Patent-5061930

Patent-5061930 - United States Patent [19] Nathanson et a1....

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Unformatted text preview: United States Patent [19] Nathanson et a1. [54] MULTI-MODE MISSILE SEEKER SYSTEM [75] Inventors: Harvey C. Nathanson. Pittsburgh, - Pa.; Thomas E. Underwood, Ed gewater. Md. Westinghouse Electric Corp.. Pittsburgh, Pa. [21] Appl. No.: 536.924 [73] Assignee: [22] Filed: Jun. 12. 1990 [51] Int. Cl.5 .............................................. .. F416 7/22 [52] US. Cl. ...................................... .. 342/13; 342/62; " 244/119 [53] Field of Search .............. .. 244/316. 3.19; 342/13. 342/ 14. 16. 62 [56] References Cited U.s. PATENT DOCUMENTS 4.037.061 5/1973 Burt . 4.190.337 2/1930 Salvaudon et a1. ................. .. 342/62 4.217.530 3/1930 Lowenschuss ...................... .. 342/13 4.735.379 5/1933 Leveque et al. . 4.323.136 4/1939 Nathanson et al. . 1" I *ii’~ ill: .11 1‘ ll ! *1! III Ir 0 I- III 1-- 'l .I I”! dig! H .1. in! FREQUENCY CONVERTER '1':- 10.90! III *: or II- .1! II .1! III III I‘ ' 1:1! or o o i...- I- III II III I‘I " :1- o e o i i it v *i 'i ' i.“ iii: it I! I. I" I! II I III ‘I 'l' 'l M! o o II II. *I. .p. “3 .1! i. r *1 “I III ii 5,061,930 Oct. 29, 1991 [11] Patent Number: [45] Date of Patent. Primary Examiner—Mark Hellner Attorney. Agent. or Firm—W. G. Sutcliff [57] ABSTRACT A broad band multimode seeker system for a missile includes a wide band phased array transmitter/ receiver unit incorporating a wafer scale phased array device with a bandwidth of about 2 GHz to 35 GHz. A multi- mode intermediate frequency unit selectively generates radar and jamming waveforms and measures parame- ters of reflected radar and external emissions of RF energy. A guidance processor manages the front end assets for selective active or semiactive radar searching and tracking. and simultaneous searching for. tracking of. homing on, and applying a selection of electronic countermeasures to, multiple defensive radars. Confir- mation of an assigned target is made through correla* tion of received RF signals with libraries of expected defensive system parameters and high resolution target profiles and preloaded target geographical coordinates. 15 Claims. 4 Drawing Sheets 73 w I E—E——_1 I I AIRCRAFT I FREQUENCY I- I I INTERFACE I GENERATOR I l 43 I 75 I I I I I INERTIAL I IIIAVEFORN 5‘3 71 I REFERENCE I I GENERATOR I I UNIT II F W I R I I FLIGHT I RECEIVER MEASUREMENT I : 47 I 55 “DE BAND l l REFERENCE l 57 l CHANNEL I _______________ ___1 I RECEIVER I |_ J US. Patent Oct... 29, 1991 Sheet 1 of 4 5,061,930 FIG.1 5,061,930 Sheet 2 of 4 29, 1991 Oct US. Patent ‘0 O O .0 .0 i9. 1' O i" .9 O .. O 0 q. 1r 0 :5 r O '4’. W: N UHL 1 llllllllllllllllllllll .I4 :4 _ B _I I I I l I I I I I I I I I II. _ _ 92$ we; 8 n _ 5 . 5 “up n a, u _ 33135: 526% _ n _ 2 “mmmmw _ _ «Ezéé zufifiomfim _ EH $25.28 wwa u _ N< mmJDQOZOE - uv_<om a "$3 _ a} $22 Em; fin». _ u _ _ _ WEE”.ng mo<LKMP2_ >ozu=oumm #2554 mommMGOmn. 52423 US. Patent Oct. 29, 1991 Sheet 3 of 4 5,061,930 ~ FIG. 3 EE®®E§ _ m‘mm WWW 53 5,061,930 Sheet 4 of 4 Oct. 29, 1991 US. Patent 22:28 Es: E mzofiommmoo § (55 3.5 323958 Eomfi Hzmzmg 242 moo: “52$: :0 29.2? mm w .UE Fm hzmzmmmmmk sttm: :mmE zo:<.m_mmoo WEE 9500 Box: .5 a zofiontmo 1.35. “.523 .ozCGfifi 5553 m2 mmfio Eomfi pzmzmo<z<z “E H2m5mo<z<z '- g 3 mm _w=o_z=oup ozfimmoomm €205 5.55m E553 mntmzéqn. ozEmEm 25m (:3 Imam—33 mflmzfi (hqo Q\< 5 mm. ozEHfi . 25m £533 :8 mm mhzmzmmsmfiz Syn-BEE: EFF—Sm ozEHFm 32mm _ .5528 525% moms. 5,061,930 1 2 have the ability to jam defensive radar and antimissile MULTI-MODE MISSILE SEEKER SYSTEM weapons systems. ' + There remains a need for an affordable missile seeker BACKGROUND OF THE INVENTION system which can operate with a high Pk (probability of 5 kill) against a heavily defended target. It is the object of the present invention to satisfy this This invention is directed to a seeker system for a need b mvidin m M ed - -1 k t missile which utilizes a wafer scale phased array seeker . y p g a u 'm. e miss} I see er Sys em Wthh can track a target whlle providing self-defense Operated in a multi-function mode to simultaneously ECM ' ' ' ' et '1 r v‘ in an i-radia- . . . . . gmde a {1.1155116 “3.16 mfg whl i? 0. “1 g t 10 It 15 the further object of the Invention to provide tron seeking and Jammmg of antrmrssrle defense radars . . . . such a missfle seeker system which can Jam a threat and antimissile guidance heads. . . . . Wthh IS wrdely separated angularly from the target 2. Background Information being tracked‘. d .Curremt radar Iguidedtmfisgeirgglz: faineefhaslzjig It is another object of the invention to provide such a “van an enna 0 ma 6 n g ' 15 missile seeker system which can operate in either an 1. Field of the Invention {Hades of Pperauon are used' 111931153116 whiCh Operates active or semiactive radar mode or in an anti-radiation in the active radar mode, the missfle transmits on board model generated radar pulses and receives radlation reflected It is yet another Object of the invention to provide from. this target to. “.5 med-1.3mm“)! duven antenn?