WO1991012480A1

WO1991012480A1 - A method for analyzing shooting training and performance results

Info

Publication number: WO1991012480A1
Application number: PCT/FI1991/000048
Authority: WO
Inventors: Juha Kostamovaara
Original assignee: Noptel Oy
Priority date: 1990-02-19
Filing date: 1991-02-18
Publication date: 1991-08-22
Also published as: FI84753C; FI900806A0; FI900806A; FI84753B

Abstract

The invention relates to an opto-electronic method for analyzing shooting training and performance results. The method is based onthe determination of differences in the angles between a firing line and a reflector (6) attached to a target (5) in two directions perpendicular to each other by means of an opto-electronic transceiver (2) attached to a weapon or a shooting device (1). The transmitter of the transceiver (2) sends visible or infrared light with a predetermined beam in its axial direction, whereby the receiver of the transceiver (2) can calculate angles Υx and Υy by which the reflector (6) deviates from the optical axis (12) of the receiver on the basis of signals produced by the reflection created by the reflector (6), and on the basis of which data and a known or separately measured firing distance and a known or separately measured speed and direction of travel of the target, the x and y coordinates of a hit or a firing point with respect to a desired point on the target can be calculated continuously during aiming and firing and after firing or merely at a specific moment determined by the firing moment.

Description

A method for analyzing shooting training and performance results

The invention relates to a method for analyzing shooting training and performance results. The method is based on the determination of differences in the angle between a line of fire and a reflector attached to a target in two directions perpendicular to each other by means of an opto-electroniσ transceiver. Shooting training is performed by sportsmen, soldiers, policemen, and hunters. The training normally takes place in closed shooting ranges to a stationary or moving target. With a moving target, estimation of deflection forms an essential part of the training. There is, however, an obvious need for training which simulates a normal shooting perform¬ ance as closely as possible and which could be performed in everyday surroundings without the risks associated with shooting with bullets. The object of the present invention is to offer such a training possibility based on opto-electrpnics.

It is previously known to replace the bullet with a narrow light beam in shooting training 1. In such a case, the target may be, e.g., a conventional -target to which a self-adhesive reflector is attached (Finnish Patent No. 68726). In this method, a re¬ ceiver monitors the return beam so as to find out whether the beam has hit the reflector or missed it. The method provides information only on whether the light beam has hit the target or not, so it is not suitable for an accurate analysis of a shooting per¬ formance.

A more accurate analysis can be achieved, e.g., by registering the point at which the bullet hits the surface of the target by means of a TV camera. It is also known to use a diffuse glass plate as a target, the surface of the plate being projected by optical means to the surface of a' position sensitive de¬ tector. As a result, the position of a narrow-beam light source attached to the weapon on the surface of the glass plate can be determined on the basis of signals generated by the detector (Finnish Patent No. 66987). A drawback of these prior art methods is that they require a separate opto-electronic target con- nected by a cable to the firing place. Therefore the methods are complicated and especially the training of shooting at a moving target is restricted. In addition, the size of the target surface is usually limited, to tens of centimetres. For this reason, it is difficult to train deflection estimation. Deflec¬ tion training is made even more difficult by the fact that the distance of the moving target and thus the required deflection usually varies' during the training, so that the interpretation of results is ambiguous.

The method of the invention for analyzing shooting training and performance results provides a decisive improvement with regard to the above- mentioned drawbacks. In the invention, the receiver provides information on hits either in the form of an individual result or in the form of a continuous electrical signal proportional to the x and y co¬ ordinates. A major advantage over prior art methods is that the method of the invention does not require any separate opto-electronic target nor a data trans¬ mission link from the target to the firing or analyzing place. This gives a greater freedom in training arrangements. Also, training with moving targets is facilitated. Another advantage over prior art methods is that the.correctness of the deflection estimation can be verified by calculation. To achieve these effects, the invention is mainly characterized by what is disclosed in the characterizing portion of claim 1. In the following the invention will be described in detail by means of an example with reference to the attached drawings, in which

Figure 1 shows a measuring equipment applying the method; Figure 2 illustrates the structure of the optical part of the transceiver;

Figure 3 illustrates the structure of the electronics of the transceiver Figure 4. shows a block diagram illustrating the structure of the measuring equipment applying the method when the training is performed at a moving target.

Figures 1, 2 and 3 show the primary embodiments of the training method when shooting at a stationary target. In Figure 1, a transceiver 2 is attached, e-g-, to a commercial weapon or a shooting device 1 (a' rifle, pistol, cannon, tank, anti-aircraft gun, etc), in which transceiver a laser diode or LED (light emitting diode) transmitter sends light with a predetermined beam towards a target 5. The transmitter 2 can be switched on by a separate switch 3 only for the time of accurate aiming for safety reasons, among other things. An acoustic sensor 4 attached to the weapon determines the moment of firing on the basis of an acoustic wave caused by the firing pin and advancing in the body of the weapon.

