Patent Publication Number: US-9423227-B2

Title: Method for optically transmitting data into and from a casing of a projectile

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation of U.S. application Ser. No. 12/426,933 filed on Apr. 20, 2009, now U.S. Pat. No. 8,110,784, which is a Continuation-In-Part Application of U.S. application Ser. No. 12/206,704 filed on Sep. 8, 2008, now U.S. Pat. No. 8,916,809, which is a Continuation-In-Part Application of U.S. application Ser. No. 11/080,260 filed on Mar. 15, 2005, now abandoned, which is a Continuation-In-Part of U.S. application Ser. No. 10/638,996 filed on Aug. 12, 2003, now U.S. Pat. No. 6,892,644, the entire contents of each of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to projectiles, and more particularly, to projectiles having a window on a portion of the casing of the projectile for transmitting data and/or power through said window. For purposes of this disclosure, a projectile is any flying object, such as munitions, rockets, or aircraft. 
     2. Prior Art 
     Projectiles typically have a casing or shell in which electronic/electrical components are housed. Transmitting data and/or power to and/or from the projectile prior to firing thereof may be a cumbersome process, particularly where the projectile has had a relatively long shelf life. 
     SUMMARY OF THE INVENTION 
     Accordingly, a projectile is provided. The projectile comprising: a casing; first and second windows provided on the casing for at least one of transmitting a first optical signal into an interior of the casing and transmitting a second optical signal from the interior of the casing; a receiving element disposed on the interior of the casing and in optical communication with one or more of the first and second windows for at least one of converting the first optical signal into electrical energy and storing data provided in the first optical signal; and a transmitting element disposed on the interior of the casing and in optical communication with one or more of the first and second windows for transmitting data provided in the second optical signal to outside the casing. 
     The first and second windows can be provided in a nose portion of the projectile. 
     At least one of the first and second optical signals can be a laser. 
     The receiving element can be a thermophotovoltaic cell. 
     The projectile can further comprise one or more electronic components disposed within the casing and operatively connected to the receiving element, wherein the receiving element provides the electrical energy to the one or more electronic components. 
     The projectile can further comprise an energy storage medium disposed within the casing and operatively connected to the receiving element, wherein the receiving element provides the electrical energy to the energy storage medium. The storage medium can be one of a capacitor and battery. 
     Also provided is a method for transmitting power and data into and from a casing of a projectile. The method comprising: transmitting a first optical signal for conversion into electrical energy into the casing of the projectile through a first optical window disposed on the casing; and transmitting a second optical signal containing data from the casing through a second optical window disposed in the casing. 
     The method can further comprise transmitting a third optical signal containing data into the casing for storage in the casing through the second optical window. 
     The method can further comprise transmitting a third optical signal containing data into the casing for storage in the casing through the first optical window. 
     The method can further comprise transmitting a fourth optical signal for conversion into electrical energy from the casing through the second optical window. 
     Still further provided is a method for transmitting power and data into and from a casing of a projectile. The method comprising: transmitting a first optical signal containing data into the casing of the projectile through an optical window disposed on the casing; and transmitting a second optical signal containing data from the casing through the optical window. 
     The method can further comprise transmitting a third optical signal for conversion into electrical energy into the casing of the projectile through the optical window. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: 
         FIG. 1  illustrates a partial sectional view of a nose portion of a projectile according to an embodiment of the present invention. 
         FIG. 2  illustrates a partial sectional view of a nose of a projectile according to another embodiment of the present invention. 
         FIG. 3  illustrates a schematic electrical diagram of an infrared (IR) transceiver for use with the projectile of  FIG. 2 . 
         FIG. 4  illustrates a projectile according to another embodiment of the present invention. 
         FIG. 5  illustrates a projectile according to another embodiment of the present invention. 
         FIG. 6  illustrates a projectile according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Although the invention is particularly suited to infra-red or optical signal communication between electronic components, such is discussed by way of example only. Those skilled in the art will appreciate that other communication means can also be utilized, such as ultrasound. 
