WO2014174035A1 - Systèmes de recherche - Google Patents

Systèmes de recherche Download PDF

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Publication number
WO2014174035A1
WO2014174035A1 PCT/EP2014/058382 EP2014058382W WO2014174035A1 WO 2014174035 A1 WO2014174035 A1 WO 2014174035A1 EP 2014058382 W EP2014058382 W EP 2014058382W WO 2014174035 A1 WO2014174035 A1 WO 2014174035A1
Authority
WO
WIPO (PCT)
Prior art keywords
target
radiation
seeker
polarisation
detector
Prior art date
Application number
PCT/EP2014/058382
Other languages
English (en)
Inventor
Mark Bray
Jason Lepley
Robert SHEARS
Original Assignee
Selex Es Ltd
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 Selex Es Ltd filed Critical Selex Es Ltd
Publication of WO2014174035A1 publication Critical patent/WO2014174035A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
    • G01S3/78—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using electromagnetic waves other than radio waves
    • G01S3/782—Systems for determining direction or deviation from predetermined direction
    • G01S3/783—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived from static detectors or detector systems
    • G01S3/784—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived from static detectors or detector systems using a mosaic of detectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G7/00—Direction control systems for self-propelled missiles
    • F41G7/20—Direction control systems for self-propelled missiles based on continuous observation of target position
    • F41G7/22—Homing guidance systems
    • F41G7/226—Semi-active homing systems, i.e. comprising a receiver and involving auxiliary illuminating means, e.g. using auxiliary guiding missiles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G3/00—Aiming or laying means
    • F41G3/14—Indirect aiming means
    • F41G3/145—Indirect aiming means using a target illuminator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G7/00—Direction control systems for self-propelled missiles
    • F41G7/20—Direction control systems for self-propelled missiles based on continuous observation of target position
    • F41G7/22—Homing guidance systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G7/00—Direction control systems for self-propelled missiles
    • F41G7/20—Direction control systems for self-propelled missiles based on continuous observation of target position
    • F41G7/22—Homing guidance systems
    • F41G7/2273—Homing guidance systems characterised by the type of waves
    • F41G7/2293—Homing guidance systems characterised by the type of waves using electromagnetic waves other than radio waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/499—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00 using polarisation effects

