DECLASSIFIED-PUBLIC DISCLOSURE IMSM-04S2-Q2 DECLASSIFIE-MISE EN LECTURE PUBLIQUE

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1 "Sm ü Isli nl N a. ^ ^ L.. APPROVED FOR PUBLIC D ISCLOSURE C O P Y N O 046 N O R T H A T L A N T I C M I L I T A R Y C O MM I T T E E C O M I T E MI L I T A I R E D E L ' A T L A N T I Q U E N O R D IMSM-II M a r c h 1969 MEM O R A N D U M F O R T H E M I L I T A R Y A G E N C Y F O R S T A N D A R D I Z A T I O N S U B J E C T : M i l i t a r y Ch a r a c t e r i s t i c s f o r the IFF M a r k X (SIF) System ( S T A N A G 5017) Reference : CMCM-26-66, 26 A u g ust 1966 The second draft of STANAG 5017, issued as Enclosure 1 to the referenced document, has b e e n ratified or a p p r oved, with so me reservations, b y the participating nations and is forwarded herewith for promulgation. E N C L O S U R E : A / S C O P Y T O : M I L R E P S M C E W G E M M L I S T B S A C E U R E P S A C L A N T R E P R.M. B A T T L E S R e a p A d m i r a l, G F F o r D i r e c t o r I n t e r n a t i o n a l M i l i t a r y S t a f f REGRADED MATO UNCLASSIFIED t A iw w e ö îtif Public Disclosure) Per Autho/tty M$M-0A&2rQ2, B...Ûate. Æi. ±? 2 VâJ a > c \ I M S M T his document consists of 38 pages [F D is

2 A P P R O V E D FO R PUBLIC D ISCLOSURE N A T O U N C L A S S IFIED E N C L O S U R E TO I MS M N O R T H ATLANTIC TREATY ORGANIZATION ORGANISATION DU TRAITE D E L ' A T L A N T I Q U E NORD MILITARY AGENCY F O R STANDARDIZATION BUR EAU M ILITAIRE D E STANDARDIZATION S T A N D A RDIZATION A G R E EMENT ACCORD D E STANDARDIZATION SUBJECT OBJ ET STANAG No,5017 (2nd D r af t) MILITARY CHAR ACTERISTICS FOR THE IFF M A R K X (SIE) SYSTEM CARACTERISTIQUES.MILITAIRES C O N C E R N A NT L E SYSTEME IFF MARK X (SIF) NATO UNCLASSIFIED ENCLOSURE to lms M mm k m m

3 K l» N A T O UNCLASSIFIED APPROVED FOR PUBLIC D ISCLOSURE 'RECORD OF AMENDMENTS DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE Amdt No Reference and date of R é f é re nce et date de 1 'amendement E NREGISTREMENT DES AMENDEMENTS Date entered Date à laquelle 1 'amendement a été" effective NATO UNCLASSIFIED -3- ENCLOSURE to IMSM By whom entered Signature and Rank Effectué par Signature et grade Remarks Observations i ü

4 w y» o [ i A P P R O V E D F OR PUBLIC DISCLOSURE A P P R O V E D F OR PUBLIC DISCLOSURE S T A N A G NO (2nd D r a f t) E n c losure: O B J E C T T E R MS OF A G R E E M E NT (T ofa) M I L I T A R Y C H A R A C T E R I S T I C S F Q F T H E I F F MARK- X (SIF). "SYSTEM N A V Y / A R MY / A I r [. A n n e x 'A* (TofA) - R a t i f i c a t i o n, I m p l e m e n t a t i o n a n d R e s e r v a t i o n s. 1. ; T o e s t a b l i s h m i l i t a r y c h a r a c t e r i s t i c s a n d s p e c i f y t h e p e r f o r m a n c e required, o f t h o s e s y s t e m e l e m e n t s w h i c h m u s t b e t r e a t e d i n a u n i f o r m m a n n e r t o m e e t the o v e r - a l l o p e r a t i o n a l r e q u i r e m e n t s of t h e IFF M a r k X (SIF) S y s t e m s i n N A T O F o r c e s. R E L A T E D D O C U M E N T S 2. a. S T A N A G Ho b. A C P c. A C P N A T O S U P P - 1 R A T I F I CA T I O N A N D I M P L E M E N T A T I O N. d. A C P N A T O S U P P - 2. A C P 16 0 N A T O S U P P - 3, A C / D / 1 6, 7 A p r i l a. D e f i n i t i o n of R a t i f i c a t i o n. R a t i f i c a t i o n is d e f i n e d as: 'The d e c l a r a t i o n b y w h i c h a n a t i o n f o r m a l l y a c c e p t s the c o n t e n t of t h i s S t a n d a r d i z a t i o n A g r e e m e n t. 1 b, D e f i n i t i o n of I m p l e m e n t a t i o n. I m p l e m e n t a t i o n is d e f i n e d as: T h e f u l f i l m e n t b y a n a t i o n ' s f o r c e s c o n c e r n e d of t h e i r o b l i g a t i o n s u n d e r t h i s S t a n d a r d i z a t i o n A g r e e m e n t, as d e f i n e d i n the D e t a i l s of A g r e e m e n t. f e. R a t i f i c a t i o n. I m p l e m e n t a t i o n a n d R e s e r v a t i o n s» A n n e x A t o t h e s e T e r m s of A g r e e m e n t s h o w s the s t a t e of r a t i f i c a t i o n a n d i m p l e m e n t a t i o n f o r this S T A N A G t o g e t h e r w i t h a n y r e s e r v a t i o n s. -1-

5 mm «y» A P P R O V E D F O R PUBCIC DISCCOSURE NATO U N C L A S S IFIED DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE AGREEMENT I4.. a. The Details of A g r e e m e nt in the followin g pages (pag es ) have h e e n approved b y those nations shown as ratifying them in Annex * A T (TofA). No departure m a y be made from the agreement without consultation w i t h the Military Agency for Standardization, h. Nations may propose alternations to the Details of Agreement at any time, should they consider them to have hecome obsolete or require improvement. Such proposals should be submitted at the earliest opportunity to the Military A g e n c y for Standardization and the Communications- E lectronics Division, where they will be processed in the same m a n n e r as the original agreement. N A T I O N A L O R D E R S. MA N U A L S A N D I N S T R U C T I O N S 5. Ratifying nations agree that national orders, manuals and instructions implementing this STANAG will include a reference to the S TANAG number for purposes of identification. Chairman. M AS D a t e of P r o m u l g a t i on N A T O U N C L A S S IF I E D -2- mm «h ä * A P P R O V F D FOR PUBLIC DISCLOSURE