     Referring now to  FIG. 1 , there is shown a partial sectional view of a nose section of a projectile  100 . The projectile has a shell  102  that defines an interior  104 . The shell preferably has a metal or composite outer portion  106  and an inner waveguide portion  108 . The inner waveguide portion  108  is preferably optical glass having appropriate cladding as is known in the art, however, other at least partially transparent materials such as plastics capable of transmitting a signal can also be utilized, such as clear epoxies. The waveguide portion  108  can be disposed on the entire inner surface of the outer portion  106  or only a portion thereof, such as a strip. Alternatively, the waveguide portion  108  can make up the entire shell  102  (no outer portion  106  is used). Still further the waveguide portion  108  can be disposed in strips which can be formed on an inner surface of the casing  102  or in channels (not shown) formed on the inner surface of the casing  102 , such as that disclosed in co-pending U.S. application Ser. No. 10/639,001, filed on the same day herewith and entitled Device Having A Casing and/or an Interior Acting As A Communication Bus Between Electronic Components, the entire contents of which is incorporated herein by its reference. For purposes of this disclosure, “casing”includes not only the shell of the projectile but the internal space therein. 
     At least one transmitter  110  is arranged on the waveguide portion  108  or proximate thereto such that an optical signal can be transmitted to the waveguide portion  108 . The transmitter  110  can be integral with a corresponding electronic component  112  or connected thereto. At another location on the waveguide portion  108  are located detectors  114  for detecting the optical signals in the waveguide portion  108 . Each detector  114  is either integral with or connected to another electronic/electrical component  116 . Thus, those skilled in the art will appreciate that any component can communicate with another component through the waveguide portion  108 , which acts as a communication bus. Of course, each of the components can have both a transmitter  110  and detector  114  such that a two-way communication can be achieved. Although not shown, multiplexers and demultiplexers can be used such that certain components can operate at selected frequencies and/or wavelengths and not interfere with other components on the bus. The components, such as the transmitter  110  and detector  114  can be fastened to the waveguide portion  108  in a number of ways, such as those also disclosed in co-pending U.S. application Ser. No. 10/639,001, filed on the same day herewith) entitled Device Having A Casing Acting As A Communication Bus Between Electronic Components, the entire contents of which has incorporated herein by its reference. 
     Those skilled in the art will also appreciate that the interior is not cluttered with components and internal wiring resulting in more components being able to occupy a given interior size or the projectile  100  being made smaller than a conventional projectile having the same number of internal components. Other advantages include:
         The optical transmission provides robust, interference free channels between physically disconnected components/systems;   The optical transmission is naturally resistant to very high g-loads and harsh environments;   For shorter distances between the transmitter and receiver encountered in projectiles, the system is inexpensive and an extremely low bit rate error (better than 10 −12 ) can be readily achieved; and   Eliminates the need for wires and related problems and space requirements.   Ease of assembly because two parts can be attached or even screwed together easily, which is very difficult with wires running from one part to the other.       

     Alternatively, ultrasound can be used to communicate between the internal components. In which case, the shell or a portion thereof needs to be able to carry an ultrasound signal between components. Such a shell, or portion thereof, may be constructed from a suitable metal. In the case of ultrasound, an ultrasonic generator is used to place signals on the “bus” (shell) and a corresponding ultrasonic detector detects the ultrasonic signals and relays them to an appropriate component. As discussed above with regard to the optical signal configuration, each component can have both an ultrasonic generator and detector such that two-way communication between components is possible and multiplexers and demultiplexers can be utilized such that certain components can operate at selected frequencies and/or wavelengths and not interfere with other components on the bus. 
     Referring now to  FIGS. 2 and 3 , another embodiment of a projectile is shown, the projectile being referred to generally by reference numeral  200 . Typically, electrical/electronic components of projectiles are encased in a potting material, such as an epoxy, to harden the components against noise and shock due to the high acceleration and/or impact experienced by the projectiles. In the embodiment of  FIGS. 2 and 3 , the potting material  202 , which can be a solid, such as an epoxy, a gel, or a liquid is disposed within a casing  201  of the projectile and is used as a communication bus between electrical/electronic components  204 . The communication can be wholly within the potting material  202  or may be partially within the potting material  202  and partially in free space. The communication through the potting material is carried out with a transmitter  206 , which outputs any wavelength radiation that can propagate through the potting material  202  and be detected by a receiver  208 . It is preferred that the potting material  202  be a solid, such as an epoxy to provide hardening of the projectile to shock and noise and it is further preferred that the radiation used as a communication medium is IR energy, preferably from a IR diode. In such an example, the epoxy need not be transparent or substantially transparent as long as it can carry an IR signal over a required distance, such as several hundred mm or less. An example of such an epoxy is Dolphon® CC-1024-A Low Viscosity Potting and Casting Epoxy Resin with RE-2000 Reactor mixed at a ratio of 10 parts resin to 1 part reactor, each of which is distributed by John C. Dolph Company. The same epoxy resin and reactor can be used for the waveguide portion  108  discussed above with regard to  FIG. 1 . 
