CA2023659A1 - Method and apparatus for improving the accuracy of fire - Google Patents
Method and apparatus for improving the accuracy of fireInfo
- Publication number
- CA2023659A1 CA2023659A1 CA 2023659 CA2023659A CA2023659A1 CA 2023659 A1 CA2023659 A1 CA 2023659A1 CA 2023659 CA2023659 CA 2023659 CA 2023659 A CA2023659 A CA 2023659A CA 2023659 A1 CA2023659 A1 CA 2023659A1
- Authority
- CA
- Canada
- Prior art keywords
- parameters
- pilot
- shots
- trajectory
- target
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F41—WEAPONS
- F41G—WEAPON SIGHTS; AIMING
- F41G3/00—Aiming or laying means
- F41G3/14—Indirect aiming means
- F41G3/142—Indirect aiming means based on observation of a first shoot; using a simulated shoot
Abstract
ABSTRACT
A method for improving the accuracy of fire of shots from a firing installation is described, in which a surveying means surveys the trajectories of pilot shots and the thus determined pilot trajectories are used for correcting the firing elements of the real shots. One or more pilot shots are fired in the direction of possible and/or known targets and from the pilot trajectories are calculated and stored trajectory-influencing, predetermined parameters and subseq-uently or directly are incorporated into the calculation of the firing elements. A simplified method variant determines by surveying only the initial portion of the shot trajectory, the departure error of the effector and which is incorporated into the calculation of the firing elements.
(fig. 1).
A method for improving the accuracy of fire of shots from a firing installation is described, in which a surveying means surveys the trajectories of pilot shots and the thus determined pilot trajectories are used for correcting the firing elements of the real shots. One or more pilot shots are fired in the direction of possible and/or known targets and from the pilot trajectories are calculated and stored trajectory-influencing, predetermined parameters and subseq-uently or directly are incorporated into the calculation of the firing elements. A simplified method variant determines by surveying only the initial portion of the shot trajectory, the departure error of the effector and which is incorporated into the calculation of the firing elements.
(fig. 1).
Description
2023~
.; , Method and aPParatuS for improving the accuracv of fire.
The invention relates to a method and an apparatus for improving the accuracy of fire of real shots or projectiles from a shooting installation, comprising a surveying means for tracking and surveying a projectile or shot along a flight path or trajectory, a computer for calculating the controllable parameters (shooting elements) and an effector (gun, launcher, etc.) servocontrolled in accordance with the controllable parameters supplied by the computer, in which the controllable parameters are calculated by means of available target parameters and known predetermined parameters and with the aid of the surveying means the trajectory of a pilot shot or projectile is surveyed and the thus determined pilot trajectory is used for correcting the controllable parameters for the real shots.
The invention is therefore in the field of fire control and more particularly relates to a method for improving the accuracy of fire of unguided and driveless projectiles. The latter includes rockets on their ballistic flight following combustion cutoff. It is assumed that the present and future location of the target, e.g. its trajec-tory or path of motion, is accurately known and cannot be influenced and is described by so-called target parameters.
However, the trajectory of the shot for attacking a target is depen-dent on numerous influences and quantities, which are referred to here as controllable parameters (e.g. shooting elements, directional quantities) and predetermined parameters.
The predetermined parameters are those having an influence on the trajectory of a shot, but which cannot be changed by the method, i.e. are not controllable. In turn, they can be placed in two clas-ses, a first class with parameters which are independent of the firing installation and the projectile, such as the wind, temperature, air pressure, etc., as a function of the location, and a second class ~ :
with parameters which depend on the shooting installation and J
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the projectile, such as the location and setting-up errors of the effectors, divergences from the e~pected shearin~ force, etc.
The basic problem of fire control is consequently to so select the controllable parameters (e.g. the direction of the gun tube from which the projectile is fired, as well as its flight characteristics), -in such a way that the projectile meets the target, even under the influer.ce of the predetermined parameters. For this purpose the predetermined parameters, e.g. the weather conditions, location and rotation position of the gun mount must be known as well as possible. -Conventional methods for improving the accuracy of fire of projectiles or shots can be subdivided into two groups.
- .~
1. The predetermined parameters are measured with conventional methods and then taken into account when calculating the cont-rollable parameters. For e~ample, by using a weather balloon ~;
the meteorological data are determined, such as e~g. the vect-orial wind velocity, pressure and temperature of the air. How-ever, these methods are usually so complicated and time-consum-ing, that they cannot be sufficiently frequently carried out in order to have adequate knowledge of the predetermined para-meters which are highly dependent on the location (of the target) and the time, e.g. the wind velocity.
.; , Method and aPParatuS for improving the accuracv of fire.
The invention relates to a method and an apparatus for improving the accuracy of fire of real shots or projectiles from a shooting installation, comprising a surveying means for tracking and surveying a projectile or shot along a flight path or trajectory, a computer for calculating the controllable parameters (shooting elements) and an effector (gun, launcher, etc.) servocontrolled in accordance with the controllable parameters supplied by the computer, in which the controllable parameters are calculated by means of available target parameters and known predetermined parameters and with the aid of the surveying means the trajectory of a pilot shot or projectile is surveyed and the thus determined pilot trajectory is used for correcting the controllable parameters for the real shots.
The invention is therefore in the field of fire control and more particularly relates to a method for improving the accuracy of fire of unguided and driveless projectiles. The latter includes rockets on their ballistic flight following combustion cutoff. It is assumed that the present and future location of the target, e.g. its trajec-tory or path of motion, is accurately known and cannot be influenced and is described by so-called target parameters.