6 mm «L a» Di APPROVED FOR PUBLIC DISCLOSURE DECLASSIFI ED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE NATO UNCLASSIFIED BELGIUM CANADA* NATION DENMARK RATIFICATION AND IMPLEMENTATION NATIONAL RATIFYING REFERENCE : No.4498, 19 Oct 66^ L (DSCES) dated 9 Nov 66 CHOD/S.158, 11 Jan 6 7 /... P RANCE* DPT 129, 23 May 6?^ Federal Republic of GERMANY GREECE* ITALY55 GE/MCEW G , 26 Peb 69/ A:6172/F,747, 25 Nov 66^ 154/NU/23790/508Ikh 30 Ausc 67/ Annex TA' to TERMS OF AGREEMENT of STANAG 5017 FORECAST DATE ACTUAL DA'TE SERVICES IMPLEMENTING. Navy Army Air Navy A m y Air Navy Army A i r Navy Army A ir Navy Army Air.,Navy Army Air Navy Army A i r LUXEMBOURG H.3781, 11+ Sep 66^ Army SUTHERLANDS / Nov 66/ A/H-2213/67/B/ NORWAY l o k / o i i / h m s / h s / CMCM FOR TUGAL* No.31»P/67, 17 Peb Sir HfiRKEY* Serial:3/5275-, 132, 12 Sep 67/ UNITED KINGDOM* AF/T2hO3/6h-Ops/ I P P / M (6 7)2, dated 6 M a r.67 2 months after promulßati on UNITED STATES* A - 5I-67(B - 106c ) 9 June 67/ NATO Effective Date ^ S e Reservations/Restrictions overleaf ^ Correspondence Reference Navy Army Air Navy Army A ir Navy A ir Navy Army Air Navy Army Air Navy Army A i r. - NATO UNCLASS I F APPROVED FOR PUBLIC DISCLOSURE

7 mmapproved FOR PUBLIC DISCLOSURE DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE RESERVATIONS C A N A DA R a t i f i c a t i o n g i v e n w i t h o u t p r e j u d i c e to f u r t h e r a m e n d m e n t s w h i c h m a y b e p r o p o s e d s u b s e q u e n t l y as t he n e e d a r i s e s. ( C D W 233O - 2, 2 k J a n 67) D E N M A R K E x i s t i n g e q u i p m e n t w i l l n o t b e m o d i f i e d, (CHQD/5.I5 Ö, 11 Jan 67) F R A N C E R a t i f i c a t i o n g i v e n o n t h e u n d e r s t a n d i n g t h a t the f o l l o w i ng c o m m e n t s w i l l b e i n c l u d e d i n t he f i r s t r e v i s i o n o f t he S T A N A G : ".... F r a n c e a g r e e s t o t h e c u r r e n t w o r d i n g of S T A N A G b u t i t i s d e e m e d a d v i s a b l e f o r t h e s a k e of c l a r i t y to m o d i f y as f o l l o w s the f i r s t s e n t e n c e of p a r a g r a p h U a ~ of D e t a i l s of Agreement 7 t o r e a d - 'The s t a n d a r d maximum, e f f e c t i v e r a d i a t e d p e a k p o w e r f r o m t h e i n t e r r o g a t o r a n t e n n a ( t r a n s m i t t e d p e a k p o w e r p l u s a e r i a l g a i n, l e s s l o s s e s ) s h a l l b e 5 2,5 db a b o v e o n e w a t t r «, E q u i p m e n t s c u r r e n t l y i n s e r v i c e w i l l n o t b e m o d i f i e d t o c o m p l y w i t h t h e s t a n d a r d s o n I d e n t i f i c a t i o n o f P o s i t i o n a n d E m e r g e n c y P o s i t i o n ( p a r a g r a p h 3 n - 3 o), ( D F T 1 2 9, 2 3 M a y 6 7 ) G R E E C E P o s i t i o n r e s e r v e d o n i m p l e m e n t a t i o n d a t e, d e p e n d i n g u p o n the p r o c u r e m e n t p r o c e e d i n g s t h r o u g h the U S M i l i t a r y A s s i s t a n c e P r o g r a m. ( A : 6 l 7 2 / F , 25 N o v 66) N A T O UNCLj IÜI I W B D -., mm

8 mm I T A L Y P o s i t i o n r e s e r v e d o n i m p l e m e n t a t i o n d a t e. A p p r o v a l o f s u c h date, o r f u r t h e r p r o p o s a l t h e r e o n, w i l l b e f o r w a r d e d a s s o o n as c u r r e n t s t u d y o n t e c h n i c a l a n d f i n a n c i a l i m p l i c a t i o n s is c o m p l e t e d. {154/ N U / 23790/ 5O 8141+, 3 0 A u g 6 7 ) P O R T U G A L R a t i f i c a t i o n g i v e n w i t h t h e f o l l o w i n g p r o v i s o r s : a. T h e P o r t u gu e s e N a v y a n d A i r F o r c e r a t i f y S TA N A G 5O I 7 ( 2 n d D r a f t ). b. A t p r e s e n t t h i s S T A N A G h as n o a p p l i c a t i o n f o r t he Army. The C i v i l A e r o n a u t i c D e p a r t m e n t s t i l l h a s t h e s a m e c o m m e n t as g i v e n i n / ^ M / M e m o 22J-8-P/64 d a t e d. 7 J u l y k _ / a n d t h e r e f o r e its r a t i f i c a t i o n r e g a r d s T U R K E Y o n l y t h e c o m p a t i b i l i t y o f the m i l i t a r y s y s t e m I F F M a r k X (SIF) o p e r a t i n g i n m o d e A, w i t h the I C A O s e c o n d a r y s u r v e i l l a n c e r a d a r (SSR) o p e r a t i n g i n m o d e 3 a n d u t i l i z i n g the t o l e r a n c e s o f t h e m o d e r n e q u i p m e n t a n d o p e r a t i o n w i t h s i d e l o b e s u p p r e s s i o n (SLS) d. It is n o t f o r e s e e n t o h a v e a n y e q u i p m e n t i n f u n c t i o n p r i o r to 1970, (N0.3 I - P / 6 7, 1 7 F eb 6 7 ) R a t i f i e d w i t h r e s e r v a t i o n t h a t t he e q u i p m e n t c u r r e n t l y 1 s e r v i c e w i l l n o t b e m o d i f i e d t o c o m p l y w i t h t h e S T A N A G. (Serial: 3 / , 12 S e p 67) U N I T E D K I N G D O M R a t i f i c a t i o n g i v e n w i t h o u t p r e j u d i c e to t h e i n c l u s i o n i n t h e s e c o n d i s s u e of t he p r o p o s e d a m e n d m e n t s a t t a c h e d. ( U K R , 30 M a r 67) I M M a Ä g M i E ) N A T O UN<

