US3293643A - Fire control system for use on board a ship - Google Patents

Fire control system for use on board a ship Download PDF

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Publication number
US3293643A
US3293643A US376965A US37696564A US3293643A US 3293643 A US3293643 A US 3293643A US 376965 A US376965 A US 376965A US 37696564 A US37696564 A US 37696564A US 3293643 A US3293643 A US 3293643A
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United States
Prior art keywords
detector
axis
target
ship
antenna
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Expired - Lifetime
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US376965A
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English (en)
Inventor
Blomqvist Ake Hugo Petrus
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Saab Bofors AB
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Bofors AB
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G5/00—Elevating or traversing control systems for guns
    • F41G5/14—Elevating or traversing control systems for guns for vehicle-borne guns
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G5/00—Elevating or traversing control systems for guns
    • F41G5/14—Elevating or traversing control systems for guns for vehicle-borne guns
    • F41G5/16—Elevating or traversing control systems for guns for vehicle-borne guns gyroscopically influenced

Definitions

  • the present invention relates to a fire control system for use on a moving carrier, particularly on board a ship, for laying a weapon on the ship for a target upon which fire is to be directed.
  • Such a fire control system comprises sighting or detecting means by which the direction and the range to the target can be measured, and a fire control computer, which from the data for the direction and range of the target from the sighting or detecting means and from other necessary data, such as the attitude, the speed and the course of the ship, the velocity and direction of the wind, the parallax, etc., computes the data necessary for the laying of the weapon on board the ship.
  • the sighting or detecting means which normally comprises a fire control radar, but which also can be of some other typefor instance, a laser sight-comprises a detector which can be directed at the target by rotation about at least one axis relative to the ship.
  • the detector must be rotatable about two preferably mutually orthogonal axes.
  • the detector comprises the antenna reflector of the radar station and consequently is rotatable about at least one axis relative to the ship, but in a fire control system for air targets it is rotatable about two mutually orthogonal axes.
  • the radar antenna In a fire control system of this type, it is generally desirable that the radar antenna, once it is directed upon the tar-get, will automatically follow the target so that the radar station will continuously supply the fire control computer with information regarding the range and direction of the target. Normally this is achieved by rotating the antenna reflector about each of its axes of rotation by means of a servomotor. The motor is controlled by a signal which is dependent on the deviation between the direction of the antenna reflector and the direction of the target.
  • a radar station In a radar station, information about the deviation between the direction of the antenna reflector and the direction of the target is obtained by providing the radar station with lobe switching or a conically scanning antenna lobe, or with several simultaneously operating antenna lobes with somewhat deviating directions, whereby the radar station can determine the deviation between the direction of the antenna reflector and the direction of the target by comparing the amplitudes of the echoes received from the target in the different lobe directions. These echoes produce signals corresponding to this deviation for control of the servomotors rotating the antenna reflector about its two axes of rotation so that the servomotors try to direct the antenna reflector :at the target and thus eliminate the deviation.
  • Several different devices in fire control radar stations for determining the deviation between the direction of the antenna reflector and the direction of the target are well known in the art, and therefore will not be described herein in detail.
  • the antenna can in principle be brought to follow the target.
  • a fire control system of this type on board a ship however, and particularly in a fire control system for air targets which are moving at very high velocities, it has been found to be practically impossible to obtain accurate and reliable atent Gr 3,293,643 Patented Dec. 20, 1966 ice target tracking in this simple way.
  • the reason for this is the fact that, partly due to the movements of the ship, such as rolling, pitching and yawing, and partly due to the high velocity of movement of the target, the deviations between the direction of the antenna reflector and the direction of the target will be comparatively large and will vary rapidly in magnitude and in a direction requiring a high amplification in the above-described servomotor control circuits for the antenna reflector in order to cause the antenna reflector to follow the target accurately.
  • the signal dependent on the deviation between the direction of the antenna reflector and the direction of the target as received from the radar station and produced by lobe switching or in some other Way, cannot, however, be given a high amplification.
  • Such signal comprises comparatively large noise components which would cause overdriving and thus create the risk that the antenna would lose the target; that is, that the target would be outside the lobe range of the antenna. If the signal is given a high amplification, the noise components may also cause overdriving of the amplifiers and the servomotors rotating the antenna. Furthermore, the wear on the servomotors and the mechanical rotating system will be increased.
  • One mode of solving this problem would be to mount the radar antenna on a gyro-stabilized platform so that the radar antenna would not participate in the movements of the ship, whereby these movements would not cause any deviations between the antenna direction and the direction of the target which would have to be eliminated by means of the antenna rotation sys tem.
  • Such gyro-stabilizing of the antenna is comparatively expensive and complicated.
  • a broad object of the present invention is to provide a fire control system of the type described above for use on board a ship, in which system the above-mentioned problems with respect to automatic target tracking by the detector, which is normally a radar antenna, are solved in a simple and reliable way.
