EP0601983A2 - A method and an apparatus for determining the flight distance covered by a projectile - Google Patents

A method and an apparatus for determining the flight distance covered by a projectile Download PDF

Info

Publication number
EP0601983A2
EP0601983A2 EP93850204A EP93850204A EP0601983A2 EP 0601983 A2 EP0601983 A2 EP 0601983A2 EP 93850204 A EP93850204 A EP 93850204A EP 93850204 A EP93850204 A EP 93850204A EP 0601983 A2 EP0601983 A2 EP 0601983A2
Authority
EP
European Patent Office
Prior art keywords
sensor
projectile
retardation
flight
seismic mass
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Withdrawn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
EP93850204A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0601983A3 (no
Inventor
Hans Richert
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 Bofors AB
Original Assignee
Bofors 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 Bofors AB filed Critical Bofors AB
Publication of EP0601983A2 publication Critical patent/EP0601983A2/en
Publication of EP0601983A3 publication Critical patent/EP0601983A3/xx
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
    • F42C15/00—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges
    • F42C15/40—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges wherein the safety or arming action is effected electrically

Definitions

  • the present invention relates to a method of continuously measuring the flight distance covered by projectiles such as different types of shells etc., and an apparatus designed in accordance therewith.
  • the flight distance of the relevant projectile is determined on each separate occasion using exclusively its retardation as a point of departure. It will hereby be possible to track the flight path of the projectile along its ballistic trajectory and, on each separate occasion, to determine its position in relation to a predetermined target.
  • the present invention may therefore be utilized to control the arming of a projectile.
  • the present invention also includes a sensor designed in accordance therewith whose substantial resilience and slight space requirements render it extremely well suited for incorporation into barrel ammunition, also including small-calibre such ammunition.
  • Conventional accelerometers are therefore unsuitable for use in barrel ammunition.
  • the present invention includes a sensor or accelerometer adapted exclusively for determination of negative acceleration levels.
  • the sensor according to the present invention is thus prevented from moving against the flight direction of the projectile, so that it will be capable of withstanding the mechanical stresses during the firing cycle.
  • the present invention may be described as comprising a method and an apparatus for continuously determining the flight distance covered on each separate occasion along the ballistic trajectory of projectiles without inherent propulsion. According to the present invention, this is effected completely within the projectile by internal signal processing on the basis of the measured value of the initial retardation of the projectile and a continuous follow-up of its progressive retardation.
  • the sensor or accelerometer utilized according to the present invention should thus be blocked in the acceleration direction and only permitted to move towards the flight direction, i.e. the direction in which it is influenced on retardation. This is achieved in that it rests against a reference plane which prevents outward flexing of the beam of the accelerator during the firing phase.
  • the accelerometer is liquid-damped, there can be formed - in one or both of the mutually abutting interfaces between the accelerometer and the supporting surface - a pattern which reduces the capillary effect between these interfaces.
  • the sensor may be provided with an overload guard which permits the accelerometer to move in an adapted piece in this direction before the overload guard is touched.
  • Relevant retardation transients may for example be a consequence of the compression to which at least shells of smaller calibre are exposed during the acceleration phase proper.
  • the overload guard which of course must be placed so that the pertinent acceleration levels of interest can be measured unimpeded during flight, may be produced from the same material as the blocking arrangement of the sensor according to the present invention in the flight direction of the projectile, or from the same material as the sensor itself such as for example silicon or glass.
  • the present invention it is possible, i.a., to produce arming systems for artillery shells which relieve the gun crew from the duty of programming in each individual case the arming of the shells, in view of the loading gear of the gun, the strength of the charge, the powder temperature etc. Instead, the arming of the projectile will be dependent in each individual case upon the relationship of the relevant flight distance to a preselected reference range.
  • Those error sources which may principally become pertinent in connection with the present invention depend upon the prevailing atmospheric conditions in the form of air pressure and winds. However, these do not give greater error margins than can be acceptable and the values obtained according to the present invention may be expected to be considerably better than those in existing systems.
  • the accelerometer or sensor 1 shown in Figs. 1-2 is made of silicon and fundamentally consists of a flexible beam 2 which bends as a function of the applied acceleration which, in this case, is negative - i.e. a retardation.