     IR technology is well known in the art, particularly in the art of remote control of electronic consumer goods. The IR data association (IrDA®) has standards for communicating data via short-range infrared transmission. Transmission rates fall within three broad categories SIR, MIR and FIR, SIR (Serial Infrared) speeds cover transmission speeds normally supported by an RS-232 port. MIR (Medium Infrared) usually refers to speeds of 0.576 Mb/s to 1.152 Mb/s. FIR (Fast Infrared) denotes transmission speeds of about 4 Mb/s. The standard has been modified for faster transmission speeds up to 16 Mb/s (referred to as very fast Infrared VFIR). Although not preferred, visible light, for example from a laser diode, may also be used to transmit communication signals through the potting material  202 . 
     The transmitters  206  may be carried on printed circuit boards  210  which may also be encased in the potting material  202  or disposed freely throughout the potting material  202 . The printed circuit boards each  210  preferably carry their own power supply, such as a battery  212  to eliminate internal wiring. Alternatively, the batteries may be charged as discussed below through the casing  201  by directing energy into the casing  201  with a charging cap. Each of the electronic/electrical components  204  has a receiver  208  for communicating with the transmitters  206 . As discussed above with regard to the first embodiment, each of the electrical/electronic components  204  preferably have a receiver  208  and a transmitter  206  such that they can carry out a two-way communication. An example of such a transceiver module  300  is shown in the schematic diagram of  FIG. 3 .  FIG. 3  shows an (IrDA®) transceiver manufactured by Sharp Inc. (2P2W1001YP) which is relatively inexpensive and contains a high speed, high efficiency low power consumption light emitting diode (LD), a silicon PIN photodiode (PD) and a low power bipolar integrated circuit. The circuit contains an LED driver (TRX) and a receiver circuit (RCX) that delivers 4 Mb/s operation for distances of 1 meter. The LED emitter transmits at a nominal wavelength of 880 nm with a radiant intensity in the range of 100 to 500 mW.sr −1 , with a radiation angle of +/−15 degrees. The pin photodiode has an integrated amplifier (AMP) and comparator (CMP), which provide a fixed voltage output over a broad range of input optical power levels and data rates. The same or similar transceiver module  300  can also be used for the other embodiments described above with regard to  FIG. 1 . 
     The casing  102  can also be provided with a window portion  403 , as shown in  FIGS. 1 and 2 , which can be used to upload or input data or instructions into components of the projectile through the waveguide portion  108  or potting material  202 . In a preferred implementation, the window portion  403  is in optical communication with the waveguide portion  108  or potting material  202  and transmits any input signals to the appropriate components on the interior of the projectile. Although described in terms of a transparent window  403  and signal, the input signal can be any signal that propagates through the waveguide portion  108  or potting material  202 , such as an IR or ultrasound signal. Furthermore, the window  403  does not have to be a transparent window but merely a portion of the shell, which is capable of transmitting a signal from the exterior of the projectile to one or more components on the interior of the projectile. Although the window  403  is shown on the tip of the nose and on a lower side of the casing, those skilled in the art will appreciate that the window  403  may be located anywhere on the casing of the projectile. 
     The window  403  can also be utilized to partially power a capacitor, rechargeable battery, or electric power storage device in the interior of the projectile, particularly for the purpose of transmitting required data. Thus, a power storage device can be charged, at least partially, thru the window  403  to enable transfer of data. The charging signal transmitted through the window may be modulated to transmit data as well. 
     Referring now to  FIG. 4 , there is shown a projectile according to another embodiment of the present invention, in which similar reference numerals from  FIG. 2  denote similar features, the projectile of  FIG. 4  being referred to generally by reference numeral  300 .  FIG. 4  is similar to that of  FIG. 2  with the exception that the potting material does not have to completely encase a portion of the projectile&#39;s interior. The interior of the projectile includes portions of free space  410  (which may be filled with air or other gases or may be evacuated. Although all of the components  204 ,  208  are shown encased in the potting material  202 , they can also be provided in the free space  410  or partially in the free space  410 . Thus, the communication between components is not only through the potting material  202  but can also be done through the free space  410  inside the projectile. The embodiment of  FIG. 4  is particularly suitable for wireless sensor communication where the use of wire harnesses is highly cumbersome and expensive and subject to harsh environments. One can, for example send a signal from a sensor mounted on one part of a component to another without wires and without generating RF noise. 
