Patent Publication Number: US-7219612-B1

Title: Naval ship decoy

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims rights under 35 U.S.C.§119(e) from U.S. Application Ser. No. 60/580,456, filed Jun. 17, 2004. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to decoys and more particularly to decoys for use in naval warfare. 
   2. Brief Description of Prior Developments 
   For many years, submarines and other submersible vessels have enjoyed the advantage of being relatively difficult to detect. In recent years, the navies of the world have begun to explore the possibility of detecting, tracking and targeting submarines and other submersibles as well as other vessels by detecting and measuring underwater electrical fields which may be produced by such vessels. 
   A need, therefore, exists for a means to reduce or delay the ability to detect, track, and target vessels by detecting and measuring characteristic underwater electrical fields produced by such vessels. 
   SUMMARY OF INVENTION 
   The present invention is a method for defeating or reducing the effectiveness of efforts to detect, track or target naval vessels by detecting and measuring characteristic underwater electrical fields produced by such vessels. This method includes the steps of ascertaining a wave form which mimics the electrical field produced by a particular type of naval vessel. A decoy is then caused to produce, amplify and transmit a wave form which mimics the electrical field by the particular type of naval vessel sought to be simulated. The decoy, therefore, will tend to be misidentified as the particular type of vessel sought to be simulated. 
   This invention also encompasses a decoy for defeating or reducing the effectiveness of efforts to detect, track or target a particular type of naval vessel by detecting or measuring the characteristic underwater electrical field produced by such a vessel. This apparatus includes a wave form generator for producing a wave form which mimics the characteristic underwater electrical field produced by said particular type of naval vessel sought to be simulated. This apparatus also includes means for amplifying and transmitting this waveform mimicking the characteristic in the electric field produced by the particular type of naval vessel sought to be simulated. The decoy will thus tend to be misidentified as said particular type of naval vessel. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is further described with reference to the accompanying drawings wherein: 
       FIG. 1  is a schematic block diagram showing a preferred embodiment of the decoy of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , a real-time or non real-time programming link to enable the commencing of an electrical field produced by a particular type of naval vessel is provided to a wave form generator  10 . This wave form generator  10  transmits a suitable wave form to power amplifier  12 . Power source  14  supplies power to both the wave form generator  10  and the power amplifier  12 . A signal which mimics the characteristic electrical field of the particular type of vessel sought to be mimicked is transmitted from a dual, quad or hex differential antenna  16 . It may be desirable to provide the decoy with the capability to be mobile, in which case an optional navigation and propulsion unit  18  which is powered by power source  14  may also be provided. 
   Those skilled in the art will appreciate that as a ship&#39;s propeller rotates it creates an alternating electrical field. It is believed that this alternating electric field establishes a spectrally pure signature which varies very little with respect to time. A relatively large signal to noise ratio may, therefore, be used. Furthermore changing flux lines actually rotate with the propeller so that 2, 4, or 6 antennas, for example, may be used. 
   Those skilled in the art will also understand that the decoy described herein may be used to mimic the characteristic electrical fields which maybe produced by particular types of naval vessels. Such decoys may be produced at a relatively low cost. While there may be practical limits to the numbers of such decoys which might be deployed by a single surface vessel or aircraft, these decoys could be deployed in substantial numbers. 
   It will therefore be appreciate that the decoy and method described herein provides a reliable and cost effective way of reducing the effectiveness or defeating efforts to detect, track and target friendly naval vessels by means of electrical fields. 
   While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.