‘ such a missile seeker system which can jam an ECM Semlactlve‘radarmissrles, Wthh are generally used In 20 source or home on a jamming target! the 311‘ t0 3” enwmnmcntr trim" 0“ Tweeter-1 “Sham” It is an additional object of the invention to provide a propagate? by a ground 01' alrbm‘le iaunCh VBhICIE' _If missile seeker system which can assess threats and auto- the target 13 a radar SYStemr some “11551155 53” Operate m matically jam the greatest threats while continuing to an anti-radiation mode 1n which they track on the RF track the target energy radiate‘i by the mug“ radar' Often a target Will 25 It is an overall object of the invention to achieve all of dlfeet a Jemmmg 5131131 at ? radar gmdfm 91135113 "33“ the above objectives with a missile seeker system which attempt to saturate ltS recelver or deceive Its tracking is of a Size and weight such that it can be used in a system. In such an environment, many missiles can practical Sized missile_ switch to a home on jam mode in which they guide on the jamming beam. 30 SUMMARY OF THE INVENTION In currently anticipated realistic combat scenarios, an These and other Objects are realized by the inventifln incoming missile Conld “mum” awesome counter' which is directed to a multi-mode seeker system for a measures: Parneller surrounding a lush Value_target missile which includes a wide band phased array trans- 5“?h.3 large Shlp- SUCh Vessels are “lumped w‘th 50' mitter/receiver unit with an electronically agile aper- Phlsncatfid and 15"7""""el'ful self defense firewmro} 53’5" 35 ture from which RF energy over a wide band of fre- tems Wthh use shipboard radars and antnmssrle missiles quencies and in directions over a widc solid ugh is to track and destroy incoming missile threats Antimis- transmitted and received_ More particular-W, thg wide sile missiles can also be launched from other vessels band I,th array transmitter/receiver unit includes a Supporting the high Value target Large numbers or wafer scale phased array device comprised of a plural- ineeming miSSiles are needed ‘30 Ovemhelm these de‘ 40 ity of semiconductor transmit and receive cells and a fefleee at greet eeet- manifold for distributing RF energy waveforms to be The meehafiieelly driven radar antennas 0f the cur" transmitted to the wafer scale phased array device and rent miSSileS have a narrow 100k angle and Slew ‘00 for gathering RF energy received by the individual slowly to track widely separated targets, search radars cells of the array, and lemming soureeS- Pheeed 31'er seekers heVe been 45 The seeker system, according to the invention, fur- deVelePed Whieh are electronieelly agile BY eentfel' ther includes a multi-mode intermediate frequency unit ling the relative Phase 0f RF energy mtween meltiple which selectively generates radar and electronic coun- ePel’tul‘eS in the array! the reenltiflg beam can be rapidly termeasure RF energy waveforms for transmission by slewed over a wide area, for instance. a 120 degree Gene the wide band phased array transmitter/ receiver unit about the center line 0f the erreY- Unfortunately; Wm 50 and which selectively detects and measures parameters ventional phased array seeker systems are too large for of reflected—radar transmitted by the system and exter- a cost efficient missile. However. [35- Pat NO- nal emissions of RF energy received by the wide band 4,323,136 diseleses a wafer scale Phased array seeker phased array transmitter/receiver unit. The system also system in which aplurality of transmit/receive cells are includes a guidance processor which is reSponsive to incorporated into a three inch (7.62 cm) or four inch 55 the measured parameters of the received reflected radar (10.16 cm) diameter wafer of semiconductor material. and external emissions and controls selection of the The seeker is indicated for use as a radar transmitter/- radar and electronic countermeasure RF waveforms receiver with a narrow band antenna, and for use as an generated by the intermediate frequency unit and con- ECM transmitter/ receiver with a broad band antenna. trols the direction in which the wide band phased array U.S. Pat. No. 4,735,379 discloses a missile guidance 60 transmitter/receiver unit transmits and receives RF system which utilizes an electronic scanning antenna. energy. This guidance processor controls the multi- Several targets can be tracked simultaneously and the mode intermediate frequency unit and the wide band course of the missile controlled to maintain the plural phased array transmitter/receiver unit to selectively targets within the range of action of the missile until a time multiplex transmission of radar and electronic particular target is singled out using prelaunch stored 65 countermeasure RF waveforms and reception of re- target characteristics which are compared with the flected radar and external emissions of RF energy for detected target returns. While this system has some selective simultaneous tracking of targets with radar capability of avoiding defensive jammers, it