  • this is achieved by controlling the servomotor system by which the detector is rotated about an axis relative to the ship, or about each of two mutually orthogonal axes in a fire control system for air targets, by means of three different signals.
  • One of these signals is a signal received in the conventional manner from the detector means itself, and is dependent on the angular deviation about the axis of rotation of the detector associated with the servomotor system between the direction of the detector and the direction of the target.
  • the second signal is received from a gyro responsive to angular velocity.
  • the gyro is so mounted on the detector that the gyro is influenced by the angular velocity of the detector about the axis of rotation for the detector associated with the servomotor system and produces a signal proportional to this angular velocity.
  • the third signal is obtained from the fire control computer, which is arranged according to the invention to compute the direction of movement and the velocity of the target and to produce a signal proportional to the angular velocity of the target, corresponding to the velocity and the direction of movement of the target, about the axis of rotation for the detector associated with the servomotor system.
  • This third signal is connected to control the servomotor system so as to impart a corresponding angular velocity to the detector about said axis of rotation.
  • the signal from the angular-velocity-responsive gyro on the detector affects the servomotor system as a negative feedback, and will stabilize the detector so that its direction in space will not 'be affected by the movements of the ship.
  • the signal received from the fire control computer which is proportional to the angular velocity of the targets about the axis of rotation of the detector will impart a movement to the detector such that the detector will automatically follow the target if the latter is moving at a constant speed on a straight course.
  • the signal received from the detecting means corresponding to the deviation between the direction of the detector and the direction of the target, need provide only such com paratively small and slow corrections of the direction of the detector as are necessary due to changes in the velocity and direction of the target, temporary external disturbances and inaccuracies in the control of the detector from the two other signals. Accordingly the signal received from the detecting means and dependent on the deviation between the direction of the detector and the direction of the target does not require large amplification.
  • an accurate and reliable target tracking is achieved in a simple manner for large and rapid movements of the ship and for large target velocities also.
  • the sighting or detecting means consists of a fire control radar for air targets, said radar having an antenna reflector which can be directed in elevation about an axis parallel with the deck plane of the ship and in traverse about an axis parallel with the mast direction of the ship.
  • the exemplified fire control system comprises a conventional radar equipment R for transmitting radar pulses and receiving radar echoes which is connected to an antenna reflector 1 in the conventional manner,
  • the antenna reflector 1 is mounted on one end of an arm 2, which is pivotable in a stand 3 about an axis H, which is assumed to be parallel with the deck plane of the ship.
  • the stand 3 is mounted on a platform 4, which is journaled in the ship in such a way that it is rotatable about an axis S, which is perpendicular to the deck plane of the ship and thus to the axis H.
  • the axis S is thu generally parallel with the [mast direction of the ship.
  • Z is an imaginary axis perpendicular to the axis H as well as to the antenna direction designated A1 in the drawing. It should be noted that these axes S, H and Z are all imaginary geometrical spatial directions which are related to the ship and the antenna system so that the direction S is always parallel to the mast direction, the direction H is always parallel with the deck plane on the ship and perpendicular to the antenna direction A1 and the direction Z is always perpendicular to the antenna direction All as well as the direction H.
  • the antenna arm 2 can be rotated about the axis H by means of a servomotor S1
  • the platform 4 can be rotated about the axis S by a servomotor S2.
  • the antenna reflector 1 can, by means of the two servomotors S1 and S2, be directed in traverse as Well as in elevation towards a target M.
  • the antenna direction is designated A1
  • the true direction to the target M is designated A2.
  • a signal generator 5 is coupled to the mechanical pivot shaft of the antenna arm 2 and produces a signal to the fire control computer 6 representing the angle H between the antenna direction A1 and the deck plane of the ship.
  • a second signal generator 7 is coupled to the platform 4 for generating a signal to the fire control computer 6 representing the angle a in the deck plane of the ship between the projection of the antenna direction Al on the deck plane and a fixed direction in the deck plane of the ship.
  • the angle a indicates the traverse direction of the antenna relative to the ship
  • the angle H indicates the elevation of the antenna relative to the ship and if the antenna is directed at the target M
  • these two angles will consequently define the direction of the target relative to the ship.
  • the radar equipment R determines in a conventional manner the range of the target by measuring the difference in time between the transmitted radar pulses and the radar echoes received from the target, and conveys to the fire control computer 6 a signal representing this range L.
  • the fire control computer will in a conventional manner compute the necessary data for the laying of a weapon on the target M and will transfer these data in any suitable manner, not specifically shown in the drawing, to the laying system of the weapon.
  • the figure shows only those parts of the fire control system which according to the invention are of interest for the automatic tracking of the target M by the antenna 1 when the antenna has been directed close to the target in any suitable conventional way.
  • the antenna reflector 1 and the radar equipment R are provided with means for lobe switching or a similar system so that the radar equipment R can measure the deviation between the antenna direction A1 and the true direction A2 to a target M.
