EP1510775A1 - Method and arrangement for aligning a gun barrel - Google Patents

Method and arrangement for aligning a gun barrel Download PDF

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Publication number
EP1510775A1
EP1510775A1 EP04445083A EP04445083A EP1510775A1 EP 1510775 A1 EP1510775 A1 EP 1510775A1 EP 04445083 A EP04445083 A EP 04445083A EP 04445083 A EP04445083 A EP 04445083A EP 1510775 A1 EP1510775 A1 EP 1510775A1
Authority
EP
European Patent Office
Prior art keywords
gun barrel
video camera
muzzle
gun
centre line
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.)
Withdrawn
Application number
EP04445083A
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German (de)
English (en)
French (fr)
Inventor
Nils-Ola Svensson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Saab AB
Original Assignee
Saab AB
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Saab AB filed Critical Saab AB
Publication of EP1510775A1 publication Critical patent/EP1510775A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G1/00—Sighting devices
    • F41G1/54—Devices for testing or checking ; Tools for adjustment of sights

Definitions

  • the present invention relates to a method and an arrangement for aligning the gun barrel with the weapon's sight in a primarily direct-shooting barrelled weapon.
  • aligning is meant that the alignment of the sight is coordinated with the actual alignment of each projectile fired out of the gun barrel at the time when the projectile leaves the gun barrel. It is well known in this connection that it is the actual alignment of the centre line of the gun barrel at the part of the gun barrel closest to the muzzle that determines the initial direction of flight of the projectile.
  • the aligning procedure can be used with medium- and large-calibre barrelled weapons, but can also be used with smaller calibre weapons.
  • medium- and large-calibre barrelled weapons are meant here all such weapons with a calibre of 20 mm and above.
  • Guns on, for example, various types of armoured vehicle need to be aligned at regular intervals with the fire control system (the sight) in order to be able to achieve maximal accuracy.
  • the alignment needs to be carried out due, for example, to distortion of the gun barrel as the result of unevenly distributed increases in temperature, play in the gun barrel bearings or the like.
  • the alignment is important in the case of direct shooting at great distances towards small targets with, for example, trajectory ammunition, where long gun barrels are normally used.
  • the alignment of the centre line of the gun barrel can vary a good deal along the length of the barrel for the reasons mentioned above.
  • a so-called muzzle reference telescope (called a Pi-Watson device in USA) that is inserted into the muzzle of the gun barrel and by means of which it is possible, from a location at the muzzle, to determine the alignment of the centre line of the gun barrel in the area closest to the muzzle.
  • a muzzle reference telescope thus makes it possible to take comparative readings to a target at a suitable distance with the muzzle reference telescope and with the sight and to combine these.
  • Another method for aligning gun barrel and sight is based on arranging a mirror at the muzzle of the gun barrel. This mirror is directed towards a special sensor in the breech end of the gun or in the turret, or alternatively directly in the sight. By sending, for example, a laser beam towards the mirror and measuring the change in the position of the reflection, the direction of the muzzle in relation to the sensor/sight can be calculated and compensated for. In a real-time system, it is thereby possible to compensate continually for changes in the direction of the muzzle.
  • a muzzle reference telescope thus means that during this operation a reference target must also be available at a sufficiently long distance. In frontline situations, this type of alignment would thus perhaps be able to be carried out once a day, while at the same time a muzzle reference telescope, which is a relatively expensive precision instrument, is normally shared between several guns. In the course of one and the same day, however, for example strong sun, wind or rain can change the strike point of the gun to such an extent that, even with very accurate shooting, the target will be missed.
  • the second type of aligning system with the mirror reference on the muzzle of the gun barrel can be subject to several different types of problem.
  • the measuring sensor that is used (some kind of light source) can be detected by the enemy using the right kind of reconnaissance equipment and the mechanical environment at the muzzle of the gun barrel is extremely harsh and therefore imposes very high requirements concerning the fixings and material of the mirror, as the angular alignment of the mirror relative to the centre line of the muzzle must, in principle, remain unchanged.
  • the mirror can become very dirty, as a result of wind and weather, surrounding terrain, etc, and also from residues from fired shots.