does not and searching for, tracking and applying electronic 5,061,930 3 countermeasures to emitters of the external emissions of RF energy. Because of the wide bandwidth of the seeker system, the multi-mode intermediate unit has a narrow band section for detecting and measuring the parameters of reflected radar RF energy and a wide band section for detecting and measuring the parame- ters of the received external emissions of RF energy. An emitter signal processing unit in the guidance processor reSponds to the parameters of external emis- sions of RF energy measured by the intermediate unit 10 and identifies and tracks multiple external emissions of RF energy. A threat lethality unit identifies external emissions of RF energy tracked by the emitter signal processing unit which pose a lethal threat to the missile. An ECM technique means generates the parameters for the intermediate frequency unit to generate electronic countermeasure RF energy waveforms to jam the exter- nal emissions identified as a lethal threat, ‘and generates the steering information for transmission of the elec- tronic countermeasure RF energy waveforms by the wide band phased array transmitter/receiver unit. The system has the capability of simultaneously jamming multiple external emissions 'which may be widely sepa- rated in angular location and frequency. A wide assort- ment of ECM techniques can be employed. The guid- ance processor includes a home—on jam capability in which guidance signals are generated for steering the missile to home on an external emission of RF energy tracked by the emitter signal processing unit. The system includes several means for singling out the assigned target where there are multiple. potential targets and external sources of RF emissions. For in- stance, the guidance processor includes a threat library 5 15 20 25 30 storing parameters for expected external emissions of 35 RF energy from the assigned target, and correlation means which correlate the stored parameters with the parameters of external emissions of RF energy tracked by the emitter signal processing means. The guidance processor also has a threat class library in which radar signatures of the assigned target are stored for compari- son with the radar return received by the system. If there is no correlation. the guidance processor can search for and transfer tracking to another more likely target. Furthermore. the correlations between the radar data and the external emitter data can be fused to pro- vide confirmation of target identification. The coordi- nates of the target can also be stored prior to launch, and used to verify a target by comparison with the calculated position of the target based upon RF energy received by the seeker system. BRIEF DESCRIPTION OF THE DRAWINGS A full understanding of the invention can be gained from the following description of the preferred embodi- ment when read in conjunction with the accompanying drawings in which: FIG. 1 is a sketch illustrating the operation of a mis- sile incorporating the missile seeker system of the inven- tion in a multi-threat environment. FIG. 2 is a schematic diagram in block form of the hardware of the missile seeker system of the invention. FIG. 3 is a schematic diagram illustrating the struc- ture of a wafer scale sensor which forms part of the missile seeker system disclosed in FIG. 2 FIG. 4 is a flow chart of the software which forms part of the missile seeker system shown in FIG. 2. 40 45 50 55 65 4 DESCRIPTION OF THEPREFERRED EMBODIMENT FIG. 1 illustrates a missile 1 incorporating the missile seeker system of the invention in flight toward a target ship 3. The missile 1 is shown operating in the active radar mode in which the missile emits a radar beam 5 and tracks on RF energy from that beam reflected by the ship 3.. The ship 3 is equipped with guidance radar 7 for a ship launched antimissile missile 9. The guidance radar 7 emits a radar beam 11 which is being jammed by a jamming beam 13 from the missile 1. The missile gen- erates an additional jamming beam 15 which jams the missile 9. At the same time. an ground based antimissile defense system 17 launches an antimissile missile 19 which is guided by a radar beam 21 emitted by a guidance radar system 23. The missile 1 generates jamming beams 25 and 27 for jamming the ground based radar 23 and ground launched antimissile missile 19 respectively. The missile 1 can also operate in other modes. For instance. instead of transmitting an active radar beam 5, the missile 1 can track in an anti—radiation mode on the radar beam 11 emitted by the ship’s radar 7. Also, if the ship tried to jam the missiles radar, the missile 1 could operate in a home on jam mode and fly down the jam- ming beam generated by the ship. Other modes of cper- ation and features will be described in the following discussion. FIG. 2 is a block diagram of the missile seeker system 29 of the invention which is incorporated into the mis- sile 1. Major subsystems of the seeker system 1 are a wide band phased array antenna unit 31. an intermediate frequency (IF) unit 33 which provides receiver and transmit waveform generation functions, and a missile guidance processor 35. These basic components of the missile seeker system 29 communicate with other mis- sile systems through external interfaces 37 over a missile data bus 39. An aircraft interface bus 41 communicates with the host aircraft. This interface can be used to provide the seeker system 29 with target location. target image characteristics. expected defensive systems and other information. The inertial reference unit interface 43 provides missile movement information which the guidance processor uses for navigation and determining missile orientation. This information is used among other things for orienting the emitted beams. determin- ing the direction of received signals and for generating flight control signals which are passed to the missiles flight controls through a flight control interface 45. An additional interface 47 to a reference channel receiver is required if the missile is to Operate in the semiactive radar mode. Also, air to air variants which require com— munication with the launch aircraft would do so through the reference channel receiver. The wide band phased array unit 31 is configured as a three channel monopulse front end using a wafer scale integrated device 49 to provide RF power amplifiers for transmit, low noise amplification for receive. an inte- grated phase/amplitude control for beam steering and illumination taper for pattern side lobe control. The wafer scale integrated device 49 is a broad band multi- element device. The exemplary wafer scale device is a 32 element 1 to l watt 2 to 35 GHz array. The 32 ele- ment array 51 is shown on a three inch wafer 53 in FIG. 2. Each transmit/ receive cell 55 of the array 51 contains redundant components and a vertical architecture as described in US. Pat. No. 4,823,136 issued on Apr. 18, 5,061,930 5 1939. With 32 one half watt cells 55, a 16 watt beam 5 should be possible for the radar mode. For jamming, the 32 one half watt cells 55 should result in an effective radiated power (ERP) jam signal 13 of about PcezzNZ or approximately 512 watts, more than enough tO jam the return from the small cross section end view Of the approaching missile. An array of any number of cells can be produced by trimming individual wafers contain- ing sets of cells so that they may be arranged side-by- side in a common plane. An array with dozens to hun- dreds of cells can be fabricated in this manner. Wideband radiating elements associated with each Of the transmit and receive cells 55 create a wide band electronically agile aperture 57 for transmitting and receiving RF signals. A manifold‘and monopulse com- biner 59 distributes RF energy to be transmitted and collects received RF energy from the individual cells Of the wafer scale array 49. It also generates the sum, and azimuth and elevation difference signals for monopulse. operation. The monopulse difference channels are mul- tiplexed-by a switch 61 to allow full monOpulse mea- surement with a two channel receiver. Alternate config- urations based On so called “single channel monopulse” wherein the three receive beams are sampled sequen- tially to allow further reduction in the complexity Of receiver hardware are similar in nature and may be preferred due to their lower cost and weight. Multiple channel monOpulse is used in the exemplary system because of its superior capability to reject the effects Of jamming. The intermediate frequency unit 33 includes a fre- quency converter 63 which mixes the RF from the wide band phased array unit 31 down to a first intermediate frequency (IF) which is nominally in the 6—10 GHz range. A variable bandwidth IF receiver 65 follows the down conversion to allow a choice Of wide band elec- tronic support measures (ESM) signal acquisition to support anti-radiation missile (ARM) guidance and electronic countermeasure (ECM), or narrow band Operation for semiactive or active radar homing guid- ance modes. For wide band operation, a parameter measurement unit 67 utilizes logarithmic amplifiers and an IF analog frequency discriminator for efficient pa- rameter measurement. A wide band phase detector is also included in the parameter measure unit 67 to sup- port wide band monOpulse angle measurement for ARM guidance, and to control the directional ECM operation inherent in the seeker design. For the narrow band Operation for either active or semiactive radar operation, a tuner 69 performs a further down conver- sion to base band using a linear receiver. A wide dy- namic range analog to digital (A/D) converter 71 pro-— vides sample data (in phase and quadrature channels) for a Fast Fourier Transform (FFT) process imple- mented in the guidance processor 35. A common frequency generator 73 provides local oscillators used for down conversion Of received signals and up conversion of either terminal homing radar or active jamming waveforms. It also generates the basic transmit waveform for homing radar and supports nor- mal dOppler radar operation as well as high