U.S. patent number 3,927,480 [Application Number 05/454,941] was granted by the patent office on 1975-12-23 for gunnery training scoring system with laser pulses.
This patent grant is currently assigned to Saab-Scania Aktiebolag. Invention is credited to Hans R. Robertsson.
United States Patent |
3,927,480 |
Robertsson |
* December 23, 1975 |
Gunnery training scoring system with laser pulses
Abstract
In apparatus for gunnery practice by which firing towards a
target comprising a reflector is simulated by laser emissions, a
first radiation emission at firing is used for ranging, to
ascertain a time interval following firing at which a round of a
selected type of ammunition will arrive at the target. After that
interval following firing, a second emission is used to obtain a
fix on the target. The second emission comprises pulses encoding
information about ammunition type and relation of point of impact
of the simulated round to target location, to be decoded at the
target and used for evaluating hit effect.
Inventors: |
Robertsson; Hans R. (Molndal,
SW) |
Assignee: |
Saab-Scania Aktiebolag
(Linkoping, SW)
|
[*] Notice: |
The portion of the term of this patent
subsequent to September 3, 1991 has been disclaimed. |
Family
ID: |
26656078 |
Appl.
No.: |
05/454,941 |
Filed: |
March 26, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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318008 |
Dec 26, 1972 |
3832791 |
|
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Current U.S.
Class: |
434/22;
356/141.1; 356/5.01 |
Current CPC
Class: |
G01S
17/88 (20130101); F41G 3/2655 (20130101); F41G
3/2683 (20130101) |
Current International
Class: |
F41G
3/00 (20060101); F41G 3/26 (20060101); G01S
17/88 (20060101); G01S 17/00 (20060101); F41G
003/26 () |
Field of
Search: |
;35/25 ;273/101.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Wolff; John H.
Parent Case Text
This application is a continuation of my copending application Ser.
No. 318,008, filed Dec. 26, 1972, now U.S. Pat. No. 3,832,791, and
is filed as a voluntary division of that earlier application.
Claims
I claim:
1. A method of evaluating the results of target practice with a
weapon which has a barrel and which is located at a weapon
position, firing at a target at a target position which is remote
from the weapon position and which may be changing due to target
motion, wherein firing from the weapon of a round of a selected
type of ammunition is simulated by emitting radiation substantially
coaxially with the weapon barrel from a directional radiation
emitter such as a laser at the instant when the weapon is fired,
and wherein a relationship between target location and the point of
impact of said simulated round is calculated at the weapon position
on the basis of detected radiation returned to the weapon position
from reflector means at the target, said method being characterized
by:
A. after a delay interval following said instant of simulated
firing, which interval substantially corresponds to the time
required for a real round of said ammunition to arrive at its point
of impact, producing a further radiation emission from said
radiation emitter that comprises a train of pulses in which is
encoded information concerning selected ammunition type and
relationship of said point of impact to target position, the
directionality of the emitter ensuring that said information is
delivered substantially only to a target at which the weapon is
effectively aimed; and
B. at the target, combining said information with other information
which relates to the vulnerability of the target, to produce an
output signifying the hit effectiveness against that target of the
simulated round as fired.
2. A method of evaluating the results of practice firing with a
weapon which has a barrel and which is located at a weapon
position, against a target at a target position which is remote
from the weapon position and which may be changing due to target
motion, wherein firing of the weapon is simulated by emitting
radition substantially coaxially with the weapon barrel from a
directional radiation emitter such as a laser, wherein the point of
impact of a simulated round of a selected type of ammunition is
calculated at the weapon position on the basis of barrel axis
orientation at an instant when the weapon is fired and detected
radiation returned to the weapon position from reflector means at
the target position, said method being characterized by:
A. producing a first radiation emission from the radiation emitter
that comprises at least one pulse and is emitted substantially at
said instant when the weapon is fired;
B. utilizing the reflected return radiation of said first radiation
emission to determine a time interval that substantially
corresponds to the time required for a round of said selected type
of ammunition to traverse the distance between the weapon and the
target;
C. after said time interval following the beginning of said first
radiation emission, producing a second radiation emission from the
radiation emitter that comprises a train of pulses in which is
encoded information concerning selected ammunition tupe and
relationship of said point of impact to target position, the
directionality of the emitter ensuring that said information is
delivered substantially only to a target at which the weapon is
effectively aimed; and
D. at the target, combining said information with other information
which relates to the vulnerability of the target and which is
stored at the target, to produce an output signifying the hit
effectiveness against that target of the simulated round as
fired.
