U.S. patent application number 10/444735 was filed with the patent office on 2004-11-25 for trajectory compensating riflescope.
Invention is credited to McCormick, Patrick.
Application Number | 20040231220 10/444735 |
Document ID | / |
Family ID | 33450733 |
Filed Date | 2004-11-25 |
United States Patent
Application |
20040231220 |
Kind Code |
A1 |
McCormick, Patrick |
November 25, 2004 |
Trajectory compensating riflescope
Abstract
Disclosed is a riflescope that incorporates physical
measurements and user specific firearm parameters to calculate and
designate the target impact point. The scope incorporates a laser
range finder with the receiver integrated into the visual sight
path thus utilizing the large objective aperture to collect as much
reflected light as possible. This ensures long distance operation
while maintaining a compact form factor. The line-of-sight laser
distance and inclination angle are measured and used to calculate
the actual horizontal target distance. A user interface keypad and
display provide a mechanism to enter in firearm and ammunition
specific parameters such as muzzle velocity and ballistic
coefficient. A barometric pressure and temperature sensor measure
the actual air density; this and the user entered ballistic
coefficient quantify the resulting bullet drag and thus resulting
final velocity. All these physical measurements and user specific
parameters are utilized to calculate the final bullet impact point.
This compensated aim point is indicated by automatically adjusting
the elevation reticle.
Inventors: |
McCormick, Patrick;
(Berthoud, CO) |
Correspondence
Address: |
Patrick McCormick
1111 Jefferson Drive
Berthoud
CO
80513
US
|
Family ID: |
33450733 |
Appl. No.: |
10/444735 |
Filed: |
May 23, 2003 |
Current U.S.
Class: |
42/120 |
Current CPC
Class: |
F41G 1/473 20130101;
F41G 3/08 20130101; F41G 3/06 20130101 |
Class at
Publication: |
042/120 |
International
Class: |
F41G 001/38 |
Claims
1-4. (canceled).
5. A scope assembly adapted for rigid attachment to a firearm, the
scope assembly comprising: an optical tube assembly having an
objective lens and an eyepiece received along a longitudinal axis
of the optical tube assembly defining a line of sight between the
eyepiece and the objective lens; a reticle received in the optical
tube assembly between the objective lens and the eyepiece; a laser
transmitter operable to send a beam of light toward an intended
target; a laser receiver maintained out of said line of sight; a
reflection filter received between the objective lens and the
eyepiece and in said line of sight, the reflection filter having a
surface oblique to the longitudinal axis of the optical tube
assembly to reflect a beam reflected from the intended target to
the laser receiver while allowing visible light to pass between the
eyepiece and the objective lens to provide an unobstructed viewing
path through the optical tube assembly; and a controller in
operable communication with the laser transmitter and the laser
receiver to facilitate determining the linear distance between the
firearm and the intended target and in operable communication with
reticle to facilitate automatic adjustment of the reticle to a
compensated aim point while the optical tube assembly remains
rigidly fixed to the firearm.
6. The scope assembly of claim 5 further comprising an angle
transducer in operable communication with the controller to send a
signal to the controller indicating the orientation of the scope
assembly relative to a horizontal plane.
7. The scope assembly of claim 6 wherein the controller is operable
to determine a horizontal distance component and a vertical
distance component for automated reticle adjustment as a function
of the signal provided by the angle transducer.
8. The scope assembly of claim 5 further comprising a motor in
operable communication with the reticle and the controller to
receive signals from the controller and to automatically adjust the
reticle upwardly or downwardly within the optical tube assembly as
a function of said signals.
9. The scope assembly of claim 8 further comprising an adjuster
manually moveable in one direction to move the reticle upwardly
within the optical tube assembly and manually moveable in another
direction to move the reticle downwardly within the optical tube
assembly and the motor being in operable communication with the
adjuster to automatically drive the adjuster in one of said
directions in response to receiving said signals from the
controller.
10. The scope assembly of claim 9 further comprising a pinion gear
and a bevel gear in meshed engagement with one another, the pinion
gear being operably attached to the motor for conjoint rotation
with the motor and the bevel gear being operably attached to the
adjuster and moving in response to the movement of the pinion
gear.