resolution waveforms such as serial synthetic Spectrum for target identification. A waveform generator 75 imposes modulation from a 10 15 20 25 6 Operation against dOppler fire control systems. Noises can be generated either by preloading the DRFM with a noise waveform or by frequency modulating the out- put Of the DRFM. This allows the seeker to have a wide range Of countermeasure technique diversity for essen- tially no additional cost. A common digital real time controller 77 generates the pulse repetition frequencies (PRFs) and envelOpe waveforms for radar Operation, and false target wave- forms for ECM techniques. The controller 77 also pro- vides timing for transmitter/receiver synchronization. The timing controls and AM/FM modulation wave- forms for ECM and radar Operation are distributed to the various front end assets via a high speed seeker control bus 79 in near real time. The guidance processor 35 contains a programmable signal processor and a data processor which implement active and semiactive radar signal processing functions which require high throughput capacity. The data pro- cessor supports target tracking algorithms, emitter iden- tification and homing processing for ARM guidance modes and technique management for active jamming functions. The missile data bus 39 provides the interface for receiver data from the seeker front end to the guid- ance processor 35, and for seeker control data to the ' real time controller ’77 which provides the tuning and 30 35 45 50 55 timing commands to the various front end assets. The missile data bus 39 also provides a common interface for data transfer to and from other external units through launch aircraft interface 41, the inertial reference unit interface 43, the flight control interface 45 and the refer- ence channel receiver interface 47. A flow diagram for the software 81 of the guidance processor 35 is shown in FIG. 4. This software imple- ments all of the signal processing and control functions necessary for the missile to seek-while-jamming. In the preferred method of Operation, the missile navigation module 83 is loaded with the coordinates Of the target prior to launch. The target coordinate and inertial refer- ence unit data are input through the aircraft and inertial reference unit interfaces 42 and 43, reSpectively. In addition, the parameters of known emitters aboard the target are downloaded through the aircraft interface 42 into a target parameter library 85. Prelaunch, the missile itself may be used as a sensor to determine these param- eters if the sensitivity Of the missile seeker exceeds that of sensors On the launch aircraft. If the target class is identified, high range resolution radar signature data can be downloaded from the aircraft into a target class library 87. For instance, if the target is known to be an aircraft carrier, the radar signature of the aircraft car- rier can be loaded into the target class library 87. Target class identification can be used as a secondary source Of identification to the emitter signature tO enhance the seekers capability tO positively identify and maintain track on its target in the presence Of potential self-pro- tection measures taken by the target. The emissions from the target are analyzed by an emitter signal processing function 89 which receives the emitter parametric measurements from the parameter measurement unit 67. The processing includes receiver management to tune the wide band phased array unit 31 in frequency to search for all emitters known to be on the target and then to perform the necessary pulse sort- real time controller (RTC) ‘77 to generate the radar and 65 ing and deinterleaving functions necessary to detect and ECM waveforms. For the countermeasure modes Of operation, the WflVBfOITn' generator 75 includes a digital RF memory (DRFM) to allow coherent transponder identify the target from the potentially large number of signals in the environment. As the missile 1 flies toward the target, the emitter signal processing functions 89 not 5,061,930 7 8 only search for target emissions for homing purposes, received from the A/D converter 71 to extract the but also search for the potential threats anticipated tobe target from clutter. The active radar detection and used against it and stored in the target parameter library tracking function 97 steers the active radar beam to 85. This search includes not only the angular sector track the target, controls the track filters and monitors containing the target, but also as much surrounding 5 errors in tracking tO schedule when tO generate the next space as can be accommodated by the'field Of regard of radar measurement. The update rate is minimized con- the phased array unit 31. A Spoiled beam is used for the sistent with good tracking data tO reduce the schedule threat signal search to allow it to be accomplished more burden on the front end assets as in the case with the rapidly. The full aperture 57 of the phased array unit 31 ECM processing. is used for measurements on the target tO enhance the 10 The active radar detection and