Patent Application
20170138710
The present invention relates to an ammunition projectile that allows for position observation when illuminated. The projectile my function with a fire control device that tracks the path of a projectile while in ballistic flight toward a given target, so as to improve precision and accuracy when aiming a subsequent projectile at the same or another target.
Tracer technology was developed by the British defense research establishment in the midst of the 1st World War. The technology continues to be used 100 years later. In machine guns, belts of ammunition are mixed—ball and tracer combinations. Unfortunately the 100 year-old technology has a number of practical drawbacks: (1) The tracer ammunition's ballistics differs from the trajectory of ball ammunition, (2) handling and inclusion of pyrotechnic tracers in ammunition significantly increases the cost of ammunition, (3) tracers cause unwanted range fires in training, (4) the glow emitted by tracers' backlights friendly forces, vehicles, equipment and aircraft and (5) tracers are not optimized for automatic tracking technology.
Simple Deployment and Use:
The invention disclosed in this application provides for a projectile affixed with retro-reflectors that reflect light from an optical strobe emitter. Where the reflected light is in the visual spectrum, a sniper spotter can observe the projectile's path and make adjustments for subsequent shots as the methodology allows a trained spotter to detect the influence of wind on the projectile and to calculate an effective adjustment for the sniper. This technique is also useful where the projectile is illuminated in the near infra-red (NIR) and the reflected beam is viewed with NIR night vision goggles.
Use and Deployment on Aircraft:
It is useful to discuss this methodology if deployed in an air-to-ground applications where the wind wash from helicopter rotors, speed of the aircraft, etc., make it very difficult to correctly place fires from door guns. Current tracer technology emits light during the entire flight path allowing enemy on the ground to quickly locate friendly helicopters. With the approach disclosed in this application, a door gunner with night vision goggle will emit short pulses of NIR laser emissions and the retro-reflectors on the ammunition will allow the gunner to track the path of ammunition. This is done without the backlighting of the helicopter which is created by tracers. The narrow beam of pulsed NIR illumination is almost undetectable and the low power required of emitters coupled with retro-reflectors reduces the signature of the gunner—especially compared to the current technique of firing visible tracer ammunition. The NIR light reflected from a projectile allows the gunner to track the trajectory of ammunition without affording the enemy with a means of detecting the helicopter.
Retro-Reflection:
Use of retro-reflectors is ubiquitous in road signs where the technology was invented in the United Kingdom and introduced in the late 1930s. Retro-reflectors reflect light to the emission source with a minimum of scattering. There are three principle types of retro-reflectors: corner cube reflectors, cat eyes and phase conjugated mirrors. The coefficient of luminosity returned in the direction of the emission source is high. In addition to their use on road signs, retro-reflectors are used in safety reflectors, high visibility clothing and surveying. NASA has also used this technology. The Apollo 11, 14 and 15 missions placed retro-reflectors on the moon surface allowing for precise measurements of the moon.
Automated Tracking, Shot Registration:
In addition to providing improved techniques to visually track the trajectory of ammunition in flight, one can also add an optical, imager or laser tracker (detector) coupled to a fire control system to further automate the system. In some cases it is useful to pulse the laser light emission to simplify the automated optical detection. Each method of automated tracking allows for “registration” of the shot at specific way points along the trajectory, when coupled to a fire control computer utilizing a regressive ballistic algorithm. Alternatively, the detector can use a MEMS steered laser tracking system where the optical detector steers the laser to maintain illumination of a retro-reflector affixed to the ammunition. In this case, the MEMS steered device measures the X and Y changes of the projectile during the entire flight path. Optical detection of MEMS steered laser emitters allow for automation so that real time “registered” data is collected.
Regressive Ballistic Algorithm and Improved Shot Placement:
An automated system can utilize acquired real time “registered” data with a regressive algorithm. A regressive algorithms use statistical processes to estimate relationships among variables and with a pattern. The algorithm improves the fidelity of predictive fire control to correct for unmeasured aiming errors due to wind turbulence, altitude-dependent wind conditions, lot-to-lot ammunition irregularities, bore sight misalignment and the like, for use when firing subsequent projectiles. Using this methodology, the merging of registered actual shot data with fire control algorithms provides for improved solution fidelity with better placement of the subsequent shot.