11. The scope assembly of claim 5 wherein the surface of the
reflection filter is inclined 45 degrees relative to the
longitudinal axis.
12. The scope assembly of claim 5 further comprising a filter lens
received between the reflection filter and the laser receiver, the
filter lens having an arcuate surface causing the reflected beam of
light from the reflection filter to converge toward the laser
receiver.
13. The scope assembly of claim 5 wherein the reflection filter
allows visible light to pass from the objective lens to the
eyepiece.
14. The scope assembly of claim 5 wherein the reticle is in said
line of sight between the reflection filter and the eyepiece.
15. The scope assembly of claim 14 wherein the reticle is
automatically adjusted in response to a signal from the
controller.
16. The scope assembly of claim 5 further comprising a barometric
pressure transducer in operable communication with the controller
to facilitate automatic adjustment of the reticle to a compensated
aim point.
17. The scope assembly of claim 5 further comprising a temperature
sensor in operable communication with the controller to facilitate
automatic adjustment of the reticle to a compensated aim point.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
FEDERALLY SPONSORED RESEARCH
[0002] Not Applicable
SEQUENCE LISTING OR PROGRAM
[0003] Not Applicable
BACKGROUND OF THE INVENTION--FIELD OF INVENTION
[0004] This invention relates generally to targeting devices used
to aim firearms and the like, and more specifically to a riflescope
that calculates a trajectory and indicates a compensated aim
point.
BACKGROUND OF THE INVENTION
[0005] Since the introduction of firearms, users have struggled to
compensate for the effects of gravity. Gravity acting on the
projectile during its time-of-flight causes a vertical drop. The
time-of-flight is a function of the horizontal target distance,
initial velocity, and deceleration due to the aerodynamics of the
projectile and drag imparted by the air resistance. This problem
has become increasingly challenging as modern improvements in
firearms and ammunition have increased their effective range.
[0006] Originally firearms were constructed with iron sights. This
made targeting difficult at longer ranges. The problem was
partially solved through the introduction of riflescopes with
telescopic sights; these provided a detailed view of the target at
longer ranges. However this introduced a new problem, the need to
adjust the aim point to compensate for the effects of gravity on
the projectile. Initially shooting enthusiasts used a sight-in
method where the projectile trajectory was determined at several
ranges. This method proved problematic since the user was required
to estimate the horizontal target distance and manually adjust the
aim point. In an attempt to improve the target range estimation
riflescopes were introduced with mil-dot reticles. Although this
provided a better method of estimating target distance, it still
required the user to manually adjust the aim point.
[0007] Thereafter, inventors proposed more advanced firearm range
estimation and compensation devices. A search of prior art did not
disclose any patents that read directly on the claims of the
instant invention. U.S. Pat. No. 5,771,623 to Pernstich et al.
(Jun. 30, 1998) discloses a complex telescopic sight that
integrates the laser transmitter, laser receiver and measured range
display into the visual sight path. Although this device as
described provides a method for accurately measuring the
line-of-sight range it is still prone to inaccuracies because it
requires the user to estimate the affects of uphill/downhill
shooting, variations in muzzle velocity, and variations in
ballistic coefficient. In addition, the incorporation of the laser
transmitter and display into the visual sight path requires a more
complex alignment and assembly resulting in a fragile arrangement
that is costly to manufacture.
[0008] U.S. Pat. No. 6,252,706 to Kaladgew (Jun. 26, 2001)
discloses a range compensating telescopic sight with automatic
aiming and adjustment. Although this device as described indicates
the use of a stepper motor to automatically adjust the original
position of the sight to the required point of aim. As proposed the
device actually moves the entire riflescope assembly, this is more
complicated than necessary and thus more expensive. The simpler
method of adjusting the aim point is to couple the stepper motor
directly to the manual elevation adjustment knob contained on
conventional riflescopes.