tracking function 97 accuracy of tracking measurements. This search per— also compares the returned radar image with the high mits the seeker electronic signal processing function 89 resolution image stored in the target library 87 to pro- to detect any fire control system which may used tO try vide additional confirmation of the target’s identify. If tO shoot the missile down. In an inner air battle situa- target emissions provide sufficient guidance data for the tion, other surface combatants or aircraft, for example, 15 emitter signal processing function 89 the active radar may be assigned reSpOnsibilities for defending critical mode may not be critical. It can still in this instance assets such as aircraft carriers. Maintaining a search for provide an independent confirmation Of the target’s such threats allows the seeker the Option of implement- identify through the comparison with the stored high ing self-protection countermeasures to enhance its prob- resolution map Of the target. If the target ceases emis- ability of surviving tO destroy the target. Measurements 20 sion, active radar homing can be initiated to fill the gap. from different intercepted emissions are compared by a If the target’s threat warning sensors detect the seeker target coordinate correlation module 91 with the ex- emissions and initiate self protection countermeasures, pected target coordinates tO assure that the emissions then the emitter signal processing function 89 can tran- from different sources are not allowed to corrupt the sition to a home on jam mode or the broad band capabil- target state estimate in the guidance tracking filter of 25 ity of the seeker can be employed tO identify a clean the emitter signal processing function 89. Co-located frequency band in which to Operate. The bandwidth of emitters from the same angle are associated and used to ' the seeker is sufficient to make the self-protection jam- check for consistency with the target platform identity mer task for the target extremely difficult. An option defined at launch. By using targeting emission sets to also exists to place the seeker frequency for active radar confirm identify, the seeker gains a measure of immu- 30 very close to a high power emitter onboard the target. nity from decoy counter measures which may capture This forces the target to deny itself either self protection other seeker guidance modes. jamming or fire control radar. For most practical ship A threat lethality assessment module 93 monitors the self-protection systems, placing the seeker a few mega- target emissions processed by the emitter signal process- hertz (5-10 MHz) from an onboard radar. will permit ing function 89 to determine the degree Of threat. If the 35 the missile seeker 29 an opportunity to operate with lethality assessment module 93 determines that the mis- impunity since the targets onboard threat warning re- sile has become engaged by a fire control system, it ceiver will have to filter out its own fire control radar initiates self-defense countermeasure operation by an emissions and will probably filter out the missile seeker ECM technique management module 95. The ECM in the process. technique management module 95 selects from an ECM 40 An onboard track data fusion function 99 in the technique library 96 and implements an ECM technique seeker guidance processor 35. allows the ARM mode optimized for the specific threat system. Since the target data from the emitter signal processing function seeker has a DRFM (in the waveform generator 75), a 89 to be compared with comparable data from the ac- full range Of ECM techniques can be supported includ- tive radar seeker 97 and the preflight target coordinates. ing: noise, repeater and coherent range and velocity 45 This serves tO confirm target identity through indepen- deception. The ECM technique management module 95 dent measurements. It also makes possible an inexpen— generates the apprOpriate ECM parameters and pro- _ sive but robust capability to overcome the effects Of vides beam steering information for the seeker. such countermeasures as emission control, chaff, active Through the use of the electronically steered beam. decoys, radar cross-section (RCS) reduction and jam- high effective radiated power (ERP) jamming can be 50 ming. All of these techniques attack only one Of the directed at emitters either on the target or elsewhere as seekers guidance techniques, and either have no effect needed. The jamming is timed integrally with emitter on or actually enhance the others. measurements on a look-through budget designed to The guidance mode management function 101 ac- Optimize the balance between the functions supported at cesses the fused track files generated by the track data any given time by the time shared front end resources. 