3. The method of claim 2, further characterized by:
D. preserving information about the orientation of the weapon
barrel axis at the beginning of said first radiation emission;
and
E. utilizing
1. said preserved information and
2. reflected return radiation from said second radiation emission
to calculate the point of impact of said simulated round of
ammunition in relation to the position of the target at the
beginning of said second radiation emission.
Description
The present invention relates to a gunnery target scoring system
with laser pulses.
The purpose of practice firings is, in the first place, to give
soldiers the ability to handle their weapon in the correct manner,
especially with regard to the sighting of the weapon towards a
target, and to train the soldiers in the tactically correct
performance. This implies among other things that they should use
the arms against a target against which fire from the weapon has a
chance of being effective.
In order to simplify such practice firings it has already been
proposed to use simulator devices in which actual firing is
replaced by a radiation pulse within the optical radiation range,
e.g. from a laser. The radiation is transmitted in the direction
which the weapon is aimed and if this aiming is correct at the
firing instant a hit is indicated in a suitable way. Simulator
devices based upon this generally described principle are more
fully disclosed in e.g. U.S. Pat. Nos. 3,257,471 and 3,104,448.
These earlier known simultator devices, however, are constructed in
such a way that the possiblity of carrying out an actual realistic
practice firing is reduced due to the complexity of the device. As
an example of this it can be observed that these known simulator
devices, in addition to optical radition, use infared and/or
radiofrequency radiation for hit determination and signaling.
It is the object of the present invention to achieve a device of
the said type by means of which sighting and firing towards a
target can be practiced under realistic conditions without any
hazard to participants in the exercise.
It is a further object of the invention to create the
pre-conditions for practicing the tactics of individual soldiers as
well as of a whole armed unit with different kinds of weapons under
combat conditions and with realistic simulation of the factors
which affect the result of firing from weapons towards different
kinds of targets. By means of the invention it is also made
possible to record a training routine for later tactical
review.
Further advantages and characteristics of the invention will become
obvious from the following description of the accompanying drawings
in which:
FIG. 1 is a position picture which shows a terrain sector with a
tactical situation during an exercise in which a tank is being
fired at by laser pulses from a second tank and an antitank
weapon.
FIG. 2 shows a reflector device which is built in conjunction with
a receiver sensitive to laser radiation.
FIG. 3 shows how the reflector device and the laser receivers are
located on a tank so that the sensitivity sectors of the laser
receivers together cover the perimeter of the tank.
FIG. 4 shows schematically the position of a target in a plane
perpendicular to the centre-line of a barrel of a weapon, the range
of vision for laser receiver and sight, and a radiation beam of the
laser emitter.
FIG. 5 is a block diagram which shows in general outline the
step-up of a device in accordance with the invention.
In the following description a device in accordance with the
invention will be described in connection with a special
application, namely the so-called duel firing of tanks. The
invention should not be considered, however, to be restricted to
such an application, but can be applied to exercises which, on the
whole, embrace all directly aimed weapons. The number of weapons
included in an exercise may be varied within wide limits. It is
also obvious that every weapon in operation in a combat practice
may be considered to represent a target when it is being fired at.
The designations weapons/targets for two units in combat with one
another are therefore interchangeable according to whether the one
or the other unit gives off fire.
In FIG. 1 a tank designated 1 can be considered a weapon owing to
the fact that it gives off simulated fire towards another tank 2 at
the moment shown in the figure. The second tank 2, which is being
fired at and should therefore be considered the target at the
moment, is also subject to simulated fire from an anti-tank weapon
3.
The simulated fire consists of laser radiation, which originates
from a laser pulse transmitter 4. This is fixed to the barrel 5 of
the gun of tank 1, in accordance with the invention, so that the
optical axis of the laser pulse transmitter 4 substantially
coincides with the centre-line of the barrel. The target 2 has a
reflector device 6 whose task it is to reflect laser radiation back
to the weapon from which it emanates. The reflector device consists
in a preferred embodiment of so-called corner-reflecting prisms,
which are capable, irrespective of the angle of incidence of
incident radiation, of reflecting such radiation in a direction
which is parallel with the direction from which it arrives.
