Abstract:
A switch modulated low duty cycle low energy mass limited radio frequency beacon system for locating spent, un-exploded or experimental munitions projectiles in a large open-air test range or within a dirt backstop. The disclosed locator beacon is mounted on a rear portion of a projectile before launch and includes a protective (and antenna length-shortening) resin dielectric material housing in which locator beacon circuit components are contained and immunized against high G forces by a combination of component supporting, energy deflecting and energy absorbing protective arrangements.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is somewhat related to the U.S. patent application Ser. No. 09/832,453 now U.S. Pat. No. 6,380,906 and Ser. No. 09/832,454, but filed on Apr. 12, 2001. The contents of these somewhat related applications are hereby incorporated by reference herein. 
    
    
     RIGHTS OF THE GOVERNMENT 
     The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty. 
    
    
     BACKGROUND OF THE INVENTION 
     In the development of military munitions devices it is often desirable to retrieve a test projectile or spent munitions device from its location of finally coming to rest (whether above ground or buried). Such removal serves the purposes of projectile (or warhead) study and improvement and also serves a test range cleanup function of removing the hazard such devices present to persons and equipment and future testing conducted in the same area of a testing range if not removed. In the testing of military hardened target-compatible munitions it is often desirable for example to study the integrity of the penetrator portion of a projectile or study the experimental content of a projectile for target impact-incurred damage and for penetrator integrity-improvement purposes. Such information is desirable in the case of both air launched munitions devices such as bombs and cannon shells and for artillery launched munitions including howitzer projectiles and naval munitions. The thus-acquired information supports development of new materials and structures. 
     FIG. 4 in the drawings herein shows a test of this type involving a typical reinforced concrete target  401 . The FIG. 4 target  401  has been penetrated by a 4-inch diameter projectile in an event producing target concrete spalling and exposure of reinforcing bars. The usual recovery method for a projectile involved in the FIG. 4 scene is to visually sift through front-end loader bucket volumes of soil from the backstop mound  410  as the soil is slowly dumped from an elevated position. Since the projectile trajectory in the backstop soil is unstable and random, projectile turns are common, and one must frequently examine numerous front-end loader bucket volumes and empty the loader slowly, often searching for hours before locating the projectile. Furthermore, such visual searching may fail if the projectile is hidden by a concurrently falling quantity of soil or by other real world effects. 
     In FIG. 4 however there is represented an actual photo of a buried projectile recovery that was accomplished in accordance with the present invention. The location accomplished in this present invention manner is sufficiently accurate to enable projectile recovery in minutes of time and by the FIG. 4 illustrated manual shoveling. As described below herein such present invention projectile location is accomplished through use of a UHF signal radiating through the ground from the usually buried test projectile. In addition to the FIG. 4 focused-area recovery, projectiles to be located may also penetrate both the target  401  and the backstop earth  410  and may also glance off the backstop earth to (with the present invention) result in an open field projectile and beacon hunt, usually involving many personnel searching through tall grass (in the case of a Florida or other open test range). A surviving beaconaccording to the present invention, whether buried or not, cuts the time and personnel required for recovery of the projectile regardless of its resting point and whether the projectile is carrying an experiment or other recoverable cargo. Larger munitions launched from aircraft for example are subject to these same difficulties and may use the system described herein for similar recovery efforts. Electronics including an amplifier appropriate to the increased range of these larger devices, and a larger antenna scaled to fit may be desired in these instances. 
     Although these discussions are premised on the usual case of recovering test or dud munitions devices the same difficulties exist with obvious compounding in the exceptional cases of needing to locate and remove a live munitions test device that has failed to detonate. Although such instances are rare and avoided through use of great care, Murphy&#39;s Law, the rules of statistical sampling and similar real world algorithms assure their occasional occurrence. In such exceptional instances the need for precise spent projectile location is, if anything, even greater and additional complexities such as time delay considerations and the need to use protective measures during the search are present. 
     Electronic locator devices intended to fill these needs may be understood to involve several special requirements not of concern in most electronic circuit uses. Perhaps the most difficult of these requirements is a tolerance for the deceleration forces experienced by a projectile or other penetrator device such as for example a bomb. Additional considerations include a locator device operating life measuring in at least tens of hours and preferably in a plural number of days—until retrieval is safe and convenient. In addition small physical size and mass, moisture immunity and temperature immunity over at least moderate ranges are also significant needs. Often as in the case of the below-disclosed preferred embodiment of the invention these requirements become substantially intertwined so that for example an increase in operating life is possible at the expense of unacceptable increased battery size and mass and impact deceleration vulnerability. In the latter instance for example a larger locator beacon battery is more susceptible to deceleration damage and can be damaged by its own inertia in spite of a surviving protective encasement. This relationship alone is a significant factor in seeking to minimize beacon mass and energy requirements and is the prompter for one special aspect of the present invention. 