The U.S. Pat. No. 8,074,555, and its predecessor Provisional Application No. 61/803,826, disclose a system for tracking the lateral drift and vertical drop of an ammunition projectile while in flight to provide a precise aim point for firing one or more subsequent projectiles. With this system, a projectile is illuminated by an optical emitter housed in the projectile. The system produces an optical strobe signals at predetermined times (T1, T2, T3 . . . ) following firing of the projectile (at time T0). An optical detector receives the optical signals and an image processor determines the lateral drift (i.e. X1, X2, X3 . . . ) and vertical drop (i.e. Y1, Y2, Y3 . . . of the projectile at the predetermined times (T1, T2, T3 . . . ) following time T0. The subject matter of this patent is incorporated herein by reference.
This prior art uses the real time data to correct for aiming errors due to gun jump, wind turbulence, altitude-dependent wind conditions, lot-to-lot ammunition irregularities, bore sight misalignment and the like, for use when firing subsequent projectiles. This system is optimized to function with projectiles that have adequate energy to power LED's to emit strobe light and where the ballistic trajectory angles are significant (e.g., with mortars, artillery and 40 mm systems).
The principal object of the present invention is to provide for an observable and trackable projectile that, when coupled to a emitter allows for the observation and recording of a projectile in flight. Further, when coupled to a fire control system, the recording of actual flight drop, drift and measurement of a projectile in flight allows for improved precision and accuracy of weapon systems.
It is a further object of the invention to provide a method that avoids the drawbacks of firing conventional tracer ammunition.
It is another object of the present invention to improve the fire control device of the type disclosed in the U.S. Pat. No. 8,074,555 to render it more reliable and less expensive.
It is still another object of this invention to improve the fire control device disclosed in the U.S. Pat. No. 8,074,555 to minimize power consumption of projectile-borne batteries, used for example in projectile fuses, and to simplify the sensor array (detector) that views the projectile.
These objects, as well as still further objects which will become apparent from the discussion that follows, are achieved, in accordance to the present invention by providing an otherwise conventional ammunition projectile with methods and apparatus that use a pulsing electro-optical emitter and an optical tracking device to locate a radiated projectile in flight.
In one preferred embodiment of the invention, retro-reflectors are affixed, coated or otherwise fitted to a projectile's rear surface provide for reflection of light that can be viewed by electro-optical devices in the vicinity of the weapon firing said projectile. The radiated light emission from the laser emitter may be in the UV, visual, NIR or MWIR spectrum. The light reflected from the retro-reflective material may be in the UV, visual, NIR or MWIR spectrum.
The provision of projectiles with retro-reflectors according to the invention allows for use of a range of emission devices and is useful without specialized detectors so the fielding of the technology is straightforward. Accordingly, the system will function in the current spectrum of night vision equipment and can be readily integrated into existing sniper's kit when fitted with a laser emitter that reflects from retro-reflectors on a projectile.
With respect to retro-reflection and recent prior art for tracers, U.S. Pat. No. 5,267,014 provided a methodology for non-contact measurement to obtain 6DOF measurement in objects by means of a retro-reflector. Earlier work in this field developed the principles of 3DOF measurement of objects by means of retro-reflectors. U.S. Pat. No. 6,097,491 identified a method to use beam splitting for measurement. Using the prior work, Ruag GmbH in Germany has developed a family of training devices incorporating retro-reflectors on targets as disclosed in U.S. Pat. No. 6,139,323, allowing for realistic military training. 3M holds a number of patents for retro-reflective device manufacture and design that are instructive and several patents that disclose methods to limit the retro-reflector's performance spectrum, for example as in U.S. Pat. No. 8,567,964. U.S. Pat. No. 6,808,467 describes a covert tracer projectile to determine aiming error using an optical collimator to steer a projectile to an illuminated target. U.S. Pat. No. 8,402,892 describes a method of producing covert tracers. U.S. Pat. No. 8,168,804 identifies types of dyes that can provide a NIR response with a Stoke's shift response.
Configuration:
The selection and orientation of the retro-reflectors affixed or coated on the projectile provides geometric line of site from the projectile's base or projectile body such that light is reflected rearward, toward the origin of the projectile's flight. The retro-reflective material is positioned and oriented on the projectile to allow for the rearward travel of light, notwithstanding that a flying projectile is subject to a yawing motion and angular flight characteristics associated with a particular projectile. The present invention provides that either a spotter or automated tracking system corrects the aim of a weapon adjusting or updating the ballistic firing solution.