  • the radar equipment R produces a first signal on the basis of the data regarding this deviation, which have been obtained by means of lobe switching or in any similar way.
  • This signal is proportional to the angular deviation 6 about the axis Z between the antenna direction All and the direction A2 to the target M and is fed from the radar equipment A to a servomotor S2 through an adder amplifier 8.
  • the system according to the invention comprises two conventional angular velocity-sensitive gyros G and G which, as schematically shown, are mounted on the antenna reflector 1 or any other member--for instance, the antenna arm 2, which moves together with the antenna reflector.
  • Gyro G is so mounted that it measures the angular velocity of the antenna reflector 1 about the axis Z and generates a voltage proportional to this angular velocity dg/dt which is fed to the adder amplifier 8 and thus to the servomotor S2. As is apparent, the angular velocity tor about the axis S.
  • the signal transmitted from gyro G to servomotor S2 for the platform 4 is consequently proportional to the angular velocity da/dl of the antenna reflector about the axis of rotation S associated with the servomotor S2.
  • the second gyro G measures the angular velocity of the antenna reflector 1 about the axis H and supplies a signal proportional to this angular velocity dH/dt to the adder amplifier 9 and thus to servomotor S1.
  • the angular velocities dg/dt and dH/dt respectively, measured by the two angular-velocity-sensitive gyros G and G reflect not only the rotational movements imparted to the antenna reflector 1 by the servomotors S1 and S2, but also the angular velocity components which are imparted to the antenna reflector about its two axes Z and H due to the rolling, pitching and yawing movements of the. ship.
  • the antenna reflector 1 When the ship is yawing, for instance, a certain angular velocity is imparted to the antenna reflector 1 about its axis S, which angular velocity will affect the gyro G as described above.
  • a certain angular velocity is imparted to the antenna reflector about the axis H and is measured by the gyro 6
  • the antenna reflector 1 When the ship is pitching and rolling, the antenna reflector 1, provided that H is not zero, will also obtain a certain angular velocity about the axis Z, the magnitude of which is dependent on the angle between the antenna direction and the axis in the horizontal plane about which the ship is tilting, and the magnitude of the elevation angle H of the antenna.
  • the signals proportional to the angular velocity dg/dt and dH/dt of the antenna reflector 1 received from the gyros G and G are fed to the servomotors S1 and S2 through the amplifiers 8 and 9 in a circuit such that they have the effect of negative feedbacks.
  • the two negative feedbacks cooperate to drive the servomotors in such a way that the angular velocities of the antenna reflector about the axes H and Z become zero, whereby the direction A1 of the antenna reflector becomes stationary in space and independent of the movements of the ship, provided the amplification in the feedback loops may be regarded as infinite.
  • These feedback loops may be readily given a high amplification whereby the antenna direction A1 is made independent of the movements of the ship with great accuracy.
  • the fire control computer 6 computes, on the basis of the supplied data, the velocity vector v of the target M; that is, the velocity and the direction of movement of the target. According to the invention the fire control computer 6 also computes the angular velocity of the target M about the axis Z in accordance with the direction of movement and the velocity of the target, and produces a signal proportional to this angular velocity a'gM/dt. This signal is fed from the fire control computer through the amplifier 8 to the servomotor S2. In this case also the magnitude dEZ'vI dull! dt (it where dM/dt is the angular velocity of the target about the axis S.
  • the signal from the fire control computer 6 to the servomotor S2 is consequently proportional to the angular velocity of the target about the S axis of rotation associated with the servomotor S2.
  • the fire control computer 6 computes also the angular velocity of the target about the axis H and produces a signal proportional to this angular velocity dHM/dt. This signal is fed through the amplifier 9 to the servomotor S1.
  • the fire control computer 6 may be an electronic digital computer, in which case the signal generators 5 and 7 are preferably digital signal generators which convey the values of the angles a and H to the fire control computer 6 directly in digital form.
  • the fire control computer 6 will then compute the quantities dM/dl and dHM/ d1 in digital form, and these digital values must be conveyed to digital-analog converters to be converted to analog signals which can control the servomotors S1 and S2.
  • the invention may also be used in a fire control system for surface targets, in which case the radar antenna 1 is rotatable about only one axis, S.
  • a fire control system for use on board of a ship, said system comprising, in combination, a sighting means for determining direction and range data of a target, said sighting means including a detector rotatable about a first axis substantially parallel to the deck plane of the ship and a second axis substantially normal thereto, first servomotor means rotating said detector about said first axis and second servomotor means rotating said detector about said second axis, said sighting means producing a first error signal corresponding to the angular deviation between the direction of said detector and the direction to the target about said first axis and a second error signal corresponding to the angular deviation between the direction of said detector and the direction to the target about a third axis perpendicular to the direction of the detector and said first axis of rotation of said detector; a first angular-velocitysensitive gyro means mounted on said detector so as to be responsive to the angular velocity of said detector about said first axis for producing a first rate signal proportional to said first
  • a fire control system comprising amplifying means having an amplification factor 1/ cos H, where H is the angle between the direction of said detector and the deck plane of the ship about said first axis of rotation of said detector, for amplifying the signal fed to said second servomotor means for rotating said detector about its second axis of rotation.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
US376965A 1963-07-02 1964-06-22 Fire control system for use on board a ship Expired - Lifetime US3293643A (en)