     Locator devices need not however be of the operating power level, detailed information providing and continuous performance nature required in the above two identified and incorporated by reference herein munitions penetration sequence data retrieval devices and their patent documents. The present beacon can instead be of a lower power, simplified signal form and of a more economical arrangement as is disclosed herein. With respect to impact tolerance the beacon of the present invention must of course survive the deceleration forces incurred when the host warhead strikes the earth or other object however it need not function during the interval of warhead deceleration. An additional notable difference between the present invention and those of the above identified and incorporated by reference copending patent documents involves the desire for smaller antenna sizes for projectile use and the resulting selection of a higher operating frequency for the present invention and of course the needed longer duration of an operating period (in contrast with an operating period measured only in milliseconds in the copending documents invention) once operation is commenced in the case of the present beacon invention. 
     SUMMARY OF THE INVENTION 
     The present invention provides an impact resistant low cost radio frequency beacon apparatus usable over a relatively long operating life, for locating and recovering a deployed munitions device at a test range or other site. The invention is of course not limited to test range use and may be employed in numerous other need-to-locate applications in both military and non-military environments. 
     It is an object of the present invention therefore to provide a munitions locator beacon. 
     It is another object of the invention to provide a munitions locator beacon capable of operating in the environment experienced by a munitions warhead device. 
     It is another object of the invention to provide a munitions locator beacon capable of operating without spatial interference to the contents of its host projectile. 
     It is another object of the invention to provide a munitions locator beacon capable of operating within the impact deceleration, size, weight, burial and operating life constraints of a munitions projectile in a test range environment. 
     It is another object of the invention to provide a launching and impact deceleration-protection arrangement for the small electronics package of a munitions locator beacon apparatus. 
     It is another object of the invention to provide an energy conserving modulation arrangement for the output signal of a munitions device locator beacon. 
     It is another object of the invention to provide a munitions device locator beacon having a multiple aspect (including multiple frequency component) impact shock protection arrangement. 
     It is another object of the invention to provide a munitions device locator beacon which can predictably withstand the extreme impact shock forces encountered in penetrating two foot reinforced concrete targets at 1234 feet per second when attached to the tail of a 54 pound munitions projectile. 
     It is another object of the invention to provide a munitions device locator beacon capable of transmitting through clay-sand over distances of up to 36 feet in order to promotes rapid location and efficient recovery of spent munitions projectiles. 
     These and other objects of the invention will become apparent as the description of the representative embodiments proceeds. 
     These and other objects of the invention are provided by spent test-munitions projectile retrieval, high G force resistant low energy requirement locator beacon apparatus comprising the combination of: 
     a selectively configured elastic resin material housing disposable in a rear location of said test-munitions projectile prior to projectile airborne launch; 
     an integrated circuit chip assembly received in said selectively configured material housing and having a radio frequency energy generating integrated circuit module with an insulating material layer and an overlying selectively energy absorbing and reflecting metallic layer covering attached elastic resin one face thereof; 
     said integrated circuit assembly further including a radio frequency energy generating chip and a keying modulator circuit of selected distinctive audio frequency keying pattern and less than twenty-five percent radio frequency energy generating integrated circuit chip output duty cycle characteristics; 
     a source of electrical energy of said duty cycle and selected audio frequency keying pattern-enabling limited size and mass connected with said keying modulator circuit and said radio frequency energy generating chip; 
     a tubular enclosure member surrounding said integrated circuit assembly and disposed within said elastic resin material housing along one axis thereof; 
     a radio frequency antenna member disposed within an axial extremity portion of said organic material housing and connected with a radio frequency energy output port of said integrated circuit assembly; 
     a portable radio frequency energy receiver, hand cartable to a selected search vicinity location for said spent test-munitions projectile. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The accompanying drawings incorporated in and forming a part of the specification, illustrates several aspects of the present invention and together with the description serve to explain the principles of the invention. In the drawings: 
     FIG. 1 shows a munitions test arrangement wherein the present invention may be used to advantage. 
     FIG. 2 shows a projectile of the penetrator device type having a present invention locator beacon attached along with sabot parts used to propel the projectile without producing hot gas damage. 
     FIG. 3 shows an elastic resin housing for a locator beacon of the present invention type, two battery types receivable in the housing and a mold for fabricating the housing. 
     FIG. 4 shows a quick present invention-assisted post-test recovery operation performed following a FIG. 1 cannon shot, a recovery replacing front end loader excavation. 
     FIG. 5 shows the physical appearance of a radio frequency receiver usable in the present invention. 
     FIG. 6 shows the projectile of FIG.  2  and FIG. 4 after dig-out. 
     FIG. 7 shows an expanded view of one arrangement for mounting electrical components according to the present invention. 
     FIG. 7A shows an expanded or blow-up view of parts of FIG.  7 . 
     FIG. 8 shows an expanded view of another arrangement for mounting electrical components according to the present invention. 
