Determination of spin parameters of a sports ball
First Claim
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1. A method for estimating a spin frequency of a rotating sports ball in flight, comprising:
- receiving, using a receiver of a radar arrangement, electromagnetic waves reflected from the rotating sports ball;
deriving, without regard to any marking on the rotating sports ball, from the received electromagnetic waves, via the radar arrangement, a signal having a first frequency corresponding to a velocity of the rotating sports ball, the signal being modulated by a modulation frequency; and
estimating, without regard to any marking on the rotating sports ball, via the radar arrangement, at at least a single point in time, the spin frequency of the rotating sports ball based on at least one frequency distance between a harmonic of the modulation frequency and one of the first frequency and an additional harmonic of the modulation frequency.
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Abstract
A method of determining spin parameters of a sports ball, such as spin axis and rotation velocity of a golf ball. The spin axis is determined solely from the trajectory of the flying ball, and the rotational velocity is determined from a frequency analysis of a signal provided by a radar, which signal comprises spectrum traces positioned equidistantly in frequency, which frequency distance relates to the spin velocity.
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Citations
21 Claims
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1. A method for estimating a spin frequency of a rotating sports ball in flight, comprising:
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receiving, using a receiver of a radar arrangement, electromagnetic waves reflected from the rotating sports ball; deriving, without regard to any marking on the rotating sports ball, from the received electromagnetic waves, via the radar arrangement, a signal having a first frequency corresponding to a velocity of the rotating sports ball, the signal being modulated by a modulation frequency; and estimating, without regard to any marking on the rotating sports ball, via the radar arrangement, at at least a single point in time, the spin frequency of the rotating sports ball based on at least one frequency distance between a harmonic of the modulation frequency and one of the first frequency and an additional harmonic of the modulation frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for estimating a spin frequency of a rotating sports ball in flight, comprising:
a receiver of a radar arrangement configured to, at at least a single point in time, receive electromagnetic waves reflected from the rotating sports ball and provide a corresponding signal, which is modulated by a modulation frequency, wherein the radar arrangement is configured to perform, without regard to any marking on the rotating sports ball, a frequency analysis of the modulated signal and detect at least one harmonic of the modulation frequency, the radar arrangement being further configured to estimate, without regard to any marking on the rotating sports ball, the spin frequency from a frequency distance between the at least one harmonic and one of a first frequency corresponding to a velocity of the rotating sports ball and an additional harmonic of the modulation frequency. - View Dependent Claims (11, 12)
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13. A system for estimating a spin frequency of a rotating sports ball in flight, comprising:
a radar arrangement configured to, at at least a single point in time, receive electromagnetic waves reflected from a rotating sports ball and provide a corresponding signal, which is modulated by a modulation frequency, wherein the radar arrangement is configured to perform, without regard to any marking on the sports ball, a frequency analysis of the modulated signal and detect at least one harmonic of the modulation frequency, the radar arrangement being further configured to estimate the spin frequency from a frequency distance between the at least one harmonic and one or more of a first frequency corresponding to a velocity of the rotating sports ball and an additional harmonic of the modulation frequency. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A system for estimating a spin frequency of a rotating sports ball in flight, comprising:
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a radar arrangement; and a computer-readable medium storing instructions which, when executed on the radar arrangement, cause the radar arrangement to perform operations comprising; receiving electromagnetic waves reflected from the rotating sports ball; deriving from the electromagnetic waves without regard to any marking on the sports ball, a signal having a first frequency corresponding to a velocity of the rotating sports ball, the signal being modulated by a modulation frequency; and estimating, at a point in time, the spin frequency of the rotating sports ball based on a frequency distance between a harmonic of the modulation frequency and one of the first frequency and an additional harmonic of the modulation frequency. - View Dependent Claims (21)
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Specification