computer point being adapted to compare the positions estimated in this way with the subsequent real positions of the public transport vehicles, and to adjust said parameter as a function of said comparison.

13. An information system according to claim 1, in which the central computer point is adapted:

to receive data from at least one of the information devices;

to determine after each broadcast instant θ

the real instant at which said information device actually receives the positions as broadcast at said broadcast instant; and

to adjust the value of the average transit time T as a function of a difference between said real instant of reception and said broadcast instant.