     FIG. 9 shows an electrical schematic diagram relating to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention high G, low energy beacon system may be used to advantage in a hardened target munitions or other munitions test arrangement such as is shown in the FIG. 1 drawing. In the FIG. 1 test arrangement a cannon or howitzer  100 , such as the 105-millimeter weapon used by the U.S. military, is aimed at close range at a test target  104 , a target backed by a mound of earth  107  useful in arresting a firedprojectile or penetrator warhead following its expected traversing of the test target  104 . Tests such as that represented in FIG. 1 are useful in shock testing fuze and electronic components housed within the penetrators. In practice it is found practical to fabricate targets such as the test target  104  from cured reinforced 5ksi concrete of for example two feet thickness; actual thickness dimensions several times this dimension are often used for real target protection however. 
     The buttressing indicated at  108  in FIG. 1 is used to keep the target  104  in the illustrated vertical condition notwithstanding the large impact force and ringing vibration energization it receives from the test projectile  110 . An indication of the energy levels encountered during a test of the FIG. 1 type occurs in the form of the stray particle  106  appearing to depart the FIG. 1 scene at an oblique angle. Such particles may originate in the target  104  or alternately may comprise a part of, or the entirety of, the projectile launched from the howitzer  100  after it has been deflected from an original course by the target or by a subterranean object for example. Providing location assistance for integral test projectiles incurring such unexpected and largely unpredictable deflections is in fact one of the benefits of the present invention locator beacon. 
     In penetrating the test target  104  a 105-millimeter (about 4 inches) projectile often undergoes impact forces having a peak value measuring in the realm of eighteen to twenty two thousand times the force of gravity (i.e., 18,000 to 22,000 G&#39;s). It may be helpful in understanding the present invention to realize that in the presence of decelerations of this magnitude a small object, such as a first class postal letter, usually weighing about one ounce, would have a weight near three hundred pounds (from the F=MA relationship) when exposed to such acceleration or deceleration. Moreover the forces attending this projectile deceleration are forces comprised of numerous Fourier series components, components resembling the all-frequency mechanical spectrum descriptive of a mathematical impulse function. These frequency components range from very low frequency sinusoids to sinusoids of frequencies above the audio range and even higher. Frequencies of this wide range are found to require special consideration when making the locator beacon apparatus of the present invention tolerant to impact force decelerations as is described below herein. 
     The projectile used in a test of the FIG. 1 type may have a general appearance as shown in FIG. 2 of the drawings when provided with a rearward facing locator beacon according the present invention. In FIG. 2 therefore there is shown a penetrator projectile  200  of the type usable with a cannon or howitzer-launching apparatus of either the airborne or ground-based type. The projectile  200  includes a forward-located penetrator warhead  202 , which may be made of hardened material such as steel. This penetrator is followed by a main charge region containing, in the case of a real weapon, a detonatable charge of explosive material and a timer or altimeter or other arrangement for initiating the rapid burning detonation of this charge. A locator beacon  204  according to the present invention is preferably disposed in a rearmost portion of the penetrator  200 . The penetrator  200  may be of any desired size with the approximately four inches diameter of a 105-millimeter warhead being typical. 
     At  208  and  210  in the FIG. 2 drawing there is shown the two halves of a sabot device usable to isolate the penetrator  200 , and especially rearward portions of the penetrator where the present invention locator beacon resides, from the hot gasses of the burning projectile propellant charge. The sabot includes internal passageways admitting small quantities of these hot gasses in order to remove the sabot from its firing position surrounding the penetrator rear area immediately after the projectile has departed a launch barrel. A threaded annular ring, used to retain the beacon by its housing flange, and including four radially directed retainer notches is shown in segments at  206  in FIG.  2  and is also visible at  600  in the FIG. 6 drawing herein. Preferably the male threads of this annular ring (not shown) engage mating female threads located in the rearward internal region of the projectile  200  to provide a secure captive retention of the locator beacon by its housing flange area. The radial notches in this annular ring permit its engagement by a tightening tool during penetrator assembly. A test payload and G data recorder is of course substituted for the main charge in the penetrator  200  during most uses of the present invention locator beacon. 
     FIG. 3 in the drawings shows several physical aspects of the present invention in an environment permitting general size assessments. Included in FIG. 3 is a completed molded housing  300  for the locator beacon and a pouring mold  302  in which this housing may be fabricated. Also appearing in FIG. 3, are a measurement ruler  308  and a U.S. penny coin  310  by which relative sizes of the molded housing and pouring mold parts may be quickly appreciated. In FIG. 3 there also appears at  304  an alkaline battery cell used in some arrangements of the invention. At  306  in FIG. 3 is a DL 1/3N Duracell® lithium battery also usable in some arrangements of the invention, the arrangements for example shown in FIG.  7  and FIG. 8 herein. A material found to be suitable for the molded housing  300  is identified in the above incorporated by reference herein patent document, Ser. No. 09/832,453, i.e., a heat curable polyurethane resin of the one component or Monothane® type, a polyals material identified as the type D 65 Casting System manufactured by Synair Corporation of PO Box 5269, Chattanooga, Tenn., 37406-0269, USA (telephone 1-800-251-7642, internet: www.synair.com). 