9 mm M ( g y» die) A P P R O V E D F O R PUBCIC DISCCOSURE APPROVED FOR PUBCIC DISCCOSURE DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE EncIos\ires I. II. A G R E E M E N T D E T A I L S OF A G R E E M E N T (DofA) A n n e x ' B r to T E E M S OF A G R E E M E N T of S T A N A G M I L I T A R Y C H A R A C T E R I S T I C S F O E T H E IFF M A R K X III. IV. V. A n n e x A n n e x A n n e x A n n e x (SIF) S Y S T E M 1 A f (DofA) (B* (DofA) ' C (DofA)!D f (DofA) A n n e x E* (DofA) G e n e r a l S y s t e m R e q u i r e m e n t s D e s c r i p t i o n of t h e B a s i c IFF M a r k X S y s t e m D e f i n i t i o n of P u l s e M e a s u r e m e n t s D e s c r i p t i o n of I F F M a r k X (SIF) S y s t e m P u r p o s e of I n t e r r o g a t i o n S i d e L o h e S u p p r e s s i o n (ISXS') 1. It is a g r e e d t h a t IFF M a r k X (SIF) S y s t e m e q u i p m e n t s, c o n t r a c t e d f o r s u b s e q u e n t t o a p p r o v a l o f t h i s S T A N A G, s h o u l d m e e t t h e c h a r a c t e r i s t i c s sp e c i f i e d h e r e i n. T h e y s p e c i f y the t e c h n i c a l p a r a m e t e r s, t o l e r a n c e s, a n d t e c h n i q u e s t o the e x t e n t r e q u i r e d t o e n s u r e p r o p e r o p e r a t i o n a n d c o m p a t i b i l i t y, i n c l u d i n g c o m p a t i b i l i t y, w h e r e a p p r o p r i a t e, w i t h t h e I n t e r n a t i o n a l C i v i l A v i a t i o n O r g a n i z a t i o n ( ICAO) S e c o n d a r y S u r v e i l l a n c e R a d a r (SSR) S y s t e m. T h e e x i s t e n c e of IFF M a r k X (SIF) S y s t e m e q u i p m e n t s w h i c h d o n o t f u l l y m e e t the m i l i t a ry c h a r a c t e r i s t i c s s p e c i f i e d h e r e i n, is r e c o g n i z e d. As a r e s u l t t h e s e e q u i p m e n t s c a n be e x p e c t e d to s u f f e r s o m e d e g r a d a t i o n i n p e r f o r m a n c e, i n a c o m m o n m i l i t a r y / c i v i l i a n e n v i r o n m e n t. E v e r y e f f o r t w i l l b e m a d e t o m e e t the c h a r a c t e r i s t i c s s p e c i f i e d h e r e i n as s o o n as it is f e a s i b l e. -3-

10 mm M M M i E APPROVED FOR PUBLIC DISCLOSURE 2. I FF M A S K X fs IFl S Y S T E M C H A R A C T E R I S T I C S ( S I G N A L S I N S P A C E ) DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE a. ^ ' R E C O M M E N D A T I O N S. (1) C e n t e r F r e q u e n c y ± 0. 5 M c / s * (2) P o l a r i z a t i o n... (3) M O D E S D e s i g n a t i o n..,. M o d e s 1, 2 a n d 3 / A (4) P u l s e D e s i g n a t i o n.. P^ a n d P^ (5) P. a n d P, i n t e r v a l s. M o d e 1. 3 ± 0. 2 M o d e 2. M o d e 3 / A. (6) P u l s e D u r a t i o n m i c r o s e c s * m i c r o s e c s m i c r o s e c s (7) P u l s e R i s e T i m e.... b e t w e e n a n d 0. 1 m i c r o s e c s 36 (8) P u l s e D e c a y T i m e.... b e t w e e n a n d 0. 2 m i c r o s e c s * (9) P^ a n d P ^ A m p l i t u d e... n o t t o e x c e e d 1 db D i f f e r e n c e It is r e c o m m e n d e d t h a t i n n e w e q u i p m e n t d e s i g n the p u l s e d e c a y t i m e b e l i m i t e d b e t w e e n a n d m i c r o s e c o n d s, t he p u l s e i n t e r v a l t o l e r a n c e b e r e d u c e d to m i c r o s e c o n d s, a n d t h e f r e q u e n c y t o l e r a n c e b e l i m i t e d t o M c/s. s, en 0TE: E x i s t e n c e of i n t e r r o g a t o r s w i t h f r e q u e n c y s t a b i l i t y n o b e t t e r t h a n 2. 5 M c / s is r e c o g n i z e d. I n a d d i t i o n, the e x i s t e n c e of i n t e r r o g a t o r s Is r e c o g n i z e d w h e r e i n t h e d u r a t i o n of p u l s e s P^ a n d P^ is b e t w e e n 0. 7 a n d 1.2 m i c r o s e c o n d s, t he r i s e t i m e is as g r e a t as 0. 2 m i c r o s e c o n d s, a n d the d e c a y t i m e is as g r e a t as 0.i+ m i c r o s e c o n d s. T h e s e e q u i p m e n t s s h a l l b e a c c o m m o d a t e d i n t h e S y s t e m, a n d t h e t r a n s p o n d e r s s h o u l d b e c a p a b l e f r e c e i v i n g a n d r e s p o n d i n g to s u c h i n t e r r o g a t o r s, a l t h o u g h t h e s i d e l o b e s u p p r e s s i o n p e r f o r m a n c e m a y b e d e g r a d e d. (See p a r a 1 o f A n n e x 'E ' ( D o f A ), p a g e ). N A T O UNC]J M M ) W (gm &g)g)[p[p[d

