GB2123643A - Cable detection from aircraft - Google Patents

Cable detection from aircraft Download PDF

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Publication number
GB2123643A
GB2123643A GB08319066A GB8319066A GB2123643A GB 2123643 A GB2123643 A GB 2123643A GB 08319066 A GB08319066 A GB 08319066A GB 8319066 A GB8319066 A GB 8319066A GB 2123643 A GB2123643 A GB 2123643A
Authority
GB
United Kingdom
Prior art keywords
cable
laser
aircraft
section
detector assembly
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Withdrawn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
GB08319066A
Other versions
GB8319066D0 (en
Inventor
John Frank Tippen
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.)
UK Secretary of State for Defence
Original Assignee
UK Secretary of State for Defence
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 UK Secretary of State for Defence filed Critical UK Secretary of State for Defence
Priority to GB08319066A priority Critical patent/GB2123643A/en
Publication of GB8319066D0 publication Critical patent/GB8319066D0/en
Publication of GB2123643A publication Critical patent/GB2123643A/en
Withdrawn legal-status Critical Current

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
    • 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
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4811—Constructional features, e.g. arrangements of optical elements common to transmitter and receiver
    • G01S7/4813—Housing arrangements
    • 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
    • G01S17/04—Systems determining the presence 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
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
    • G01S17/933—Lidar systems specially adapted for specific applications for anti-collision purposes of aircraft or spacecraft

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Electromagnetism (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Optical Radar Systems And Details Thereof (AREA)
  • Lasers (AREA)

Abstract

A cable detector assembly for a helicopter or other aircraft for providing a warning of the presence of cables which might constitute a low flying hazard, includes a laser (7), optical means, such as for example a lens system (10) which shapes the the output beam of the laser into an oval or other elongate section, a detector (13) for detecting reflected laser light, and mounting means (21) for mounting the optical means in an aircraft such that the major cross sectional axis of the output beam is generally horizontal. The flattening of the beam shape is intended to increase the proportion of the laser beam that illuminates the cable. <IMAGE>