     The D 65 casting system provides a heat cured elastic urethane resin of hardness  65  on the Durometer Shore hardness D scale (a relatively hard non metallic material) after pouring at a dry heated temperature between 130 and 158 degrees Fahrenheit and oven curing at an optimum temperature of 275 degrees Fahrenheit. During cure the D 65 material passes through a water-thin phase allowing entrapped air bubble escape from the mold  302 . The D 65 material is described in a Synair Corporation Monothane® product bulletin also identifying other softer materials. Persons skilled in the electrical, resin materials and casting systems arts can substitute other materials, including dual component materials from the same or other sources, for the D 65 material. The pouring mold  302  in FIG. 3 may be machined from aluminum or other metals or alternately may be fabricated from resin materials as is disclosed in the above referenced Synair literature. The shape of the housing  300  is selected to provide desirable physical strength for the housing structure, electrical isolation of the beacon antenna from attenuating and antenna effective length-altering moisture and other earth components and a desirable extension of the electrical length of the beacon antenna all in the manner also described in the above incorporated by reference herein Ser. No. 09/832,453, filed Apr. 12, 2001, now U.S. Pat. No. 6,380,906. Said shape is intentionally tapered to reduce the housing exposure area when tumbling across soil down range of a test-firing event. Square like ends for housing  300  have in fact broken off during testing. 
     As disclosed in connection with drawings of FIG.  7  and FIG. 8 herein a fiberglass-reinforced tube as shown at  744  and  844  in these drawings may alternately be disposed in either a horizontal or a vertical orientation with respect to the molded housing  300  in order to provide physical protection for the beacon electrical circuitry. The housing  300  appears at  738  and  838  in the FIG.  7  and FIG. 8 drawings. 
     FIG. 4 in the drawings is briefly described earlier herein and shows a draftsman&#39;s rendition of photographs representing a typical earth-involved recovery environment for a projectile and its locator beacon according to the present invention. The concrete target  401  shown in the FIG. 4 drawing has been penetrated at  400  by a projectile of the FIG. 2 type, i.e., the projectile represented at  110  in FIG.  1 . During this penetration the target incurred the frontal and rear side spalling fractures indicated at  404  and  406  and the reinforcing bar damage shown at  402  while the projectile and present invention beacon incurred impact deceleration and shock wave propagation through the projectile from its point of impact. The FIG. 4 projectile has also of course incurred an initial period of large acceleration force during the time of launching from a cannon or other apparatus: however in most instances these launch acceleration forces are of lesser magnitude than impact deceleration forces and are not considered paramount with respect to the present invention. The present invention may be arranged to have favored tolerance for either acceleration or deceleration forces if needed however. 
     A shock wave propagating along the lengthwise axis of a projectile such as the projectile  200  is believed to be reasonably characterized by the mathematical impulse function when the shock wave originates in an abrupt event such as a target impact; this shock wave propagates from front to back of the projectile. The characterization of the shock wave according to the mathematical impulse function is helpful for understanding purposes as well as being analytically convenient in view of the extensive consideration of this function in classical mathematics texts. With respect to the present invention beacon the wide frequency spectrum description of this impulse function may be advantageously considered to include.both high frequency components and low frequency components, components separately considered in protecting the beacon apparatus from impact damage. The ceramic package containing the disclosed HX1003 radio frequency energy generating integrated circuit chip is for example found to be especially susceptible to impact damage, particularly to the higher of these impulse function-related frequency components. 
     At  738  in the FIG. 7 drawing is represented the outline of the molded housing  300  for enclosing the locator beacon electronics at the rear of a projectile, the housing as first appears in the FIG. 3 drawing. The relationships between the housing  738 , the forward direction of the projectile and the projectile travel direction are indicated by the arrow  736  in FIG. 7; the orthogonal disposition of the electronic components with respect to the projectile travel direction is also apparent from this drawing. Surrounding the electronic circuit elements in the FIG. 7 drawing is a circumferentially closed tubular protection member  704  providing isolation of these components from higher frequency portions of the target impact-generated shock wave. This tubular protection member may have an inside diameter of about one half inch and an outside diameter of about 0.7 inch as indicated at  734  in FIG.  7 . The action of this tubular protection member  704  is to convey or conduct higher frequency shock wave components around the enclosed electronic circuit elements rather than allow shock wave interaction with the electronic circuit elements, particularly the ceramic package at  700 . 