In addition to the aiming area, the target 5 comprises a reflector 6, such as a corner prism or an adhesive reflector, having reflection properties far superior to those of the surroundings, the portion of the transmitted power which has fallen on the surface - of the reflector being returned by the reflector to¬ wards the transceiver. The reflector may be posi¬ tioned either at the aiming point or outside the actual aiming point. The receiver of the transceiver comprises a positive lens and a position sensitive detector positioned in the focus plane of the lens or in the vicinity of the focus plane. This arrangement enables the determination of differences in the. angle between the optical axis of the target reflector and the receiver in two directions perpendicular to each- other on the basis of signals generated by the posi¬ tion sensitive detector. On the basis of the angle differences, the x and y coordinates of an aiming or hit point with respect to the reflector can be calculated. For the calculation, the distance between the firing place and the target has to be known. In normal training situations, this distance is known. The training may also be performed from a distance shorter than the firing distance typical of the used weapon, since the results can be scaled to correspond to a longer distance. The specific arrangement of Figure 1 comprises a computer 7 completed with elec¬ tronic means associated with the operation of the transceiver, and a plotter 8. The computer calculates the coordinates and the path of the hit point and displays the results on the display in the form of graphical curves and tables and, if required, outputs the data to the plotter 8. In the arrangement of the method, the effective size of the target is de- termined by the beam size of the transmitter, whereas it is not dependent on the size of the reflector 6.

Figure 2 shows one structural principle of the optical part of the transceiver.- The transmitter con¬ sists of a laser or LE diode 9 the light of which is collimated by means of a lens 10. Thereafter the beam is transferred by means of prisms 11 to the optical axis 12 of the receiver. This arrangement is not necessary as the illumination could also be carried out in parallel. The choice of the structure depends, among other things, on the type of detector to be used. The size of the beam of the transmitter is determined by the ratio of the active area of the transmitter diode 9 to the focal distance of the lens 10. For example, if the size of the active area is 100 μm and the focal distance of the lens is 5 mm, the divergence of the transmitter beam will be 20 mrad. Thereby the diameter of the beam and, as a con¬ sequence, that of the target is 2 m at a distance of 100 m. The receiver consists of a filter 16 which reduces the noise caused by background light; a lens 13; and a position sensitive detector 14. The re¬ ceiver operates in such a way that the x and y co¬ ordinates of the aiming point or hit point with respect to the reflector acting as the centre of the ^* target can be determined on the basis of current signals generated by the position sensitive detector 14. The position sensitive detector 14 may be either a continuously operating diode (lateral effect posi¬ tion sensitive detector LE-PSD) or a four-element diode (four quadrant position sensitive detector, FQ- PSD). An advantage of the FQ-PSD is the lower noise level; on the other hand, it has the disadvantage of being more sensitive to the non-homogeneities of the beam. This is due to the fact that when the FQ-PSD is used the light spot on the surface of the detector is larger in size than when using the LE-PSD, so that variations in the distribution of luminosity within the spot are more significant. The FQ-PSD is placed in front of the focal plane 15 of the lens and the LE-PSD is placed in the focal plane 15. This arrange- ment ensures that the deviation of the mass centre of the light spot formed on the surface of the receiver diode from the centre of the detector indicates the angle, deviation of the reflector from the optical axis of the receiver. The visual field of the re¬ ceiver is so dimensioned that it is of the same order as the beam size of the receiver.

Figure 3 shows one way of realizing the electronic part of the transceiver. In the embodiment of .the figure, the detector diode of the receiver is a four-element detector 18. The transmitter diode is pulsed by a transmitter 17 at a desired frequency, typically between 1 and 10 kHz. The receiver channel contains transimpedance pre-amplifiers 19 for each diode element (A, B, C and D 18), post-amplifiers 20 with adjustable gain, phase detectors 21 and lowpass filters 22. The computer determines the position of the light spot on the surface of the position sensitive detector on the basis of the amplitudes of the channel signals. Angles _χ ^* and at which the target is visible with respect to the optical axis of the receiver can then be calculated from the position of the light spot and the dimensions of the optical part of the receiver. The x and y coordinates - with respect to the centre of the target can be calculated from the angle results and the known distance. The reading of the channel signals can be performed, e.g., in such a manner that the computer reads each channel signal separately through a multiplexer 23 and converts the results into digital form by means of an A/D converter 24. One input in the multiplexer is formed by an output proportional to the sum 25 of the channel signals, which output can be used in the level control of channel amplification. It is of great importance to choose the correct deflection when shooting at a moving target. The amount of required deflection depends on the distance of the target from the firing place, the speed and direction of travel of the target, and the speed of the projectile. At shooting training, the speed of the projectile can be assumed to be known. In the training method of the invention, the distance, direction of travel and speed of the target are obtained by combining an equipment capable of de- termining the distance of the target with the above- mentioned direction measurement. The basic structure of the measuring equipment is thereby such as shown _f in Figure 4. In addition to the above-described direction measuring equipment 27, the training weapon is provided with a laser distance measuring sensor 26 and angle gauges 28. The laser distance measurement may be based on the measurement of the time of travel of a pulse, for instance. The laser receiver of the transceiver thereby sends short light pulses (e.g. 10 to 20 ns) to the target, which reflects back the light power fallen upon its -surface towards the transceiver. The receiver of the transceiver detects the reflected light pulses. By measuring the dif¬ ference in the time of travel of the transmitted and the reflected light pulse, the distance of the target can be determined. If the target -moves at a known speed and in a known direction with respect to the aiming direction, the deflection can be determined with sufficient accuracy merely on the basis of the distance measuring data. The trainer thus aims at the front side with respect to the direction of travel of the reflector. The angle difference signals of the target with respect to the aiming direction are obtained from the direction sensor and the distance data are obtained from the distance measuring sensor, on the basis of which information the computer can calculate the shooting result or the path of the aim¬ ing point. The transmitter beam of the distance measuring sensor has to be equal in size to that of the direction measuring sensor in order that the dis¬ tance measuring result could be obtained even though the optical axis of the transceiver would not point directly to the target.