Description

SPECIFICATION Improvements in or relating to cable detection from an aircraft This invention relates to cable detection from aircraft, including helicopters, to provide a warning to the aircraft pilot of the presence of cables which might constitute a low flying hazard.
It has been proposed to detect cables which are strung between pylons by using an airborne laser directed forwardly along the fore and aft axis of a helicopter and detecting reflected laser light from the cables.
The present invention provides an improved means of cable detection.
According to the present invention a cable detector assembly for an aircraft comprises means for generating a laser beam, optical means in the path of the beam for beam shaping to provide an output beam having an elongate section, a detector for detecting reflected laser light, and mounting means for mounting the optical means in an aircraft such that the major cross sectional axis of the output beam is generally horizontal.
The mounting means may include stabilising means for maintaining the major cross sectional axis of the output beam generally horizontal during aircraft manoeuvres.
The assembly may include means for scanning the output beam in a vertical plane.
The optical means may comprise a bundle of optical fibres arranged to provide beam shaping, or may comprise a lens or lenses.
A cable detector assembly in accordance with the invention.
Figure 1 is a diagram showing a section of laser beam produced by a known laser.
Figure 2 is a diagram showing a section of a laser beam produced by a cable detector in accordance with the invention.
Figure 3 is a side view of an optical fibre bundle used for beam shaping in accordance with the present invention.
Figure 4 is a section of an input end of the bundle of Figure 3.
Figure 5 is a section of an output end of the bundle of Figure 3.
Figure 6 is a cable detector assembly in accordance with the invention.
Referring to Figure 1, a laser beam 2 from a laser (not shown) has a circular cross section and is incident on a horizontal cable 1. The area of the cable 1 which acts as reflecting surface for the incident laser light is shown as a shaded portion 3. The ratio of the reflecting surface area to the cross sectional area of the beam 2 is small and a correspondingly small part of the incident energy is reflected back towards the laser.
Figure 2 shows an oval section laser beam 5 produced by the assembly of Figure 3 and incident on a cable 4. The area of the cable which acts as a reflecting surface is shown as the shaded portion 6. The ratio of the reflecting surface area to the cross sectional area of the beam 5 is much higher than that in Figure 1 and the proportion of incident energy which is reflected is correspondingly higher.
Figure 6 shows a cable detector assembly 1 5 and a remote cable 14, shown in cross section. A continuous wave carbon dioxide laser 7 housed in a container 27 emits a laser beam 8 which is directed by a reflector 9 to a lens system 10 which shapes the beam into an oval section output beam 11 which has its major axis parallel to the cable 14. Laser light is reflected from the cable as a beam 12 which is directed to a laser detector 1 3 by the reflector 9. The output beam 11 and the reflected beam 12 pass through a window 23 in the container 27.
The container 27 is mounted on a bearing 16 and pedestal 28 and linked to an eccentric drive mechanism 20 driven by an electric motor 19 on a platform 1 7. The platform 17 is carried on a gyro stabiliser 21 mounted on a part of an aircraft 22.
In operation the laser 1 5 is run continuously and the container 27 which houses the laser is rocked about the bearing 1 6 by the eccentric drive mechanism 20 so that the output beam 11 scans in a vertical plane across the cable 14 and is reflected as the beam 12. The laser detector 1 3 will detect the reflected beam 1 2 periodically at the scanning frequency.
The platform 1 7 is gyro stabilised so that it remains horizontal during aircraft roll.
Figure 3 shows an alternative means of beam shaping to the lens system 10 of Figure 6, and comprises an optical fibre bundle 26 which transforms an incident, circular section laser beam 24 into an oval section beam 25. Figures 4 and 5 show cross-sections on lines A-A and B B, respectively, of the fibre bundle of Figure 3.
Claims
1. A cable detector assembly for an aircraft comprising means for generating a laser beam, optical means in the path of the beam for beam shaping to provide an output beam having an elongate section, a detector for detecting reflected laser light, and mounting means for mounting the optical means in an aircraft such that the major cross sectional axis of the output beam is generally horizontal.
2. A cable detector assembly as claimed in claim 1 wherein the mounting means includes stabilising means for maintaining the major cross sectional axis of the output beam generally horizontal during flight.
3. A cable detector assembly as claimed in claim 1 or claim 2 further including means for scanning the output beam in a vertical plane.
4. A cable detector assembly as claimed in any of the previous claims wherein the optical means comprises a bundle of optical fibres arranged to provide beam shaping.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to cable detection from an aircraft This invention relates to cable detection from aircraft, including helicopters, to provide a warning to the aircraft pilot of the presence of cables which might constitute a low flying hazard. It has been proposed to detect cables which are strung between pylons by using an airborne laser directed forwardly along the fore and aft axis of a helicopter and detecting reflected laser light from the cables. The present invention provides an improved means of cable detection. According to the present invention a cable detector assembly for an aircraft comprises means for generating a laser beam, optical means in the path of the beam for beam shaping to provide an output beam having an elongate section, a detector for detecting reflected laser light, and mounting means for mounting the optical means in an aircraft such that the major cross sectional axis of the output beam is generally horizontal. The mounting means may include stabilising means for maintaining the major cross sectional axis of the output beam generally horizontal during aircraft manoeuvres. The assembly may include means for scanning the output beam in a vertical plane. The optical means may comprise a bundle of optical fibres arranged to provide beam shaping, or may comprise a lens or lenses. A cable detector assembly in accordance with the invention. Figure 1 is a diagram showing a section of laser beam produced by a known laser. Figure 2 is a diagram showing a section of a laser beam produced by a cable detector in accordance with the invention. Figure 3 is a side view of an optical fibre bundle used for beam shaping in accordance with the present invention. Figure 4 is a section of an input end of the bundle of Figure 3. Figure 5 is a section of an output end of the bundle of Figure 3. Figure 6 is a cable detector assembly in accordance with the invention. Referring to Figure 1, a laser beam 2 from a laser (not shown) has a circular cross section and is incident on a horizontal cable 1. The area of the cable 1 which acts as reflecting surface for the incident laser light is shown as a shaded portion 3. The ratio of the reflecting surface area to the cross sectional area of the beam 2 is small and a correspondingly small part of the incident energy is reflected back towards the laser. Figure 2 shows an oval section laser beam 5 produced by the assembly of Figure 3 and incident on a cable 4. The area of the cable which acts as a reflecting surface is shown as the shaded portion 6. The ratio of the reflecting surface area to the cross sectional area of the beam 5 is much higher than that in Figure 1 and the proportion of incident energy which is reflected is correspondingly higher. Figure 6 shows a cable detector assembly 1 5 and a remote cable 14, shown in cross section. A continuous wave carbon dioxide laser 7 housed in a container 27 emits a laser beam 8 which is directed by a reflector 9 to a lens system 10 which shapes the beam into an oval section output beam 11 which has its major axis parallel to the cable 14. Laser light is reflected from the cable as a beam 12 which is directed to a laser detector 1 3 by the reflector 9. The output beam 11 and the reflected beam 12 pass through a window 23 in the container 27. The container 27 is mounted on a bearing 16 and pedestal 28 and linked to an eccentric drive mechanism 20 driven by an electric motor 19 on a platform 1 7. The platform 17 is carried on a gyro stabiliser 21 mounted on a part of an aircraft 22. In operation the laser 1 5 is run continuously and the container 27 which houses the laser is rocked about the bearing 1 6 by the eccentric drive mechanism 20 so that the output beam 11 scans in a vertical plane across the cable 14 and is reflected as the beam 12. The laser detector 1 3 will detect the reflected beam 1 2 periodically at the scanning frequency. The platform 1 7 is gyro stabilised so that it remains horizontal during aircraft roll. Figure 3 shows an alternative means of beam shaping to the lens system 10 of Figure 6, and comprises an optical fibre bundle 26 which transforms an incident, circular section laser beam 24 into an oval section beam 25. Figures 4 and 5 show cross-sections on lines A-A and B B, respectively, of the fibre bundle of Figure 3. Claims
1. A cable detector assembly for an aircraft comprising means for generating a laser beam, optical means in the path of the beam for beam shaping to provide an output beam having an elongate section, a detector for detecting reflected laser light, and mounting means for mounting the optical means in an aircraft such that the major cross sectional axis of the output beam is generally horizontal.
2. A cable detector assembly as claimed in claim 1 wherein the mounting means includes stabilising means for maintaining the major cross sectional axis of the output beam generally horizontal during flight.
3. A cable detector assembly as claimed in claim 1 or claim 2 further including means for scanning the output beam in a vertical plane.
4. A cable detector assembly as claimed in any of the previous claims wherein the optical means comprises a bundle of optical fibres arranged to provide beam shaping.
5. A cable detector assembly as claimed in any of claim 1, 2 or 3 wherein the optical means comprises a lens or set of lenses.
6. A cable detector assembly substantially as described herein with reference to the drawings.
GB08319066A 1982-07-19 1983-07-14 Cable detection from aircraft Withdrawn GB2123643A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08319066A GB2123643A (en) 1982-07-19 1983-07-14 Cable detection from aircraft

