The present invention relates to determining the launch parameters of an object in flight after being launched. More particularly, the present invention relates to the determination of the launch angle and the aim angle of an object that has been launched, such as, for example, a golf ball that has been struck with a golf club.
In some applications, it is desirable to determine the launch parameters of an object that is in flight after being launched from an initial position, including the angle at which the object is launched relative to the ground (launch angle) and the angle by which the object""s initial trajectory deviates to the left or right from a desired straight trajectory (aim angle). For example, the launch parameters of a golf ball in conjunction with other parameters such as ball velocity, spin rate and rotation axis may be used to accurately predict the trajectory followed by the golf ball after it as been struck with a golf club. Such information can be useful in golf simulator applications, golf equipment research and development applications, training systems, equipment selection systems, and the like.
In view of the forgoing, one objective of the present invention is to provide for the efficient and accurate determination of the launch angle of an object in flight after being launched, such as a golf ball struck by a golf club.
Another objective of the present invention is to provide for the efficient and accurate determination of the aim angle of an object in flight after being launched, such as a golf ball struck by a golf club.
These and other objectives and advantages are achieved by various aspects of the present invention. According to one aspect of the present invention, a method for determining an approximate launch angle of an object in flight after being launched from an initial position, such as a golf ball struck by a golf club, involves positioning a sensor for measuring the velocity of the object while in flight in a known geometrical relation with the initial position. In this regard, the sensor is preferably an active transmitter/receiver device, such as a Doppler Radar transceiver. The sensor may be positioned forward or rearward of the initial position. In one embodiment, the sensor is positioned at a known distance, for example, between two to six feet, forward of the initial position. Preferably, the sensor is positioned close to a projection of a straight flight path onto the ground expected when the object is launched on a direct bearing towards a desired target location. By way of example, the sensor may be positioned directly between a tee from which a golf ball is to be launched and a desired target hole in a green. When the object is launched on a direct bearing towards a desired target location, such condition may be understood as having an aim angle of zero. The velocity of the object while in flight is measured using the sensor. The launch angle is then calculated using a mathematical model. The mathematical model may describe the relationship between the measured velocity of the object as a function of elapsed time since the object was launched and the known geometrical relation between the sensor and the initial position.
According to another aspect of the present invention, a method for determining at least one launch parameter of an object in flight after being launched from an initial position, such as a golf ball struck by a golf club, involves positioning a plurality of sensors for measuring the velocity of the object while in flight in known geometrical relations with the initial position. In this regard, each of the sensors is preferably an active transmitter/receiver device, such as a Doppler Radar transceiver. Each of the sensors is used to measure the velocity of the object while in flight. Independent launch angle calculations corresponding to each of the sensors are then performed using a mathematical model. In this regard, the mathematical model may describe the relationship between the measured velocity of the object as a function of elapsed time since the object was launched and the known geometrical relation between the sensor and the initial position. The results of the independent launch angle calculations are then used to obtain at least one approximate launch parameter.
The sensors may be positioned such that the launch angle, the aim angle, or both are obtainable by direct calculation using the results of the independent launch angle calculations, interpolation of the results of the launch angle calculations, or examination of the results of the independent launch angle calculations. In this regard, each of the sensors may be positioned along a line that is substantially perpendicular to a projection onto the ground of a straight flight path expected when the object is launched with an aim angle of zero (i.e. on a direct bearing to a desired target location). The line is at a known distance, for example, between about four to six feet, measured along the projection of the expected straight flight path forward of the initial position. The sensors may be positioned along the line at locations corresponding to selected aim angles. With the sensors thus positioned, an approximate aim angle may be obtained by direct calculation from ratios of the results of the independent launch angle calculations. An approximate launch angle may be obtained by examining the results of the independent launch angle calculations to determine which of the launch angle calculations resulted in the smallest calculated launch angle and the smallest calculated launch angle is selected as the launch angle of the object.
According to an additional aspect of the present invention, an apparatus for use in determining the launch angle of an object in flight after being launched from an initial position, such as a golf ball struck by a golf club, includes a sensor for measuring the velocity of the object while in flight that is positionable in a known geometrical relation with initial position. In this regard, the sensor is preferably an active transmitter/receiver device, such as a Doppler Radar transceiver. The sensor may be positionable forward or rearward of the initial position. In one embodiment, the sensor is positionable at a known distance, for example, between two to six feet, forward of the initial position. Preferably, the sensor is positionable close to a projection of a straight flight path onto the ground expected when the object is launched with an aim angle of zero (i.e. when it is launched on a direct bearing to a desired target location). The apparatus also includes a computing device, interfaceable with the sensor, for calculating the launch angle using a mathematical model. The mathematical model may describe the relationship between the measured velocity of the object as a function of elapsed time since the object was launched and the known geometrical relation between the sensor and the initial position. The computing device for calculating the launch angle may comprise a computer programmed for computing the launch angle in accordance with the mathematical model.
According to a further aspect of the present invention, an apparatus for determining at least one launch parameter of an object in flight after being launched from an initial position, such as a golf ball struck by a golf club, includes a plurality of sensors for measuring the velocity of the object while in flight that are positionable in known geometrical relations with the initial position. In this regard, each of the sensors is preferably an active transmitter/receiver device, such as a Doppler Radar transceiver. The apparatus also includes a computing device, interfaceable with each of the sensors, for performing independent launch angle calculations corresponding with each sensor using a mathematical model. In this regard, the mathematical model may describe the relationship between the measured velocity of the object as a function of elapsed time since the object was launched and the known geometrical relation between the sensor and the initial position. The computing device may be a computer programmed for performing the independent launch angle calculations in accordance with the mathematical model. At least one approximate launch parameter is obtainable from the results of the independent launch angle calculations.
These and other features and advantages of the present invention will be apparent upon a review of the following detailed description when taken in conjunction with the accompanying figures.