M-5N5A VAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA _0 DTIC ELECTEf" NOV 1 419 THi1s4 (cid:127)SIS 94-34965 THE IR MISSILE (SPIN-SCAN AND CON-SCAN SEEKERS) COUNTERMEASURES by Ting Li Chang September, 1994 Thesis Advisor: Alfred W.Cooper Approved for public release; distribution is unlimited. 94 1110 Ci&2 REPORT DOCUMENTATION PAGE Fo AppiwdOMB No 0704-01it Pubbc reportai bowdcn for dauesc iccoon of information u esba(cid:127)u(cid:127)d to avwmc I hour per responac, mduiumthh e time for revicwm utsv;oon, seaarciwng exinalg data sourcm gaihenag and manmurnag the da-an eded and romplsng amd r'vierwig the coitenon of informao. Send comumi rqadve ths btwden esatnai or any o ther aspect of daisc obection of rnoinatoon, mcludmn suggestions for reducing thu burden, to Wasiwigton Headquarten Ser'.j, Directorate for Inonnaton Operationi and Reports, 1215 Jeffersom Dams Hisgh%), Suite 1204. Arimnon, %A 222024302Z and to the office of .Managemen and Budget Paprwork Redcaon Prowe (0704-0118) Washinton DC 20303 I AGENCY USE ONLY (Leave blank) 2 REPORT DATE 3 REPORT TYPE AND DATES COVERED I September, 1994 1 Master's Thesis 4. TITLE AND SUBTIrLE THE IR MISSILE (SPIN-SCAN AND CON-SCAN 5 FUNDING NUMBERS SEEKERS) COUNTERMEASURES (M) 6 AUTfHOR(S) Chang.Ting Li 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 9 PERFORMING Naval Postgraduate School ORGANIZATION Monterev CA 93943.5000 REPORT NUMBER 9 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) I1) SPONSORING/MONITORING AGENCY REPORT NUMBER I I SUPPLEMENTARY NOTES The views expressed in this thesis are those of the author and do not reflect the - official polich or position of the Dpartment of Defense or the U.S Government 12a DISTRIBTIMON/AVAILABil.ITY STATEMENT 12b. DISTRIBUTION CODE Approved for public releasc. distribution is unlimited "A 13 AWBS'iALACT maximum 200 words) In thL combat scenario where the infrared nussile is an almost continuous threat during the operation, fighter aircraft are currently quite suscptible to being killed in attacks by infrared missils. Theoretical analysis applied to an encounter simulation seem, to indicate that it is possible to use the infrared Active Jammer and the expendable decoy ( flare ) to defeat the infrared mnussilt (spin-scan and con-scan seekers). The th, -retical analysis of a simplified case of a spin-scan and cor.-scan reticle with amplitude modulation, frequency modunlation ;id phae modulation leads to expressions for the targets' positions. as seen by the mnissile seeker, under no-jamiung condition. The- signal waveforms consist of target radiation power falling on the reticle and the reticle modulation function. We apply sigr.al processing techniques to the modulated signal to determine the tracking error rate under no-jammung, active jamming and flare jamming different conditions, and by comparing with the unjammed tracking error rate. to deterrmne the differences and efftctiveness of jammuing. The analytical result is simulated by means of a simulation program (MATLAB). which evaluates the change in the missile LOS (line of sight ) rotation tale and the impact on the rmssile guidance operation. The analysis indica'cd -.u :,essfuI jammrung in the different jamming source situations. Following the jamrrung analysis. one can use the result to do further operational analysis as in OT&E ( operation test and evaluation ) and to cvaluat: the operational effectiveness of the lammers and to develop operational tactics to further increase the survivability of the fighter aircraft in the combat situation. 14 SUBJECT TERMS Infrared missile (spin-scan and con-3can seekers) 15 NUMBER OF countermeasure, aircraft surviability PAGES 80 16 PRICE CODE 17 SECURITY 18 SECURITY 19 SECURITY 20 LIMITATION CLASSIFICATION CLASSIFICATION CLASSIFICATION OF OF REPORT OF THIS PAGE OF ABSTRACT ABSTRACT Unclassified Unclassified Unclassified UL NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed b,%A NSI Std 2ý19-18 299-102 ii Approved for public release; distribution is unlimited. THE IR MISSILE (SPIN-SCAN AND CON-SCAN SEEKERS) Acce~iiof Fer COUNTERMEASURES NTIS CRAMI OTIC TAB by unannounced Justification. ..... Ting Li Chang By... Lieutenant Colonel, Republic of China Air Force Di~tributiton I B.S.,Republic of China Air Force Academy, 1981 Availability Codes A~vail andjor Dt Specia Submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN SYSTEMS ENGINEERING from the NAVAL POSTGRADUATE SCHOOL September 1994 Author: ~~igihn Approved by: -___n Alfred W. Cooper, Thesis Advisor Frederic H. Levien, Chairmian Electronic Warfare Academuic Group ABSTRACT In the combat scenario where the infrared missile is an almost continuous threat during the operation, fighter aircraft are currently quite susceptible to being killed in attacks by infrared missiles. Theoretical analysis applied to an encounter simulation seems to indicate that it is possible to use the infrared Active Jammer and the Expendable Decoy (flare ) to defeat the infrared missile (spin-scan and con-scan seekers). The theoretical analysis of a simplified case of a