11 mm mmapproved FOR PUBLIC DISCLOSURE U A T O U N C L A S S I F XED b. R e n l y T r a n s m i s s i o n s (1) C e n t e r F r e q u e n c y 1 O 9 O ± 3 * 9 M c / s (2) P o l a r i z a t i on V e r t i c a l (3) M O D E D e s i g n a t i o n s M O D E S 1, 2 a n d 3 / A (U) F r a m i n g P u l s e s T h e r e p l y f u n c t i o n s h a l l e m p l o y (5) I n f o r m a t i o n P u l s e s a s i g n a l c o m p r i s i n g t w o f r a m i n g p u l s e s s p a c e d 2 0, 3 m i c r o s e c o n d s as t h e m o s t e l e m e n t a r y code. I n f o rm a t i on p u l s e s s h a l l b e s p a c e d i n i n c r e m e n t s of I.I4.5 m i c r o s e c o n d s f r o m t h e f i r s t f r a m i n g p u l s e. (6) I n f o r m a t i o n P u l s e s D e s i g n a t i o n - P u l s e P o s i t i o n f M i c r o s e e o n d s ) G 1 1,4-5 A C 2 4»35 a S \ 8, 7 0 X ( R e s t r i c t e d U s e ) 1 0, 1 5 B 1 1 1,6 0 D B D \ V N A T O U N C L A S S I F IED - 5 -

12 APPROVED FOR PUBLIC DISCLOSURE N A T O U N C L A S S I F I E D (7) (8) (9) (10) (11) (12) (13) (14) M O D E 1 E m p l o y s p u l s e p o s i t i o n, A 2, A^, a n d Bg M O D E 2 E m p l o y s a l l p u l s e p o s i t i o n s A, B, C a n d D M O D E 3 / A E m p l o y s all p u l s e p o s i t i o n s A a n d B P u l s e D u r a t i o n P u l s e R i s e T i m e 0, ,1 m i c r o s e c s B e t w e e n 0, 0 5 a n d 0, 1 m i c r o s e c s P u l s e D e c a y T i m e B e t w e e n a n d 0. 2 m i c r o s ecs P u l s e A m p l i t u d e N o t t o e x c e e d 1 db D i f f e r e n c e ( b e t w e e n a n y t w o p u l s e s i n a r e p l y t r a i n ) R e p l y P u l s e P o s i t i o n s T o l e r a n c e s - T h e p u l s e s p a c i n g t o l e r a n c e s f o r e a c h p u l s e ( i n c l u d i n g t h e l a s t f r a m i n g p u l s e ) w i t h r e s p e c t to t h e f i r s t f r a m i n g p u l s e of a r e p l y g r o u p s h a l l h e + 0, 1 m i c r o s e c o n d s I n l / P a n d E m e r g e n c y, t o l e r a n c e s b e t w e e n the l a s t f r a m i n g p u l s e of one p u l s e t r a i n a n d t he f i r s t f r a m i n g p u l s e of the f o l l o w i n g t r a i n s h a l l b e +0.1 m i c r o s e c o n d. T h e p u l s e s p a c i n g t o l e r a n c e of a n y p u l s e i n a r e p l y g r o u p w i t h r e s p e c t to a n y o t h e r p u l s e ( e x c e p t the f i r s t f r a m i n g p u l s e ) s h a l l n o t e x c e e d + 0,1 5 m i c r o s e c o n d. N O T E N A T O I t is r e c o g n i z e d t h a t s o m e e x i s t i n g t r a n s p o n d e r d e s i g n s m a y n ot b e a b l e to m e e t the a b o v e i / P a n d E m e r g e n c y t o l e r a n c e s. à UNCI A P P R O V E D F O R P U B L IC DISCLOSURE

13 M O M e m»! A P P R O V E D F O R P U B L IC DISCLOSURE APPROVED FOR PUBLIC DISCLOSURE R E C O M M E N D A T I O N : It is r e c o m m e n d e d t h a t i n n e w e q u i p m e n t d e s i g n t h a t r e p l y p u l s e p o s i t i o n t o l e r a n c e s b e t i g h t e n e d t o + 0, 0 5 a n d + 0, 0 8 m i c r o s e c o n d s r e s p e c t i v e l y. (1 3 ) C o d e N o m e n c l a t u r e - T he c o d e d e s i g n a t i o n s s h a l l c o n s i s t o f d i g i t s w h i c h l i e b e t w e e n O a n d 7, i n c l u s i v e, a n d s h a l l c o n s i s t of t h e s u m o f the s u b s c r i p t s o f t h e p u l s e n u m b e r s e mp l o y e d as f o l l o w s : D i g i t P u l s e G r o u p F i r s t A S e c o n d B T h i r d C F o u r t h D E x a m p l e s 1, C o d e 36 w o u l d c o n s i s t of i n f o r m a t i o n p u l s e s A ^, A ^, (la s "k " ^ 0 d i g i t s o m i t t e d w h e r e 61+ o r less c o d e s a re used), 2. C o d e 2057 w o u l d c o n s i s t o f Ag, C^, D ^, D 2, D ^ 3. I F F M A R K X fsif ) T R A N S P O N D E R C H A R A C T E R I S T I C S a. R e p l y. T h e t r a n s p o n d e r s h a l l r e p l y w h e n it r e c e i v e s a n i n t e r r o g a t i o n as d e f i n e d i n p a r a g r a p h 2a, i n c l u d i n g the n o t e, u n l e s s p r e v e n t e d f r o m r e p l y i n g b y s u p p r e s s i o n a c t i o n. -7-