  • a third method for aligning gun barrel and sight is described in US-A-4 879 814 in which the use is proposed of a laser source arranged in the gun's breech or chamber, which laser source is designed as a dummy shell and which, when it is activated, sends a laser beam coordinated with the centre line of the gun barrel which gives a sufficiently sharp reflection at a long distance (1200 metres is stated in the text) to make possible alignment of the gun barrel and sight at the strike point of the laser beam.
  • This method does not provide any actual ability to correct for such important sources of error as deflection of the gun barrel caused by the force of gravity and/or uneven heating up of the gun barrel, etc., but it must rather be regarded as a way of achieving a fairly rough alignment of the average centre line of the gun barrel with the sight.
  • Another disadvantage of the method is that the target that is illuminated by the laser must have certain characteristics of a flat mirror in order for the method to be able to be applied.
  • the use is proposed quite simply of a flat mirror and method claims 1-3 refer, in fact, to the use of a flat mirror.
  • a new method and arrangement are now proposed instead for aligning a gun barrel and sight in particular for medium- and large-calibre barrelled weapons intended for direct shooting at long distances, which method and arrangement utilize a video camera.
  • the method according to the invention is based on the video camera being arranged inside the gun barrel on a level with the breech or chamber, with the line of sight of the camera coinciding with the direction of fire of the gun barrel and with its optical axis precisely centred with the centre line of the gun barrel on a level with its position in the gun barrel.
  • the video camera is then used for aligning the sight with the centre line of the gun barrel on a level with the breech and also for determining gun barrel distortions and compensating the sight setting accordingly.
  • the projected image of the muzzle of the barrel which is obtained by the camera is measured and the alignment of the centre line of the gun barrel at the muzzle is calculated from the deviations between this image and the actual cross section of the gun barrel, using a calculation unit interacting with the camera or incorporated into the camera, after which the sight setting can be compensated accordingly.
  • the video camera can thus be a part of an optical measuring system, which must be able to measure the muzzle geometry of the gun barrel very accurately, that is the muzzle geometry as such and the centre line position of the muzzle in relation to the centre line of the chamber.
  • the camera is to be designed in such a way that, in addition to being able to be focused on the muzzle of the gun barrel, it is also able to be focused on infinity, that is it is able to look at an object a long distance beyond the muzzle of the gun barrel, that is it can be directed towards a point or target in the terrain.
  • the latter function also makes it possible to align the gun barrel and sight directly on a distant target and, in frontline situations when the sight function has been lost, for example due to external damage, the video camera would be able to replace the sight by first using this to direct the gun towards an enemy target and then by replacing it immediately afterwards by a live shell to attack the target.
  • the characteristic location of the video camera according to the invention means that the camera can either have the external shape of a dummy shell that fits the gun's chamber and is loaded into the gun's chamber in the same way as a live shell, or can quite simply be built into the end or rear part of the gun and is thus, in the latter case, ready for taking measurements, provided the gun is not loaded with a live shell.
  • the measurement data that is obtained from the optical measuring system is able to be transferred directly to the fire control system.
  • this type of measurement to objects in the terrain must, however, be supplemented by measurements that define the angling of the muzzle of the gun barrel, in most cases in the form of a deflection at the muzzle.
  • this angling or deflection is determined by the shape of the image of the muzzle of the gun barrel projected on the image plane of the video camera being compared with the actual shape of the muzzle.
  • Each angling or deflection of the muzzle of the gun barrel gives an image of the muzzle projected on the image plane of the video camera that has a more or less elliptical shape instead of the actual circular shape of the muzzle. This is because the deflected part of the inner wall of the gun barrel delimits the image of the muzzle in the video camera.
  • the degree of deviation from a circle is thus a measurement of the angle of the muzzle in relation to the alignment of the gun barrel on a level with the breech.
  • a suitably programmed microprocessor or the like can easily calculate the actual alignment of the centre line of the gun barrel at the muzzle. As pointed out above, it is the alignment of this part of the centre line that primarily determines the direction of the shot fired out of the gun barrel when it leaves the gun barrel.