  • the outer, free end of the beam 2 is designed as a so-called seismic mass 3.
  • the arrow F indicates the flight direction of the shell in which the sensor 1 is intended to be employed.
  • the movement (flexing) of the beam initiated by the acceleration (the retardation) is recorded by means of two strain-sensitive piezo resistors 4 and 5 placed in the weakest portion of the beam.
  • Two further corresponding resistors 6 and 7 are disposed on that portion of the sensor which is not affected by the bending or flexing of the beam on retardation (negative acceleration) acting on the shell. These totally four resistors 4-7 are coupled in a conventional measurement bridge (a Wheatstone bridge) with open earth so as to permit offset compensation of the sensor (see Fig. 3).
  • Figs. 2 a and b show where the sensor is permanently connected, for example glued, to the supporting surface 8, namely along the surfaces 9 and 10. Between the seismic mass 3 and the supporting surface 8 of the accelerometer, there has been marked what appears to be a narrow gap 11. However, this marking 11 should only be interpreted such that the seismic mass is supported there but is free to move away from the supporting surface 8.
  • the senor 1 rests on a supporting surface 8.
  • the supporting surface 8 may be manufactured from the same material as the sensor or from other material of sufficiently slight elasticity and flexibility.
  • the distance covered by the shell is calculated in the signal processing electronics whose fundamental construction is apparent from Fig. 4.
  • the initial value of the retardation signal is sampled in order to calculate therefrom the discharge velocity, i.e. vo.
  • the retardation is integrated twice.
  • the discharge velocity is integrated so as to obtain a covered distance without taking into account the retardation caused by air resistance.
  • the double-integrated retardation signal caused by the air resistance is subtracted in order, by such means, to obtain the true distance flown along the ballistic trajectory of the projectile. Thereafter, comparison may be made between this signal and a predetermined reference range in order, at any given distance flown, to permit an event to occur inside the shell, for example arming.
  • acc measured acceleration i.e. retardation
  • a o initial retardation i.e. the value which is obtained when the shell departs from the gun barrel or tube.
  • the ⁇ of the block diagram designates that operation which gives the value for v o .
  • v o t i.e. that flight distance which would have been achieved if the shell had not been affected by air resistance.
  • the double integral of the measured retardation gives the air resistance ratio which, together with v o t, gives a value of the flown distance s(t) and s ref marks that comparative value which is to determine when any particular function such as arming, initiation etc. is to take place, i.e. as long as s(t) ⁇ s ref , nothing will happen.
  • the inventive concept as herein disclosed is exclusively to utilize the retardation for distance determination, and to utilize an accelerometer adapted for these negative acceleration levels.
  • the accelerometer according to the present invention is prevented from moving in a direction opposed to the flight direction of the shell during the firing phase so as not to fail on application of this impact loading. As a result of this solution, there will be obtained sufficient accuracy in the distance measurement without requiring extreme resolutions of the components of the system.
  • Fig. 2 b shows an accelerometer corresponding to that of Fig. 2 a, but in Fig. 2 b, the original sensor according to the present invention has been supplemented with an overload guard disposed in the measurement direction, i.e. in the flight direction of the pertinent projectile ahead of the seismic mass 3 of the sensor.
  • This overload guard is designed so as to permit the seismic mass 3 of the sensor to move sufficiently in the measurement direction for an unimpeded determination of the acceleration levels of interest (i.e. the actual retardation) during the flight of the projectile, but prevents such overloads of the measurement system as may be caused by possible acceleration transients in the firing phase proper.
  • the overload guard may suitably be manufactured from silicon, glass or other material possessing corresponding properties.
  • liquid-damped accelerometers of the type relevant here to reduce the capillary effect between the moving part of the accelerometer and the supporting surface by forming a pattern in one or both of the mutually abutting interfaces, i.e. the surfaces on either side of the contact surface marking 8.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Length Measuring Devices With Unspecified Measuring Means (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Measurement Of Distances Traversed On The Ground (AREA)
EP93850204A 1992-11-12 1993-10-28 A method and an apparatus for determining the flight distance covered by a projectile Withdrawn EP0601983A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9203378A SE9203378L (sv) 1992-11-12 1992-11-12 Sätt och anordning för bestämning av en projektil tillryggalagd flygsträcka
SE9203378 1992-11-12

Publications (2)

Publication Number Publication Date
EP0601983A2 true EP0601983A2 (en) 1994-06-15
EP0601983A3 EP0601983A3 (no) 1994-08-31

Family

ID=20387782

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93850204A Withdrawn EP0601983A2 (en) 1992-11-12 1993-10-28 A method and an apparatus for determining the flight distance covered by a projectile

Country Status (4)