[0009] U.S. Pat. No. 6,269,581 to Groh (Aug. 7, 2001) discloses a
range compensating riflescope that calculates and automatically
indicates an impact point with a display integrated into the visual
sight path. As described the display indicates the calculated
impact point with a horizontal line, however to provide the
necessary accuracy this display would need a very fine resolution
resulting in higher component costs. In addition, the optical
alignment and mounting of the display to provide an adequate level
of accuracy would be complex and costly to manufacture. As with the
previous invention, this prior art fails to identify a method to
compensate for the affects of shooting uphill or downhill. As
described the invention uses the bullet weight as the parameter of
interest to determine the deceleration due to drag from air
resistance. However, the actual parameter that characterizes the
deceleration due to drag from air resistance is the bullets
commonly published ballistic coefficient. In addition, the
invention describes the calculation is based on a user input
parameter of elevation to factor in the air pressure and resulting
resistance. However, air pressure is dependent on elevation,
current weather conditions, and temperature. Therefore a much
simpler and more accurate method is to incorporate a barometric
pressure and temperature sensor to calculate the current air
density.
[0010] While several features exhibited within these references are
incorporated into this invention, alone and in combination with
other elements, the present invention is sufficiently different so
as to make it distinguishable over the prior art.
BACKGROUND OF THE INVENTION--OBJECTS AND ADVANTAGES
[0011] Accordingly, several objects and advantages or my invention
are:
[0012] (a) to provide increased effective range in a compact form
factor by utilizing the large visual sight path objective aperture
to collect a greater amount of reflected laser light;
[0013] (b) to provide improved accuracy for uphill and downhill
operation by incorporating laser range finding technology and
inclination angle measurement to calculate the horizontal distance
to the selected target;
[0014] (c) to provide improved accuracy by calculating the
compensated aim point with user entered muzzle velocity;
[0015] (d) to provide improved accuracy by calculating the
compensated aim point with user entered ballistic coefficient;
[0016] (e) to provide improved accuracy by calculating the
compensated aim point using a barometric pressure and temperature
sensor to determine the air density and resulting drag;
[0017] (f) to provide improved accuracy by automatically adjusting
the elevation reticle to indicate the compensated aiming point;
[0018] (g) to provide an improved targeting device that can be used
in a manner identical to that of a conventional riflescope in the
event of battery failure or if so desired;
[0019] Further objects and advantages are to provide an improved
targeting device that is lightweight, compact and easy to use.
Still further objects and advantages will become apparent from a
consideration of the ensuing description and drawings.
SUMMARY
[0020] In accordance with the present invention a trajectory
compensating riflescope that is comprised of an otherwise
traditional riflescope that incorporates measurements to determine
the horizontal target distance and air density. In addition, a user
interface is provided to enter firearm and ammunition specific
parameters such as muzzle velocity and ballistic coefficient. These
measurements and parameters are applied to calculate and
automatically adjust the elevation reticle to a compensated aim
point.
DRAWINGS--FIGURES
[0021] FIG. 1A is a left-rear perspective view of a trajectory
compensating riflescope, according to the preferred embodiment of
the present invention.
[0022] FIG. 1B is a right-front perspective view of a trajectory
compensating targeting device, according to the preferred
embodiment of the present invention.
[0023] FIG. 2 is a left-rear exploded perspective view of a
trajectory compensating targeting device, according to the
preferred embodiment of the present invention.
[0024] FIG. 3 is a left-rear exploded perspective view of the top
protective housing assembly, according to the preferred embodiment
of the present invention.
[0025] FIG. 4 is an exploded perspective view of the internal scope
assembly, according to the preferred embodiment of the present
invention.
[0026] FIG. 5 is an exploded perspective view of the bottom
protective housing assembly, according to the preferred embodiment
of the present invention.
[0027] FIG. 6 is an exploded perspective view of the display
assembly, according to the preferred embodiment of the present
invention.
[0028] FIG. 7 is an exploded perspective view of the objective
section assembly, according to the preferred embodiment of the
present invention.
[0029] FIG. 8 is an exploded perspective view of the receiver
assembly, according to the preferred embodiment of the present
invention.
[0030] FIG. 9 is a cross sectional view of the receiver assembly,
according to the preferred embodiment of the present invention.
[0031] FIG. 10 is an exploded perspective view of the automatic
elevation adjustment assembly, according to the preferred
embodiment of the present invention.
[0032] FIG. 11 is an exploded perspective view of the rear scope
assembly, according to the preferred embodiment of the present
invention.
[0033] FIG. 12 is an exploded perspective view of the transmitter
assembly, according to the preferred embodiment of the present
invention.