     Referring now to  FIG. 5 , the window  403  may also be used for transmitting power optically from an external source  500  to a receiving element  502  inside the casing or a receiving element  504  on the casing via a bus  506 . The optical source  500  can be a laser (or other relatively high optical signal) and the receiving element  502 ,  504  can be a thermophotovoltaic (TPV) cell or the like that is tuned to efficiently transform the laser energy to electrical energy. The generated electrical energy may then be used directly by the electronic elements  508  within the projectile or stored in an electrical storage medium  507  such as a capacitor or rechargeable battery. The TPV and laser technology used for such a purpose is well known in the art. 
     Hereinafter, the optical source  500  used for optically transmitting power from an exterior source into the casing is generally referred to as a “charging laser source” and the receiving element  502 ,  504  is generally referred to as a “TPV cell”. 
     Alternatively, at least one additional window may be used for transmitting the aforementioned laser (or other relatively high energy optical) signal to the aforementioned receiving element. 
     The window through which the aforementioned laser may be integral to the structure of the casing and be at least partially transparent to the transmitted optical energy. 
     In addition, the same optical (such as laser) source used to transmit energy into the casing may be modulated to also transmit data into the interior of the housing. The modulated signal can be received by the same optical energy to electrical energy conversion device (preferably the aforementioned TPV cells) and then passed to the interior electronics  508  or a data storage medium  509  directly or through an existing communications bus. 
     Also provided is an intermediate means of aligning the charging laser source  500  with the casing window  403 . The intermediate means can be designed for rapid placement and removal, self-align the laser source with the provided casing window, does not require a person to hold it in place during charging, and provides a level of safety by ensuring that laser light is confined in the window area and that it would not transmit into free space to cause damage to equipment or injury to those around. 
     The intermediate means can be a “cap”  510  that is placed on the nose of the projectile. The window  403  is preferably on the tip of the projectile such as window  403  shown in  FIG. 5  to simplify the alignment task. When the window cannot be provided on the tip of the projectile, it is preferably still provided on the nose area so that a “cap” can still be used for the case of ease of placement and removal. The cap and nose contact surfaces can be provided with the alignment features that ensures proper alignment of the laser source with the window. Safety switches can also be provided such that if the cap is not properly positioned on the projectile nose, the laser power is not switched. In place of the electrical switch to power the laser beam and in addition to the electrical switch, mechanical means can also be provided to block the laser beam if the cap is not properly positioned on the nose of the projectile. 
     It is appreciated by those familiar with the art that the aforementioned intermediate means may be designed to similarly align the laser beam with one or more windows positioned almost anywhere on the surface of the casing. The intermediate means may then be clamped to the projectile or held by magnets of elastic bands or springs or even manually or using other means of temporary attachment known in the art. 
     In another embodiment, as shown in  FIG. 6 , first and second windows  403   a,    403   b  are provided on the projectile casing, each corresponding to an IR transceiver  500  (as discussed above). Similar to that shown in  FIG. 5 , a cap  510   a  may be provided on the nose of the projectile to align the transceivers  500  with their respective windows  403   a ,  403   b.    
     In the configuration of  FIG. 6 , power can be transmitted into the projectile through the first window as discussed above and data can be transmitted into and/or out of the casing through the second window  403   b  using the aforementioned IR transceivers  500 . Those skilled in the art will appreciate that other data/power transfers into and out from the casing through combinations of the first and second windows are possible. For example, data can be transmitted into the casing through the first window  403   a  and data transmitted out of the casing through a second window  403   b  by the IR transmitters  500 . In this configuration, the rate at which that data can be transmitted in and out of the casing can be significantly increased. Alternatively, power can be transmitted into the casing through one of the windows  403   a  and power can be transmitted from the casing through the other window  403   b . Of course, a single window ( 403 ,  403   a  or  403   b ) can be utilized to transmit power into the projectile and transmit data into and out from the projectile. 
     The transceivers  500  positioned outside of the casing can be connected directly to the communications bus  506  provided within the casing. In the case where data is transmitted from the casing through one of the windows  403 ,  403   a ,  403   b , a transmitting element can be disposed on the interior of the casing and in optical communication with one or more of the first and second windows, such as on the communication bus  506 , for transmitting data to outside the casing. Such a transmitter can be the receiving element  504  operating as a transmitter. 
     While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.