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8220846 1982-07-19
GB08319066A GB2123643A (en) 1982-07-19 1983-07-14 Cable detection from aircraft

Publications (2)

Publication Number Publication Date
GB8319066D0 GB8319066D0 (en) 1983-08-17
GB2123643A true GB2123643A (en) 1984-02-01

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB08319066A Withdrawn GB2123643A (en) 1982-07-19 1983-07-14 Cable detection from aircraft

Country Status (1)

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GB (1) GB2123643A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2200811A (en) * 1987-02-09 1988-08-10 Atomic Energy Authority Uk Monitoring of displacement
WO1992004643A1 (en) * 1990-09-07 1992-03-19 Alenia Aeritalia & Selenia S.P.A. Detector of suspended cables for avionic applications
WO2005043189A1 (en) * 2003-10-31 2005-05-12 Ricardo Palacios De La Olla High-voltage line warning/detector assembly

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1288115A (en) * 1969-07-07 1972-09-06
GB1494561A (en) * 1974-01-19 1977-12-07 Eltro Gmbh Method for detecting and indicating obstacles to a lowflying air-borne body

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1288115A (en) * 1969-07-07 1972-09-06
GB1494561A (en) * 1974-01-19 1977-12-07 Eltro Gmbh Method for detecting and indicating obstacles to a lowflying air-borne body

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2200811A (en) * 1987-02-09 1988-08-10 Atomic Energy Authority Uk Monitoring of displacement
WO1992004643A1 (en) * 1990-09-07 1992-03-19 Alenia Aeritalia & Selenia S.P.A. Detector of suspended cables for avionic applications
US5296909A (en) * 1990-09-07 1994-03-22 Alenia Aeritalia & Selenia S.P.A. Detector of suspended cables for avionic applications
WO2005043189A1 (en) * 2003-10-31 2005-05-12 Ricardo Palacios De La Olla High-voltage line warning/detector assembly
ES2241467A1 (en) * 2003-10-31 2005-10-16 Ricardo Palacios De La Olla High-voltage line warning/detector assembly

Also Published As

Publication number Publication date
GB8319066D0 (en) 1983-08-17

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)