However, the trajectory of the shot for attacking a target is depen-dent on numerous influences and quantities, which are referred to here as controllable parameters (e.g. shooting elements, directional quantities) and predetermined parameters.
The predetermined parameters are those having an influence on the trajectory of a shot, but which cannot be changed by the method, i.e. are not controllable. In turn, they can be placed in two clas-ses, a first class with parameters which are independent of the firing installation and the projectile, such as the wind, temperature, air pressure, etc., as a function of the location, and a second class ~ :
with parameters which depend on the shooting installation and J
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. .
the projectile, such as the location and setting-up errors of the effectors, divergences from the e~pected shearin~ force, etc.
The basic problem of fire control is consequently to so select the controllable parameters (e.g. the direction of the gun tube from which the projectile is fired, as well as its flight characteristics), -in such a way that the projectile meets the target, even under the influer.ce of the predetermined parameters. For this purpose the predetermined parameters, e.g. the weather conditions, location and rotation position of the gun mount must be known as well as possible. -Conventional methods for improving the accuracy of fire of projectiles or shots can be subdivided into two groups.
- .~
1. The predetermined parameters are measured with conventional methods and then taken into account when calculating the cont-rollable parameters. For e~ample, by using a weather balloon ~;
the meteorological data are determined, such as e~g. the vect-orial wind velocity, pressure and temperature of the air. How-ever, these methods are usually so complicated and time-consum-ing, that they cannot be sufficiently frequently carried out in order to have adequate knowledge of the predetermined para-meters which are highly dependent on the location (of the target) and the time, e.g. the wind velocity.
2. The trajectories of the real shots sre measured, which have already been fired at the target and correspondingly the traj-ectories of the subsequent real shots are corrected. This so-called CLFC (Closed Loop Fire Control) method is admittedly insensitive to the dependence of the controllable parameters and the predetermined parameters on the time and place, because it is carried out at the correct place and at the correct time, but this method presupposes a long burst of fire, whose duration -must be long enough, compared with the flight time of the proj-ectiles. It also requires a large number of sensors (tracking ~` " 2 0 2 ~
and surveying means) for surveying the flight paths of the target and the projectiles, because said flight paths often differ greatly from one another. Finally, for time reasons, it cannot itself identify the predetermined parameters and can in fact only correct their action on the trajectories of the projectiles. -In other words it is also not possible to obtain information as to the reasons for the divergence between the measured and the expected trajectory, i.e. which predetermined parameters have entered the calculation with values differing from the true conditions. Therefore these corrections of the effects ~ ~-of the predetermined parameters by corresponding effects of ~-the controllable parameters are at least locally difficult to transfer, because they are still dependent on the target location if the actual predetermined parameters are not dependent thereon.-~
For example, it is not advantageous at the start of a burst of firing to use the aforementioned corrections from the end of the preceding burst of firing if the target is locally rapidly moving. ~ ~-A method of the aforementioned type and which in principle belongs ~ -to the aforementioned second group, is known from Swiss Patent 501 ~ -203. For firing at a known target a pilot shot or projectile is fired with the same flight characteristics as the intended real shot or projectile and the pilot trajectory of the pilot shot is determined by the cooperation of the surveying means (radar) with the trajectory computer. On the basis of the pilot trajectory determined, it is also possible to determine in the trajectory computer the directional errors of the effector or the deviation of the cutoff point of the pilot trajectory compared with the preselected-target object. Such directional errQrs result from the effect of unknown disturbance variables, such as wind, pressure, temperature, etc., which are ref-erred to here as predetermined parameters. This known method can only determine the effect of all these disturbance variables on the trajectories of pilot shots and take them into account by correcting the trajectory of the real shot, but not said disturbance variables.
2023~
.: `
On the basis of Swiss Patent 501 203, the problem of the present invention is to be able to rapidly incorporate into the ~ire control calculation those predetermined parameters (unknown disturbance vari- -ables), which are to be incorporated into a correction of the control-lable parameters, and still to make them available for the entire area to be covered by the effector or effectors when there is no specific target.
For solving this problem in a method as defined in the preamble of claim 1, it is proposed that one or more pilot shots are fired in the direction of possible and/or known targets and that from the pilot trajectories the predetermined parameters are calculated and stored and subsequently or directly incorporated into the calculation of the controllable parameters from the target parameters of a given target. Further appropriate procedures with respect to the method are defined in the subclaims.
The basic idea of the inventive method is that not only should the locally and/or time difficulty transferable effect of all the locally and/or time adequately transferable predetermined parameters on the trajectories of the shots or the influence of these effects on the controllable parameters and therefore the fire control calculation i9 determined and taken into consideration, but also the actual pre-determined parameters. For certain applications some of these, namely the ones which are dependent on the firing installation and the proj-ectile, can be dealt with on a priority basis. For this purpose the trajectories of pilot shots are surveyed and which need not neces-sarily strike a target, but are instead shot at wherever it is sub-sequently assumed a target could be. It is possible to use the same surveying means which will subsequently survey the target or the target firing. In the same way the pilot shots can be shot from the same effector which is subsequently used for firing the real -shots. Sufficient time is available to intensively evaluate the measured values and on the basis of the effect of the predetermined parameters to determine these as a cause, so that the corresponding ` 2023~
corrections of the controllable parameters can in particular be better locally transferred, in that they are dependent on the predetermined parameters and the target location. The inventive method can be automated and can be periodically carried out at times of high alert.
