Object locator system

• US 5,446,701 A
• Filed: 08/10/1993
• Issued: 08/29/1995
• Est. Priority Date: 08/28/1992
• Status: Expired due to Fees

• Current Assignee: TEEM Systems Incorporated
• Original Assignee: TEEM Systems Incorporated
• Inventors: Ellingson, Gary L., Eidsness, John L., Van de Loo, Dale P., Utke, Reinhold E., Aslakson, Joel T.
• Primary Examiner(s): Eldred, J. Woodrow
• Application Number:
  US08/104,813
• Time in Patent Office: 749 Days
• Field of Search: 367/118, 367/124, 367/125, 367/127, 367/129, 367/128
• US Class Current: 367/118
• CPC Class Codes: A63B 2024/0028 Tracking the path of an object, e.g. a ball inside a soccer pitch
• CPC Class Codes: A63B 2024/0031 at the starting point
• CPC Class Codes: A63B 2024/004 Multiple detectors or sensors each defining a different zone
• CPC Class Codes: A63B 2220/13 Relative positions
• CPC Class Codes: A63B 2220/802 Ultra-sound sensors
• CPC Class Codes: A63B 2225/02 Testing, calibrating or measuring of equipment
• CPC Class Codes: A63B 2225/50 Wireless data transmission, e.g. by radio transmitters or telemetry
• CPC Class Codes: A63B 2243/0025 Football
• CPC Class Codes: A63B 2243/007 American football
• CPC Class Codes: A63B 24/0021 Tracking a path or terminating locations
• CPC Class Codes: A63B 43/00 Balls with special arrangements
• CPC Class Codes: A63B 71/0605 Decision makers and devices using detection means facilitating arbitration
• CPC Class Codes: G01S 1/026 of associated receivers
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: G01S 5/22 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/28 takes precedence

Abstract

An object locating system, especially for use in locating a gaming ball in the game of football, utilizes a series of three sensors positioned on one side of a football playing field and a calibration source positioned on the other side. The calibration source emits an ultrasonic signal which is received by the sensors in order to provide a calibration signal. A ball marking unit is positionable on the field at a location of the ball and emits an ultrasonic signal which is received by the sensors and an RF signal which is received by the calibration source in order to turn the calibration source off. The sensors provide signals in which a processing unit calculates time delays by a time acquisition process in order to determine the position of the ball. In an alternate embodiment, the ball marking unit emits only an RF signal which is received by the sensors. The sensors again provide signals which are analyzed by the processing unit to determine delay between receipt of the signals at the sensors. Additionally, an automatic ball marking unit on a track drive can be controlled by the processing unit to automatically provide a visual representation of the ball'"'"'s location.

Claims

1. A method of determining a position of an object comprising the steps of:

establishing an object area which is graphically represented by a first cylindrical coordinate system having a first origin and a second cylindrical coordinate system having a second origin;

positioning a reference receiver at a reference location in the object area, a first additional receiver at a first additional location in the object area and a second additional receiver at a second additional location in the object area;

transmitting a signal from the object;

measuring, at a processing unit operable to process siqnals received by the reference receivers, and the first and second additional receivers, a first time delay as a function of the difference between receipt times of the signal received at the reference location and a signal received at the processinq unit via the first additional location;

measuring, at the processing unit a second time delay as a function of the difference between receipt times of the signal received at the reference location and a signal received at the processinq unit via the second additional location;

determining which ray of the first cylindrical coordinate system represents the first time delay and which ray of the second cylindrical coordinate system represents the second time delay; and

determining whether a first position along the ray of the first coordinate system and a second position along the ray of the second coordinate system are located within a predetermined tolerance.

2. The method according to claim 1 wherein the step of determining a first and second position includes the steps of incrementing the first position along the ray of the first coordinate system to establish a new first position, incrementing the second position along the ray of the second coordinate system to establish a new second position, determining whether the new first and second positions are within the predetermined tolerance, and repeating the steps of incrementing and determining the new first and second positions until the new first and second positions are within the predetermined tolerance.

3. The method according to claim 1 further comprising the steps of determining a correction factor and applying the correction factor to the first and second time delays prior to the step of determining the rays of the first and second coordinate systems.

4. The method according to claim 2 further comprising the step of initializing the first and second positions to zero prior to incrementing the first and second positions.

5. The method according to claim 1 wherein the first and second coordinate systems utilize elliptical cylindrical coordinates.

6. The method of claim 1 comprising the further steps of:

determining whether the object is to be repositioned at a previously determined position;

whenever the object is not to be repositioned, indicating the position of the object and saving coordinates of the position for future use; and

whenever the object is to be repositioned, comparing the position just determined with the previously determined position and providing an indication of results of the comparison.

7. A method of determining a position of an object in a space with preselected boundaries comprising the steps of:

positioning a reference receiver and a plurality of signal receivers in a predetermined pattern within the space;

transmitting a locating signal from the object for receipt by the reference receiver and by each of the plurality of signal receivers;

retransmitting the locating signal from each of plurality of signal receivers to a processing unit operable to process locating signals received by the reference receiver and the plurality of signal receivers;

determining delay times between receipt of the locating signal directly by the reference receiver and receipt of the locating signal by the processing unit by way of each of the plurality of signal receivers; and

determining the location of the object as a function of the delay times.

8. The method of claim 7 wherein each delay time defines a unique coordinate path in one of a plurality of coordinate systems, each associated with one of the plurality of signal receivers, and wherein the object position is that position defined as where the plurality of coordinate paths converge within a preselected tolerance.