BALLISTIC RANGING METHODS AND SYSTEMS FOR INCLINED SHOOTING

• US 20070137088A1
• Filed: 11/01/2006
• Published: 06/21/2007
• Est. Priority Date: 11/01/2005
• Status: Active Grant

• Current Assignee: Leupold & Stevens Incorporated
• Original Assignee: Leupold & Stevens Incorporated
• Inventors: Lesser, Tim, York, Andrew, Peters, Victoria, Regan, Rick
• Granted Patent: US 7,654,029 B2
• Time in Patent Office: Days
• US Class Current: 42/111
• CPC Class Codes: F41G 1/473 for lead-indicating or range-finding, e.g. for use with rifles or shotguns
• CPC Class Codes: F41G 3/02 using an independent line of sight
• CPC Class Codes: F41G 3/06 with rangefinder rangefinders per se G01C
• CPC Class Codes: F41G 3/08 with means for compensating for speed, direction, temperature, pressure, or humidity of the atmosphere measuring G01
• CPC Class Codes: F41G 3/142 based on observation of a first shoot; using a simulated shoot training F41G3/26

Abstract

A method for shooting a projectile weapon involves determining the inclination of a line of sight from a vantage point to a target and a line-of-sight range to the target, then predicting a trajectory parameter at the line-of-sight range, for a preselected projectile. Using the trajectory parameter, an equivalent horizontal range may then be determined, wherein the equivalent horizontal range is the range at which the trajectory parameter would be expected to occur if the projectile were shot from the vantage point toward a theoretical target located in a horizontal plane intersecting the vantage point. The equivalent horizontal range may be utilized to compensate for ballistic drop when shooting the projectile weapon. The method may be embodied in a handheld laser rangefinder including a memory for storing ballistic data. Systems for automatic hold over adjustment in a weapon aiming device are also disclosed.

Claims

1. A method for inclined shooting of projectile weapons, comprising:

determining an inclination of a line of sight between a vantage point and a target that is elevated or depressed relative to the vantage point;

determining a line-of-sight range from the vantage point to the target;

predicting a trajectory parameter expected at the line-of-sight range for a preselected projectile if shot from the vantage point toward the target; and

using the trajectory parameter, determining an equivalent horizontal range at which the trajectory parameter would occur if shooting the projectile from the vantage point toward a theoretical target located in a horizontal plane intersecting the vantage point.

2. The method of claim 1, further comprising displaying the equivalent horizontal range.

3. The method of claim 1, further comprising highlighting a reticle aiming mark corresponding to the equivalent horizontal range.

4. The method of claim 1, further comprising:

aiming a projectile weapon at the target, including compensating for ballistic drop based on the equivalent horizontal range; and

shooting the projectile weapon.

5. The method of claim 1, further comprising:

based on the equivalent horizontal range, adjusting a holdover of a projectile weapon; and

shooting the projectile weapon.

6. The method of claim 1, wherein:

the inclination and the line-of-sight range are both determined by a handheld laser rangefinder including an inclinometer and a computer processor; and

the trajectory parameter and the equivalent horizontal range are both calculated by the computer processor of the laser rangefinder.

7. The method of claim 1, wherein the trajectory parameter includes a ballistic path height of the projectile relative to the line of sight.

8. The method of claim 1, wherein the trajectory parameter includes a ballistic drop of the projectile relative to a line of initial trajectory of the projectile.

9. The method of claim 1, wherein the projectile is characterized by a ballistic coefficient and the step of predicting the trajectory parameter is based on the ballistic coefficient.

10. The method of claim 1, wherein the step of predicting the trajectory parameter is based on a set of shooting conditions for the projectile.

11. The method of claim 10, wherein the inclination, the line-of-sight range, and at least some of the shooting conditions are determined by a handheld laser rangefinder;

and

the trajectory parameter and the equivalent horizontal range are calculated by the handheld laser rangefinder.

12. The method of claim 10, wherein the set of shooting conditions includes one or more of the following:

(a) an initial velocity of the projectile;

(b) an altitude of the vantage point above sea level;

(c) a barometric pressure;

(d) an ambient temperature;

(e) a relative humidity;

(f) a sighted-in range of a weapon aiming device;

(g) a height of a weapon aiming device above a bore line of a weapon;

(h) a compass heading of the line of sight; and

(i) geographic location of the vantage point.

13. The method of claim 12, wherein the inclination, the line-of-sight range, the barometric pressure, the ambient temperature, and the relative humidity are measured by a handheld laser rangefinder;

and

the trajectory parameter and the equivalent horizontal range are calculated by a computer processor of the handheld laser rangefinder.

14. The method of claim 12, wherein the geographic location of the vantage point is determined by a global positioning system receiver integrated with or in direct communication with a laser rangefinder.