55 fusion function 99 and the current navigation function The capability Of being able to support not only self 83 and optimizes the selection of a guidance mode protection jamming against the target, but also to be which include the active mode, semiactive mode, hom- able to use it against emitters not associated with the ing and self-protection ECM. It also determines which target is made possible by use of the wafer scale front target to track and can switch targets if data received end technology which providesacompact light weight, 60 from the track data fusion function 99 indicate that electronically agile aperture. another target better matches the assigned target. The When the navigation function 83 concludes that the guidance mode management function 101 also utilizes missile is within a programmed terminal approach data from the navigation function 83 tO generate missile range, the seeker has an Option tO initiate an active radar control signals 103 which are passed to the flight con- homing guidance mode. The active radar detection and 65 trols through the flight control interface 45. In applica- tracking module 97 generates waveform data and beam tions where a semiactive radar mode is feasible (e.g., steering information to the intermediate frequency unit air-tO-air), the guidance mode management function 101 33. A Fast Fourier Transform is applied to target data includes that data in its control mode optimization Oper- 5,061,930 9 ation. Semiactive data is sensed through the same hard- ware and signal processing functions as active radar but with a reference signal being provided by a reference receiver through the reference channel receiver inter- face 47. An RF management function 105 develops usage schedules for the functions which the guidance mode management function 101 selects. Since in general, the functions are in conflict for hardware resources, arbitra- tion must be performed. Target tracking update mea- surements do not generally require high asset duty cy- cles. Update rates from one to perhaps ten Hertz suffice for most tracking functions independent of whether active, semiactive or ARM homing guidance modes are being used. Data collection requirements for the neces- sary measurements are generally low (a few millisec- onds) compared to the update rate. This allows a rea- sonable amount of schedule for emitter search and self- protection jamming to be interleafed. When jamming is needed, it tends to be a relatively high user of asset duty cycle (perhaps 80—90 percent to maintain effectiveness), hence, the task for the RF management function 105 is to schedule asset utilization in such a way as to optimize overall missile performance. While this is a significant extension in the sophistication of missile seekers com- pared to systems in current inventory, it is not difficult to achieve. Given the extraordinary resource of the high gain seeker front end which has the bandwidth and the sensitivity to support all of these guidance modes, scheduling is relatively straight forward to implement. Real time micromanagement of the front end resources, including such functions as beam steering, receiver dwell timing, receiver tuning, and coherent integration period timing are performed by the real tirne control processor 77 under the control of the RF management function 105 and the guidance processor 35.. While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alterna- tives to those details could be deveIOped in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illus- trative only and not limiting as to the scope of the in- vention which is to be given the full breadth of the appended claims and any and all equivalents thereof. What is claimed is: 1. A multi-mode seeker system for a missile compris- ing: a wide band phased array transmitter/receiver unit having an electronically agile aperture through which RF energy over a wide band of frequencies and in directions over a wide angle in both azimuth and elevation is transmitted and received; a multiu-mode intermediate frequency unit selectively generating radar and electronic countermeasure RF energy waveforms for transmission by said wide band phased array transmitter/receiver unit, and selectively detecting and measuring parame- ters of reflected radar and external emissions of RF energy received by said wide band phased array 60 transmitter/receiver unit; and a guidance processor responsive to the measured parameters controlling selection of said radar and electronic countermeasure RF energy waveforms 10 15 20 25 30 35 45 50 55 10 2. The system of claim 1 wherein said wide band phased array transmitter receiver unit includes a wafer scale phased array device comprising a plurality of semiconductor transmit and receive cells and a mani- fold for distributing RF energy waveforms to be trans- mitted to and for gathering RF energy received by, said semiconductor transmit and receive cells. 