Electronic ballistic computer for tank fire control system

Claim 2

A land vehicle fire control ballistic computer comprising: computer channel means including a plurality of circuits including first circuit means having an input coupled to receive a range signal for operating on the range signal in accordance with a transfer function related to ballistic equations which includes terms for selected standard conditions including standard ballistic conditions and standard environmental conditions for a selected one of a plurality of ammunition types and second and third circuit means in a first output channel and a second output channel respectively for operating on the operated on range signal in accordance with transfer functions related to ballistic equations which include terms for the standard conditions to produce a time-of-flight signal on the first output channel and a superelevation signal on the second output channel; and partial derivative multiplier means each coupled in said computer channel means between the range signal input and the time-of-flight and superelevation signal outputs and to the output of selected circuit means to receive the output signals from said circuit means for changing the output signals in accordance with a first order approximation partial derivative (1+K( Delta u/uo) corresponding to small order changes Delta u in any selected standard conditions uo where K is a positive or negative constant, uo is the general case for any of the standard conditions for correcting the time-of-flight signal and the superelevation signal for changes in the selected condition.

Claim 3

The land vehicle fire control ballistic computer of claim 1 in which said plurality of circuit means includes a plurality of individual operational amplifiers including a first common operational amplifier for operating on the range signal in accordance with a normalizing standard condition transfer function said second circuit means includes a second and a third operational amplifier coupled in series circuit relationship to operate on the operated on range signal for producing a time-of-flight signal on the first output channel and said third circuit means Includes other first and second operational amplifier means coupled in series circuit relationship with one another to operate on the operated on range signal for producing the superelevation signal in said second output channel; and each of said partial derivative multiplier means includes a multiplier circuit each selectively coupled in said computer channel means between the range signal input and the time-of-flight signal output and superelevation output and between the output of selected ones of said plurality of operational amplifiers and to the input of any subsequent means in said computer channel means for operably multiplying the output signal of selected operational amplifiers in accordance with the first order approximation partial derivative corresponding to changes in selected standard conditions for correcting the time-of-flight signal and the superelevation signal for changes in the selected standard conditions.

Claim 4

The land vehicle fire control ballistic computer of claim 2 further including additional circuit means for producing fire control deflection signals and elevation signals in response to the time-of-flight signal and the superelevation signal including means for operating on the superelevation signal by a transfer function corresponding to a selected ballistic drift constant for an ammunition type and means for selectively summing the resultant signal with an angular turret rate in azimuth signal times the time-of-flight signal, and a crosswind signal times a crosswind coefficient constant signal for a selected ammunition type having combined therewith a partial derivative factor corresponding to the effects of changes in standard condition air pressure and air temperature times the time-of-flight time to produce a corrected deflection signal.

Claim 5

The land vehicle fire control ballistic computer of claim 3 in which said additional circuit means operates on the time-of-flight signal by a transfer function for an angular turret rate in elevation and selectively combines the resulting signal with the superelevation signal to produce a corrected elevation signal.

Claim 6

The land vehicle fire control ballistic computer of claim 1 in which said plurality of circuit means further includes additional circuit means for producing fire control deflection and elevation signals in response to the time-of-flight signal and the superelevation signal including means for operating on the superelevation signal by a transfer function corresponding to selected ballistic drift constant for an ammunition type and means for selectively summing the resultant signal with an angular turret rate in azimuth signal times the time-of-flight signal, and a crosswind signal times a crosswind coefficient constant signal for a selected ammunition type having combined therewith a partial derivative factor corresponding to the effects of changes in standard condition air pressure and air temperature times the time-of-flight time to produce a corrected deflection signal.

Claim 7

The land vehicle fire control ballistic computer of claim 5 in which said additional circuit means multiples the the time-of-flight signal by an angular turret rate in elevation signal and selectively sums the signal with the superelevation signal to produce a corrected elevation signal.

Claim 8

The ballistic computer for producing fire control signals for the ballistics of projectile types wherein the improvement comprises: first means coupled to receive a range signal for multiplying the received range signal by a function comprising a normalizing function to produce a normalized range signal which is standardized relative to a single function common to the ballistics of a plurality of projectile types; a first output channel for producing a time-of-flight signal and a second output channel for producing a superelevation signal, each of said output channels including a second means and a third means, said second means coupled to receive the normalized range signal for multiplying the norMalized range signal by the single function common to the ballistics of a plurality of projectile types for producing a function signal, and said third means coupled to receive the function signal from said second means for multiplying the function signal by a function comprising an unnormalizing function for producing the ballistic signals for the projectile type; and partial derivative means selectively coupled to receive the signal produced by at least one of said first through third means for multiplying the signal by the ratio of change in a standard condition to the standard condition and to sum the ratio of change in standard condition and the produced signal to produce a partial derivative signal times the produced signal.