Cone of Illumination:
Preferably the radiation source is laser source adapted to be affixed to the weapon so that the cone of illumination of the laser source intersects with the ballistic path of the projectile. The cone of laser light dispersion should encompass the ballistic path of the flight and also allow for post shot movement of the laser affixed to the weapon.
Spectrum:
Depending upon the type of laser and retro-reflectors, the illumination frequency may be in one of the UV, visual, and IR spectral bands. Both the laser source and radiation detector may utilize narrow pass filters to allow for stealth in illuminating the projectile and simplified signal processing and detector construction. To add stealth, a dye coating can be applied to the retro-reflective surface to use a well-known “stokes shift” to shift the return signal's frequency from a high energy state UV to a lower energy state NIR. Thus it may be possible to illuminate the projectile with UV laser light while detecting the re-emitted light in the NIR spectrum. One should note that this feature does reduce the reflected light as the “stokes effect” consumes energy when light shifts from a higher energy wavelength to a lower energy wavelength and this approach is not currently supportable using off the shelf retro-reflective supplies.
Detectors:
An automated system's radiation detector can be included in a spotting scope allowing a sniper's spotter to manually calculate the azimuth and elevation of the next shot. Preferably the radiation detector is an optical detector or digital camera that measures the ballistic path of the projectile at pre-set intervals.
Laser Emission and Reflection for Tracking:
The aim-correcting system preferably includes the following components:
It is possible to use the two steps above for a visual observation of the illuminated shot by a spotter in a sniper-spotter team. It is also useful to provide automated tracking and use that feature to provide for improved ballistic aiming solutions using regressive analysis using prior shot data.
Automated Tracking:
It is desirable to further automate the system. One approach to automate tracking is a system with the following additional elements (3 to 6):
As an alternative automated system to the system described above it is possible to use an automated system comprising the following elements (7 to 9):
Using the actual measurements, an automated device utilizes a regressive ballistic algorithm, coupled with a computer to calculate an improved aim point for subsequent shots of ammunition. Additional shooting allows for repeated regressive analysis to improve the aim-point.
The output device of the system may provide an automated adjusted aiming point to the operator or a spotter. Alternatively, the output device may allow for the manual computation of an adjusted aim point by the spotter or gunner.
In another preferred embodiment of the present invention an otherwise conventional ammunition projectile is provided with a coating of fluorescent dye material, on or near its rear surface, whereby the dye re-emits radiation in response to excitation by laser light.
The fluorescent dye, optimized to luminance in response to laser radiation, exploits a natural phenomenon known as “laser-induced-fluorescence.” The dye is coated on an external rear surface of the projectile. The coating is preferably covered by a transparent shield or coating and, for example, it may be disposed on the inside surface of a transparent window on the rear of the projectile.
The present invention thus provides a system for correcting the aim of a weapon that is operative to launch such a fluorescent dye enhanced projectile on a ballistic path toward a target. The aim-correcting system preferably includes the following components:
Using this aim-correcting device the aim of the weapon may be adjusted after the launch of one projectile to compensate for aiming errors prior to the next launch of another projectile.
By means of this system, either the signal processor or the computer calculates the lateral drift and the vertical drop of the projectile at the predetermined times.
Preferably the radiation source is laser source adapted to be affixed to the weapon so that the cone of illumination of the laser source intersects with the ballistic path of the projectile and excites the photo-luminescent material.
Preferably the radiation detector is a digital camera for producing an image of the ballistic path of the projectile.
Depending upon the type of fluorescent dye material, the frequency of the excitation radiation may be in one of the UV, visual and IR spectral bands.
Both the laser source and radiation detector may utilize narrow pass filters that provide for stealth in illuminating the projectile and simplified signal processing and optical detector construction as the technique provides for optimized signal to noise ratios.
The radiation source preferably includes a narrow band-pass filter for selectively passing a narrow spectrum of laser light to the projectile to excite the fluorescent dye. The radiation detecting device preferably also includes a narrow band pass filter allowing only the re-emitted light from the fluorescent dye to pass to the detector, thereby minimizing the data processing required of the detector output.