From the effect of the predetermined parameters, conclusions are drawn regarding the predetermined parameters as a cause. This conc-lusion is possible as a result of modern calculating and computing processes and the extended Kalman filter is particularly suitable for this. The movement of the projectile is described by a stoch- ~-astic differential equation, whose vector of state e.g. contains the position and velocity of the projectile. In the inventive method the vector of state is broadened by the sought predetermined parame-ters, in that the latter are no longer considered and dealt with ~-as invariable parameters, but as variables of state. However, the controllable psrameters are still looked upon and dealt with as invar-iable parameters. As a result of known, e~actly defined, algebraic transformations the algorithm of the extended Kalman filter is formed from the stochastic differential equation of the projectile movement and which calculates from the measured values of the trajectories of the pilot shots estimates for all the variables of state and there-fore the predetermined parameters. This estimate of the variables of state is based on a stepwise improvement, which i9 based on an initial estimate (initialization), which can e.g. result from an earlier performance of the inventive method or a conventional measure-ment. Further details of this will be given in connection with fig. 2.
The partial derivation of the measured values is calculated and used in accordance with the predetermined parameters. In the case of effector-dependent predetermined parameters, e.g. setting-up errors and muzzle velocity, said partial derivation tends to be large close to the effector and small remote from the effector. In the case of effector-independent predetermined parameters, e.g. meteorological data, it is small close to the effector and large remote from the effector. This facilitates the differentiation of effector-dependent 2023~ ~
and effector-independent predetermined parameters on the basis of a single pilot shot. In addition, such a differentiation requires the evaluation of many pilot shots in widely differing directions if it is to be reliable and accurate.
Particularly for firing at moving targets, i.e. with variable target parameters, the surveying means according to the invention can survey or track both the trajectories of the pilot shots and the path of motion of the target. The pilot shots can also be of a different nature to the real shots, so that the movement thereof is described by a different differential equation and influenced in a different way from the predetermined parameters. Thus, according to the inven-tion different pilot shots are surveyed, which react differently on the parameters to be determined. Thus, e.g. the pilot shots can carry besides or in place of an explosive charge special devices, e.g. transponders, corner reflectors, Luneberg lenses, etc., which facilitate the surveying or tracking thereof. For this and other reasons theg can have a different shape, different mass and even a different calibre. They can differ at random from the real shots and from one another, provided that their trajectories are influenced by the same predetermined parameters. Also from this standpoint the predetermined parameters can be better transferred than their action on the controllable parameters or on the trajectories of the shots. However, obviously the real shots can serve as pilot shots and in particular preceding real shots can serve as pilot shots for a following round.
The importance of not only determining the effect of the predeter~
mined parameters, but these predetermined parameters themselves, can be illustrated by the following example. A pilot shot or proj-ectile i9 fired northwards and as an effect the surveying means obser-ves an eastward deviation. The cause can be two predetermined para~
meters, namely 1. a west wind or 2. a setting-up error with respect to the azimuth angle position of the gun mount. A targetthen appears in the south. Then the trajectories of the real shots must in the first , .
2~2~9 : -case be corrected to the west and in the second to the east. This example clearly shows that the pilot shots must be fired wherever it might be necessary to fire real shots. Only in this way is it possible to estimate or identify the parameters and differentiate them from one another.
The example also shows that the method can differentiate between the effect of predetermined parameters which are dependent on the shot and gun (in the present example setting-up errors) and those which are not dependent on the shot and gun (i.e. influence factors, such as the west wind mentioned in the example).
The influences of different predetermined parameters are also revealed along the trajectory in different ways. Thus, the initial mo~ement of the projectile is firstly dependent on the influence factors, which are linked with the shooting installation and the actual proj-ectile, whereas e.g. an unexpectedly rapid drop following the zenith could have meteorological causes.
For specific fields of use and firing installations it can therefore be adequate to use a simplified modelling and from a measurement of a specific portion of the trajectory to draw conclusions regarding that part of the predetermined parameters mainly influencing the same. This makes it possible to derive a simplified method variant, which is described hereinafter.
The fundamental idea of this method variant is based on the simpli-fying assumption that the course of the first part of the trajectory of a projectile or shot, e.g. the first 300 to 800 m after it leaves the tube, is approximately only dependent on the predetermined param-eters, which are dependent on the projectile and the gun, i.e. the estimates of said parameters can be determined solely by surveying the first part of the trajectory. The prerequisite for this is that the trajectory can be surveyed from the outset. It is characterized by a saving of computing effort and permits shorter reaction times.
...,.~
2023~
This method is particularly suitable for increasing the hit capacity of artillery tubular weapon fire control units if the existing tact-ical sequences are not to be modified. Thus, prior to the actual true shooting, a so-called variance shooting is carried out in which generally one or more shots are fired by a control or guidance gun.
If the trajectories of these pilot shots are surveyed and modelled according to the simplified inventive method, from the first part of the trajectory is obtained ~he effective vO vector (amount, azi-muth and elevation). Apart from wind influences which can be ignored for the initial phase, this makes it possible to establish the sett-ing-up errors of the control gun and the deviations of the departure velocity amount calculated back to the muzzle compared with the exp-ected value. These estimates avoid systematic and statistical devia-tions of the control gun and the pilot shot being transferred to the real shots or firing. It is also possible to establish the posi-tion coordinates of the effector from which the projectile has come as predetermined parameters from said first trajectory portion.
The simplified inventive method can also be extended to true shots -or part of the latter. Two further advantages are associated there-with. Firstly there is no need for the usual, generally inaccurate measuring of the vO amount, e.g. via the Doppler effect, whose imprec-ision is due to departure errors, twisting effects of the projectile, powder after-effects, etc. and secondly the location coordinates of the gun relative to the trajectory surveying means can be checked and corresponding corrections can be derived therefrom.