In accordance with the invention, the weapon has an element that is
sensitive to laser radiation and which consists of a
position-sensitive detector 14 directly connected to the
transmitter 4, and circuits for the determination of the distance
to the target and the position of an expected detonation point of a
real projectile in relation to the target. The position-sensitive
detector is build as a unit combined with the laser pulse
transmitter 4 and is therefore not discernible in FIG. 1. This and
the circuits just mentioned will instead be described in connection
with FIG. 5.
The laser radiation originating from the laser pulse transmitter 4,
as can be seen from FIG. 1, is of two kinds. The one kind is a
laser pulse train with substantially fixed frequency intended for
the measuring of the position of the target. In a manner known in
itself the distance between the weapon 1 and the target 2 is
calculated by measurement of the transit time for laser pulses
emitted by the laser pulse transmitter 4, reflected in the
reflector element 6 of the target and detected in the
position-sensitive detector. From the center of intensity of laser
pulses reflected from different reflector elements 6 on the target
2 the position of the target 2 in relation to the center-line of
the barrel 5 is also measured out by the position-sensitive
detector. The second type of laser radiation is laser pulse signal
which constitutes the simulated fire itself and which in coded form
contains on the one hand information regarding the precalculated
detonation point in relation to the target with regard to the
position of the target, the movement during the firing time and the
type of ammunition, on the other hand the firing distance, kind of
arms, type of ammunition and possibly further information. The
invention is not restricted to any particular kind of coding. All
types of coding which give high probability of correct transmission
and which require relatively small numbers of pulses are useable.
For the control of the laser pulse transmitter in order for it to
transmit pulse signals there is an element capable of being
programmed, which will be described in detail in connection with
FIG. 5.
For the reeption and exploitation of the laser pulse signal the
target 2 has elements sensitive to laser radiation consisting of a
number of detectors 7 and calculating and indicating elements. As
can be seen from FIG. 3, the detectors 7 are so arranged that their
sensitivity sectors, which are each approximately 60.degree.,
together cover the perimeter of the weapon. The detectors 7 are
adapted so that they receive the laser pulse signal, and
determination is made from the coded information as to whether the
firing weapon is effective against the target and the effect of the
firing with regard to type of ammunition, firing distance and
calculated position of the target in relation to the position of
the expected detonation point.
It is evident from what has been said earlier, regarding the
relationship weapon/target, that the weapon 1 as well as the target
2 and the anti-tank weapon 3 are identically equipped with regard
to laser pulse transmitter 4, reflector element 6 and the other
devices mentioned. In FIG. 2 is shown how a reflector 6 and a
detector 7 can practically be build together as a unit which can be
attached by means of screws or strong permanent magnets.
As stated above, FIG. 4 is taken at the plane of the tank 2 in FIG.
1, considering it as the target and the tank 1 of that figure as
comprising the weapon. In FIG. 4 numerals 8, 9 and 10 designate
rectangular shaped areas which in the order given represent: the
range of vision of the sight of the tank 1, the range of vision of
the position-sensitive detector placed in connection to the laser
pulse transmitter 4, and the surface in the plane of the figure
illuminated by the radiation beam of the laser transmitter. 11 and
12 are two lines which constitute projections of a vertical plane
and a plane perpendicular to this, the line of intersection of
which planes constitutes the extension of the center-line of the
barrel 5. The point of intersection between the lines 11, and 12 is
designated in the figure by 13 and this is the point, therefore,
where the extension of the center-line of the barrel intersects the
plane of the figure. The point 13 is at the same time the origin of
coordinates of the range of vision of the position-sensitive
detector 14, that is to say, its optical axis coincides with the
extension of the center-line of the barrel 5. The origin of
coordinates of the detector is the point to which is related the
position of the target in elevation and in lateral direction. In
the figure the deviation of the target in elevation is designated
a.sub.h and the deviation in lateral direction a.sub.s. The object
is of course to require that the weapon should be so aimed that
a.sub.h and a.sub.s correspond at the moment of firing to the
correct elevation and lateral setting, respectively, having regard
to the type of ammunition, firing distance and any target
displacement during the firing time, the demand for correctness
being conditioned by the extension of the target and by the
effective range of the projectile.
