Education and demonstration – Organized armed or unarmed conflict or shooting – Gunnery
Reexamination Certificate
2002-05-20
2004-09-21
Fernstrom, Kurt (Department: 3712)
Education and demonstration
Organized armed or unarmed conflict or shooting
Gunnery
C434S019000
Reexamination Certificate
active
06793494
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to military training equipment, and more particularly, to an improved laser transmitter mounted on a rifle for use by a soldier in war games.
2. Description of Related Art
U.S. Army regulations require a soldier to “zero” his or her small arms weapon twice each year. This weapon is typically an M16A1 or M16A2 rifle. The rifle is zeroed by shooting live ammunition at a target twenty-five meters away. The location of a cluster of bullet holes relative to a target reticle is observed and azimuth and elevation adjustments are made to the conventional or so-called “iron” sights of the rifle until the bullets strike at or near the reticle with a higher frequency, thus indicating that the iron sights are correctly adjusted. The parameters of the number of degrees of azimuth and elevation are recorded by the soldier on an adhesive label applied to the rifle so that the conventional sights can be re-set if they should become misaligned, e.g. from the weapon being disassembled for cleaning or repair.
The trajectory of the bullet, as it leaves the rifle, is curved slightly downwardly due to the effects of gravity. Thus, the conventional sights of the M16A2 rifle may be adjusted to achieve a 95% “kill” rate at twenty-five meters and a 95% kill rate at three-hundred meters. A soldier aiming at a target between these two ranges would achieve a much lower kill rate. The geometry of a direct line of sight intersecting a curved bullet trajectory necessarily imposes this limitation on all small arms weapons.
For many years the U.S. Army has trained soldiers with a multiple integrated laser engagement system (MILES). One aspect of MILES involves a small arms laser transmitter (SAT) being affixed to the stock of a small arms weapon such as an M16A1 rifle or a machine gun. Each soldier is fitted with detectors on his or her helmet and on a body harness adapted to detect a laser “bullet” hit. The soldier pulls the trigger of his or her weapon to fire a blank or blanks to simulate the firing of an actual round or multiple rounds. An audio sensor or a photo-optic sensor detects the firing of the blank round(s) and simultaneously energizes a laser diode in the SAT which emits a laser beam toward the target which is in the conventional sights of the weapon.
When fitting the SAT to a rifle or machine gun barrel, in the past it has been necessary to align the transmitter so that a soldier can accurately hit a target with a short burst from the laser diode once he or she has the target located in the conventional rifle sights. According to one prior art approach, the SAT was bolted to the rifle stock and the conventional sights of the weapon were adjusted to align with the laser beam. The disadvantage of this approach is that the conventional weapon sights had to be readjusted in order to use the rifle with live rounds. Thus the rifle was rendered useless for actual combat unless and until it was zeroed. To overcome this disadvantage, later SATs incorporated mechanical linkages for changing the orientation of the laser.
Aligning a SAT has generally been performed using a fixture. One type of prior art small arms alignment fixture (SAAF) that has been used by the U.S. Army for alignment of the early MILES SAT consists of a complex array of one hundred forty-four detectors which are used in conjunction with thirty-five printed circuit boards to determine where the laser hits with respect to a target reticle. The difficulty in using this prior art target array SAAF is that the soldier aims his or her weapon at the array which is twenty-five meters away without the use of a stable platform. In many cases, the soldier fires his or her weapon in a manner which results in the aim point not being at the desired location. The fact that the array is located twenty-five meters away from the soldier also introduces visibility limitations due to snow, fog, wind and poor lighting conditions at sunrise or dusk.
Furthermore, the prior art target array SAAF calculates the number of error “clicks” in both azimuth and elevation. The number of clicks is then displayed on the prior art target array SAAF using four sets of electromechanical display indicators. A soldier must turn his conventional SAT's adjustors the corresponding number of clicks in the correct direction. He or she must then aim and fire the weapon again and make additional corresponding adjustments. This iterative process continues until the soldier obtains a zero indication on the prior art target array SAAF. This is a very time consuming and tedious process due to normal aiming errors incurred each time the soldier has to reacquire the target reticle. It is not uncommon for a soldier to take fifteen minutes to align the SAT to the best of his or her ability and still not have it accurately aligned.
Not only is the alignment process utilizing the prior art target array SAAF time consuming, it also expensive because a large amount of blank ammunition must be used. The laser of a conventional SAT will not fire without a blank cartridge being ignited or by using a special dry fire trigger cable. The prior art target array SAAF does not support optical sights, different small arms weapon types, or night vision devices. Nor does the prior art array target SAAF accurately verify the laser beam energy and encoding of a received laser beam.
In response, SATs which eliminate the need to utilize a large target array have been developed by Cubic Defense Systems, Inc. and deployed by the U.S. Army as part of Cubic's MILES 2000 ® training system. The exercise events and casualties are recorded, replayed and analyzed in detail during “after action reviews” (AARs). The MILES 2000 SATs are adjustable for more rapid and accurate alignment of their laser output. The transmitters feature adjustable powers and coding to enable the man-worn portion of the MILES 2000 system to discriminate between kills made by different small arms and different players.
The MILES 2000 SAT is disclosed in the aforementioned U.S. Pat. No. 5,476,385 of Parikh et. al. It uses a pair of optical wedges that are rotated to steer the laser beam and align the same with the boresight of the rifle. This approach, while achieving a reasonable degree of aligning the laser beam with the conventional sights, requires a relatively expensive construction of the MILES 2000 SAT. This is attributable to the cost of the beam steering components such as the glass wedges, stainless steel gears, shafts, drive gears, housing, etc. The components must be small in size which makes mechanical design tolerances extremely tight. Furthermore the SAT—equipped rifle must be inserted into a portable box-like MILES 2000 SAAF in order to accomplish the bore sighting in a semi-automatic fashion. See the aforementioned U.S. Pat. No. 5,410,815 of Parikh et al. The portable MILES 2000 SAAF itself is a relatively expensive device which must be calibrated.
As disclosed in the pending application referenced above, high temperature resistant adhesive has been used to avoid changes in focal length due heating of the weapon induced by firing repeated blank rounds. Such changes in focal length can severely impact the accuracy of the SAT—equipped rifle once it has been properly bore sighted. Another major problem in maintaining the accuracy of a SAT is attributable to the high accelerations induced in the SAT when a round is discharged. In the case of a machine gun, forces as high as one-thousand times the force of gravity can be generated in all three axes. This can lead to misalignment of parts inside the SAT which can either shift the laser beam away from the preferred alignment or diffuse the beam so that the accuracy of the SAT over long ranges in unacceptably diminished.
Prior attempts to design an accurate SAT have led to unduly expensive and complex solutions because they have been based on aligning the laser beam with the conventional sights of the weapon Since the laser beam travels in an absolutely straight path, it needs to be somewhat downw
Roes John B.
Varshneya Deepak
Cubic Corporation
Fernstrom Kurt
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