Compared with the known methsd, the presently described variant of the inventive method solves the problem that there is no longer any error transfer from the control gun to the remaining guns, because each vO deviation introduced by the control gun is transferred to ;
the remaining guns and therefore to all the true shots, e.g. a too large amount of the initial velocity of the pilot shot gives a too wide impact in the target area. According to the method used up to now, i.e. using human or electronic observers in the target area, this deviation is e.g. attributed to the effect of meteorological :; .
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influences and the departure elements of all the guns for true shoot-ing are therefore elevation-corrected by a corresponding compensation value. However, as apart from the control gun, the other guns do not have the too large initial velocity amount, the following true shooting will have too short hit positions. However, if with the simplified inventive method the vO vector of the pilot projectile is calculated, then its influence is eliminated from the calculation of the predetermined parameters relevant for the correc'ion of the departure values and the hit position of the true shooting will not suffer from this error. If the pilot shooting reveals that there is a setting-up error, there are two sensible assumptions for taking it into account. If it is to be assumed that the setting-up error only relates to the control gun, it can be deducted from the directi-onal values of the remaining guns in the battery, which are controll-able parameters calculated on the basis of the pilot firing. ~Iowever, if it is to be assumed that all the guns have the same setting-up error, it can be taken into account when calculating the directional values of all the guns.
If the simplified method is also used for true shooting and if a trajectory surveying means is available which is able to survey the shots of all the guns in the initial phase of the trajectory, it is also possible to determine the individual setting-up errors and departure velocities of the shots.
For performing the inventive method a shooting installation is requi-red which has at least the following, per se known components: at least one sensor as the surveying and tracking means, e.g. radar, laser, t.v. or Flir, with an at least biaxial sensor servo, which can give a random direction to the parallel lines of sight of the sensors combined into a common line of sight and keep same directed permanently on the target or projectile to be measured; at least one effector, e.g. gun or rocket launcher with in each case at least one biaxial effector servo, which adjusts the controllable parameters, such as e.g. the departure direction of the projectile; at least one :, .......... . :. . :. .
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preferably digital computer, which estimates the predetermined para-meters as variables of state and controls the sensor servo and effec-tor servo; as well as data channels, which link the sensors with the computer or computers and effectors, together with at least one type of pilot projectiles.
An example for realizing the shooting installation appropriate for the inventive method and a block circuit diagram of the latter are shown by the two following drawings.
Fig. 1 diagrammatically shows a side view of a firing installation.
Fig. 2 is a fire control system for a shooting installation accor-ding to fig. 1 in the form of a block circuit diagram. ~
~ -Fig. 1 in diagrammatic side view shows as a use example of the inven-tive method a firing installation 100, which comprises a surveying means 20 and a weapon system (effector) 10, from which a shot or projectile 15 can be fired on a trajectory or flight path 1. The surveying means 20 constructed as a stationary or mobile, automotive unit is provided e.g. with a radar, laser, IR or TV tracking unit 21 as a sensor and by means of this individual or several time-succ-eeding fired shots 15 can be surveyed over a given period of time and sighted over a given local area with a beam S or beams Sl n.
:~:
The weapon system 10, which is also constructed as a stationary or mobile, automotive unit and which can also be constructionally comb-ined with the surveying means containing the fire control computer, ~ -has a weapon tube 11, which is adjustable for attacking targets with the aid of not shown means with respect to the controllable para- -meters, such as the directional quantities azimuth and elevation. -Fig. 2 shows in block circuit diagram form the principle of the above-described firing installation 100, in which 22 is a command post, 35 a firing control computer unit, 10 the weapon system and 15 or l51_n the fired shots, 20 the surveying means and 25 a computer with ' 2~23~'~9 memory. The data channels between the blocks carry the following informations:
information on the available fixed or variable target parameters;
43 controllable parameters such as firin8 elements and directional quantities;
47 measured trajectory parameters of the pilot shots Sl n;
48 calculated, predetermined parameters.
According to fig. 1 the trajectories 11 n between the weapon system and the shots 151 n and the test beams Sl n between the shots 151_n and the surveying means are also shown in fig. 2.
The functional sequence of the inventive method can be gathered in the following way from the block circuit diagram of fi8. 2. From the command post 22 via data channel 40 data of the target parameters are supplied to the firing control computer unit 35 and the latter supplies the calculated controllable parameters via data channel 43 to the weapon system 10. The trajectories 11 n of the projectiles or shots 151 n fired by the weapon system 10 are surveyed or tracked by the surveying or tracking means 20 and the trajectory data are supplied via data channel 47 to computer 25. The latter calculates and optionally intermediately stores the predetermined parameters, which are supplied via data channel 48 to the firing control computer unit 35. The latter takes account of the predetermined parameters when calculating the controllable parameters, which are supplied to the weapon system 10 via the data channel 43, in order to be able to fire real shots or projectiles with the corresponding weapon sett-ing. In a special method variant an estimate of the vO vector is calculated from the survey of the first trajectory portion and its amount and direction varies from the theoretically e~pected vO vector.
By taking into account this result enabling direct conclusions to be drawn on the departure error, it is ensured that systematic and statistical deviations of the control gun and the pilot or initial shot are not transferred to the following true shots.
` -` 2 0 2 '~
If in a possible embodiment of the inventive method, particularly for firing at moving targets, both the trajectories of the pilot shots and the path of motion of the target are surveyed by the same surveying means 20, then the firing control computer unit 35 can be constructionally combined with the computer 25, which obviates the inputting of target parameters via data channel 40.