14 E M «IL Ä»!]! A P P R O V E D F O R PUBCIC DISCCOSURE DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE b. N o R e p l y. T h e t r a n s p o n d e r s h a l l n o t r e p l y u n d e r e i t h e r o f the f o l l o w i n g c o n d i t i o n s : (1) W h e n t h e i n t e r v a l b e t w e e n i n t e r r o g a t i o n p u l s e s a n d d i f f e r f r o m the s p e c i f i e d s p a c i n g f o r t he p a r t i c u l a r m o d e s e t t i n g b y m o r e t h a n 1.0 microsecofls. N O T E : I t is r e c o g n i z ed t h a t s o m e t r a n s p o n d e r s m a y r e p l y w h e n t he s p a c i n g b e t w e e n P ^ a n d d i f f e r s f r o m the n o r m a l h y 2. 0 m i c r o s e c o n d s. (2) U p o n r e c e i p t of a n y s i g n a l p u l s e. c. D e a d T i m e. A f t e r r e c e p t i o n o f a p r o p e r i n t e r r o g a t i o n, t he t r a n s p o n d e r s h a l l n o t r e p l y t o a n y o t h e r i n t e r r o g a t i o n at l e a s t f o r the d u r a t i o n of t h e r e p l y p u l s e t r a i n. T h i s d e a d t i m e s h a l l e n d n o l a t e r t h a n 125 m i c r o s e c o n d s a f t e r t h e t r a n s m i s s i o n of t h e l a s t r e p l y p u l s e of t he g r o u p. S u r f a c e t r a n s p o n d e r s m a y h a v e d e a d t i m e s of a p p r o x i m a t e l y 225 m i c r o s e c o n d s. d. R e c e i v e r S e n s i t i v i t y and D y n a m i c R a n g e. T h e m i n i m u m t r i g g e r i n g l e v e l of the t r a n s p o n d e r s h a l l b e s u c h t h a t i n t h e a b s e n ce of s u p p r e s s i o n a c t i o n, r e p l i e s a r e g e n e r a t e d t o at l e a s t $Ofa of the i n t e r r o g a t i n g s i g n a l s w h e n t h e a m p l i t u d e o f t h e s e s i g n a l s r e c e i v e d at the a n t e n n a of the t r a n s p o n d e r is n o m i n a l l y 71 d b b e l o w 1 m i l l i w a t t w i t h l i m i t s b e t w e e n 69 a n d 7 7 d b b e l o w 1 m i l l i w a t t. T h e r e p l y a n d s u p p r e s s i o n c h a r a c t e r i s t i c s s h a l l a p p l y o v e r a r e c e i v e d s i g n a l a m p l i t u d e r a n g e f r o m a m i n i m u m t r i g g e r i n g l e v e l to 50 db a b o v e t h a t l e v e l. - 8 mm «[ L a» ûppprwpn f o r Puri in nisr.i dsiirf

15 n r n i s y» D i D e. R e c e i v e r B a n d w i d t h, T h e b a n d w i d t h of t h e r e c e i v e r s h a l l b e c e n t e r e d o n I O 3O m e g a c y c l e s a n d s h a l l b e a d e q u a t e t o r e p r o d u c e t h e i n t e r r o g a t o r p u l s e train, d e s c r i b e d i n p a r a g r a p h 2 a a n d to a c c o m m o d a t e t h e i n t e r r o g a t o r t r a n s m i t t e r f r e q u e n c y t o l e r a n c e a n d t r a n s p o n d e r r e c e i v e r l o c a l o s c i l l a t o r d r i f t s O u t s i d e the b a n d w i d t h I O 3 0, p l u s o r m i n u s 2 5 M c / s, t h e s e n s i t i v i t y of s u p e r h e t e r o d y n e r e c e i v e r s s h a l l b e at l e a s t 6 0 db b e l o w n o r m a l. N O T E : T h e b a n d w i d t h s p e c i f i c a t i o n f o r r e c e i v e r s u s i n g o t h e r t h a n s u p e r h e t e r o d y n e t e c h n i q u e s, i f i t d i f f e r s f r o m a b o v e, s h a l l b e a g r e e d w h e n n e c e s s a r y. f. P u l s e W i d t h D i s c r i m i n a t i o n. S i g n a l s of r e c e i v e d a m p l i t u d e b e t w e e n m i n i m u m t r i g g e r i n g l e v e l a n d 6 db a b o v e t h i s l e v e l, a n d of a d u r a t i o n l e s s t h a n 0. 3 m i c r o s e c o n d, s h a l l n o t c a u s e t h e t r a n s p o n d e r to i n i t i a t e r e p l y o r s u p p r e s s i o n a c t i o n. A n y p u l s e of a d u r a t i o n m o r e t h a n 1. 5 m i c r o s e c o n d s a p p e a r i n g w i t h i n t h e t r a n s p o n d e r r e c e i v e r b a n d w i d t h (see p a r a 3 e ), s h a l l n o t c a u s e t h e t r a n s p o n d e r t o i n i t i a t e r e p l y o r s u p p r e s s i o n a c t i o n., E c h o S u p p r e s s i o n a n d R e c o v e r y. T he t r a n s p o n d e r s h a l l c o n t a i n e c h o s u p p r e s s i o n c i r c u i t r y d e s i g n e d to p e r m i t n o r m a l o p e r a t i o n i n the p r e s e n c e o f e c h o e s o f s i g n a l s i n s p a c e a n d b e c o m p a t i b l e w i t h t h e r e q u i r e m e n t s p e c i f i e d i n p a r a g r a p h 5 d (2) b e l o w» m did