  • the method according to the invention thus also comprises an indirect method of measuring the alignment of the gun barrel and, by this means, of obtaining information about the displacement of the muzzle in relation to the sight line.
  • the application of the invention involves the optical detecting unit in the form of the video camera being caused to send information that it has gathered to an image processing unit that can be integrated with the fire control system or can be a free-standing unit.
  • the geometry is measured of the image of the muzzle of the gun barrel recorded in the optical detecting unit (the video camera) in the form of the number of pixels comprised in the image and their position in the image.
  • positional displacements, changes in geometry and the like can be calculated and converted to information relating to data required by the fire control system concerning changes in angle, etc.
  • Alarm functions can also be included in the same system, that give warnings or prevent the opening of fire in the event of the discovery of major damage or wear to the gun barrel.
  • the optical measuring system can be used as a provisional sight, by means of the gun barrel being first aimed at the target using the video camera in the arrangement according to the invention, after which loading and firing are carried out.
  • the target can be measured and its position when the projectile reaches it can be determined with relatively good precision.
  • the information is sent via the video target tracker to the fire control system, if this has not been completely put out of action, or is sent straight out to a video monitor to be dealt with directly by the gunner.
  • Special means can be arranged to determine the orientation of the video camera relative to the vertical axis of the gun barrel. These can be in the form of direction-sensing sensors arranged in association with or on the video camera. There can also be a mechanical link with, for example, recesses in the gun barrel and projecting parts on the video camera.
  • 1 indicates the sectioned gun barrel of a gun mounted in an armoured vehicle (not shown).
  • the figure also shows the centre line 2 of the gun barrel 1 and its breech end 3.
  • the video camera 5 in the arrangement according to the invention is arranged in the breech or chamber 4 of the gun barrel 1.
  • this has suitably the external shape of a dummy shell and is inserted in the chamber without clearance.
  • the dummy shell can be provided with projecting parts (not shown) that interact with recesses in the gun barrel to achieve well-defined orientation of the video camera.
  • the design can comprise direction-sensing sensors.
  • the measurement values measured by the video camera or measuring camera 5 are sent via the cable 6 to an image processing unit 7 which is linked by cables 8 and 9 respectively to a video target tracker 10 and to the gun's ordinary fire control system 11, which in turn can be linked to the turret and gun barrel servo system via a cable 12.
  • the image processing unit 7 can also be integrated with the video camera in the dummy shell.
  • the video target tracker is an option in our system and does not necessarily need to be included in the invention in its most general form. As the component functions in the whole of this system only involve normal technical fire control technology that is not covered by the invention, these components will not be discussed here in greater detail.
  • the image processing unit 7 is also linked via a cable 13 directly to a monitor 15 arranged at the position of the gunner 14.
  • the monitor also has a direct link 16 to the video target tracker 10 which, in turn, has a direct link 17 to the fire control system 11.
  • the gun barrel 1 is angled downwards by the force of gravity, uneven heating or the like, which has resulted in the centre line 2 of the gun barrel being displaced by the distance x at the muzzle 19 of the gun barrel in comparison with the centre line at the breech 4, where the video camera 5 is located.
  • This deflection can also be given solely as an angle, in the form of the angle v.
  • the image plane 20 of the video camera 5 shows a projected image 21 of the muzzle of the gun barrel 1 which is elliptical. This is because the image is delimited at its upper edge by the edge of the muzzle of the deflected gun barrel and is delimited at its lower edge by the lower internal wall of the gun barrel.
  • the position of the centre line of the gun barrel at the muzzle has been marked 2y in Figure 2, while the direct linear projection of the centre line of the gun barrel on a level with the breech, that is where the video camera 5 is located, has been marked by 2i.
  • the deflection of the gun barrel is thus calculated from this elliptical image of the muzzle of the gun barrel by a comparison with the actual circular cross section of the muzzle.
  • the actual direction of the centre line of the gun barrel at the muzzle can then be calculated using the same data.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)
EP04445083A 2003-08-28 2004-08-20 Method and arrangement for aligning a gun barrel Withdrawn EP1510775A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0302302 2003-08-28
SE0302302A SE524913C2 (sv) 2003-08-28 2003-08-28 Sätt och anordning för ensning av eldrör

