GB2233470A - Passive infra-red beacon having a reflector array - Google Patents
Passive infra-red beacon having a reflector array Download PDFInfo
- Publication number
- GB2233470A GB2233470A GB8914513A GB8914513A GB2233470A GB 2233470 A GB2233470 A GB 2233470A GB 8914513 A GB8914513 A GB 8914513A GB 8914513 A GB8914513 A GB 8914513A GB 2233470 A GB2233470 A GB 2233470A
- Authority
- GB
- United Kingdom
- Prior art keywords
- infra
- red
- beacon
- reflectors
- ground
- 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.)
- Granted
Links
- 230000005855 radiation Effects 0.000 claims description 11
- 229910000831 Steel Inorganic materials 0.000 abstract description 6
- 239000010959 steel Substances 0.000 abstract description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052782 aluminium Inorganic materials 0.000 abstract description 3
- 239000004411 aluminium Substances 0.000 abstract description 3
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/12—Reflex reflectors
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Aerials With Secondary Devices (AREA)
Abstract
An infra-red beacon is formed by a plurality of infra-red reflectors 2 arranged so that when the beacon is observed some of the reflectors 2B show an image of the ground and some 2A show an image of the sky. The reflectors may be aluminium sheets 2, hinged on a steel rod 3 and linked by steel rods 3A, 3B. Wire 4 holds the reflectors in a desired position. <IMAGE>
Description
Infra-Red Beacon
This invention relates to beacons visible to infrared sensors.
There are many types of such beacons known, however all of them depend on generating and broadcasting infrared radiation. The need for a power supply makes such beacons expensive, and also produces a demand for regular maintainance if reliability is to be maintained.
This invention is intended to provide a passive infra-red beacon.
This invention provides an infra-red beacon comprising a plurality of infra-red reflectors arranged in an array, some of the reflectors being arranged to reflect infra-red radiation from the sky in a substantially horizontal direction, and some of the reflectors being arranged to reflect infra-red radiation from the ground in a substantially horizontal direction.
An infra-red beacon embodying the invention will now be described with reference to the accompanying figures in which;
Figure 1 shows an infra-red beacon embodying the invention in its operating position, and
Figure 2 shows the same infra-red beacon in a storring or travelling position.
Referring to Figures 1 and 2 an infra-red beacon 1 is formed by a plurality of rectangular aluminium sheets 2.
The sheets 2 are all hinged side by side on a steel rod 3. Alternate sheets 2A are linked at their lower ends by a steel rod 3A, while the other alternative sheets 2B are linked at their lower ends by a steel rod 3B.
The steel rods 3A and 3B are linked by a wire 4.
The length of the wire 4 is chosen so that when the two sets of alternate sheets 2A and 2B are opened out and the beacon 1 is placed on level ground the sheets 2 will be at approximately 45 degrees to the ground when the wire 4 is taut.
When not in use the beacon 1 can be folded flat with all of the sheets 2 co-planar, as shown in Figure 2, making transportation simple.
When in use the beacon 1 is placed on the ground at the point to be marked and is placed with the two sets of alternate sheets 2A and 2B opened out to the limit allowed by the wire 4.
The aluminium sheets 2A and 2B act as infra-red mirrors. When the beacon 1 is within the field of view of an infra-red sensor 5 the sheets 2A reflecting infra-red radiation from the sky 6 to the infra-red sensor S and the sheets 2B reflecting infra-red radiation from the ground 7 to the infra-red sensor 5. As a result the infra-red sensor 5 sees alternate strips of sky 6 and ground 7.
Due to the symmetry of the beacon, an infra-red sensor placed on the opposite side of the beacon would receive infra-red radiation from the sky 6 reflected from the sheet 2B and infra-red radiation from the ground 7 reflected from the sheet 2A.
The sky 6 and the ground 7 will be at different temperatures, and so the alternate strips of sky 6 and ground 7 -seen by the infra-red sensor 5 will appear as strips of contrasting temperatures, making the beacon 1 stand out in the infra-red view of the area.
Claims (6)
1. An infra-red beacon comprising a plurality of infrared reflectors arranged in an array, some of the reflectors being arranged to reflect infra-red radiation from the sky in a first direction, and some of the reflectors being arranged to reflect infra-red radiation from the ground in substantially the first direction.
2. An infra-red beacon as claimed in claim 1 in which the first direction is a range of directions including the horizontal.
3. An infra-red beacon as claimed in claim 1 in which the infra-red reflectors are formed by the surfaces of planar reflective elements.
4. An infra-red beacon comprising a plurality of infrared reflectors arranged in an array, each reflector being arranged to reflect infra-red radiation from the sky in a first direction and to reflect infra-red radiation from the ground in a second direction opposite the first.
5. An infra red beacon as claimed in claim 3 in which the planar reflective elements are arranged side by side at approximately 45 degrees to the horizontal with adjacent elements being perpendicular to one another.
6. An infra-red beacon substantially as described with reference to and substantially as shown in the accompanying figures.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8914513A GB2233470B (en) | 1989-06-23 | 1989-06-23 | Infra-red beacon |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8914513A GB2233470B (en) | 1989-06-23 | 1989-06-23 | Infra-red beacon |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8914513D0 GB8914513D0 (en) | 1989-11-08 |
| GB2233470A true GB2233470A (en) | 1991-01-09 |
| GB2233470B GB2233470B (en) | 1993-03-24 |
Family
ID=10658986
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8914513A Expired - Fee Related GB2233470B (en) | 1989-06-23 | 1989-06-23 | Infra-red beacon |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2233470B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994006046A1 (en) * | 1992-09-04 | 1994-03-17 | The Australian National University | Optical reflector arrays and apparatus using such arrays |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0014825A2 (en) * | 1979-02-07 | 1980-09-03 | Heimann GmbH | Optical apparatus for passive infrared movement detector |
| FR2551586A1 (en) * | 1983-09-05 | 1985-03-08 | Plastimo Sa | Radar reflector. |
| GB2145813A (en) * | 1983-08-26 | 1985-04-03 | Matsushita Electric Works Ltd | Infrared intrusion detector |
-
1989
- 1989-06-23 GB GB8914513A patent/GB2233470B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0014825A2 (en) * | 1979-02-07 | 1980-09-03 | Heimann GmbH | Optical apparatus for passive infrared movement detector |
| GB2145813A (en) * | 1983-08-26 | 1985-04-03 | Matsushita Electric Works Ltd | Infrared intrusion detector |
| FR2551586A1 (en) * | 1983-09-05 | 1985-03-08 | Plastimo Sa | Radar reflector. |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994006046A1 (en) * | 1992-09-04 | 1994-03-17 | The Australian National University | Optical reflector arrays and apparatus using such arrays |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8914513D0 (en) | 1989-11-08 |
| GB2233470B (en) | 1993-03-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930624 |