16 N A T O U N C L A S S I F I E D (1) D e s e n s i t i z a t i o n. U p o n r e c e i p t of* a n y p u l s e m o re h. t h a n Ö. 7 m i c ro s e c o n d s i n d u r a t i o n, t h e s e n s i t i v i t y of the r e c e i v e r s h a l l b e l o w e re d s o t h a t a s e c o n d p u l s e 9 d b or m o r e b e l o w the a m p l i t u d e o f the f i r s t p u l s e, a n d at a p o s i t i o n 2 m i c r o s e c o n d s a f t e r t he f i r s t p u l s e, s h a l l h e r e j e c t e d, N O T E : S i n g l e p u l s es of d u r a t i o n less t h a n 0. 7 m i c r o s e c o n d s, o r b e t w e e n 1, 2 a n d 1. 5 m i c r o s e c o n d s, a r e n o t r e q u i r e d t o c a u s e t h e s p e c i f i e d d e s e n s i t i z a t i o n, h u t s h o u l d n o t c a u s e d e s e n s i t i z a t i o n of d u r a t i o n o r a m o u n t to g r e a t e r t h a n p e r m i t t e d b y p a r a g r a p h 3 g (l). (2) R e c o v e r y, F o l l o w i n g d e s e n s i t i z a t i o n, t he r e c e i v e r s h a l l r e c o v e r s e n s i t i v i t y ( w i t h i n 3 d b of m i n i m u m t r i g g e r i n g l e v e l ) w i t h i n 15 m i c r o s e c o n d s a f t e r r e c e p t i o n o f a d e s e n s i t i s i n g p u l s e n o t e x c e e d i n g a p u l s e w i d t h of 1. 2 m i c r o s e c o n d s a n d h a v i n g a s i g n a l s t r e n g t h u p t o 50 db a b o v e m i n i m u m t r i g g e r i n g level. R e c o v e r y s h a l l h e n o m i n a l l y l i n e a r at a n a v e r a g e r a t e n o t e x c e e d i n g 3 «5 db p e r m i c r o s e c o n d. R a n d o m T r i g g e r i n g R a t e. I n s t a l l a t i o n i n the a i r c r a f t s h a l l b e m a d e i n s u c h m a n n e r t h a t w i t h a l l p o s s i b l e i n t e r f e r i n g e q u i p m e n t s i n s t a l l e d i n t he s a m e a i r c r a f t o p e r a t i n g i n t h e i r n o r m a l m a n n e r o n op e r a t i o n a l c h a n n e l s of m a x i m u m i n t e r f e r e n c e, b u t w i t h t h e a b s e n c e o f b o n a f i d e i n t e r r o g a t i o n s, the r a n d om t r i g g e r i n g r a t e ( s q u i t t e r ) of t h e t r a n s p o n d e r s h a l l not e x c e e d t h i r t y r e p l i e s p e r s e c o n d, as i n t e g r a t e d o v e r a n i n t e r v a l e q u i v a l e n t t o at l e a s t l e s s, N A T O

17 » 1 «y * o i A P P R O V E D F O R PUBLIC D IS C L O S U R E i, I n t e r f e r e n c e S u p p r e s s i o n P u l s e s, In. c e r t a i n i n s t a l l a t i o n s, DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE p r o v i s i o n s m a y b e n e e d e d f o r the a p p l i c a t i o n o f s u p p r e s s i o n p u l s e s, f r o m e x t e r n a l e q u i p m e n t ( s u p p r e s s o rs), t o d i s a b l e the t r a n s p o n d e r w h i l e o t h e r e q u i p m e n t is t r a n s m i t t i n g,. T h e r e c e i v e r s h a l l r e g a i n n o r m a l s e n s i t i v i t y, w i t h i n 3 db, n l a t e r t h a n 15 m i c r o s e c o n d s a f t e r the e n d of e a c h s u p p r e s s i o n p u l s e. P r o v i s i o n s m a y b e n e e d e d f o r g e n e r a t i n g a n d p r o v i d i n g s u p p r e s s i o n p u l s e s t o s u p p r e s s o t h e r p u l s e e q u i p m e n t o p e r a t i n g i n the a i r c r a f t, j.. R e p l y R a t e L i m i t C o n t r o l, T o p r o t e c t t h e s y s t e m f r o m the e f f e c t s of t ra n s p on d e r ov e r - i n t e r r o g a t i o n w h e n a p r e d e t e r m i n e d m a x i m u m h a s b e e n r e a c h e d, a r e p l y l i m i t c o n t r o l s h a l l b e i n c o r p o r a t e d i n t h e e q u i p m e n t. T h e r a n g e of t h i s c o n t r o l s h a l l p e r m i t a d j u s t m e n t s o as to l i m i t r e p l i e s to at l e a s t a n y v a l u e b e t w e e n 5OG a n d 2 O O O r e p l i e s t r a i n s p e r s e c o n d, w i t h o u t r e g a r d t o t h e n u m b e r of p u l s e s i n e a c h r eply. S e n s i t i v i t y r e d u c t i o n i n e x c e s s o f 3 db s h a l l n o t t a k e e f f e c t u n t i l 5 0 % of the s e l e c t e d m a x i m u m p e r m i t t e d r e p l i e s is e x c e e d e d. R E G O M M E H D A T I O N : T h e v a l u e t o w h i c h t h e r e p l y r a t e is l i m i t e d s h o u l d b e s et f o r a p p r o x i m a t e l y r e p l i e s p e r s e c o n d, k. R e p l y D e l a y a n d J i t t e r. T h e t i m e d e l a y b e t w e e n t he a r r i v a l, at the t r a n s p o n d e r r e c e i v e r, o f t h e l e a d i n g e d g e of P^, a n d the t r a n s m i s s i on of t h e l e a d i n g e d g e of the f i r s t p u l s e o f t h e r e p l y s h a l l b e , 5 m i c r o s e c o n d s. T h e t o t a l j i t t e r o f t h e r e p l y p u l s e c o d e g r o u p w i t h r e s p e c t to s h a l l n o t e x c e e d 0, 1 m i c r o s e c o n d s.