The radiation beam of the laser transmitter 4 has such an extension
that in elevation it is at least greater than what corresponds to
the elevational setting angle of the barrel 5 at the greatest
firing distance, and that in lateral direction it covers at least
the distance between two detectors 7 at the smallest firing
distance. This means, in other words, that the cross-section of the
radiation beam has such a height that no compensation is required
for the elevation setting of the gun barrel and such a width that
if the weapon 1 is aimed substantially correctly at the target 2,
at least some of the detectors 7 will be attained by the laser
radiation even at the shortest firing distance, without it being
necessary to aim the radiation beam towards a special detector.
The block diagram in FIG. 5 will now be described by its function.
It is assumed that the weapon 1 is aimed at the target 2, which may
be in movement or be at a standstill. In the figure will be found
again the laser pulse transmitter 4, the reflector 6, the detector
7 and the aforementioned position-sensitive detector, which is here
designated 14. In tracking, the gun barrel is made to point towards
the target 2 and consequently the laser pulse transmitter 4 and the
position-sensitive detector 14 are also aimed towards the target.
As in real combat, the weapon is fired when the aiming is
considered to be correct. The firing is effected by means of the
trigger 15 of the weapon and thereby an automatic procedure is
started which, in accordance with the invention, is initiated by a
command to the laser transmitter from a control element 16 to emit
a laser pulse train of a duration of a few thousandths of a second
and comprising a number of laser pulses. The frequency of the laser
pulse train is substantially constant and is controlled by an
oscillator 17 which is connected via a measuring pulse generator 18
to the control element 16. It is the task of the generator 18 to
convert the output signal of the oscillator 17 to a form such that
the laser pulses emitted under its control cannot be mistaken for
the earlier mentioned laser pulse signal that carries information.
If the aiming of the weapon is sufficiently accurate, the laser
pulses will encounter the reflector 6, from which they are
reflected towards the position-sensitive detector 14. From the
transit time of the laser pulses, measured by the time from the
instant when they leave the laser pulse transmitter 4 until they
are reflected by means of the reflector 6 and, via a
semitransparent mirror 19, are detected in the detector 14, the
distance between the weapon 1 and the target 2 can be calculated by
means of a computer device 20 connected to the detector 14. At the
same time, the angular deflection at the instant of firing between
the center-line of the barrel 5 and the center of intensity of the
reflected laser radiation is calculated by means of an angular
position computer device 21.
Since the target is assumed to be moving, although the movement may
temporarily be zero, an essential part of the training will be
concerned with correct sighting. On the basis of the movement of
the target, the angular position of the target at the firing
instant as well as the end of the firing time will be of interest.
The firing time -- that is, the time required for a supposed
missile to traverse its trajectory -- depends upon the type of
ammunition used, and therefore a manually adjustable ammunition
selector 22 is provided, to enable simulation of shooting with any
of a variety of types of ammunition. Once the distance to the
target 2 and the type of ammunition are known, the firing time can
be calculated in a computer device 23. At the end of the firing
time another laser pulse train is emitted and the agnular position
of the target in relation to the center-line of the gun barrel is
calculated anew in the device 21. owing to tracking, the
center-line of the gun barrel has been turned about a certain angle
in space during the firing time. By means of a two-axis gyro 24 the
lateral as well as the elevational magnitude of the angle of such
rotation of the gun barrel is determined.
The ammunition selector 22 is connected to a computer device 25
which also has an input connection from the distance computing
element 20 and which is adapted to calculate, with regard for the
type of ammunition selected, the correct setting for the firing
distance. Once data are obtained concerning the correct setting,
the angular position of the target in elevation at the start and
end of the firing time, the angle of gun barrel rotation in the
elevational direction furing the firing time, and the firing
distance, it is possible to calculate the position in elevation of
the detonation point; and this is done in computer device 26. In an
analogous manner that device calculates the position of the
detonation point in the lateral direction from the lateral angular
position of the target at the start and finish of the firing time,
the lateral angle of rotation of the barrel during the firing time
and the firing distance. The position of detonation is calculated
on the one hand as the elevational and lateral distance in relation
to the target, on the other hand as the angular deflections in
relation to the center-line of the barrel. In accordance with a
special characteristic of the invention, these latter quantities
can be made apparent by means of a detonation position indicator 27
belonging to the computer device 26 and adapted to generate a
luminous spot which is reflected into the sight of the weapon and
the position of which corresponds to the detonation point of a real
projectile discharged according to the above.