[0034] FIG. 13 is a block diagram of the electronics and their
associated hardware interface, according to the preferred
embodiment of the present invention.
DRAWINGS--Reference Numerals
[0035] 20. Trajectory Compensating Riflescope Assembly
[0036] 22. Conventional Riflescope Manual Reticle Adjustment Dust
Cap
[0037] 24. Power Switch
[0038] 26. Battery Compartment Cover
[0039] 30. Upper Protective Housing Assembly
[0040] 32. Upper Protective Housing
[0041] 34. Data Entry Button Keypad
[0042] 36. Display Hinge Pin
[0043] 40. Internal Trajectory Compensating Riflescope Assembly
[0044] 50. Lower Protective Housing Assembly
[0045] 52. Lower Protective Housing
[0046] 54. Activation Button Keypad
[0047] 60. Display Assembly
[0048] 62. Display Bezel
[0049] 64. LCD Display
[0050] 66. Display Housing
[0051] 70. Objective Section Assembly
[0052] 72. Conventional Riflescope Objective Tube Assembly
[0053] 74. Battery Holder Bracket
[0054] 75. Battery Compartment
[0055] 76. Front Bracket
[0056] 77. User Interface Printed Circuit Board
[0057] 79. Conventional Riflescope Objective Lens Assembly
[0058] 79. Transmitter Protective Lens
[0059] 80. Receiver Assembly
[0060] 81. Laser Receiver
[0061] 83. Main Printed Circuit Board Standoff
[0062] 83. Receiver Mount
[0063] 84. Receiver Lens Collet
[0064] 85. Plano-Convex Narrow Pass-Band Filter Lens
[0065] 86. Receiver Housing
[0066] 87. Notch Reflection Filter
[0067] 88. Center Tube Mount
[0068] 90. Automatic Elevation Reticle Adjustment Stepper Motor
Assembly
[0069] 92. Stepper Motor
[0070] 94. Stepper Motor Mount
[0071] 96. Bevel Pinion Gear
[0072] 100. Rear Scope Section Assembly
[0073] 101. Manual Elevation Adjustment Knob
[0074] 102. Automatic Elevation Adjustment Gear
[0075] 104. Conventional Riflescope Eyepiece Assembly
[0076] 105. Conventional Riflescope Magnification Adjustment Knob
Assembly
[0077] 106. Conventional Riflescope Center Tube Assembly
[0078] 108. Conventional Riflescope Manual Windage Reticle
Adjustment Knob Assembly
[0079] 110. Transmitter Assembly
[0080] 112. Laser Collet
[0081] 114. Laser Transmitter
[0082] 116. Collimating Lens
[0083] 118. Transmitter Housing Tube
[0084] 120. Main Printed Circuit Board Assembly
[0085] 121. Micro-Controller
[0086] 122. Stepper Motor Driver
[0087] 123. Pulsed Laser Driver
[0088] 124. Detection Discriminator
[0089] 125. Time-of-Flight Detection
[0090] 126. Tilt Angle Transducer
[0091] 127. Barometric Pressure Transducer
[0092] 128. Temperature Sensor
[0093] 129. Nonvolatile Memory
DETAILED DESCRIPTION--FIGS. 1-8 & 10-12--PREFERRED
EMBODIMENT
[0094] A preferred embodiment of the trajectory compensating
riflescope, hereinafter riflescope 20 of the present invention is
illustrated in FIG. 1A (left rear) and FIG. 1B (right front)
perspective views.
[0095] As shown in FIG. 2, an upper protective housing, shell, or
enclosure assembly 30 is secured to an internal riflescope assembly
40 using eight flathead machine screws, four threaded through the
left side and four threaded through the right side. The manual
reticle adjustment dust caps 22A and 22B consisting of formed and
machined thin wall aluminum are threaded onto both the top of the
upper protective housing assembly and center tube assembly sealing
against the protective housing assemblies creating a weather tight
seal. A power switch 24 is snapped into the upper protective
housing assembly sealing tightly to protect against weather. A
battery compartment cover 26 consisting of injection molded plastic
is fastened to the internal scope assembly using two socket head
cap screws creating a weather tight seal with the upper protective
housing. A lower protective housing assembly 50 has a molded lip
that overlaps the upper protective housing assembly, creating a
weather tight seal and covering the eight flathead machine screws.