If the speed and direction of travel of the target is not known in advance, it is necessary that the measuring equipment is able to measure the posi¬ tion of the target as well as the changing of the position with respect to the coordinate system of the training device. On the basis of successive measure- ments of coordinates, the distance, direction of travel and speed of the target can be calculated at each specific moment. The coordinates can be determined by journalling the training device with respect to a point, and by measuring, in addition to the measuring of distance, the horizontal and vertical angles of the training device by the angle gauges 28 in the training situation. In some applica¬ tions, in which it *.can be assumed that the target moves along an even surface, it is_^ sufficient to measure the horizontal angle only. The coordinate measuring apparatus need . not necessarily be po¬ sitioned in the training device but it may be a separate independent unit which follows the target and measures its positional coordinates continuously. If the coordinate measuring apparatus is a separate unit, its position with respect to the firing place has to be known. Also, the measuring arrangement may be such that the coordinate measuring apparatus is positioned in close vicinity to the training place, whereby the coordinate measuring can be approximated to be coaxial with the direction measurement with sufficient accuracy.

The invention is not restricted to the embodi¬ ment disclosed in the description and the drawings, but it can be modified within the scope of the attached claims.

Claims

Claims:

1. Opto-electronic method for analyzing shoot¬ ing training and performance results, wherein a transceiver (2) is attached to a weapon or a shooting device (1) and a target area having reflection properties superior to those of the surroundings, such as a reflector (6), is attached to a target (5) or close to it, and wherein the transmitter of the transceiver (2) sends visible or infrared light with* a predetermined beam in the direction of its axis, c h a r a c t e r i z e d in that the receiver of the transceiver (2) calculates angles Ox and Oy by which the reflector (6) deviates from the optical axis (12) of the receiver on the basis of signals produced by the reflection from the reflector^" (6), and on the basis of which data and a known or separ¬ ately measured firing distance and, with a moving target, also on the basis of a known or separately measured speed and direction of travel of the target, the x and y coordinates of a hit or a firing point with respect to a desired point on the target are calculated continuously during aiming and firing, after firing or merely at a specific moment determined by the firing moment.

2. Method according to claim 1, c h a r a c ¬ t e r i z e d in that the receiver of the trans¬ ceiver (2) is a position sensitive detector posi¬ tioned in the focal plane or close to the focal plane of a positive lens.

3. Method according to claim 1 or 2, c h a r -*- a c t e r i z e d in that the reflector (6) is a corner prism.

4. Method according to any of the claims 1 to 3, c h a r a c t e r i z e d in that the light source of the transceiver (2) is a photodiode (LED).

5. Method according to any of the claims 1 to

4, c h a r a c t e r i z e d in that the effective size of the target area is adjusted by varying the divergence of the transmitter beam.

6. Method according to any of the claims 1 to

5, c h a r a c t e r i z e d in that suitable separ¬ ate or integrated counters and display means are con¬ nected to the transceiver (2), the results and numbers of shots and hits being calculated and dis¬ played by means of said counters and display means.

7. Method according to any of the claims 1 to

6, c h a r a c t e r i z e d in that the firing dis¬ tance to the target (5) is measured by means of a distance measuring equipment based on the measurement of the time 04 travel of a laser pulse and attached to the weapon or shooting device (1).

8. Method according to any of the claims 1 to

7, c h a r a c t e r i z e d in that the speed and direction of travel of the target (5) are determined by calculation from successive coordinates represent¬ ing the momentary position of the target (5) measured at known time intervals.

9. Method according to claim 8, c h a r a c - t e r i z e d in that the coordinates representing the position of the target (5) are determined on the basis of measuring data obtained from a distance measuring sensor (26) attached to the weapon or shooting device (1) and from angle gauges (28) attached to the weapon or the shooting device for indicating the horizontal angles of deflection of said weapon or shooting device with respect to a point.

10. Method according to claim 8, c h a r a c - t e r i z e d in that the coordinates representing the position of the target (5) are determined by means of a separate measuring apparatus to be directed towards the target manually or automatical¬ ly. .