15. The method of claim 1, further comprising identifying the projectile as belonging to one of at least two different groups of projectiles, each group having a nominal ballistic characteristic, and wherein the trajectory parameter is determined based on the nominal ballistic characteristic.

16. The method of claim 15, wherein the nominal ballistic characteristic is characteristic of a ballistic coefficient and an initial velocity of the projectile.

17. A portable system for facilitating inclined shooting of projectile weapons, comprising:

a ranging system for measuring a line-of-sight range from a vantage point to a target that is elevated or depressed relative to the vantage point;

an inclinometer mounted in alignment with the ranging system for measuring an inclination of a line of sight between the vantage point and the target; and

a computer processor in communication with the ranging system and the inclinometer; and

a computer software program operable on the computer processor to determine a predicted trajectory parameter at the line-of-sight range for a preselected projectile.

18. The system of claim 17, wherein the computer software is further operable on the computer processor to determine an equivalent horizontal range at which the trajectory parameter would occur if shooting the projectile from the vantage point toward a theoretical target located in a horizontal plane intersecting the vantage point.

19. The system of claim 18, further comprising an electronic display in operative association with the computer processor for displaying the equivalent horizontal range.

20. The system of claim 19, wherein the electronic display includes:

a first data display section for displaying the equivalent horizontal range; and

a second data display section for displaying the line-of-sight range.

21. The system of claim 18, further comprising an electronic display in operative association with the computer processor for displaying a reticle pattern including multiple aiming marks spaced apart along a vertical axis, one of the aiming marks corresponding to a sighted-in range and the other aiming marks corresponding to holdover ranges different from the sighted-in range, the electronic display responsive to the computer processor for displaying or emphasizing the display of a selected one of the aiming marks corresponding to the sighted-in range or holdover range closest to the equivalent horizontal range.

22. The system of claim 18, further comprising a signaling module in communication with the computer processor, the signaling module operable to transmit to a weapon aiming device a signal representative of the equivalent horizontal range.

23. The system of claim 22, further comprising a riflescope including an electronic reticle display having multiple aiming marks spaced apart along a vertical axis within a field of view of the riflescope, one of the aiming marks corresponding to a sighted-in range of the riflescope and the other aiming marks corresponding to holdover ranges different from the sighted-in range, the electronic reticle display operative, in response to receipt of the signal from the signaling module, to display or emphasize the display of a selected one of the aiming marks corresponding to the holdover range closest to the equivalent horizontal range.

24. The system of claim 23, wherein the selected aiming mark intermittently blinks in response to the signal.

25. The system of claim 17, further comprising an electronic display in operative association with the computer processor.

26. The system of claim 17, wherein the computer software is further operable to calculate an angular elevation adjustment for an aiming device.

27. The system of claim 26, further comprising an electronic display operable to display the angular elevation adjustment.

28. The system of claim 26, further comprising a signaling module operable to transmit to a weapon aiming device a signal representative of the angular elevation adjustment.

29. The system of claim 28, further comprising a riflescope including an automatic elevation adjustment mechanism responsive to the signal.

30. The system of claim 17, wherein the predicted trajectory parameter includes ballistic path height relative to the line of sight, and further comprising an electronic display in operative association with the computer processor for displaying a reticle pattern including multiple aiming marks spaced apart along a vertical axis, one of the aiming marks corresponding to a sighted-in range of a projectile weapon and the other aiming marks corresponding to holdover ranges different from the sighted-in range, the electronic display responsive to the computer processor for displaying or emphasizing the display of a selected one of the aiming marks corresponding to the sighted-in range or holdover range corresponding to the ballistic path height.

31. The system of claim 17, further comprising a signaling module operable to transmit to a weapon aiming device a signal representative of the trajectory parameter.

32. The system of claim 31, further comprising a riflescope in operative association with the ranging system, the riflescope including:

an electronic reticle display having multiple aiming marks spaced apart along a vertical axis and corresponding to holdover ranges different from a sighted-in range of the riflescope, the electronic reticle display responsive to the signal for displaying or emphasizing the display of a selected one of the aiming marks corresponding to the trajectory parameter.

33. The weapon aiming device of claim 32, wherein the selected aiming mark intermittently blinks in response to the signal.

34. A method for aiming a projectile weapon that shoots a preselected projectile at a nominal initial velocity, comprising:

based on at least the preselected projectile, identifying a selected projectile group corresponding to the preselected projectile and its nominal initial velocity from at least two different predetermined groups of projectiles, each group having a nominal ballistic characteristic;

determining a range to a target; and

based on the nominal ballistic characteristic and the range to the target, automatically determining an aiming adjustment for aiming the projectile weapon.

35. The method of claim 34, wherein the nominal ballistic characteristic is characteristic of a ballistic coefficient of the preselected projectile and the nominal initial velocity of the preselected projectile.