For example, it is not advantageous at the start of a burst of firing to use the aforementioned corrections from the end of the preceding burst of firing if the target is locally rapidly moving. ~ ~-A method of the aforementioned type and which in principle belongs ~ -to the aforementioned second group, is known from Swiss Patent 501 ~ -203. For firing at a known target a pilot shot or projectile is fired with the same flight characteristics as the intended real shot or projectile and the pilot trajectory of the pilot shot is determined by the cooperation of the surveying means (radar) with the trajectory computer. On the basis of the pilot trajectory determined, it is also possible to determine in the trajectory computer the directional errors of the effector or the deviation of the cutoff point of the pilot trajectory compared with the preselected-target object. Such directional errQrs result from the effect of unknown disturbance variables, such as wind, pressure, temperature, etc., which are ref-erred to here as predetermined parameters. This known method can only determine the effect of all these disturbance variables on the trajectories of pilot shots and take them into account by correcting the trajectory of the real shot, but not said disturbance variables.
2023~
.: `
On the basis of Swiss Patent 501 203, the problem of the present invention is to be able to rapidly incorporate into the ~ire control calculation those predetermined parameters (unknown disturbance vari- -ables), which are to be incorporated into a correction of the control-lable parameters, and still to make them available for the entire area to be covered by the effector or effectors when there is no specific target.
For solving this problem in a method as defined in the preamble of claim 1, it is proposed that one or more pilot shots are fired in the direction of possible and/or known targets and that from the pilot trajectories the predetermined parameters are calculated and stored and subsequently or directly incorporated into the calculation of the controllable parameters from the target parameters of a given target. Further appropriate procedures with respect to the method are defined in the subclaims.
The basic idea of the inventive method is that not only should the locally and/or time difficulty transferable effect of all the locally and/or time adequately transferable predetermined parameters on the trajectories of the shots or the influence of these effects on the controllable parameters and therefore the fire control calculation i9 determined and taken into consideration, but also the actual pre-determined parameters. For certain applications some of these, namely the ones which are dependent on the firing installation and the proj-ectile, can be dealt with on a priority basis. For this purpose the trajectories of pilot shots are surveyed and which need not neces-sarily strike a target, but are instead shot at wherever it is sub-sequently assumed a target could be. It is possible to use the same surveying means which will subsequently survey the target or the target firing. In the same way the pilot shots can be shot from the same effector which is subsequently used for firing the real -shots. Sufficient time is available to intensively evaluate the measured values and on the basis of the effect of the predetermined parameters to determine these as a cause, so that the corresponding ` 2023~
corrections of the controllable parameters can in particular be better locally transferred, in that they are dependent on the predetermined parameters and the target location. The inventive method can be automated and can be periodically carried out at times of high alert.
From the effect of the predetermined parameters, conclusions are drawn regarding the predetermined parameters as a cause. This conc-lusion is possible as a result of modern calculating and computing processes and the extended Kalman filter is particularly suitable for this. The movement of the projectile is described by a stoch- ~-astic differential equation, whose vector of state e.g. contains the position and velocity of the projectile. In the inventive method the vector of state is broadened by the sought predetermined parame-ters, in that the latter are no longer considered and dealt with ~-as invariable parameters, but as variables of state. However, the controllable psrameters are still looked upon and dealt with as invar-iable parameters. As a result of known, e~actly defined, algebraic transformations the algorithm of the extended Kalman filter is formed from the stochastic differential equation of the projectile movement and which calculates from the measured values of the trajectories of the pilot shots estimates for all the variables of state and there-fore the predetermined parameters. This estimate of the variables of state is based on a stepwise improvement, which i9 based on an initial estimate (initialization), which can e.g. result from an earlier performance of the inventive method or a conventional measure-ment. Further details of this will be given in connection with fig. 2.
The partial derivation of the measured values is calculated and used in accordance with the predetermined parameters. In the case of effector-dependent predetermined parameters, e.g. setting-up errors and muzzle velocity, said partial derivation tends to be large close to the effector and small remote from the effector. In the case of effector-independent predetermined parameters, e.g. meteorological data, it is small close to the effector and large remote from the effector. This facilitates the differentiation of effector-dependent 2023~ ~
and effector-independent predetermined parameters on the basis of a single pilot shot. In addition, such a differentiation requires the evaluation of many pilot shots in widely differing directions if it is to be reliable and accurate.
Particularly for firing at moving targets, i.e. with variable target parameters, the surveying means according to the invention can survey or track both the trajectories of the pilot shots and the path of motion of the target. The pilot shots can also be of a different nature to the real shots, so that the movement thereof is described by a different differential equation and influenced in a different way from the predetermined parameters. Thus, according to the inven-tion different pilot shots are surveyed, which react differently on the parameters to be determined. Thus, e.g. the pilot shots can carry besides or in place of an explosive charge special devices, e.g. transponders, corner reflectors, Luneberg lenses, etc., which facilitate the surveying or tracking thereof. For this and other reasons theg can have a different shape, different mass and even a different calibre. They can differ at random from the real shots and from one another, provided that their trajectories are influenced by the same predetermined parameters. Also from this standpoint the predetermined parameters can be better transferred than their action on the controllable parameters or on the trajectories of the shots. However, obviously the real shots can serve as pilot shots and in particular preceding real shots can serve as pilot shots for a following round.