Claim 9

The ballistic computer for producing fire control signals for the ballistics of projectile types wherein the improvement comprises: first means coupled to receive a range signal for multiplying the received range signal by a function comprising a normalizing function to produce a normalized range signal which is standardized relative to a single function common to the ballistics of a plurality of projectile types; a first output channel for producing a time-of-flight signal and a second output channel for producing a superelevation signal, each of said output channels including a second means and a third means, said second means coupled to receive the normalized range signal for multiplying the norMalized range signal by the single function common to the ballistics of a plurality of projectile types for producing a function signal, and said third means coupled to receive the function signal from said second means for multiplying the function signal by a function comprising an unnormalizing function for producing the ballistic signals for the projectile type; and partial derivative means selectively coupled to receive the signal produced by at least one of said first through third means for multiplying the signal by the ratio of change in a standard condition to the standard condition and to sum the ratio of change in standard condition and the produced signal to produce a partial derivative signal times the produced signal.

Claim 10

The ballistic computer of claim 7 wherein said partial derivative multiplier means includes a first partial derivative circuit means coupled in series circuit relationship between first means and said second means for summing the approximate partial derivative corresponding to changes in selected standard conditions relative to the standard conditions for correcting the normalized range signal in accordance with the effects thereon of the changes in selected standard conditions.

Claim 11

The ballistic computer of claim 8 wherein said first partial derivative circuit means combines a signal corresponding to the effects of changes in air pressure and air temperature on the normalized range signal.

Claim 12

The ballistic computer of claim 8 wherein said first partial derivative circuit means generates and combines with the normalized range signal, a signal where Delta T is the change in air temperature, To is the standard condition air temperature, Delta P is the change in air pressure and Po is the standard condition air pressure.

Claim 13

The ballistic computer of claim 8 in which the last said circuit means multiplies the time-of-flight signal by an angular turret rate in elevation signal and selectively sums the signal with the superelevation signal to produce a corrected elevation signal.

Claim 14

The ballistic computer of claim 8 wherein said partial derivative multiplier means includes a second partial derivative circuit means and a third partial derivative circuit means coupled in series circuit relationship to receive the ballistic signal from said third means for summing the approximate partial derivative corresponding to changes in selected standard conditions relative to the standard conditions for correcting the ballistic signals in accordance with the effects thereon of the changes in selected standard conditions.

Claim 15

The ballistic computer of claim 12 wherein said second partial derivative circuit means sums a signal corresponding to the effects of changes in air pressure and air temperature on the ballistic signals and said third partial derivative circuit means sums a signal corresponding to the effects of changes in muzzle velocity as a result of changes in propellant grain temperature, and a function of effective full charge.

Claim 16

The ballistic computer of claim 13 wherein said second partial derivative circuit means sums a signal where Delta T is the change in air temperature, To is the standard condition air temperature, Delta P is the change in air pressure, and Po is a standard condition air pressure and said third partial derivative circuit means sums a signal proportional to where Delta Tg is the change in propellant grain temperature, Tg is standard condition propellant grain temperature, Kg is derived ballistic constant for an ammunition type, E.F.C. is the effective full charge, Ke is a derived ballistic constant for an ammunition type and k is a + or 1 having a magnitude greater than

Claim 17

The ballistic computer of claim 12 in which said first means and said third means multiply the received signals by linear functions deriVed from the effects of ballistic conditions and environmental conditions including the projectile mass m, projectile diameter d, drag coefficient KD, and atmospheric density p, and initial projectile velocity Vo, and said second means multiples the received normalized range signal by a nonlinear function.

Claim 18

The ballistic computer of claim 15 in which said first means multiplies the received normalized range signals by approximately the term m/pd2KD and one of said third means multiplies the received signals by approximately the term mg/2pd2VoKD.

Claim 19

The ballistic computer of claim 15 in which said first means multiplies the received normalized range signals by approximately the term m/pd2KD and one of said third means multiplies the received signals by approximately the term m/pd2VoKD.

Claim 20

The ballistic computer of claim 12 in which said first means and said third means are adjustable for multiplying the received signals by individual ones of a plurality of constant functions, each including individual terms derived from the effects of ballistic conditions and environmental conditions on individual ones of a plurality of projectile types.

Claim 21

The ballistic computer of claim 7 including means for producing fire control deflection and elevation signals in response to the time-of-flight signal and the superelevation signal including means for multiplying the superelevation signal by a selected ballistic drift constant for an ammunition type and selectively summing the resultant signal with an angular turret rate in azimuth signal times the time-of-flight signal, a crosswind signal times a crosswind coefficient constant for a selected ammunition type having summed therewith a partial derivative corresponding to the effects of changes in standard condition air pressure and air temperature times the time-of-flight time to produce a corrected deflection signal.

Claim 22

The ballistic computer of claim 7 in which said first means and said third means multiply the received signals by linear functions derived from the effects of ballistic conditions and environmental conditions including the projectile mass m, projectile diameter d, drag coefficient KD, and atmospheric density p, and initial projectile velocity Vo and said second means multiples the received normalized range signal by a nonlinear function.

Claim 23

The ballistic computer of claim 7 in which said first means and said third means are adjustable for multiplying the received signals by individual ones of a plurality of constant functions, each including individual terms derived from the effects of ballistic conditions and environmental conditions on individual ones of a plurality of projectile types.