18 mma P P R O V E D F O R PUBLIC D IS C L O S U R E m. T r a n s p o n d e r P o w e r O u t p u t. T h e p e a k p u l s e p o w e r a v a i l a b l e at the a n t e n n a e n d of t h e t r a n s m i s s i o n l i n e of the t r a n s p o n d e r s h a l l b e 2 b ± 3 db a b o v e 1 w a t t at r e p l y r a t e s as h i g h as 2 O O O p e r s e c o n d f o r a 9 - p u l s e c o d e d r e p l y. I n s o m e a p p l i c a t i o n s t h e p o w e r r e q u i r e m e n t m a y b e g r e a t e r b y as m u c h as 3 db. R E C O M M E N D A T I O N : It is r e c o m m e n d e d t h a t t he p e a k p u l s e p o w e r b e 2b ± 3 d b a b o v e 1 w a t t a t r e p l y r a t e s as h i g h as 1 2 O O p e r s e c o n d f o r a 15- p u l s e c o d e d reply. N O T E : T h e s i d e a n d b a c k l o b e l e v e l of i n t e r r o g a t o r - a n t e n n a d e s i g n s m a k e s it i m p o r t a n t t h a t this c h a r a c t e r i s t i c b e h e l d w i t h i n t i g h t l i m i t s f o r the b e n e f i t o f i n t e r r o g a t o r s e m p l o y i n g s e n s i t i v i t y time c o n t r o l o n t h e r e c e i v e r. A n a p p r e c i a b l e d e c r e a s e i n e f f e c t i v e r a d i a t e d p o w e r l e v e l w i l l c a u s e g a p s i n s y s t e m c o v e r a g e, w h i l e e x c e s s i v e p o w e r m a y r e s u l t i n s i d e l o b e b r e a k t h r o u g h a n d o t h e r u n d e s i r a b l e e f f e c t I n c o r p o r a t i o n i n t o t h e s y s t e m o f i m p r o v e d i n t e r r o g a t o r - a n t e n n a d e s i g n s, u s e o f s i d e - l o b e s u p p r e s s i o n a n d o t h e r e q u i p m e n t i m p r o v e m e n t s w i l l m a k e f u r t h e r r e l a x a t i o n of this t o l e r a n c e p o s s i b l e. T r a n s p o n d e r A n t e n n a R B C O M M E K D A T I O N ; It is r e c o m m e n d e d t h a t t h e t r a n s p o n d e r a n t e n n a ( a ), w h e n i n s t a l l e d o n a n a i r c r a f t, h a v e a r a d i a t e d p a t t e r n w h i c h is e s s e n t i a l l y o m n i d i r e c t i o n a l i n the h o r i z o n t a l p l a n e a nd

19 mm NATO UNCLASSIFIED a vertical b eamwidth of at least + 30 degrees from the horizontal p l a n e» The transponder power output defined in paragraph 3 1. assumes use of the equivalent of a simple quarter-wave antenna. n. Identification of Position. Provision for an l/p response shall be made. The characteristics of the l/p response require further coordination for standardization. NOTE: The present civil Identity response and the IFF Mark X SIF I/P response are incompatible. Until there.is agreement on a standardized I/P - Identity characteristic, the response described in paragraph 5 of Annex *D to Details of Agreement will be used* o. Emergency Position. Provisions for a distinct Emergency Response for Modes 1, 2 and 3/A shall be made«, This feature when selected by the pilot, will cause the transponder to reply to Modes 1, 2 and 3/A interrogations with the operating codes in Modes 1 and 2, and Code 77 in Mode 3/A followed by three sets of "bracket pulses" for a total of four trains spaced at 2L\.,63 microseconds measured between leading edges of the first framing pulses. Where Codes are in use, C ode 7700 will replace Code 77. N O T E : It is recognised that certain procedures exist which require the transmission of a discrete code in Mode 3 at all times. Where such a situation exists, operational procedures or a technical solution may be required, to insure that military operational

20 IMS D[FDi A P P R O V E D F O R PUBCIC D IS C C O S U R E NATO UNCLASSIFIED I4.. LOW P osition. A LOW position on the transponder control box shall be provided. A controllable reduction from normal receiver sensitivity to a LOW sensitivity position shall be provided until (or unless) requirements stated herein for suppression of side lobes have been implemented.. This reduction should be set at approximately 12 db. c[. STANDBY Position. A STANDBY position on the transp onder control box shall be provided (See paragraph 8 of Annex *Dr to Details of Agreement), r, Modes and Codes Control. Automatic selection of Mode 1 shall be possible when the transponder master control is set to NORMAL operation. Selection of Mode 2 and Mode 3/A shall be provided by switches which permit optional selection. Reply code selection of Modes 1 and 3/A shall be provided and available for the operator. Mode 2 reply code selection shall also be provided, but not necessarily available to the operator. _s. Spurious Radiation, C-W radiation shall not exceed a level of 70 db below 1 watt, IFF MARK X (SIF ) INTERROGATOR R E S PQNSQR CHARACTERIST ICS a. Power O u t p u t. The standard maximum effective radiated peak power of the interrogator shall be 52.5 db above one watt. In some applications the effective radiated power may be greater (e.g. to provide an IFF range capability ïo the detection range of the associated radar)j but in such cases provision shall be made to reduce the peak p ower to withi n the above standard. NATO UNCLASSIFIED A P P R O V E D F O R PUBCIC DISCCOSURE

21 mm APPROVED FOR PUBLIC DISCLOSURE NATO UNCLASSIFIED Interrogator Repetition Frequency. The maximum interrogation repetition frequency shall he 1^-50 interrogations per second. To minimize unnecessary transpond er triggering and the resulting high density of non-synchronous responses ("fruit") interrogators shall use the lowest practicable interrogation repetition frequency that is consistent with the display characteristics, the interrogator antenna beamwidth and the antenna r otation speed employed. Receiver Sensitivity. The design receiver sensitivity shall not he less than 90 db below one milliw att, measured at an RMS signal plus noise to noise ratio of 2:1, for a 200-mile facility. Receiver Sensitivity Time Control (STG) A l s o Galled GTC-G-aln Time Control. The receiver sensitivity shall be reduced at short ranges to minimize reply path reflections and pulse stretching. At zero range the gain shall be reduced to an adjustable value between 10 and 14-0 db below maximum sensitivity. The recovery rate shall be adjusted to suit local c onditions. Receiver Bandwidth and Video Response. The bandwidth of the receiver shall be centered on 1090 megacycles and shall he adequate to reproduce the transponder pulse train described in paragraph 2 b above and to accommodate the transponder transmitter frequency tolerance and interrogator receiver local oscillator drift. The bandwidth. -15-

