POSITIONING SYSTEM AND METHOD

• US 20120274515A1
• Filed: 11/04/2010
• Published: 11/01/2012
• Est. Priority Date: 11/04/2009
• Status: Active Grant

• Current Assignee: Gamesontrack A/S
• Original Assignee: Gamesontrack A/S
• Inventors: Theilgaard, Niels Bo
• Granted Patent: US 9,063,218 B2
• Time in Patent Office: Days
• US Class Current: 342/463
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location

Abstract

The present invention relates to a positioning system and method. The system and the method are particularly well-suited for indoor positioning of several idle objects or moving objects, preferably with very short time between two successive position determinations. According to the invention, two signals of different propagation velocities (preferably ultra-sound and radio frequency) are sent out by an object. Alternatively, the radio signal can be sent out from a central unit. Preferably the transmission takes place simultaneously. Based on the time difference between reception of the two signals at two or more base receivers, the position of the object relative to the basic positions is determined.

Claims

1. A method for determination of an object'"'"'s position in relation to two or more basic positions, comprising:

transmission of a first signal from either a transmitter placed on the object or from a transmitter placed externally in a central unit, and a second signal from a transmission system placed on the object, wherein the two signals are selected so that the propagation velocity of the first signal through the object'"'"'s ambient atmosphere is substantially higher than the propagation velocity of the second signal, wherein the first signal is a radio signal within the range of 700 MHz to 2.4 GHz and wherein the second signal is an ultra-sound signal within the range of 30 kHz to 80kHz;

reception of the two transmitted signals with at least two base receivers, each placed at one of the two or more basic positions at a given distance from each other;

determination in each base receiver of a signal level of the second signal received in the given base receiver resulting in a total of two or more signal levels;

determination of the time difference between reception of the two signals in each base receiver;

wherein determination of the time difference comprises start of a timer at reception of the first signal and stop of the timer at reception of the second signal, provided that the first signal and the second signal are each exceeding pre-defined threshold values, and

calculation of the object'"'"'s position in relation to the basic positions by selecting two or more base receivers having the highest signal levels and being above a pre-defined threshold value for the second signal defining a lower limit value below which the second signal is not applied for position determination on the basis of the specific time difference, wherein a choice of the two or more base receivers to be used in the determination of the time difference is made on the basis of a highest signal level of the second signal and calculating the object'"'"'s position on the basis of the determined time differences and the basic positions of the selected two or more base receivers.

10. The method according to claim 1, wherein transmission of the first and the second signal is initiated by a time sharing and identification of each object controlled from the central unit.

11. The method according to claim 1, wherein the initialization signal comprises an identification, which uniquely identifies a given transmitter and, wherein the method comprises detection of the received initiation signal from the transmission systems and transmission of at least one other signal if an object transmission system detects a match between the initiation signal and the object transmission system'"'"'s identification.

12. The method according to claim 1, wherein the ultra-sound signal is transmitted from the ultra-sound transmitter through a given geometric construction in the transmitter through which the ultra-sound signal is transmitted via the transmission system, so that the signal strength is concentrated in the direction of the receivers.

13. The method according to claim 1, wherein the distance from an object to a given base receiver is calculated on the basis of an assumption that the first signal is received simultaneously with the transmission of such signal and the distance in this connection is calculated substantially as the propagation velocity of the second signal multiplied by the time lapse between reception of the first and the second signal.

2-9. -9. (canceled)

14. A positioning system for determination of an object'"'"'s position in relation to two or more basic positions, comprising:

one or more transmitter(s) either placed on the object and/or placed externally of the object in a central unit and, wherein said transmitter is adapted for transmission of a first signal;

a transmission system placed on the object for transmission of a second signal, wherein the first signal is a radio signal within the range of 700 MHz to 2.4 GHz and, wherein the second signal is an ultra-sound signal within the range of 30 kHz to 80 kHz;

wherein the transmission of signals takes place simultaneously and the selection of the two signals is such that the propagation velocity of the first signal through the objects ambient atmosphere is substantially higher than the propagation velocity of the second signal;

a number of base receivers each placed at one of the two or in its more basic positions at a given distance from each other for the reception of the two transmitted signals;

a detector in each base receiver adapted to determine a signal level of the second signal received in the given base receiver resulting in a total of two or more signal levels; and

a computer adapted to determine the time difference between reception of the two signals in each base receiver and a detector for determination of the second signal'"'"'s strength;

wherein determination of the time difference comprises start of a timer at the reception of the first signal and stop of the timer at the reception of the second signal, provided that the first signal and the second signal both exceed pre-defined threshold values, wherein

the computer is further adapted to calculate the object'"'"'s position in relation to the basic positions by selecting two or more base receivers having the highest signal levels and being above a pre-defined threshold value for the second signal defining a lower limit value below which the second signal is not applied for position determination on the basis of the specific time difference, wherein a choice of the two or more base receivers to be used in the determination of the time difference is made on the basis of a highest signal level of the second signal and calculating the object'"'"'s position on the basis of the determined time differences and the basic positions of the selected two or more base receivers.

15. The positioning system according to claim 14, wherein the central unit includes or is connected to a screen displaying X-Y-Z positions and the driven routes of all objects in real time.

16. The positioning system according to claim 14, wherein the objects are model trains, whereby identification and control of each train'"'"'s movements and positions and passages of manually drawn sections on the screen on top of the automatically drawn track plan.

17. The positioning system according to claim 14, wherein the objects are self-propelled trains, robots and cars;

whereby the same objects'"'"' routes and positions are applied for control of task solving or games in relation to a task plan or game plan on a screen.