Publications (1)

Publication Number Publication Date
EP1510775A1 true EP1510775A1 (en) 2005-03-02

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EP04445083A Withdrawn EP1510775A1 (en) 2003-08-28 2004-08-20 Method and arrangement for aligning a gun barrel

Country Status (2)

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EP (1) EP1510775A1 (sv)
SE (1) SE524913C2 (sv)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014170581A1 (fr) 2013-04-19 2014-10-23 Star Nav Equipement pour le reglage d'une arme
BE1023708B1 (fr) * 2016-05-31 2017-06-22 Cockerill Maintenance & Ingenierie Sa Dispositif et méthode de simbleautage
CN108302980A (zh) * 2018-03-05 2018-07-20 南通大学 基于炮膛的静对静光学直瞄方法及直瞄装置
CN108344362A (zh) * 2017-05-27 2018-07-31 中国科学院上海技术物理研究所 一种高精度轴系旋转精度的光学测量装置及方法
RU2710853C1 (ru) * 2019-05-31 2020-01-14 Виталий Анатольевич Денисов Устройство наведения артиллерийских ствольных систем

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0092324A2 (en) * 1982-04-17 1983-10-26 The Marconi Company Limited Gun with means for verifying the boreline direction
GB2183315A (en) * 1985-11-22 1987-06-03 Ferranti Plc Determining gun muzzle displacement
EP0577017A1 (de) * 1992-06-27 1994-01-05 DST Deutsche System-Technik GmbH Gerät zum Testen des dynamischen Verhaltens von Rohrwaffen
WO2002027259A2 (en) * 2000-09-29 2002-04-04 C.I. System Ltd. Method and apparatus for the precise alignment of a weapon relative to a sight

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0092324A2 (en) * 1982-04-17 1983-10-26 The Marconi Company Limited Gun with means for verifying the boreline direction
GB2183315A (en) * 1985-11-22 1987-06-03 Ferranti Plc Determining gun muzzle displacement
EP0577017A1 (de) * 1992-06-27 1994-01-05 DST Deutsche System-Technik GmbH Gerät zum Testen des dynamischen Verhaltens von Rohrwaffen
WO2002027259A2 (en) * 2000-09-29 2002-04-04 C.I. System Ltd. Method and apparatus for the precise alignment of a weapon relative to a sight

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014170581A1 (fr) 2013-04-19 2014-10-23 Star Nav Equipement pour le reglage d'une arme
BE1023708B1 (fr) * 2016-05-31 2017-06-22 Cockerill Maintenance & Ingenierie Sa Dispositif et méthode de simbleautage
WO2017207487A1 (fr) 2016-05-31 2017-12-07 Cmi Defence S.A. Dispositif et méthode de simbleautage
US11435164B2 (en) 2016-05-31 2022-09-06 Cmi Defence S.A. Boresighting device and method
CN108344362A (zh) * 2017-05-27 2018-07-31 中国科学院上海技术物理研究所 一种高精度轴系旋转精度的光学测量装置及方法
CN108302980A (zh) * 2018-03-05 2018-07-20 南通大学 基于炮膛的静对静光学直瞄方法及直瞄装置
RU2710853C1 (ru) * 2019-05-31 2020-01-14 Виталий Анатольевич Денисов Устройство наведения артиллерийских ствольных систем

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Publication number Publication date
SE0302302L (sv) 2004-10-19
SE524913C2 (sv) 2004-10-19

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