The output device of the system may be a display for the operator who manually adjusts the aim in the weapon's bore sight or it may automatically adjust the aim of the weapon, for example by passing the projectile drift and drop data to the fire control device of the weapon.
For a full understanding of the present invention, reference should now be made to the following detailed description of the preferred embodiments of the invention as illustrated in the accompanying drawings.
The preferred embodiments of the present invention will now be described with reference to
Identical elements in the various figures are designated with the same reference numerals.
According to a first preferred embodiment of the present invention, a projectile is fitted with retro-reflectors on its rear surface. An emitter is incorporated into a weapon system or into a stand-alone a spotter's scope. The emitter is slightly depressed from the axis of the barrel and focuses a cone of light in a tight beam that coincides with the ballistic trajectory of the projectile. The emitter illuminates the projectile's path in the spectrum allowing a spotter or sensors to precisely measure the ballistic trajectory. The system may also provide the capability to use automated tracking of the retro-reflectors affixed to a projectile. The invention is a kit that when mounted or incorporated into a weapon or spotting scope provides a methodology to adjust fires.
Cone of Illumination and Retro-Reflectors:
An illuminator emits UV, visual, NIR or MWIR light that illuminates the ballistic trajectory of the projectile. When attached to a weapon, the axis of the cone of illumination is slightly depressed from the center of axis of the barrel. When using the technique to illuminate an entire cone of light, the dispersion of the light emission and the angle of depression illuminate the projectiles ballistic flight path. The resulting depressed angle and dispersion is calculated for the caliber of the weapon system. Where a MEMs steerable laser beam is used, the laser search zone is limited to the light cone intersecting the ballistic path of the projectile. When incorporated into a sniper's scope the scope is pointed at the target and the zone of illumination is elevated above the target. The optical radiation traverses the space between the emitter and the projectile and light is reflected from reflected off the retro-reflectors affixed to the projectile. The retro-reflectors are affixed to the trajectory to with a geometry to return the incidence of light rearward during the trajectory of flight considering the yaw of the projectile and angle of attack. The signal may be continuous or emitted and reflected from the cat's eye or corner cube retro-reflective material affixed to the projectile.
Automated Optical Detection with Pulsed Signals:
Where the signals are pulsed at predetermined times (T1, T2, T3, etc.) following the time of firing (T0), an optical detector incorporated into the weapon or aligned with the spotting scope detects the angular geometry (projectile location in the sky) of the radiation reflected from the projectile as well as the duration (time length) of this reflected strobe in its field of view. The laser strobe emitter emits light at precise time intervals after launch or cartridge setback. The computer calculates the actual flight position at these precise post-firing intervals to the location that is forecasted by the original solution algorithm. The collected image is digitally processed and X and Y coordinates of the projectile's reflected strobe signal are identified by the laser's illumination of the projectile at predetermined time intervals. The “delta” positions are recorded (stored/registered). When a gunner subsequently wishes to engage new targets, the computer associated with the system uses an algorithm to identify a precise aim point solution using the observed trajectory of previous shots, thereby re-measuring and re-calibrating the distance and relative target elevation for subsequent firing of the weapon.
Table 1 is a time diagram illustrating the sequence of tracking when using strobe illumination signals where a shot where p is the required processing time for a subsequent fire control solution.
Automated Optical Detection with Continuous Signal Tracing:
New tracking technology includes MEMS steerable lasers that allow for continuous X and Y adjustment of a micro laser illuminating a projectile affixed with a retro-reflector.
The system of the present invention is shown generally in
It should be noted, that the human in the loop remains a formable influence as spotters remain critical to the sniper profession. Accordingly, where manual calculations are used the invention provides for improving the observation and registration of shots as the methodology of reflecting optical emission from a projectile in flight until impact enhanced the spotter and sniper's ability to observe and correct errors using current practices. The registered information provides both an improved manual shooting technique and, where automation is available a methodology to track the projectile and improve the placement of subsequent shots.
The system allows the fire control computers to readily observe and calculate fire control solutions that reduce or eliminate (1) occasion-to-occasion errors, (2) ammunition lot-to-lot errors, and (3) bore sight misalignment.