The device 26 for computing the position of the detonation point is
connected to a coding device 28 which is also connected to the
ammunition selector 22 and the distance computer device 20.
According to the invention, the coding device 28 can be programmed
in accordance with the type of weapon and the type of ammunition
and is adapted to command the laser pulse transmitter to emit a
coded laser pulse signal that interrupts the laser pulse train and
contains in coded form, in addition to the data just mentioned,
also the calculated distance and the lateral as well as elevational
distance of the detonation point in relation to the target. The
laser pulse signal is produced in response to a coded signal
generated by the coding device 28, on the basis of an output signal
from the oscillator 17 and acting via the control element upon the
laser pulse transmitter 4.
The laser pulse signal is perceived by the target 2 as if it were
the actual firing and is received by means of detector 7 which is
adapted to convert the laser pulse signal to an electric pulse
signal. This passes via a hit receiver 29 and a decoder 30 to a hit
data computer 31. The hit receiver 29 has the tank of amplifying
the detector signal and filtering out disturbances in the same. The
decoder 30 is connected to an oscillator 32 with the same frequency
as the oscillator 17 and is adapted to produce the original
information from the coded signal. The hit computer 31 is adapted
on the one hand to determine from the information transmitted
whether the weapon is effective against the target with regard to
the type of ammunition used, and on the other hand, through
comparison between the extension of the target in the firing
direction and the divergence of the detonation point in the lateral
and elevational direction, to calculate the effect of the
detonation. It has to be borne in mind that a projectile which in
itself has the capacity of completely knocking out the target by a
direct hit from a certain direction, brings about only moderate
damage with a similar hit from another direction or when its
detonation takes place to one side of the target. To this end the
signals from different detectors 7 and different types of
ammunition are allotted different weight. The effect of the
detonations is considered as a number, the "hit effect number," the
magnitude of which thus depends on the susceptibility of the target
in the firing direction to the type of ammunition in question. When
a hit is made, a visual hit indicator is released, for example a
rotating spotlight which is made to rotate a number of turns
corresponding to the "hit effect number," so as to give the firing
tank 1 an idea of the effect of the simulated firing. Connected to
the hit data computer is a hit effect counter 33 which at the start
of the practice is pre-set to a number which corresponds to the
total effect of the firing that is required to knock out the
target. The counter is adapted to be counted down by each "hit
effect number" from the hit data computer 31, and when the position
of the counter is zero, the counter gives a signal to a hit
indicator 34 which has the task of indicating when the target has
been knocked out. At the same time the electric supply to the
target is cut so that it stops and loses the capacity of giving off
fire that it has previously possessed during the whole time. As a
sign that the target has been knocked out, light and smoke signals
may be released.
According to a special characteristic of the invention, an
ammunition counter 35 in the weapon is coupled to the trigger 15
and to the ammunition selector 22 and is adapted to be preset to a
number corresponding to the number of projectiles of the respective
type of ammunition which the weapon normally carries. The counter
35 is counted down for each firing, and it stops when the count
down has reached zero, preventing any further firing of the
particular type of ammunition the exhaustion of which is thus
simulated.
It is obvious that if it is intended only to practice dual firing
against stationary targets, the device in accordance with the
invention can be substantially simplified. Since in the base of
stationary target its angular position is the same at the beginning
and at the end of the firing time, this need not be calculated so
that the computer device 23 can be omitted. Consequently no gyro 24
is required and it is sufficient to measure the distance and the
angular deflection of the target only once, that is to say only one
laser pulse train is required, which implies a simpler set-up of
the computer device 26 for the position of the detonation
point.
Those skilled in the art will appreciate that the invention can be
embodied in forms other than as herein disclosed for purposes of
illustration.
The invention is defined by the following claims:
* * * * *