spin-scan and con-scan reticle with amplitude modulation, frequency modulation and phase modulation leads to expressions for the targets' positions, as seen by the missile seeker, under no-jamming condition. The signal waveforms consist of target radiation power falling on the reticle and the reticle modulation function. We apply signal processing techniques to the modulated signal to determine the tracking error rate under no-jamming, active jamming and flare jamming different conditions, and by comparing with the unjammed tracking error rate, to determine the differences and effectiveness of jamming. The analytical result is simulated by means of a simulation program (MATLAB), which evaluates the change in the missile LOS (line of sight ) rotation rate and the impact on the missile guidance operation. The analysis indicated successful jamming in the different jamming source situations. Following the jamming analysis, one can use the result to do further operational analysis as in OT&E ( operation test and evaluation ) and to evaluate the operational effectiveness of the jammers and to develop operational tactics to further increase the survivability of the fighter aircraft in the combat situation iv TABLE OF CONTENTS INTRODUCTION ........ I A. BACKGROUND ...... ........ I B . SC O P E . . . . . . . . . . . . . . . .. . . . . . . . . I C. GENERAL SCENARIO 2 THE AIRCRAFT IR SIGNATURE CHARACTERISTICS. 3 A. GENERAL INFRARED SIGNATURE FACTORS ......... 3 I Jet Engine Signature Approximation . .. . 44..... 2. Plume Radiation . 5 3. Aerodynamic Heating 6 4. Solar Reflection .. . . .. . .. ... ... . .... 7 5. Earthshine .. . . . ... . 8 B. ATMOSPHERIC TRANSMISSION. 9 of C. INFRARED SIGNATURE IN THE MISSION PROFILE .... 9 Ill. THE INFRARED MISSILE SYSTEM. 10 A. AIRFRAME AND PROPULSION 10 B GUIDANCE AND STEERING 10 C IR MISSILE SEEKER 12 I Sensor 12 1' 2. Seekers 12 a. Spin-Scan Seeker .3.. ....... .. . 3 b Ccn-Scan Seeker ...... 15 IV. THE FALSE TARGET SIGNAL 17 A INFRARED FLARES ..... . 17 1. Flare Intensity 17 2. Flare Ejection 18 B. ACTIVE IR JAMMER. 18 V. SPIN-SCAN SEEKERS VS. FLARE AND IR JAMMER 19 A. BACKGROUND TO THE ANALYSIS ..... ....... 19 B. ANALYSIS ........ 19 C. THE ACTIVE IR JAMMER . ......... 20 I Target And Jamming Signal Seen By The Seeker 20 2. The Tracking Error Signal Output 22 a. The Seeker With No Jamming .... 26 b The Seeker Under Jamming Condition. 27 (1) Jamming Power Fixed And Modulation Frequency Varied 27 (2) Jamming Power Varied And Modulation Frequency Fixed 29 (3) Jamming Power And Modulation Frequency Varied 31 D FLARE JAMMING 34 1 Target And Flare Signal Seen By The Seeker 34 2 The Tracking Error Signal Output 35 vi E COMMENT AND RESULT ... 41 VI. CON-SCAN SEEKERS VS FLARE AND IR JAMMER ...... 42 A. BACKGROUND TO THE ANALYSIS ............... 42 B. ANALYSIS ...... ... .... 42 C FLUX SIGNAL 44 D. CON-SCAN SEEKER WITH NO JAMMING ....... 45 E. CON-SCAN SEEKER UNDER ACTIVE IR JAMMING . 49 I Target And Jamming Signal Seen By The Seeker. 49 2. The Tracking Error Signal Output 5I a. The Jamming Modulation Frequency Same As The Reticle Modulation Frequency .. ..... 52 b The Jamming Modulation Frequency Different From The Reticle Modulation Frequency . . . 54 F CON-SCAN SEEKER UNDER FLARE JAMMING 59 G COMMENT AND RESULT 64 VII CONCLUSION 66 APPENDIX A SAMPLE OF THE SIMULATION PROGRAM. 67 LIST OF REFERENCES 69 INITIAL DISTRIBUTION LIST 71 vii ACKNOWLEDGMENT The author would like to acknowledge the financial support of this research by the Naval Postgraduate School Direct Funded Research Program through E W Academic group. The author wants to thank Prof A.W.Cooper for his guidance and patience during the work in performing this Thesis Finally, I thank most of all my Parents and my wife, Ruey-Chen, for their encouragement and love and my two lovely sons,Chun-Po and Chun-Chieh, who received little time and attention over many past months Vill I. INTRODUCTION A. BACKGROUND Aircraft on an operational mission will not only be threated by surface to air missiles but they will also be threated by air-to-air missiles, which include missiles with many different guidance systems In the past experience we find that the JR missile is the most efficient weapons threat to the aircraft B. SCOPE This thesis will address a particular aspect of this threat - the threat by the infrared guided missile. This is because IR mis.'-.es are rather successful, as observed in the last 30 years, the kills of aircraft by IR missiles almost reach to 93% of the total compared to 5% for the radar missile and Gunfire For this thesis, we will consider aircraft that are already deployed, therefore the scope of survivability enhancement by vulnerability reduction is more limited than increasing survivability by susceptibility reduction Hence we will concentrate on the easier task of finding measures to reduce the susceptibility of these aircraft to being hit by an IR missile Due to US government restrictions on dissemination of security-sensitive information, this thesis will be constrained to a more generic treatment of the problem