Fire control computers can readily adjust aim points using sensors to measure air temperature, pressure, firing geometry and standard muzzle velocities; however, practical considerations still limit the accuracy of calculated solutions. Lot-to-Lot ammunition variations along with occasions-to-occasion errors still result in limitations in the accuracy of fire control solutions. These errors also include those errors that result from varying wind conditions. Hence, measurement of the actual observed projectile drift and drop is necessary to allow fire control systems to provide improved aiming solutions.
System Overview:
As illustrated in
The system's signal processor identifies the X,Y location of the detected strobe signal against the sky or backdrop, as shown in
The measurement of observed projectile drift and vertical drop are obtained by an image processor to isolate the strobe tracer's position. Simultaneously, angular changes in the detector are measured. The image processor search and detects the strobe images at pre-set intervals after firing.
After detecting the actual observed azimuth drift and drop of a cartridge with an emitted light (
Fire control computer calculates a new fire control solution after measuring actual drift and drop of an observed “strobe tracer” projectile, as illustrated in
The diagram of
The system and methodology according to the invention allow fire control devices to adjust the aim point (in azimuth and elevation) so that subsequently fired cartridges hit the intended target by using actual observed azimuth drift and vertical drop. With the actual drift observed by the fire control's optical sensor, the fire control computer calculates improved solutions for new engagements. As subsequent volleys are fired, the coded regressive algorithm improves the fire control solution as it repeatedly measures the actual trajectory of cartridge with an increasing sample size.
One should also note that the invention can be incorporated into spotting scopes where the observed shot methodology and hand-held calculators currently used by snipers is also improved.
In the system shown in
In
After acquiring the target, the computer 40 and software 42 directs the steerable MEMS laser 61. During the projectile's flight, the laser X and Y azimuth and elevation corresponds to the steered MEMS laser 61. The X and Y location of the X and Y MEMS laser azimuth and elevation is recorded with specific clock time (48) stamps. The computer then runs a coded sub-routine with the regressive algorithm and passes “registration” data output 51 to the fire control device for refinement of the aim point for the next projectile to be fired. Where a return is lost, the device reinitiates a search track from the vicinity of the previous contact in a pattern in the cone 20.
According to a second preferred embodiment of the present invention, the projectile has a layer of photo-luminescent material, instead of retro-reflective material, on its rear surface. This embodiment of the invention provides for a method and means collecting optical location signals emitted by the luminescent material on the projectile while in flight after firing from a weapon, and for simultaneously recording movement and/or acceleration. These optical signals are transmitted from a projectile in either the visual, ultraviolet and infra-red spectrum. The signals are re-emitted from the projectile at predetermined times (T1z, T2z, T3z, etc.) following the time of firing (T0). An optical detector incorporated into the weapon launcher or on an associated platform detects the angular geometry (projectile location in the sky) of the radiation re-emitted by the photo-luminescent material on the projectile as well as the duration (time length) of this re-emitted strobe in its field of view.
The operating sequence of the system according to the invention is depicted in Table 1 below.
The system according to the invention has the capability to detect the laser-induced fluorescence (“LIF”) of a projectile while in flight. The re-emission in response to the LIF occurs the short period of time (z) after transmission of the laser strobe excitation.
When a phosphor is included with the projectile dye, the system can utilize phosphor thermometry. By measuring this re-emitted light duration (z) the system can use temperature differences observed on projectiles in flight to further differentiate between and among the locations of multiple projectiles when the rate of fire is such that multiple projectiles are in flight at the same time.
The system of the present invention is shown generally in
The laser strobe emits light at precise time intervals after launch or cartridge setback. The weapon fire control system compares the actual flight position at these precise post-firing intervals to the location that is forecasted by the original solution algorithm. The “delta” positions are recorded (stored/registered) and the fire control provides a gunner with new “corrected” aim points using the registered shots.
The optical signals emitted by the fluorescent dye material on the projectile are collected by an optical detector, such as an IR camera, co-located with the weapon. The image is digitally processed and X and Y coordinates of the projectile's strobe signal are identified by collection at the predetermined time intervals. When a gunner subsequently wishes to engage new targets, the computer associated with the system uses an algorithm to identify a precise aim point solution using the observed trajectory of previous shots, thereby re-measuring and re-calibrating the distance and relative target elevation for subsequent firing of the weapon.