Country Link
EP (1) EP0601983A2 (no)
JP (1) JPH06201396A (no)
NO (1) NO934080D0 (no)
SE (1) SE9203378L (no)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080261189A1 (en) 2005-02-23 2008-10-23 Muneomi Katayama Internet Lesson System

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3478604A (en) * 1968-05-17 1969-11-18 Us Army Electronic solid-state accelerometer
DE2528770A1 (de) * 1975-06-27 1977-01-13 Messerschmitt Boelkow Blohm Einrichtung zur vorrohrsicherung eines zuenders
GB2183040A (en) * 1985-11-19 1987-05-28 Stc Plc Transducer
EP0231161A2 (en) * 1986-01-29 1987-08-05 Aktiebolaget Bofors Apparatus for reducing projectile spread
EP0348985A2 (de) * 1988-06-30 1990-01-03 Asea Brown Boveri Aktiengesellschaft Zündeinrichtung für Sprenggeschosse
US4987781A (en) * 1989-05-03 1991-01-29 Sensym, Incorporated Accelerometer chip
DE4100451A1 (de) * 1990-01-12 1991-07-25 Nissan Motor Halbleiterbeschleunigungsmesser

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3478604A (en) * 1968-05-17 1969-11-18 Us Army Electronic solid-state accelerometer
DE2528770A1 (de) * 1975-06-27 1977-01-13 Messerschmitt Boelkow Blohm Einrichtung zur vorrohrsicherung eines zuenders
GB2183040A (en) * 1985-11-19 1987-05-28 Stc Plc Transducer
EP0231161A2 (en) * 1986-01-29 1987-08-05 Aktiebolaget Bofors Apparatus for reducing projectile spread
EP0348985A2 (de) * 1988-06-30 1990-01-03 Asea Brown Boveri Aktiengesellschaft Zündeinrichtung für Sprenggeschosse
US4987781A (en) * 1989-05-03 1991-01-29 Sensym, Incorporated Accelerometer chip
DE4100451A1 (de) * 1990-01-12 1991-07-25 Nissan Motor Halbleiterbeschleunigungsmesser

Also Published As

Publication number Publication date
SE470288B (sv) 1994-01-10
SE9203378L (sv) 1994-01-10
JPH06201396A (ja) 1994-07-19
EP0601983A3 (no) 1994-08-31
SE9203378D0 (sv) 1992-11-12
NO934080D0 (no) 1993-11-11
NO934080L (no) 1994-05-13

Similar Documents

Publication Publication Date Title
EP0783095B1 (en) Passive velocity data system
US5775636A (en) Guided artillery projectile and method
US6216595B1 (en) Process for the in-flight programming of a trigger time for a projectile element
US6345785B1 (en) Drag-brake deployment method and apparatus for range error correction of spinning, gun-launched artillery projectiles
US6782748B2 (en) High-G acceleration protection by caging
US5795988A (en) Gyroscope noise reduction and drift compensation
US9115968B1 (en) Course self-correcting projectile
KR870005230A (ko) 자동 조준기 보정 시스템 및 그 조준방법
US8093539B2 (en) Integrated reference source and target designator system for high-precision guidance of guided munitions
US4606514A (en) Method for homing a projectile onto a target and for determining the ballistic trajectory thereof as well as arrangements for implementing the method
JP3891619B2 (ja) プログラム可能発射体の爆発時間の決定法
CA2190385C (en) Method and device for determining the disaggregation time of a programmable projectile
US5341743A (en) Directed-effect munition
JP3220173B2 (ja) ミサイルの垂直速度および高度を正確に決定するためのシステム
RU2666378C1 (ru) Способ дистанционного подрыва снаряда
EP0601983A2 (en) A method and an apparatus for determining the flight distance covered by a projectile
GB2421083A (en) Magnetic Null Accelerometer
KR101944596B1 (ko) 기상 데이터 보정 방법 및 장치
EP1117972B1 (en) Highly accurate long range optically-aided inertially guided type missile
US4160250A (en) Active radar missile launch envelope computation system
Tahk et al. Observability characteristics of angle-only measurement under proportional navigation
US4456202A (en) Burst height compensation
US6422119B1 (en) Method and device for transferring information to programmable projectiles
RU2676301C1 (ru) Способ стрельбы зенитными снарядами
IL204223A (en) Head start method - shell and vehicle battle

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE CH DE DK ES FR GB GR IT LI NL SE

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH DE DK ES FR GB GR IT LI NL SE

17P Request for examination filed

Effective date: 19950131

17Q First examination report despatched

Effective date: 19960805

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19970218