The importance of not only determining the effect of the predeter~
mined parameters, but these predetermined parameters themselves, can be illustrated by the following example. A pilot shot or proj-ectile i9 fired northwards and as an effect the surveying means obser-ves an eastward deviation. The cause can be two predetermined para~
meters, namely 1. a west wind or 2. a setting-up error with respect to the azimuth angle position of the gun mount. A targetthen appears in the south. Then the trajectories of the real shots must in the first , .
2~2~9 : -case be corrected to the west and in the second to the east. This example clearly shows that the pilot shots must be fired wherever it might be necessary to fire real shots. Only in this way is it possible to estimate or identify the parameters and differentiate them from one another.
The example also shows that the method can differentiate between the effect of predetermined parameters which are dependent on the shot and gun (in the present example setting-up errors) and those which are not dependent on the shot and gun (i.e. influence factors, such as the west wind mentioned in the example).
The influences of different predetermined parameters are also revealed along the trajectory in different ways. Thus, the initial mo~ement of the projectile is firstly dependent on the influence factors, which are linked with the shooting installation and the actual proj-ectile, whereas e.g. an unexpectedly rapid drop following the zenith could have meteorological causes.
For specific fields of use and firing installations it can therefore be adequate to use a simplified modelling and from a measurement of a specific portion of the trajectory to draw conclusions regarding that part of the predetermined parameters mainly influencing the same. This makes it possible to derive a simplified method variant, which is described hereinafter.
The fundamental idea of this method variant is based on the simpli-fying assumption that the course of the first part of the trajectory of a projectile or shot, e.g. the first 300 to 800 m after it leaves the tube, is approximately only dependent on the predetermined param-eters, which are dependent on the projectile and the gun, i.e. the estimates of said parameters can be determined solely by surveying the first part of the trajectory. The prerequisite for this is that the trajectory can be surveyed from the outset. It is characterized by a saving of computing effort and permits shorter reaction times.
...,.~
2023~
This method is particularly suitable for increasing the hit capacity of artillery tubular weapon fire control units if the existing tact-ical sequences are not to be modified. Thus, prior to the actual true shooting, a so-called variance shooting is carried out in which generally one or more shots are fired by a control or guidance gun.
If the trajectories of these pilot shots are surveyed and modelled according to the simplified inventive method, from the first part of the trajectory is obtained ~he effective vO vector (amount, azi-muth and elevation). Apart from wind influences which can be ignored for the initial phase, this makes it possible to establish the sett-ing-up errors of the control gun and the deviations of the departure velocity amount calculated back to the muzzle compared with the exp-ected value. These estimates avoid systematic and statistical devia-tions of the control gun and the pilot shot being transferred to the real shots or firing. It is also possible to establish the posi-tion coordinates of the effector from which the projectile has come as predetermined parameters from said first trajectory portion.
The simplified inventive method can also be extended to true shots -or part of the latter. Two further advantages are associated there-with. Firstly there is no need for the usual, generally inaccurate measuring of the vO amount, e.g. via the Doppler effect, whose imprec-ision is due to departure errors, twisting effects of the projectile, powder after-effects, etc. and secondly the location coordinates of the gun relative to the trajectory surveying means can be checked and corresponding corrections can be derived therefrom.
Compared with the known methsd, the presently described variant of the inventive method solves the problem that there is no longer any error transfer from the control gun to the remaining guns, because each vO deviation introduced by the control gun is transferred to ;
the remaining guns and therefore to all the true shots, e.g. a too large amount of the initial velocity of the pilot shot gives a too wide impact in the target area. According to the method used up to now, i.e. using human or electronic observers in the target area, this deviation is e.g. attributed to the effect of meteorological :; .
. .
~ ,. : . , 2~23~
influences and the departure elements of all the guns for true shoot-ing are therefore elevation-corrected by a corresponding compensation value. However, as apart from the control gun, the other guns do not have the too large initial velocity amount, the following true shooting will have too short hit positions. However, if with the simplified inventive method the vO vector of the pilot projectile is calculated, then its influence is eliminated from the calculation of the predetermined parameters relevant for the correc'ion of the departure values and the hit position of the true shooting will not suffer from this error. If the pilot shooting reveals that there is a setting-up error, there are two sensible assumptions for taking it into account. If it is to be assumed that the setting-up error only relates to the control gun, it can be deducted from the directi-onal values of the remaining guns in the battery, which are controll-able parameters calculated on the basis of the pilot firing. ~Iowever, if it is to be assumed that all the guns have the same setting-up error, it can be taken into account when calculating the directional values of all the guns.
If the simplified method is also used for true shooting and if a trajectory surveying means is available which is able to survey the shots of all the guns in the initial phase of the trajectory, it is also possible to determine the individual setting-up errors and departure velocities of the shots.
For performing the inventive method a shooting installation is requi-red which has at least the following, per se known components: at least one sensor as the surveying and tracking means, e.g. radar, laser, t.v. or Flir, with an at least biaxial sensor servo, which can give a random direction to the parallel lines of sight of the sensors combined into a common line of sight and keep same directed permanently on the target or projectile to be measured; at least one effector, e.g. gun or rocket launcher with in each case at least one biaxial effector servo, which adjusts the controllable parameters, such as e.g. the departure direction of the projectile; at least one :, .......... . :. . :. .
:. ~: .. : :. . : . . .
~ y :~ .
!
2~23$~;~
preferably digital computer, which estimates the predetermined para-meters as variables of state and controls the sensor servo and effec-tor servo; as well as data channels, which link the sensors with the computer or computers and effectors, together with at least one type of pilot projectiles.
An example for realizing the shooting installation appropriate for the inventive method and a block circuit diagram of the latter are shown by the two following drawings.