The lower housing assembly is secured to the internal scope
assembly using eight flathead machine screws threaded up through
the bottom. The top and bottom housings seal to form a weather
tight and protective shell for the various internal riflescope
components.
[0096] As shown in FIG. 3, an upper protective housing 32 is
constructed of injection-molded plastic providing a shell that is
rigid and can absorb impact and repel abrasion. A data entry button
keypad 34 consisting of molded silicone rubber is fastened to the
internal surface of an upper protective housing using an adhesive,
this forms a weather tight seal. A display hinge pin 36 consisting
of aluminum rod stock is inserted through the upper protective
housing and a display assembly 60 providing a pivot for opening and
closing the display assembly.
[0097] As shown in FIG. 4, an objective section assembly 70 is
secured to the front of a receiver assembly 80 using two setscrews,
one threaded through the left side and one threaded through the
right side. A rear riflescope section assembly 100 is secured to
the rear of the receiver assembly using two setscrews, one threaded
through the left side and one threaded through the right side. An
automatic elevation reticle adjustment assembly 90 is slide over
and positioned onto the rear scope section assembly then secured
using two setscrews, one threaded through the left side and one
threaded through the right side. A main printed circuit board
assembly 120 is fastened to the top of the objective section
assembly and the receiver assembly using four pan-head machine
screws.
[0098] As shown in FIG. 5, a bottom protective housing 52 is
constructed of injection-molded plastic providing a shell that is
rigid and can absorb impact and repel abrasion. An activation
button keypad 54 consisting of molded silicone rubber is attached
to the internal surface of the bottom protective housing using an
adhesive forming a weather tight seal.
[0099] As shown in FIG. 6, a display housing 62 is constructed of
injection-molded plastic providing a shell that that is rigid and
can absorb impact and repel abrasion. A display 64 is positioned
into a cavity of the display housing. A display bezel 66
constructed of injection-molded plastic is snapped into the display
housing. This locates and secures the display by sandwiching it
between the display housing and display bezel.
[0100] As shown in FIG. 7, a conventional riflescope objective tube
assembly 72 is constructed of thin wall aluminum tubing. A battery
compartment bracket or mount 74 consisting of machined aluminum is
fastened to the objective tube using two setscrews, one threaded
through the left side and one threaded through the right side. A
9-Volt battery compartment or holder 75 consisting of injection
molded plastic and metal terminal contacts is fastened to the
battery compartment bracket using two flathead machine screws, one
located on a bottom tab and one located on a rear tab. A front
bracket 76 consisting of machined aluminum is fastened to the
objective tube using two setscrews, one threaded through the left
side and one threaded through the right side. A button printed
circuit board 77 is attached to the front bracket using tow
pan-head machine screws and the battery compartment bracket using
two pan-head machine screws. A conventional riflescope objective
lens assembly 78 consisting of a plano-convex shaped glass lens
held in a threaded metallic ring is positioned using internal
threads contained in the front of the objective tube. A transmitter
protective lens 79 consisting of glass is attached to the face of
the front bracket with adhesive creating a weather tight seal. A
laser transmitter assembly 110 is threaded into the rear of the
front bracket.
[0101] As shown in FIG. 8, a receiver mount 83 consisting of
machined aluminum contains a cavity for locating and securing a
laser receiver, photodiode, or photo-detector 81. A set of two
printed circuit board standoffs 82 used to secure the main printed
circuit board are threaded into the top of the receiver mount. The
receiver mount is secured to the top of a receiver housing 86
consisting of machined aluminum using four socket head cap screws
located in each of the corners. A plano-convex narrow pass-band
filter lens 85 consisting of thin film coated glass is located in a
cavity in the receiver housing. The lens is secured into the
receiver housing with a threaded receiver collet 84 also consisting
of machined aluminum. A notch reflection filter 87 is positioned at
a 45.degree. angle and secured by sandwiching it between the
receiver housing and a center tube mount 88 consisting of machined
aluminum. The center tube mount is fastened to the receiver housing
with four socket head cap screws, one located in each corner.
