US 11,938,375 B2
System and method for determining a spin axis of a sports ball
Fredrik Tuxen, Rungsted Kyst (DK); Michael Ungstrup, Vedbaek (DK); and Kasper Mackeprang, Vedbaek (DK)
Assigned to TRACKMAN A/S, Vedbaek (DK)
Filed by TRACKMAN A/S, Vedbaek (DK)
Filed on Aug. 11, 2022, as Appl. No. 17/819,098.
Application 17/819,098 is a continuation of application No. 16/949,250, filed on Oct. 21, 2020, granted, now 11,446,546.
Application 16/949,250 is a continuation of application No. 16/215,793, filed on Dec. 11, 2018, granted, now 10,850,179, issued on Dec. 1, 2020.
Claims priority of provisional application 62/642,369, filed on Mar. 13, 2018.
Prior Publication US 2022/0387851 A1, Dec. 8, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. A63B 24/00 (2006.01); A63B 69/36 (2006.01); G01S 7/35 (2006.01); G01S 13/58 (2006.01); G01S 13/88 (2006.01)
CPC A63B 24/0021 (2013.01) [A63B 69/3658 (2013.01); G01S 13/58 (2013.01); G01S 13/583 (2013.01); G01S 13/88 (2013.01); A63B 2024/0034 (2013.01); A63B 2220/35 (2013.01); G01S 7/356 (2021.05)] 22 Claims
OG exemplary drawing
 
1. A method for determining a spin axis of a sports ball, comprising:
transmitting a signal, via a first radar, into a target area into which the sports ball is to be launched, the first radar including three receivers arranged so that a minimum of three receivers are not co-linear, the signal being reflected back to the receivers by the sports ball;
receiving, by the first radar, the received reflected signal via the receivers;
performing a frequency analysis on the received reflected signal received by the first radar at a first point in time to determine a frequency spectrum comprising a range of frequencies received by the first radar corresponding to differing velocities relative to the first radar of different portions of the sports ball as the sports ball is spinning;
separating the determined frequency spectrum into a plurality of frequency components; and
determining for each of the frequency components a first phase difference between signals received at a first pair of the three receivers and a second phase difference between signals received at a second pair of the three receivers and identifying a component of the spin axis of the sports ball based on the determined first and second phase differences.