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Application Number Priority Date Filing Date Title
SE736163 1963-07-02

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US3293643A true US3293643A (en) 1966-12-20

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US (1) US3293643A (da)
CH (1) CH434030A (da)
DE (1) DE1274473B (da)
DK (1) DK111438B (da)
FI (1) FI43273C (da)
GB (1) GB1056815A (da)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3504979A (en) * 1965-10-21 1970-04-07 Gen Dynamics Corp Optical communication system
US3697992A (en) * 1970-07-09 1972-10-10 Us Navy Servo compensation for inertia change
JPS51110950A (ja) * 1975-03-26 1976-09-30 Nippon Telegraph & Telephone Eiseitsushinyosenpakuantena
US5247867A (en) * 1992-01-16 1993-09-28 Hughes Missile Systems Company Target tailoring of defensive automatic gun system muzzle velocity
WO1998040761A1 (en) * 1997-03-11 1998-09-17 Orbit Communications, Tracking And Telemetry Ltd. Satellite tracking system
US7312744B1 (en) * 2003-12-19 2007-12-25 Tom Ramstack System for administering a restricted flight zone using radar and lasers
US20140085124A1 (en) * 2012-05-30 2014-03-27 Honeywell International Inc. Systems and methods for using radar-adaptive beam pattern for wingtip protection

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3662975B2 (ja) * 1994-07-22 2005-06-22 日本無線株式会社 追尾型アレイアンテナ装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3099005A (en) * 1957-10-01 1963-07-23 Rca Corp Stabilized tracking system
US3176292A (en) * 1946-03-29 1965-03-30 Sperry Rand Corp Regenerative tracking system

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2660793A (en) * 1942-05-22 1953-12-01 Sperry Corp Stabilized tracking and fire control system
US2715776A (en) * 1942-05-25 1955-08-23 Sperry Rand Corp Stabilized gun control system with aided tracking
US2709303A (en) * 1947-05-17 1955-05-31 Sperry Corp Computing gun sight
US2878466A (en) * 1951-10-06 1959-03-17 Hughes Aircraft Co Disturbed line-of-sight fire control system
US2992423A (en) * 1954-05-03 1961-07-11 Hughes Aircraft Co Rocket launch control systems

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3176292A (en) * 1946-03-29 1965-03-30 Sperry Rand Corp Regenerative tracking system
US3099005A (en) * 1957-10-01 1963-07-23 Rca Corp Stabilized tracking system

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3504979A (en) * 1965-10-21 1970-04-07 Gen Dynamics Corp Optical communication system
US3697992A (en) * 1970-07-09 1972-10-10 Us Navy Servo compensation for inertia change
JPS51110950A (ja) * 1975-03-26 1976-09-30 Nippon Telegraph & Telephone Eiseitsushinyosenpakuantena
US5247867A (en) * 1992-01-16 1993-09-28 Hughes Missile Systems Company Target tailoring of defensive automatic gun system muzzle velocity
WO1998040761A1 (en) * 1997-03-11 1998-09-17 Orbit Communications, Tracking And Telemetry Ltd. Satellite tracking system
US7312744B1 (en) * 2003-12-19 2007-12-25 Tom Ramstack System for administering a restricted flight zone using radar and lasers
US20140085124A1 (en) * 2012-05-30 2014-03-27 Honeywell International Inc. Systems and methods for using radar-adaptive beam pattern for wingtip protection

Also Published As

Publication number Publication date
CH434030A (de) 1967-04-15
DE1274473B (de) 1968-08-01
FI43273C (fi) 1971-02-10
FI43273B (da) 1970-11-02
GB1056815A (en) 1967-02-01
DK111438B (da) 1968-08-19

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