Fig. 1 diagrammatically shows a side view of a firing installation.
Fig. 2 is a fire control system for a shooting installation accor-ding to fig. 1 in the form of a block circuit diagram. ~
~ -Fig. 1 in diagrammatic side view shows as a use example of the inven-tive method a firing installation 100, which comprises a surveying means 20 and a weapon system (effector) 10, from which a shot or projectile 15 can be fired on a trajectory or flight path 1. The surveying means 20 constructed as a stationary or mobile, automotive unit is provided e.g. with a radar, laser, IR or TV tracking unit 21 as a sensor and by means of this individual or several time-succ-eeding fired shots 15 can be surveyed over a given period of time and sighted over a given local area with a beam S or beams Sl n.
:~:
The weapon system 10, which is also constructed as a stationary or mobile, automotive unit and which can also be constructionally comb-ined with the surveying means containing the fire control computer, ~ -has a weapon tube 11, which is adjustable for attacking targets with the aid of not shown means with respect to the controllable para- -meters, such as the directional quantities azimuth and elevation. -Fig. 2 shows in block circuit diagram form the principle of the above-described firing installation 100, in which 22 is a command post, 35 a firing control computer unit, 10 the weapon system and 15 or l51_n the fired shots, 20 the surveying means and 25 a computer with ' 2~23~'~9 memory. The data channels between the blocks carry the following informations:
information on the available fixed or variable target parameters;
43 controllable parameters such as firin8 elements and directional quantities;
47 measured trajectory parameters of the pilot shots Sl n;
48 calculated, predetermined parameters.
According to fig. 1 the trajectories 11 n between the weapon system and the shots 151 n and the test beams Sl n between the shots 151_n and the surveying means are also shown in fig. 2.
The functional sequence of the inventive method can be gathered in the following way from the block circuit diagram of fi8. 2. From the command post 22 via data channel 40 data of the target parameters are supplied to the firing control computer unit 35 and the latter supplies the calculated controllable parameters via data channel 43 to the weapon system 10. The trajectories 11 n of the projectiles or shots 151 n fired by the weapon system 10 are surveyed or tracked by the surveying or tracking means 20 and the trajectory data are supplied via data channel 47 to computer 25. The latter calculates and optionally intermediately stores the predetermined parameters, which are supplied via data channel 48 to the firing control computer unit 35. The latter takes account of the predetermined parameters when calculating the controllable parameters, which are supplied to the weapon system 10 via the data channel 43, in order to be able to fire real shots or projectiles with the corresponding weapon sett-ing. In a special method variant an estimate of the vO vector is calculated from the survey of the first trajectory portion and its amount and direction varies from the theoretically e~pected vO vector.
By taking into account this result enabling direct conclusions to be drawn on the departure error, it is ensured that systematic and statistical deviations of the control gun and the pilot or initial shot are not transferred to the following true shots.
` -` 2 0 2 '~
If in a possible embodiment of the inventive method, particularly for firing at moving targets, both the trajectories of the pilot shots and the path of motion of the target are surveyed by the same surveying means 20, then the firing control computer unit 35 can be constructionally combined with the computer 25, which obviates the inputting of target parameters via data channel 40.
Claims (14)
1. Method for improving the accuracy of fire of real shots from a firing installation, comprising in each case at least one surveying means for surveying and tracking a shot or projectile along its flight path or trajectory, a computer for calculating the controllable parameters, particularly the firing direction and an effector, servocontrolled in accordance with the control-lable parameters supplied by the computer and in particular a gun or a launcher, whereby the controllable parameters are calculated by means of available target parameters and known, predetermined parameters and with the aid of the surveying means the trajectory of a pilot shot or projectile is surveyed and the thus determined pilot trajectory is used for correcting the controllable parameters for the true shots or projectiles, characterized in that one or more pilot shots are fired in the direction of possible targets and/or known targets and that from the measured pilot trajectories the predetermined para-meters are calculated and stored and subsequently or directly incorporated into the calculation of the controllable parameters from the target parameters of a specific target.
2. Method according to claim 1, characterized in that from the surveyed pilot trajectories the predetermined parameters for the locally selected areas or ranges are calculated and stored and together with the target parameters of an existing target are incorporated into the calculation of the controllable para-meters for said target those stored predetermined parameters, whose associated ranges have been measured by the trajectory of the real projectile used.
3. Method according to one of the claims 1 or 2, characterized in that the predetermined parameters are estimated as variables of state of an extended Kalman filter, which is based on an initial estimate, which results from an earlier estimate or a conventional measurement of the predetermined parameters.
4. Method according to one of the preceding claims, characterized in that pilot shots are surveyed, which react differently from the real shots to the predetermined parameters.
5. Method according to claim 4, characterized in that pilot shots are surveyed, which react differently to the predetermined para-meters.
6. Method according to one of the preceding claims, characterized in that for shooting in particular at moving targets with vari-able target parameters, the surveying means surveys both the trajectories of the pilot shots and also the target.
7. Method according to one of the claims 1 or 2, characterized in that from a first projectile trajectory portion measured and which is a few hundred metres long and starts at the tube outlet, equipment-dependent parameters are separately calculated from the predetermined parameters and taken into account in the calculation of the controllable parameters.
8. Method according to claim 7, characterized in that as an equip-ment-dependent parameter the vo vector is calculated and there-fore the departure error determined, which is taken into account in calculating the controllable parameters.
9. Method according to claim 7, characterized in that as the equip-ment-dependent parameter are determined the position coordinates of the effectors relative to the trajectory surveying means.