Optical emissions include light in the ultraviolet, infra red and visual wavelengths. The weapon's fire control unit has the capability to emit a cone of light (modulated to strobe at a set time) that intersects with the ballistic path of the projectile. Normally, the laser emission will be aligned vertically. The laser's horizontal alignment will drop slightly at an inclination so the top edge of the laser light illumination cone is aligned horizontally with the centerline of the barrel. This geometry allows the laser light cone to cover the entire ballistic drop of the projectile.
The laser emitter adjacent the weapon transmits a short, intense light strobe signal at predetermined times after set back during the flight path of the projectile. This occurs at T1=(time of emission+z), T2=(time of emission+z), T3=(time of emission+z), Tn=(time of emission+z) where z is the time delay in milliseconds. Using this technique it is possible to select dye combinations where the laser strobe transmits strobe signals at a given frequency and the dye's optical response differs in its response frequency. This is used by the optimize system to preclude detection by potential adversaries. It is possible, in fact, to harness the heat of the projectile to change the spectral response of the dye.
The transmission of electromagnetic (optical) signals differs under certain atmospheric conditions and frequencies. The delay (z) between the laser's production of a light strobe and the tracer's fluoresced re-emitted response, as well as the length (duration) of the response signal, are used by the fire-control detection software to eliminate detection of stray reflective light that occurs when the laser beam strobe signal reflects off of objects and to distinguish between multiple projectiles.
Projectile flight geometry provides for reflection of light rearward to the gunner's position at pre-set intervals though the entire flight path. The fire control device associated with the weapon optically identifies the position (T1=position x1, y1, T2=position x2, y2, T3=position x3, y3, . . . Tn=position xn, yn) of the projectile at set intervals.
The invention provides for a system to collect optical location signals from a projectile in flight which are excited by an optical light source (visual, ultraviolet and infra-red). The fire control uses observed time-location and angular observation data to compute an improved ballistic solution.
The system allows the fire control computers to readily observe and calculate fire control solutions that reduce or eliminate (1) occasion-to-occasion errors, (2) ammunition lot-to-lot errors, and (3) bore sight misalignment.
Fire control computers can readily adjust aim points using sensors to measure air temperature, pressure, firing geometry and standard muzzle velocities; however, practical considerations still limit the accuracy of calculated solutions. Lot-to-Lot ammunition variations along with occasions-to-occasion errors still result in limitations in the accuracy of fire control solutions. These errors also include those errors that result from varying wind conditions. Hence, measurement of the actual observed projectile drift and drop is necessary to allow fire control systems to provide improved aiming solutions.
The current generation of fire-control devices use ballistic tables and metrological sensors to calculate a predicted hit point (gunner aiming point). Some fire control systems allow users to input manual drift and elevation offsets, but these manual offsets are generally linear. Hence, the current generation fire control devices continue to provide inaccurate aim points due to the fact that they only calculate a limited number of inputs while many “unsolved” sources of errors are not factored in. Unsolved errors include (a) bore sight misalignment, (b) lot-to-lot errors, (c) occasion-to-occasion errors and (d) limitations in existing wind sensor technology. All unsolved errors degrade the accuracy and precision of weapon fire control solutions.
The projectile's stimulated dye response occurs at discrete intervals (at T1+z, T2+z, T3+z, . . . Tn+z, where z is the response delay) that are observed by fire control devices equipped with optical sensors. The dye's strobe response to laser illumination identifies the position of the projectile at set time intervals after set-back (time T0). The system according to the invention optically collects the strobe light emissions at predetermined post firing (post set-back or launch) time windows. The projectile's fluorescent dye emits light strobe pulses that are collected by an optical detector (e.g. a camera) and digitally recorded. At each pre-set time window the device also records changes in the X and Y orientation of dye emission. The system's image processing software measures or signal processing algorithms calculate the X and Y location of the optical strobe emission at the pre-set time window.
The system's signal processor identifies the X,Y location of the detected dye strobe signal against the sky or backdrop, thereby determining the actual drift and drop of the projectile as seen from the gunner's position.
The measurement of observed projectile drift and vertical drop are obtained by an image processor to isolate the strobe tracer's position. Simultaneously, angular changes in the detector are measured. The image processor search and detects the strobe images at pre-set intervals after firing. Alternatively, the signal processor detects the signal at pre-set intervals after firing.
Post firing resonance can create shifting fields of view. The system measures the angular changes of the platform or optical detector (camera) at the same moment that the projectile's strobe signal is recorded.