     The tubular protection member  704  in FIG. 7 may be made of G-10 fiberglass-reinforced plastic material as is available from The Mc Master Carr Company and may have either a 0.7 inch or a 1.2 inch length depending on whether the battery  708  is contained within the tubular protection member  704  or in another location. Preferably any empty or void spaces within the tubular protection member  704 , spaces such as are indicated at  728  and  730  in FIG. 7, are filled with a potting or casting material to add both wiring support and strength/rigidity to the overall FIG. 7 assembly. A material such as Emerson Cumming Stycast 1090® (Emerson Cumming is a division of National Starch and Chemical Limited of Windsor Court, Kingswood Business Park, London Road, High Wycombe, Bucks, England and is represented in the U.S. by Ideal Instrument Company, 863 Washington Street, Canton, Mass. 02021-2513) or the Hardman 4001 epoxy resins available from Elementis Specialties Performance Polymers of 600 Cortland Street, Belleville, N.J. may be used for this filling purpose and is preferably disposed in a void-free manner. Similar filling may be used in open spaces surrounding the tubular protection member  704 , the spaces indicated at  729  in FIG. 7 for example. 
     At  716  in the FIG. 7 drawing there is represented a contoured strip of conductive metal such as copper serving the purpose of conveying the output of the radio frequency circuit package  700  from a pin  4  node on the lower face of the package around the edge and to the upper surface of the package where the antenna  710  is attached at the node  732 . Similar conductors each isolated from the other are preferred for connecting to the power and output-enable signal nodes of the package  700  notwithstanding the presence of the metal protection layer  720 . The antenna  710  connects with the first of these conductors  716  at  732 . The antenna  710  is made to have an electrical length of one-quarter wavelength while surrounded by the polyurethane material of the housing  738  in the manner described in the above-identified Ser. No. 09/832,453, patent document. The antenna  710  preferably consists of a solid 20 AWG copper conductor wound around for example a three eights inch diameter form and disposed in a rearmost part of the housing  738  (as mounted on the projectile) either during housing molding or by drilling and plugging the housing  738  end wall after its molding. A ground connection (i.e., the wire  750 ,  850  and  950  described subsequently herein) is brought out from the tube  704  in either FIG. 7 or FIG.  8 . At  712  and  714  in FIG. 7 are shown a pair of leads connecting the battery  708  with the electronics board  706 ; these leads are also physically supported by the above identified filling material of spaces  728  and  730 . The retaining annular ring  740  capturing the housing  738  in FIG. 7 within a projectile body is of the threaded periphery type as shown in segregated form at  206  in FIG.  2  and discussed in connection with FIG.  2  and FIG. 6 herein. 
     When the components or elements of the present invention beacon apparatus are disposed in the manner shown in FIG. 7 the shock wave resulting from projectile  110  impact with a target travels along the vertical axis of the FIG. 7 drawing and thereby arrives at the electronic elements and the battery  708  (actually at the tubular member protecting these elements) in substantial coincidence. In the preceding and following paragraphs the FIG.  7  and FIG. 8 descriptions involving this shock wave are somewhat intertwined however similar drawing numbers differing only by their  700  or  800  highest order digit are used to clarify the two different descriptions and to also relate similar parts appearing in the two drawings. 
     Both FIG.  7  and FIG. 8 in the drawings therefore show physical arrangements for protecting the beacon transmitter electronic components from impact and shock wave damage. In the FIG. 7 drawing these beacon electronic components are shown disposed along an orthogonal direction with respect to a longitudinal axis of the projectile  200  while in FIG. 8 the electronic components are stacked along the longitudinal axis while remaining orthogonal to the shock wave. Each of these dispositions has been found to provide component tolerance of deceleration forces in the 20,000 G range and is therefore believed to be successfully usable as is otherwise dictated by projectile size and shape considerations. Cut-away lines  722 ,  742 ,  822  and  842  in FIG.  7  and FIG. 8 respectively show interior parts of the FIG.  7  and FIG. 8 arrangements of the invention. 
     In the FIG. 8 showing of the invention the deceleration shockwave from encountering a hardened target proceeds from the forward-most wide flange  843  end of the FIG. 8 housing  838  to the tapered section housing the antenna. In the FIG. 8 stack of electronic components, the following forward to aft order of component stacking within the protective tube  844  is preferred in response to this shockwave. 
     1. The stainless steel case of the 3 volt DL1/3 lithium battery  808  is disposed lowest in the stack and is the first to see the shockwave. 
     2. A double copper clad FR-4 material circuit board  806  with a non-component side or empty side touching the aft side of battery  808  is next in the stack. The top or aft side of the circuit board  806  holds the CD4060 CMOS counter-oscillator circuit chip  802  which is located below the ceramic HX1003 circuit package  800  in the FIG. 8 view and therefore does not appear in the FIG. 8 drawing. This disposition may be understood from the exploded partial view of chip  702  and other components shown in the FIG. 7A drawing. 
     3. A type 1095 steel flame hardened hack-saw blade segment shock mitigator  820  is placed on top of or aft of the CD4060 chip  802  in FIG.  8 . The blade segment is supported by the Stycast 1095 potting compound described both above and below; this compound fills spaces between the circuit board  808  and the HX1003 circuit package  800  and indeed fills the voids within the FIG. 8 fiberglass tube  810 . The 1095 steel has a hard surface that deflects high frequency shock components and a carbon-steel internal grain structure that is a poor conductor of lower frequency sound. This special steel and the thus-far ordering of components in the FIG. 8 stack are desirable to protect the overlying HX1003 ceramic transmitter chip  800 . 