Definitions

  • the invention relates to seeker systems. More specifically, but not exclusively it relates to semi active laser (SAL) seeker systems.
  • SAL semi active laser
  • Semi-active laser detectors are a mature technology. In the simplest instances they use simple PIN photodiodes to detect the laser pulses originating at a designator and reflecting from a target. They must reliably detect the pulse energy above both background illumination and any noise in the detector; and they must also measure accurately the timing of the pulse to detect so that this matches the correct code emitting from a designator. Increased timing accuracy can also be exploited using techniques such as last pulse logic to avoid the seeker being seduced by reflections between the designator and the target e.g. from battlefield smoke. They must provide a signal, that gives the position of the laser spot relative to some origin (normally the boresight of the camera), to the guidance system. Known sensors use four PIN diode elements in a quadrant arrangement to provide the fast response and the position. A newer sensor is disclosed, and summarised below, that uses a single semiconductor element.
  • one of the factors that govern whether the seeker can detect the pulse above background illumination (clutter) is the range to target.
  • An increase in the maximum operating range can be achieved either by limiting the clutter e.g. by using a bandpass optical filter centred on the laser wavelength; by reducing the collection time of the sensor, e.g. for semiconductors reducing the integration time; or by increasing the laser pulse energy (this may be unattractive for reasons of safety or power/size/weight increase).
  • the problem addressed by the present invention is the requirement to increase the operating range of a platform by improving the signal to clutter noise ratio in the detector. If the atmospheric absorption at the signal wavelength is low, the signal loss with range, for a diffuse reflection, can be taken to vary as 1/r2 where r is the range. Thus an increase in the signal to noise ratio of 3dB gives a 2 improvement of the range or approximately 41 %.
  • a seeker system comprising a radiation source emitting radiation towards a target and a detector detecting radiation reflected by the target, the seeker system further comprising optical elements disposed between the source and the target, said elements acting so as to polarise the radiation emitted toward the target, and further optical elements disposed between the target and the detector, said further elements acting so as to detect only the radiation reflected by the target of a given polarisation, thereby improving the signal to noise ratio of the seeker system.
  • the present invention uses the polarisation of laser pulses to further suppress clutter that can provide range increases of up to 41 % over known detectors. It is a further advantage of the invention that a seeker in the form of the present invention will not be seduced by secondary reflections from other objects or light scattered by the atmosphere between the designator and the target. Polarisation can be used to distinguish these false reflections from the correct reflection from the target. Additionally, the system is able to provide a seeker system capable of operation in misty or foggy atmospheres.
  • Figure 1 is a schematic diagram of the seeker system comprising a designator 1 including a radiation emitter 2 and the seeker 3 including a detector 18 as two separate units within the whole seeker system.
  • the seeker system comprises a designator 1 and a seeker 3.
  • the designator 1 comprises a radiation emitter 2 such as, for example, a laser.
  • the laser 2 emits radiation towards a target to be detected 10.
  • the radiation may be pulses or laser light but other wavelength of radiation may be used with a suitable emitter replacing the laser 2 of the present embodiment.
  • the radiation emitted by the laser 2 is transmitted through a series of simple optical elements 4, 6 that in the present invention comprise a polariser 4 and a quarter waveplate 6.
  • the radiation emitted by the designator 3 in the present invention is therefore polarised and is transmitted 8 towards the target 10.
  • the radiation is reflected by the target 10 and as such the nature of the polarisation is affected, depending on the nature of the polarisation of the transmitted radiation 8.
  • the radiation reflected 12 is detected by the seeker 3.
  • the radiation 12 is transmitted through a quarter waveplate 14 and a polariser 16 to the detector 18. It will be appreciated that the waveplates 6, 14 and the polarisers 4, 16 are matched to take account of the change in polarisation of the radiation caused by reflection by the target 10.
  • one form of the present invention uses a single analogue PIN sensor, such as one found in the prior art cited above, together with a single set of polarising optics.
  • a single analogue PIN sensor such as one found in the prior art cited above
  • polarising optics such as one found in the prior art cited above
  • the seeker 3 should 'see' the odd reflections (first, third, fifth etc) but be blind to the even ones (second, fourth, sixth etc).
  • polarisation mitigates the problem of secondary reflection. If a strong polarisation signature is expected but its type is not known a priori, e.g., circular or linear, and if linear the orientation of the polarisation, some adaptation may be possible in the optics e.g. rotating the plane of polarisation of the polariser for linear polarisation.
  • the integration characteristic sensing time for position detection may be improved and this in turn may improve the signal to clutter ratio. Additionally, complexity, cost, size and weight; may be reduced.
  • the invention relies on ensuring that the reflection from the target 10 has a strong known polarisation.
  • This may be either linear or circular, and may be natural e.g. legacy laser designators have a linear polarisation and, provided this is oriented in a known direction e.g. vertically, the reflected polarisation may be known.
  • the present invention includes the potential to control this actively i.e. by putting elements 4, 6 on the designator 1 , or passively i.e. by taking advantage of the polarised nature of the light emitting from the laser.
  • the receiving elements 14, 16 can be matched to the reflected polarisation radiation 12 and allow for the use of the single element rather than the switchable sets envisaged in prior art.
  • linear polarisation is used rotating it to a particular orientation may be beneficial e.g. sky light is linearly polarised tangential to a circle centred on the sun - orienting the polarisation to be normal to this may provide benefits in suppressing sky light reflection. This can be achieved by placing simple optical elements in front of the designation laser.
  • Circular polarisation is particularly attractive as it is rare that it occurs in nature. It is also beneficial as it will not constrain the rotational orientation of the seeker 3 or the designator 1 with respect to each other.
  • linear polarisation has a disadvantage in the polariser 16 in the seeker 3 must be aligned with the plane of polarisation of the detected light 12, which may vary.
  • circular polarisation By controlling the state of polarisation of the pulse at the seeker 3, single fixed optical polarising element 16 in front of the detector 18, again reducing cost, size and weight, and providing the improved signal to clutter ratio from the first pulse.
  • the invention includes simple optical elements 14, 16 in front of the detector 18 within the seeker 3 to match the polarisation of the reflected laser pulse 12.
  • simple optical elements 14, 16 in front of the detector 18 within the seeker 3 to match the polarisation of the reflected laser pulse 12.
  • a quarter waveplate 14 and a polariser 16 may be used.
  • the background illumination will have a low degree of polarisation, these will allow the seeker 3 to capture all of the pulse energy 12, (less a small amount due to insertion loss of the components), while rejecting half of the background, (less a small amount due to insertion loss of the components).
  • a quarter waveplate 14 and a polariser 16 may be used.
  • the optical components may vary depending on the polarisation to be detected.
  • linear polarisers such as polaroids may be used for linear polarisation.
  • the invention need not be limited to the embodiment having a single PIN detector. Any suitable detector such as a quadrant detector may be used.
  • Figure 1 is a schematic representation of a Semi Active Laser application for the present invention where the transmitting portion of the system is remote from the receiving detector.
  • the transmitting and receiving portions of the system it will be appreciated that it is possible for the transmitting and receiving portions of the system to be co-located at a single position or on a single platform. This would be particularly advantageous in an imaging system such as a Burst Illumination Lidar (BIL) system.
  • BIL Burst Illumination Lidar