After detecting the actual observed azimuth drift and drop of a cartridge, a weapon's fire control system can utilize two methods to provide improved fire control solutions. The fire control system can (1) reset subsequent fire control solutions to use actual observed drift and drop, or (2) establish a correction factor which modifies the calculated fire control solution. Hence, use of actual observed data provides for a more accurate fire control solution.
Fire control computer calculates a new fire control solution after measuring actual drift and drop of an observed “strobe tracer” projectile.
The system and methodology according to the invention allow fire control devices to adjust the aim point (in azimuth and elevation) so that subsequently fired cartridges hit the intended target by using actual observed azimuth drift and vertical drop. With the actual drift observed by the fire control's optical sensor, the fire control computer calculates improved solutions for new engagements. As subsequent volleys are fired, the fire control may use commonly known mathematical algorithms to further improve the precision of the corrected aim point as it repeatedly measures the actual position of cartridge drift and azimuth with a larger sample size.
In the system shown in
The algorithm develops fire control solutions (aim points) using actual, observed azimuth and elevation.
The sensors 134 are used to identify various parameters of the weapon 112. Such sensors can be of various types, for example, position sensors, sensors for gun elevation, optical sensors and the like. The emitter 133 is a high-powered laser which is triggered by the computer 140 to produce a strobe of light.
The optical detector 136 can be any type of image capturing device, for example a video camera, infrared camera or the like. It produces electronic signals representing the images and passes them to a signal processor 138. The processor 138 determines X,Y location and as well as the time duration of each received response from a projectile in flight. This information is passed to the computer 140 for calculating a lateral correction and a vertical correction in the aim of the weapon 112.
The fire control device measures the angular position of the weapon 112 when the weapon fires a projectile aimed at a target. This angular position information includes a radial azimuth/elevation barrel centerline and elevation of barrel/fire control elevation, The angular position is measured by the sensors 134 and this information is also passed to the computer 140.
The computer determines the drift and drop of the fired projectile and passes this data to the fire control device for adjusting the aim point of for the next projectile to be fired.
The time delay (z) of the re-emitted signal allows the computer 140 to disregard reflections received by the detector 138 from stray objects. The time duration of the re-emitted signal allows the computer to distinguish between multiple projectiles in flight which have been rapidly fired successively by the weapon 112. Closer (and therefore hotter) projectiles will have shorter duration re-emissions that the projectiles that are further away (and therefore cooler).
Comparison of Systems in First and Second Embodiments:
The first embodiment of the present invention concerns a optically “trackable” projectile fitted with a retro-reflective tracer. Such a system may be coupled to an apparatus allowing for the recording of the projectile's flight path and may be coupled with a methodology for improving the fidelity of aiming solutions in weapons using projectiles with one or more retro-reflectors. In the second preferred embodiment the projectile uses a projectiles with photo-luminescent material (e.g., a fluorescent dye) applied to the projectile body to provide laser-induced fluorescence. Like a projectile fitted with a retro-reflector, the projectile may be coupled with a apparatus that allows for the recording of the projectile's flight path.
In the discussion above, when referring to times T1+z, T2+z, TN+z, z was the time addition (in milliseconds) from re-emission delay, post illumination of the laser induced fluorescence. When applying the same methodology to retro-reflective tracers it is possible to use the same formulas, but in such a case it is useful to use a definition of “z” whereby z is the time it takes for light to travel (2× back and forth) over the distance after emission. For example, the light from an emitter (with a target at 500 meters) will travel back and forth (1000 meters) in 3.33 micro-seconds. In this circumstance, the technique allows for obtaining distinct range data of the projectiles (in flight) which can be useful for regressive algorithms. This is also useful for distinguishing among the many projectiles in flight with a machine gun firing continuously at 800 rounds per second.
There has thus been shown and described a novel trackable ammunition projectile which fulfills all the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.
This application claims priority from the U.S. Provisional Application No. 61/803,826 filed Mar. 21, 2013; U.S. patent application Ser. No. 14/220,404 filed Mar. 20, 2014; and U.S. Provisional Application No. 62/201,255 filed Aug. 5, 2015. The subject matter of said patent application Ser. No. 14/220,404 is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62201255 | Aug 2015 | US |