     4. A layer of Kapton® polymerized plastic film insulating tape prevents the hack-saw blade segment or steel shock mitigator  820  from shorting the HX1003 ceramic transmitter chip  800  terminals which are located on the lower surface of the transmitter chip  800  housing. The transmitter connections are brought around to the sides and top of the chip with copper foil strips for access as shown at  812  and  814  however connections to these copper foil strips are omitted for drawing clarity. 
     5. A spiral wound ⅜ inch diameter antenna  804  is attached to the antenna terminal copper foil stripe  814 . The antenna is electrically a quarter wave long when dielectrically lengthened by the surrounding Monothane resin of the housing  838  and an overlying representative bag of clay sand. (The greatest antenna efficiency is needed when the antenna is buried in the backstop or down range soil as may be appreciated from the mission of FIG.  7  and FIG. 8 devices and as is explained in the above identified Ser. No. 09/832,453, filed Apr. 12, 2001, now U.S. Pat. No. 6,380,906. 
     Referring again to the FIG. 7 drawing, the battery  724  in this arrangement of the invention is disposed on its side adjacent to the FR-4 material electronics board  706  and the HX 1003 ceramic transmitter module  700 . With exception of the battery  724 , the stacking order and orientation of components with respect to the fore-aft shock wave is the same in FIG. 7 as was described for FIG. 8; ie . the FR-4 board components are followed by the steel hack-saw blade segment shock mitigator or steel deflector/diffuser  720 , the Kapton polyimide plastic tape  718  and the copper foil antenna connection  716 . The FR-4 board  706  is square in FIG. 7 in contrast with the round shape in FIG.  8 . The board  706  is made to be a tight fit in the tube  744  diameter. The lower half of the tube  744  is usable for electrical connections and the remaining voids are filled with Sytcast 1095 or Hardman 1004 epoxy. The break wire  750  in FIG. 7 ( 950  in FIG. 9) is brought out of the body  738  just above the locking ring  740  as it seats on the flange  743 . 
     Possible variations for the composition of the 1095 steel shock mitigators  720  and  820  in FIG.  7  and FIG. 8 are KOVAR® or INVAR® steel alloys which also display the properties of surface hardness found useful to deflect high frequency shock components as well as providing low speed internal propagation of sound energy. The sound propagation characteristics of these materials are in fact less than those of the 1095 steel. Other arrangements of the FIG.  7  and FIG. 8 embodiments of the invention may dispose a protective assembly of steel layers on each side of the ceramic package of the radio frequency energy generator chips  700  and  800 . Such arrangements may be useful for example in the FIG. 8 axial disposition arrangement of the invention under more extreme conditions. 
     FIG. 9 in the drawings shows a preferred electrical schematic diagram for the locator beacon of the present invention. In the FIG. 9 schematic diagram the HX 1003 radio frequency energy generator circuit chips  700  and  800  appear in electrical schematic form at  902  and a modulation circuit such as a CD 4060 CMOS clock counter circuit appears at  900 . These integrated circuit devices are available respectively from RF Monolithics, Incorporated of Dallas, Tex. and from National Semiconductor Corporation of Santa Clara, Calif. In FIG. 9 these integrated circuit devices are energized by the battery  904  which represents the batteries  708  and  808  in FIG.  7  and FIG.  8 . The integrated circuit devices  900  and  902  provide a switched or keyed carrier output signal to the antenna represented at  922 . In view of a need for minimum mass and space usage in the munitions projectile environment of the invention, the apparatus in the FIG. 9 schematic diagram is arranged to have the lowest possible component mass and part count, the smallest component physical sizes and the lowest energy requirements deemed practical as is described subsequently herein. 
     Additional components appearing in the FIG. 9 schematic diagram include the RC network appendage to the CD 4060 CMOS clock counter circuit  900  as appears at  910 ,  912  and  914  and the two discrete transistors  916  and  918  connecting with the clock counter circuit output signal ports. These NPN junction transistors include the integral base resistors  926  and  927  (and thereby enable a direct connection with the output pins of the  4060  circuit without additional component space or mass) and may be embodied as transistors of the Panasonic UN5210 type. A current limiting resistor  920 , of for example fifteen kilo ohms value, is employed at one signal output node of the CD 4060 clock counter in order that each of the illustrated counter output nodes may cause the combined signal node  930  to become grounded during reset and thereby inactivate the enable input port of the HX 1003 radio frequency signal generator for certain time intervals as is explained below. Two of these deactivations occur by way of conduction in the transistors  916  and  918 . A deactivation of the entire FIG. 9 circuit as described below may be used to hold the apparatus in readiness for operation during storage intervals. 