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

L'invention concerne un système de recherche, un rayonnement émis par un laser (2) étant incident sur une cible (10). Le rayonnement émis est polarisé par une série de composants optiques (4, 6) et est réfléchi par la cible (10). La réflexion du rayonnement change la nature de la polarisation du rayonnement et le système de recherche est accordé pour détecter uniquement un rayonnement d'une polarisation donnée. Les composants optiques de la partie émettrice (1) du système et les composants optiques de la partie système de recherche (3) du système sont mis en correspondance de sorte que le rayonnement d'autres polarisations ne soit pas incident sur le détecteur (18). Cette mise en correspondance des composants optiques simples améliore le rapport signal sur bruit et donc la plage jusqu'à la cible (10) peut être augmentée.
PCT/EP2014/058382 2013-04-26 2014-04-24 Systèmes de recherche WO2014174035A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB201307628A GB2515000A (en) 2013-04-26 2013-04-26 Seeker system
GB1307628.6 2013-04-26

Publications (1)

Publication Number Publication Date
WO2014174035A1 true WO2014174035A1 (fr) 2014-10-30

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2014/058382 WO2014174035A1 (fr) 2013-04-26 2014-04-24 Systèmes de recherche

Country Status (2)

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GB (1) GB2515000A (fr)
WO (1) WO2014174035A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2652659C1 (ru) * 2017-04-25 2018-04-28 федеральное государственное автономное образовательное учреждение высшего образования "Санкт-Петербургский национальный исследовательский университет информационных технологий, механики и оптики" (Университет ИТМО) Способ обнаружения наблюдателя
CN110260975A (zh) * 2019-05-07 2019-09-20 中国人民解放军国防科技大学 一种主动偏振光逆反射体探测方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102016115277A1 (de) 2016-08-17 2018-02-22 Julian Berlow Optische Vorrichtung

Citations (4)

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US4333008A (en) * 1975-04-21 1982-06-01 Sanders Associates, Inc. Polarization coded doublet laser detection system
FR2592721A1 (fr) * 1986-01-08 1987-07-10 Signaux Entr Electriques Procede et dispositif de telemetrie ecartometrie laser sur cibles cooperatives
GB2301967A (en) * 1992-04-10 1996-12-18 Gec Marconi Avionics Holdings An optical remote object sensing apparatus
US20120170116A1 (en) * 2011-01-04 2012-07-05 Gurton Kristan P Enhanced image contrast between diffuse and specularly reflecting objects using active polarimetric imaging

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DE3114279C2 (de) * 1981-04-09 1983-06-16 Messerschmitt-Bölkow-Blohm GmbH, 8000 München Zielsuchkopf für Flugkörper
JP5209288B2 (ja) * 2007-12-13 2013-06-12 株式会社Ｉｈｉエアロスペース 目標追尾誘導装置及び方法
US7745777B2 (en) * 2008-03-11 2010-06-29 Northrop Grumman Space And Mission Systems Corp. Active imaging system that recaptures and processes a reflected illumination beam
US8598501B2 (en) * 2011-06-30 2013-12-03 Northrop Grumman Guidance an Electronics Co., Inc. GPS independent guidance sensor system for gun-launched projectiles

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4333008A (en) * 1975-04-21 1982-06-01 Sanders Associates, Inc. Polarization coded doublet laser detection system
FR2592721A1 (fr) * 1986-01-08 1987-07-10 Signaux Entr Electriques Procede et dispositif de telemetrie ecartometrie laser sur cibles cooperatives
GB2301967A (en) * 1992-04-10 1996-12-18 Gec Marconi Avionics Holdings An optical remote object sensing apparatus
US20120170116A1 (en) * 2011-01-04 2012-07-05 Gurton Kristan P Enhanced image contrast between diffuse and specularly reflecting objects using active polarimetric imaging

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2652659C1 (ru) * 2017-04-25 2018-04-28 федеральное государственное автономное образовательное учреждение высшего образования "Санкт-Петербургский национальный исследовательский университет информационных технологий, механики и оптики" (Университет ИТМО) Способ обнаружения наблюдателя
CN110260975A (zh) * 2019-05-07 2019-09-20 中国人民解放军国防科技大学 一种主动偏振光逆反射体探测方法

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Publication number Publication date
GB201307628D0 (en) 2013-06-12
GB2515000A (en) 2014-12-17

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