3. The system of claim 2 wherein said wide band phased array transmitter/receiver unit transmits and receives RF energy over a range of frequencies from about 2 GHz to about 35 GHz. 4. The system of claim 2 wherein said guidance pro- cessor includes means controlling said multi-mode in- termediate frequency unit and said wide band phased array transmitter/ receiver unit to selectively time mul- tiplex transmission of radar and electronic countermea- sure RF energy waveforms and reception of reflected radar and external emissions of RF energy for selective simultaneous tracking of targets with radar, and search- ing for, tracking and applying electronic countermea- sures to emitters of said external emissions of RF en- ergy. 5. The system of claim 4 wherein said multi-mode intermediate frequency unit includes first narrowband means detecting and measuring parameters of said re- flected radar RF energy and second wide band means detecting and measuring parameters of received exter- nal emissions of RF energy. 6. The system of claim 5 wherein said guidance pro- cessor includes emitter signal processing means respon— sive to the parameters of external emissions of RF en- ergy measured by said second wide band means for identifying and tracking multiple external emissions of RF energy. '7. The system of claim 6 wherein said guidance pro- cessor includes threat leathality means identifying exter- nal emissions of RF energy tracked by said emitter signal processing means which pose a lethal threat, and ECM technique means generating parameters for said intermediate frequency unit to generate said electronic countermeasure RF energy waveform to jam the exter- nal emission identified as a lethal threat and generating steering information for transmission of said electronic countermeasure RF energy waveform by said wide band phased array transmitter/receiver unit. 8. The system of claim 7 wherein said ECM tech- nique means includes means for generating parameters for said intermediate frequency unit to generate time multiplexed electronic countermeasure RF energy waveforms and for simultaneously jamming multiple external emissions of RF energy identified as lethal threats by said lethal threat means and generating steer- ing information for transmission of said time multi- plexed electronic countermeasure RF energy wave- forms by said wide band phased array transmitter/- receiver unit. 9. The system of claim 6 wherein said guidance pro- cessor includes means for selectively generating guid- ance signals for steering said missile to selectively home on an external emission of RF energy tracked by said emitter signal processing means. 10. The system of claim 6 wherein said guidance processor includes a threat library storing parameters generated by said intermediate frequency unit and 65 for expected external emissions of RF energy from an for controlling the direction in which the wide band phased array transmitter/receiver unit trans- mits and receives RF energy. assigned target, and correlation means correlating pa- rameters of the external emissions of RF energy tracked by said emitter signal processing means with the stored 5,061,930 11 parameters of said expected external emissions of RF energy to identify the assigned target. 11. The system of claim .10 wherein said guidance processor includes active radar tracking means reSpon- sive to parameters of radar RF energy measured by said first narrowband means to actively radar track a target illuminated by radar waveforms transmitted by said wide band phased array transmitter/receiver unit, a target class library storing expected parameters of radar RF energy expected to be reflected by the assigned target and means correlating the measured parameters of radar RF energy received with the expected parame- ters of radar RF energy to identify the assigned target. 12. The system of claim 11 including means fusing identification of the assigned target by said correlation means and identification of the assigned target using said threat class library to confirm the assigned target. 13. The system of claim 6 wherein said guidance processor includes means storing the expected geo- 5 10 15 12 flight, determining therefrom and the parameters of received RF energy the geographic location of targets being tracked, and correlating the determined geo- graphic location of a target with the expected geo- graphic location to confirm tracking of the assigned target. 14. The system claim 4 wherein said guidance proces- sor includes means for storing parameters for identify— ing an assigned target and means correlating said stored parameters with the measured parameters of received RF energy to identify received RF energy associated with the assigned target. 15. The system of claim 14 wherein said guidance processor includes means to generate signals guiding said missile to the assigned target by tracking the re- ceived RF energy identified as associated with the as- signed target, and to transfer guidance to another target when the measured parameters of received RF energy associated with said another target better correlate with graphic coordinates of an assigned target, and means 20 the said stored parameters for the assigned target. tracking the geographic position of the missile during 25 30 35 45 50 55 65 t * t * t ...
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Patent-5061930 - United States Patent [19] Nathanson et a1....

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