     The usual configuration of the FIG. 9 circuit in a test projectile is to have the battery  904  connected permanently once the test apparatus is assembled. For this purpose the FIG. 9 apparatus allows all circuits to be placed in their stand-by/off states by pulling the reset pin, pin  12 , of the CD4060 circuit high or up to the positive level of battery  904 . This is described in greater detail below. When launching breaks the wire  750 ,  850 ,  950 , the pin  12  reset terminal goes low-false and the counter outputs will rise and turn on the HX1003 transmitter. This turn-on results in a ⅛ duty cycle modulation pattern as is described below herein. 
     During operation of the circuit described by the FIG. 9 schematic diagram the clock portion of the CD 4060 clock counter circuit  900  is caused to operate at a clock frequency in the range of one to two kilohertz by selecting appropriate values for the RC network at  910 ,  912  and  914 . Values such as 10 picofarads, 1.5 megohms and 3.3 megohms respectively for example provide this clock frequency and ultimately result in an audible and distinctive “beep-beep-rest” modulation audio signal with a 1 kilohertz voice being produced by the radio frequency signal output from the beacon. 
     This modulation signal also causes a one eighth time or 12.5 percent duty cycle in the FIG. 9 circuits and hence enables a reduced battery size requirement at  904  in the FIG. 9 diagram. This is because the electrical circuit shown in FIG. 9 performs an “ON” and “OFF” or keyed modulation of the radio frequency energy generator circuit  902  in lieu of amplitude modulation or some other form of continuous radio frequency carrier presence modulation. This low duty cycle and the keyed modulation arrangement are believed to be especially desirable for present beacon use because of the limited battery size and mass thus enabled. The energy efficient switched or key modulated radio frequency signal generates slightly wider sideband frequencies in the radio frequency output of the FIG. 9 apparatus than does other modulation arrangements, a factor which may be of concern in some uses of the invention. This attribute of the FIG. 9 circuits may be reduced with use of a RC network on the modulation line to slow the modulation rise time. Clearly other low duty cycle modulation arrangements of this nature and of perhaps even better energy conservation capability can be tapped from the CD4060 counter outputs or otherwise arranged. 
     The battery shown at  904  in the FIG. 9 schematic diagram may be of differing types that are primarily selected for being capable of surviving the described projectile acceleration and deceleration forces while also providing desirable energy to mass and energy to size ratios. In particular batteries of the lithium, alkaline, mercury, silver oxide and thermal battery types have proven successful in present invention use especially when selected or modified to have high G-force immunity. A specific battery from this group found to be desirable is the Duracell® DL1/3N, a 160 milliampere-hour lithium battery: this is in fact the battery represented at  306  in the FIG. 3 drawing. Battery orientation with the positive terminal closest to the projectile front is preferred to withstand for the deceleration force. Other battery locations outside the tubular protection member  704  are also possible. When operated at a radio frequency power level of 1-milliwatt an operating life of over six days and 16 hours is achievable with the DL1/3N battery and the described modulation arrangement. 
     At  946 ,  948  and  950  in the FIG. 9 schematic diagram there is shown a resistor pair and loop wire combination usable to transition the entire FIG. 9 circuit apparatus between “OFF” and “ON” or standby and active modes of operation and moreover to accomplish this change of operating mode automatically upon launching of the FIG. 1 projectile from the howitzer or other launching apparatus. These components operate by way of the pin  12  reset input node of the CD 4060 CMOS clock counter circuit  900  and serve in the FIG. 9 illustrated condition to hold this reset input node in a high or logically active condition. With such a pin  12  input high condition the output signal from each of the CD 4060 CMOS clock counter circuit output nodes  1 ,  3  and  7  is in a low voltage or logically inactive condition and both the node  930  and the disable input at pin  1  of the HX 1003 transmitter circuit chip  930  are also in this low condition. With a low disable node input the transmitter circuit chip  930  is also held in an inactive condition where it emits no radio frequency energy from the pin  4  output node and most significantly thus consumes a few microwatts of battery  904  energy. By holding the pin  12  input of the CD 4060 CMOS clock counter circuit in this high state therefore the entire FIG. 9 circuit is maintained in a 20 microwatt energy consumption state suitable for a pre launch condition or for at least short term storage of the locator beacon apparatus. 
     During howitzer launch of the projectile  110  and the attached beacon apparatus the loop of typically 28 gauge copper wire  950  in FIG. 9, the loop corresponding to the wire loops  750  and  850  in the FIG.  7  and FIG. 8 drawings, is interrupted by the motions and thermal displays of the launch event. With this interruption the logical status of the CD 4060 CMOS clock counter circuit pin  12  and the HX 1003 transmitter circuit chip  930  pin  1  inputs are made true so that both circuit chips become active and the desired modulated radio frequency energy signal is generated. A low-true open circuit level of the CD 4060 CMOS clock counter circuit pin  12  input is assured by the resistor  946 , which is of about 330 kilo ohms value, pulling the pin  12  input down to ground when current flow from the battery  904  and the resistor  948  (of about 100 kilo ohms value) is removed from pin  12  by loop  950  interruption. Since the CD 4060 CMOS clock counter circuit is of the low energy consumption CMOS type and the transmitter chip  902  is specified to require little current in its disabled state the greatest energy consumption occurring during operation of the FIG. 9 circuit apparatus probably occurs in the series connected resistors  946  and  948 . With the stated values of these resistors and a 3 volt 160 milliamp-hour battery at  904  this disabled or standby current is of about 7 microamperes magnitude and would therefore consume 10 percent of the specified battery  904  life in 2.3 thousand hours or 100 days. 