Claim 24

The ballistic computer of claim 7 in which said first means multiplies the received signals by approximately the function m/pd2KD; one of said third means operates on the received signals by approximately the function mg/2pd2VoKD; and the other of said third means operates on the received signals by approximately the function m/pd2VoKD where: m projectile mass p air density d projectile diameter KD projectile drag coefficient Vo projectile initial velocity g gravitational effects.

Claim 25

The computer of claim 22 in which one of said second means multiplies the received signal by a function approximating and the other of said second means multiplies the received signal by the function approximating (e(R/Rn)-1) where: R range 1/Rn NORMALIZING function about

Claim 26

The ballistic computer of claim 7 wherein said partial derivative circuit includes: circuit multiplier means coupled to directly receive the output signal from at least one of said first, second, or third means for multiplying the output signal in operable parallel circuit relationship with the output of at least one of said first, second, or third means by a signal related to the ratio of change in at least one of the predetermined conditions relative to the predetermined condition to produce a product signal; and summing means coupled in series circuit relationship with said first, second, and third means for directly receiving the product signal and directly receiving the output signal for summing the product signal and the output signal to produce the corrected signal.

Claim 27

The ballistic computer of claim 24 in which said circuit multiplier means is a master-slave time-division multiplier, said master multiplier being operable to receive input signals corresponding to the ratio of change in a standard condition to the standard condition to feed the received signal to a slave multiplier and said slave multiplier multiplies the output signal from at least one of said first, second, and third means by the ratio of change in a standard condition to the standard condition signal.

Claim 28

The ballistic computer comprising: first means coupled to receive a range signal R for normalizing the range signal in accordance with standard conditions to produce a normalized range signal R/Rn where 1/Rn is a normalizing signal; means for multiplying the normalized range signal R/Rn by an approximate in-line partial derivative (1-( Delta Rn/Rn) where Delta Rn is the change in the range normalizing signal to compensate for the effects of changes in the standard conditions air pressure and air temperature on the range; first and second nonlinear function generator means coupled to receive the corrected normalized range signal from said multiplier means for respectively generating a first nonlinear function signal common to a plurality of ammunition types and related to time-of-flight and a second nonlinear function signal common to a plurality of ammunition types and related to superelevation; first and second multiplier means coupled to said first and second nonlinear function generator means, respectively, for receiving and multiplying the nonlinear function signals by respective unnormalizing terms for standard conditions to produce a time-of-flight signal tf and a superelevation signal epsilon ; third multiplier means and fourth multiplier means coupled in series circuit relationship to said first multiplier means and said second multiplier means to respectively multiply the time-of-flight signal and superelevation signal by approximate first order partial derivatives is the standard condition muzzle velocity to correct for changes in the standard conditions of air temperature, air pressure, propellent grain temperature, and effective full charge; means for multiplying the superelevation signals by ballistic drift constant signal for an ammunition type and to multiply the time-of-flight signal by the product of a ballistic crosswind constant signal for a specific ammunition type and a crosswind signal, to generate signals related to ballistic drift and crosswind deflection, respectively; and means for feeding the superelevation signal to an elevation channel and to sum and feed the ballistic drift and crosswind deflection signals to a deflection channel and resolver means for converting the signals to fire control elevation and deflection coordinate signals.

Claim 29

The ballistic computer comprising: first means coupled to receive a range signal R for normalizing the range signal in accordance with standard conditions to produce a normalized range signal R/Rn where 1/Rn is a normalizing signal; means for multiplying the normalized range signal R/Rn by an approximate in-line partial derivative (1-( Delta Rn/Rn) where Delta Rn is the change in the range normalizing signal to compensate for the effects of changes in the standard conditions air pressure and air temperature on the range; first and second nonlinear function generator means coupled to receive the corrected normalized range signal from said multiplier means for respectively generating a first nonlinear function signal common to a plurality of ammunition types and related to time-of-flight and a second nonlinear function signal common to a plurality of ammunition types and related to superelevation; first and second multiplier means coupled to said first and second nonlinear function generator means, respectively, for receiving and multiplying the nonlinear function signals by respective unnormalizing terms for standard conditions to produce a time-of-flight signal tf and a superelevation signal epsilon ; third multiplier means and fourth multiplier means coupled in series circuit relationship to said first multiplier means and said second multiplier means to respectively multiply the time-of-flight signal and superelevation signal by approximate first order partial derivatives is the standard condition muzzle velocity to correct for changes in the standard conditions of air temperature, air pressure, propellent grain temperature, and effective full charge; means for multiplying the superelevation signals by ballistic drift constant signal for an ammunition type and to multiply the time-of-flight signal by the product of a ballistic crosswind constant signal for a specific ammunition type and a crosswind signal, to generate signals related to ballistic drift and crosswind deflection, respectively; and means for feeding the superelevation signal to an elevation channel and to sum and feed the ballistic drift and crosswind deflection signals to a deflection channel and resolver means for converting the signals to fire control elevation and deflection coordinate signals.