[0102] As shown in FIG. 10, a stepper motor 92 is fastened to a
motor mount 94 consisting of machined aluminum using two pan-head
machine screws. A bevel pinion gear 96 consisting of machined
plastic is attached to the stepper motor with a keyed press
fit.
[0103] As shown in FIG. 11, a manual elevation adjustment knob 101
consisting of machined aluminum round stock is joined to a bevel
ring gear 102 consisting of machined plastic. These two components
are fastened to a conventional riflescope center tube assembly 107
using two socket head cap screws. A conventional riflescope
eyepiece assembly 104 is threaded onto the conventional riflescope
center tube assembly. A conventional riflescope magnification
adjustment knob assembly 105 consisting of injection molded plastic
is attached to the conventional riflescope center tube assembly
using a single socket head cap screw. A conventional riflescope
manual windage adjustment knob assembly 108 consisting of machined
aluminum round stock is attached to the conventional riflescope
center tube assembly using two socket head cap screws.
[0104] As shown in FIG. 12, a laser transmitter or diode 114 is
loaded into the rear of a transmitter housing tube or mount 116
consisting machined aluminum round stock. The laser transmitter is
locked into place by sandwiching it between an internal shoulder in
the transmitter housing tube and a threaded laser collet 112
consisting of machined aluminum round stock. A collimating lens 118
consisting of a glass lens and a threaded outer metal ring is
positioned by rotating it inside the internally threaded
transmitter housing. Once the desired location is achieved the
collimating lens is locked into place using adhesive.
[0105] Operation--FIGS. 2-13
[0106] Once the trajectory compensating riflescope is mounted to
the firearm the user must perform a zeroing calibration operation,
this procedure is identical to that used for conventional
riflescopes. The manual elevation adjustment knob 101 and the
windage adjustment knob 108 (FIG. 11) are rotated the corresponding
number of clicks to zero out the mounting position. This also
establishes a sighted in distance when the trajectory compensating
riflescope is used as a conventional riflescope.
[0107] When the electronics are not enabled, the manner of using
the automatic trajectory compensating targeting riflescope is
identical to that for riflescopes in present use. The operation as
a normal riflescope is necessary to ensure useful operation in the
event of battery failure.
[0108] To make use of the automatic compensation mode, the user
must toggle the power switch 24 (FIG. 2) to the on position. As
shown in FIG. 13, this will cause the micro-controller 121 to read
the muzzle velocity and ballistic coefficient parameters from the
nonvolatile memory 129. These parameters must be previously entered
using the data entry button keypad 34 (FIG. 3) prior to actual use
by opening the hinged display assembly 60, and stepping through
preprogrammed menu options shown on the display 64 (FIG. 6).
[0109] The user then views the intended target through eyepiece 104
(FIG. 11) and lines up the reticle center point with the intended
target. The user then depresses the activation button 54 (FIG. 5),
triggering the automatic compensation electronics. As depicted in
the electronics block diagram in FIG. 13, the micro-controller 121
will generate a trigger that is routed into both the pulsed laser
driver 123 and time-of-flight detection circuit 125. In parallel,
this trigger starts the high-speed timer in the time-of-flight
detection circuit and signals the pulsed laser driver to generate a
pulse of high current into the laser transmitter 104. The
collimating lens 118 (FIG. 12) tightly focuses the pulsed laser
light providing a low divergent beam that provides long-range
operation.
[0110] The laser light is then reflected off the target, objective
lens 78 (FIG. 7) collects and focuses the reflected light into the
receiver section assembly 80 (FIG. 4). As shown in FIGS. 8 and 9,
the notch reflection filter 87 housed in the receiver section
assembly reflects the laser light straight up while passing the
visual light axially through to the rear scope section assembly 100
(FIG. 4). The laser light is then filtered a second time and
focused onto the photodiode as it passes through the plano-convex
narrow-band filter lens 85. Once the reflected laser light exceeds
a calibrated threshold in the detection discriminator 124 (FIG. 13)
a trigger is sent to stop the high-speed timer in the
time-of-flight detection circuit.