     A receiver for the signals emitted by the described beacon/transmitter is shown in physical form at  500  in FIG. 5 of the drawings and is represented at  940  in the FIG. 9 schematic diagram. This receiver is preferably disposed in a battery energized hand-cartable small package arrangement usable under portable conditions by range personnel under conditions such as suggested by the FIG.  1  and FIG. 4 drawings. In the FIG. 9 diagram the receiver  940  is represented to convert radio frequency signals intercepted by the antenna  946  into audio sounds  944  emitted from a transducer device or loudspeaker disposed at  942  on the receiver housing. Although this receiver may be of many conventional types, a receiver capable of efficiently converting a keyed or pulse modulated radio frequency carrier to an audio frequency tone or of generating some visual or audible or manifestation of having received the described signals is desired. A receiver of the amplifier sequenced hybrid or ASH type offers significant advantages for this use. Such receivers are also available, in the form of a major components kit or in other form, from RF Monolithics Incorporated of Dallas, Tex. Advantages in the nature of sensitivity, large dynamic range, small size and overall simplicity are often attributed to such receivers. A loudspeaker and associated amplifier are preferably added to an RF Monolithics RX1300 receiver circuit chip to comprise the receiver  940 . 
     By way of supplementing and summarizing the thus far recited disclosure of the present invention while using concise other words and an altered description viewpoint it may be appreciated that the invention is concerned with shock hardening a ceramic radio frequency transmitter chip commercial product. To accomplish this a leading shape and a steel shield are used to protect the transmitter chip. Shock hardening the system also involves reducing system mass and battery requirements. This in turn is assisted by the reduced duty cycle on-off keyed amplitude modulation (AM) arrangement used and by minimizing the AM tone modulator components. 
     To be more specific, unlike a classic 100% AM tone transmitter playing continuous modulation power against carrier power (often by varying the potential applied to some transmitter amplifier stage and frequently by using power consuming class A linear amplifier stages following a low level modulator) the present invention modulation is “ON-OFF keyed” at the tone rate. It is thus a function of the tone modulator to minimize battery mass by placing the transmitter in its standby or sleep mode for half of the tone rate and at least half of all time. In practice, three digital counter outputs are used to disable (i.e., modulate) the transmitter carrier so that the 50% duty cycle of the tone is curtailed by 50% over time. Another output signal twice as fast as the 50% cycle time, also curtails the tone, giving a distinctive “beep-beep-quiet” signature to the modulated radio frequency signal while limiting power consumption to one eighth of the continuous transmitter requirement. It is also disclosed that when the counter is held in a reset mode using an external enabling break-wire loop, all of these counter signals combine to present a logic low state to the transmitter RF module. This places the transmitter in a low power standby mode. The quiescent counter current is less than 12 micro amperes while the off state current for the transmitter is about one micro ampere. Thus stand by power and off power between emitted signal “beeps” is about 60 micro-watts. 
     Testing experience has shown the ceramic transmitter is the component of the beacon most susceptible to failure during impact, followed by soft alkaline battery cells. Protection of the transmitter component is herein achieved with use of a tubular reinforced plastic body having its axis either normal to or parallel with the impact force in order to redirect some of the shock wave away from the electronics within the tube. After the shock wave is deflected by the tubular shape, metal sheet applied to the ceramic microcircuit base has sufficient surface hardness to deflect high frequency shock and provides internal diffusive qualities to attenuate lower frequencies. In practice, the type 1095 steel from a hacksaw blade has demonstrated surface hardness and a spherical carbon-iron molecular matrix that mitigates sound. KOVAR, a Cobalt steel alloy and Invar 36, a Nickel alloy steel, are believed to be feasible similar ceramic chip protector materials. A 0.022-inch thick piece of steel is therefore attached to the bottom or bottom and top faces of the ceramic circuit package using a thin void-less coat of hot glue. Shielding more sides may help conquer inertial shocks above 22 k-G. The metal blade piece may be insulated to prevent shorting connections. Electrical connections to the circuit package are made from the ceramic base with copper foil rather than by conventional mounting to a circuit board. The base of the ceramic module is made normal to the axis of impact to realize the benefit of mitigation by shape and sheet material as discussed. If batteries, tone board, and RF chip are stacked along the axis of impact, this order from the impact face is maintained to shadow the ceramic RF chip. It is found to be desirable to place the heaviest piece of the stack nearest the impact face and the ceramic RF module with antenna in a rearward location. 
     The foregoing description of the preferred embodiment has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the inventions in various embodiments and with various modifications as are suited to the particular scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.