10. Method according to claims 7 or 8, characterized in that in the correction of the controllable parameters for guns other than the control gun are only used the predetermined parameters independent of the projectile and gun determined with the aid of pilot shots from the control gun.
11. Method according to one of the claims 7,8 or 9, characterized in that with all the parameters identified from the measured data of the projectile trajectory, including the vo vectors determined from each surveyed trajectory, a constantly updated data bank is formed.
12. Method according to claim 11, characterized in that the calculat-ed, equipment-dependent, predetermined parameters are stored in a data bank and are kept availably on request.
13. Method according to claim 10, characterized in that from the data of the updated data bank is calculated and kept available an approximate wind profile as a function of the height and time and derivable from the surveyed projectile trajectories.
14. Firing installation (100) for performing the method according to at least one of the claims 1 to 12, characterized by the combination of the following known components: surveying means (20) with at least one sensor (21) having at least one biaxial sensor servo, which constantly keeps the sight line or lines directed onto the target or projectile (15) to be surveyed, at least one effector (11) with in each case at least one biaxial effector servo, at least one computer with memory (35), which controls the sensor servo and the effector servo, as well as at least one pilot shot and at least one real shot.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH20789 | 1989-01-24 | ||
| CH207/89-2 | 1989-01-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2023659A1 true CA2023659A1 (en) | 1990-07-25 |
Family
ID=4181697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2023659 Abandoned CA2023659A1 (en) | 1989-01-24 | 1990-01-24 | Method and apparatus for improving the accuracy of fire |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0411073A1 (en) |
| BR (1) | BR9004712A (en) |
| CA (1) | CA2023659A1 (en) |
| WO (1) | WO1990008936A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011114277A1 (en) * | 2010-03-14 | 2011-09-22 | Rafael Advanced Defense Systems Ltd. | System and method for registration of artillery fire |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5454265A (en) * | 1991-06-20 | 1995-10-03 | Diehl Gmbh & Co. | Installation for the measurement of the altitude of a surface wind, particularly for improving the hitting accuracy of unguided projectiles |
| FI98957C (en) * | 1996-06-19 | 1997-09-10 | Pekka Pylkkaenen | A method of repairing the trajectory of a cannon, grenade or rocket launcher or similar projectile |
| DE19718947B4 (en) * | 1997-05-05 | 2005-04-28 | Rheinmetall W & M Gmbh | pilot floor |
| GB0223437D0 (en) * | 2002-10-03 | 2003-02-26 | Alenia Marconi Systems Ltd | Improvements in or relating to targeting systems |
| US7121183B2 (en) * | 2004-03-29 | 2006-10-17 | Honeywell International Inc. | Methods and systems for estimating weapon effectiveness |
| KR101244440B1 (en) | 2004-07-02 | 2013-03-18 | 트랙맨 에이/에스 | A method and an apparatus for determining a deviation between an actual direction of a launched projectile and a predetermined direction |
| US9645235B2 (en) | 2005-03-03 | 2017-05-09 | Trackman A/S | Determination of spin parameters of a sports ball |
| EP1853362B8 (en) | 2005-03-03 | 2010-07-28 | Trackman A/S | Determination of spin parameters of a sports ball |
| US10393870B2 (en) | 2005-03-03 | 2019-08-27 | Trackman A/S | Determination of spin parameters of a sports ball |
| KR102408358B1 (en) | 2009-01-29 | 2022-06-14 | 트랙맨 에이/에스 | An assembly comprising a radar and an imaging element |
| EP2605036B1 (en) | 2011-12-16 | 2019-10-23 | Trackman A/S | A method and a sensor for determining a direction-of-arrival of impingent radiation |
| US10379214B2 (en) | 2016-07-11 | 2019-08-13 | Trackman A/S | Device, system and method for tracking multiple projectiles |
| US10444339B2 (en) | 2016-10-31 | 2019-10-15 | Trackman A/S | Skid and roll tracking system |
| US10989791B2 (en) | 2016-12-05 | 2021-04-27 | Trackman A/S | Device, system, and method for tracking an object using radar data and imager data |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH550375A (en) * | 1972-10-05 | 1974-06-14 | Contraves Ag | ARTILLERY PILOT FLOOR. |
| US3848509A (en) * | 1972-10-31 | 1974-11-19 | Us Navy | Closed-loop gun control system |
| FR2250095B1 (en) * | 1973-11-07 | 1978-11-17 | Dassault Electronique | |
| US4449041A (en) * | 1980-10-03 | 1984-05-15 | Raytheon Company | Method of controlling antiaircraft fire |
| SE460501B (en) * | 1986-09-17 | 1989-10-16 | Bofors Ab | SET UP AND DEVICE TO FOLLOW A ROCKET PROJECT IN ITS RANGE |
-
1990
- 1990-01-24 EP EP19900901529 patent/EP0411073A1/en not_active Withdrawn
- 1990-01-24 WO PCT/CH1990/000015 patent/WO1990008936A1/en not_active Application Discontinuation
- 1990-01-24 CA CA 2023659 patent/CA2023659A1/en not_active Abandoned
- 1990-01-24 BR BR909004712A patent/BR9004712A/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011114277A1 (en) * | 2010-03-14 | 2011-09-22 | Rafael Advanced Defense Systems Ltd. | System and method for registration of artillery fire |
| US8794119B2 (en) | 2010-03-14 | 2014-08-05 | Rafael Advanced Defense Systems Ltd. | System and method for registration of artillery fire |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0411073A1 (en) | 1991-02-06 |
| WO1990008936A1 (en) | 1990-08-09 |
| BR9004712A (en) | 1991-07-30 |
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