The invention relates to instrumentation structures with reduced electromagnetic radiation interference and interference characteristics.
Instrumentation structures may house sensors, such as optical devices. The optical devices may include, for example, infrared cameras, visible light cameras, laser range finders, etc. A instrumentation structure in accordance with the invention may used in a variety of settings including, for example, security systems, aircraft, watercraft, land vehicles, and stationary structures. The user may be, for example, a commercial, governmental, or private entity. The user may desire that the instrumentation structure be compatible with airborne or ground based radar or other electromagnetic radiation transmitters or receivers. Significant advantages are associated with enabling use of instrument systems which mitigate signal returns from the instrumentation structure or interference with radio frequency systems or system operators which receive undesirable radar returns off the instrumentation structure. For example, an instrumentation structure in accordance with the invention can reduce clutter or interference on an air traffic control system which could distract an air traffic controller in controlling aircraft viewed on a radar screen.
One aspect of the invention is an instrumentation structure having radar absorbent material (RAM) fixed thereon.
In the drawings, which are not necessarily to scale, like or corresponding parts are denoted by like or corresponding reference numerals.
Supporting structure for instrumentation structure 10 may include a base 12 and a tilt support structure. The tilt support structure may be stationary with respect to rotation of the ball 14 around the X-axis and may rotate with the ball 14 with respect to rotation around the Y-axis. The tilt support structure may include a throat 24 (
RAM may be fixed to exterior surfaces of the instrumentation structure 10. RAM 36 (
The RAM 50 (
RAM 70 (
RAM 80 (
Generally, the base 12 of instrumentation structure 10 is fixed to a mounting structure and the ball 14 and ears 20, 22 depend downwardly from the base 12. In this orientation, the base 12 may have a lesser radar cross-section than the remainder of the instrumentation structure 10. Thus, a thickness of the RAM 80, 88 fixed to base 12 may be less than a thickness of the RAM 36, 50, 70 fixed to ears 20, 22 and neck 18. In one embodiment, a thickness of the RAM 80, 88 is about 0.06 inches and a thickness of the RAM 36, 50, 70 is about 0.25 inches.
RAM may be supplied in generally rectangular sheets. The processes of shaping the RAM, forming slots in the RAM, forming notches in the RAM, forming openings in the RAM, etc., may be performed using a water jet cutter 120 (
Alternative embodiments may employ a radar absorbing coating for the ball 14 or other portions of the instrumentation structure which RAM layers are not applied to. Radar absorbing coatings can be composed of vinyl latex paint and carbon nanotube filaments. Finely ground Mylar and neoprene can be added during mixing of the coating. Adding ground carbon to the paint mixture can provide good coverage and results. Some types of electromagnetic energy can be influenced by increasing or reducing the thickness of the coating. Surface preparation is important to prevent delamination or peeling.
RAM sealant or caulking material may have the same carbon nanotube filaments in a vinyl latex caulk base. This thickened substance can contain a finely ground carbon, Mylar and neoprene mix added as a last step before application. Surface preparation again is very important to prevent delamination, pealing or flaking A two part applicator can be used to apply a multi-layered sealant or caulking material but care must be taken to apply the carbon, Mylar and neoprene mix side of the applicator to the metal surface.
References to caulk, caulking material or sealant should be understood to be examples of different methods, design features or structures for use in creating seal or edge terminations or transitions for the RAM materials to the surface which a RAM material is applied to. References to caulk, caulking materials or sealants should be understood to also include a termination or transition structure which is designed as a part of the RAM material edge areas. Thus, caulk, caulking material or structure references should be understood to be a reference to a transition or seam design feature of the RAM or structures which are formed into the RAM seams or edges or access holes or areas through the RAM itself.
While the invention has been described with reference to certain preferred embodiments, numerous changes, alterations, and modifications to the described embodiments are possible without departing from the spirit and scope of the invention as defined in the appended claims, and equivalents thereof.
The invention described herein was made in the performance of official duties by employees of the Department of the Navy and may be manufactured, used, licensed by or for the United States Government for any governmental purpose without payment of any royalties thereon.
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