[0111] As shown in FIG. 13, the micro-controller 121 will then
receive a trigger from the time-of-flight detection circuit 125
indicating that a measurement is complete. The micro-controller
then samples the inclination angle transducer 126. The measured
line-of-sight distance and inclination angle are used to calculate
the actual horizontal target distance. In addition, the
microcontroller samples the barometric pressure transducer 127 and
temperature sensor 128; these two values are applied to the ideal
gas law equation to calculate the actual air density thus factoring
in the air resistance that will affect the flight velocity. The
microcontroller then uses the measured data and user specific
parameters to calculate the elevation reticle adjustment necessary
to precisely impact the target.
[0112] Lastly, the micro-controller signals the stepper motor
driver circuit 122 to drive the stepper motor 92 (FIG. 10) to the
position where the elevation reticle as viewed through the eyepiece
will precisely aligned with the projectile impact point on the
target. The elevation reticle will return to the default or zero
calibration position after switching off the power switch 24 (FIG.
2).
[0113] Advantages
[0114] From the descriptions above, a number of advantages of my
trajectory compensating riflescope become evident:
[0115] (a) The integration of the laser receiver system into the
viewing optics reduces the overall form factor and weight. In
addition, using the large aperture of the objective lens to collect
the reflected laser light provides for lower light level detection
and thus greater effective range.
[0116] (b) Incorporating the user settable muzzle velocity value
provides a critical parameter in calculating the time over which
the projectile will be influenced by gravity thus resulting in a
more accurate determination of the final impact point.
[0117] (c) Incorporating the user settable ballistic coefficient
value provides a critical parameter in calculating the time over
which the projectile will be influenced by gravity thus resulting
in a more accurate determination of the final impact point. This
value indicates how well a specific bullet can overcome air
resistance and maintain flight velocity.
[0118] (d) Incorporating the measurement of the barometric pressure
and temperature values provides a critical parameter in calculating
the time over which the projectile will be influenced by gravity
thus resulting in a more accurate determination of the final impact
point. These two values are applied to the ideal gas law equation
to calculate the actual air density thus factoring in the air
resistance that will affect the flight velocity.
[0119] (e) Gravity only affects the projectile over the horizontal
distance traveled. Implementing both the line of sight laser
distance measurement and inclination angle provides a method to
determine the horizontal distance when shooting uphill or
downhill.
[0120] (f) Indicating the compensated aim point by automatically
adjusting the elevation reticle eliminates the need to guess at the
adjusted aim point.
[0121] (g) Providing operation as a conventional riflescope ensures
useful functionality in the event of battery failure.
[0122] (h) The manual windage and elevation adjustments provide a
mechanism to calibrate the zero aim point at a given target
distance thus compensating for variability in mounting position on
the firearm.
[0123] Conclusion, Ramifications, and Scope
[0124] Thus the reader will see that the trajectory compensating
riflescope of the invention provides a compact, lightweight, yet
economical device that is highly accurate and easy to use.
[0125] While my above description contains many specificities,
these should not be construed as limiting the scope of the
invention, but rather as exemplification of one preferred
embodiment thereof. Many other variations are possible. For
example, the laser transmitter could also be integrated into the
visual sight path. The range finding apparatus could be modular and
not integrated into the visual sight path. The laser distance
measurement method could implement a phase shift method instead of
pulsed time of flight method. The material choices could vary for
each of the individual components. The use of a conventional
riflescope could be eliminated to change the overall device form
factor. The accuracy could be sacrificed by eliminating the
barometric pressure, temperature, and inclination angle sensors to
reduce overall cost. The user interface could be simplified or
eliminated to reduce cost. The user specific parameters such as
muzzle velocity and ballistic coefficient could be entered using a
computer interface or preset at the factory. The user input could
be simplified by using a lookup table to identify the muzzle
velocity and ballistic coefficient values for entered firearm and
ammunition types. Although not implemented due to the additional
cost, an anemometer could be added to measure the head wind and
compensate for the additional drag thus providing greater accuracy.
In addition, an anemometer that measures and compensates for
crosswind could be added and used to automatically adjust the
windage reticle. The method of indicating the compensated aim point
could consist of a secondary elevation and/or windage reticle.
[0126] Accordingly, the scope of the invention should be determined
not by the embodiment(s) illustrated, but by the appended claims
and their legal equivalents.
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