22 » 1 M tm M IE ) N A T O U N C L A S S I F I E D s h a l l n o t b e m o r e t h a n 21+ m e g a c y c l e s at 1+0 db b e l o w m a x i m u m s e n s i t i v i t y. T h e s e n s i t i v i t y o f the r e c e i v e r to s i g n a l s o u t s i d e t h i s b a n d w i d t h s h a l l b e at l e a s t 60 db b e l o w n o r m a l. Th e v i d e o r e s p o n s e, at a n y r a n g e w i t h S T C p r o v i s i o n s o p e r a t i v e, s h a l l b e c a p a b l e of r e p r o d u c i n g t h e p u l s e t r a i n s d e s c r i b e d i n p a r a g r a p h 2 b w i t h o u t a p p r e c i a b l e p u l s e s t r e t c h i n g or d i s t o r t i o n o v e r a d y n a m i c r a n g e f r o m r e c e i v e r t h r e s h o l d t o a l e v e l 21+ db a b o v e t h r e s h o ld. f. I m a g e R e s p o n s e. T h e i m a g e r e s p o n s e s h a l l b e at l e a s t 6 0 db b e l o w m a x i m u m s e n s i t i v i t y. A z i m u t h A c c u r a c y. T h e e l e c t r i c a l a l i g n m e n t of t h e m a i n l o b e of the r a d i a t i o n p a t t e r n, w i t h r e s p e c t to the a s s o c i a t e d d i s p l y, s h a l l b e s u c h as t o p e r m i t r e c e i v e d r e s p o n s e s to b e d i s p l a y e d w i t h i n 1 o f t r u e o r i e n t a t i o n, R E C O M M E N DA T I O N : T h e b e a m w i d t h of t h e d i r e c t i o n a l i n t e r r o g a t o r a n t e n n a s h o u l d b e n o w i d e r t h a n r e q u i r e d to m e e t o p e r a t i o n al r e q u i r e m e n t s. T he s i d e a n d b a c k l o b e r a d i a t i d W of the d i r e c t i o n a l a n t e n n a s h o u l d b e at l e a s t 2k d b b e l o w t he p e a k of t h e m a i n b e a m, 4 S v s t e m M o n i t o r. R E C O M M E N D A T I O N : P r o v i s i o n s s h o u l d b e m a d e to m o n i t o r t h e g r o u n d i n t e r r o g a t o r c o n t i n u a l l y f o r a n y d e g r a d i t i o n of p e r f o r m a n c e e x c e e d i n g the a l l o w a b l e s y s t e m t o l e r a n c e s a n d t o p r o v i d e a n a u d i b l e, o r e q u i v a l e n t N A T O

23 mm M t g i œ D I F D i E APPROVED FOR PUBLIC DISCLOSURE i* I m p u l s i v e I n t e r f e r e n c e S u p p r e s s i o n (IIS) ( D e f r u l t i n g DECLASSIFIED-PUBLIC DISCLOSURE IMSM-04S2- Q2 DECLASSIFIE-MISE EN LECTURE PUBLIQUE E q u i p m e n t ). R E C O M M E N D A T I O N : D e f r u i t i n g e q u i p m e n t, c a p a b l e of r e m o v i n g n o n - s y n c h r o n o u s s i g n a l s f r o m t h e i n t e r r o g a t o r r e c e i v e r v i d e o, s h o u l d b e u s e d w h e n e v e r o t h e r I n t e r r o g a t o r s, o r o t h e r e q u i p m e n t s, i n t h e a r e a a r e r e s p o n s i b l e f o r g e n e r a t i n g e x c e s s ive u n d e s i r a b l e s i g n a l s. S p u r i o u s R a d i a t i o n. C - W r a d i a t i o n s h a l l n o t e x c e e d a l e v e l of* 7 6 db b e l o w 1 watt, 5. IFF M A R K X (SIF) S Y S T E M I N T E R R O G A T I O N S I D E L O B E S U P P R E S S I O H a. G e n e r a l O p e r a t i on, W h e n i m p l e m e n t e d f o r m i l i t a r y use, t h e f o l l o w i n g I F F M A E K X (SIF) S y s t e m I S L S c h a r a c t e r i s t i c s w i l l a p p l y : (l) A t t he i n t e r r o g a t o r s i t e, i n a d d i t i o n t o t he n o r m a l t w o - p u l s e i n t e r r o g a t i o n that is r a d i a t e d f r o m a n a r r o w b e a m r o t a t i n g a n t e n n a, a t h i r d or c o n t r o l p u l s e is r a d i a t e d f r o m a n a n t e n n a t h a t h a s e i t h e r a n o n m i - d i r e c t i o n a l o r s h a p e d m u l t i - d i r e c t i on a l p a t t e r n i n the a x i m u t h p l a n e. This c o n t r o l p u l s e is r a d i a t e d at a t i m e a p p r o v i m a t e l y 2 m i c r o s e c o n d s a f t e r the fir*st i n t e r r o g a t i on p u l s e a n d a t a n e f f e c t i v e r a d i a t e d p ow e r s o m e w h a t g r e a t e r t h a n t h a t o f the g r e a t e s t s i d e l o b e of the d i r e c t i o n a l a n t e n n a IM Ü M t ê M l I I

24 N A T O mi U N C L A S S IFIED (2) At the a i r borne t r a n s p o n d er, the a m p l i t u d e s of the b. f i r s t i n t e r r o g a t i o n p u l s e a n d the control pulse are c o m p a r e d and, if the control p ulse is equal to or g r e a t e r t han the p r e c e d i n g i n t e r r o g a t i o n pulse, the i n t e r r o g a t i o n is s u p p r e s s ed. If the i n t e r r o g a t i o n pulse has a 9 db or m o r e advan tage o v e r the control pulse, the i n t e r r o g a t i o n is not s u p p r e s s e d and a r e p l y is t r a n s m i t t ed. If the i n t e r r o g a t i o n p ulse is g r e a t e r t h a n the control pulse, b u t less t h a n 9 db, the t r a n s p o n d e r m a y or m a y not reply. (3 ) The ISLS System thus usee a third or control p ulse in the i n t e r r o g a t i o n t r a i n to i d e n t i f y a side lobe interrogation. The s u p p r e s s i o n of a side lobe i n t e r rogation is a c c o m p l i s h e d i n the t r a n s p o n d e r, a f t e r r e c o g n i t i o n of the p r o p e r a m p l i t u d e ratio, b y d i s a b l i n g the d e c oders f o r a p e r i o d of a p p r o x i m a t e l y microseconds. ISLS C o n t r o l T r a n s m i s s i o n s (Three P u l s e ) (Sign als in Space) (1) C e n t e r F r e q u e n c y (2) M a x i m u m D i f f e r e n c e b e t w e e n I n t e r r o g a t i o n / I S L S C o n t r o l F r e q u e n c y (3 ) P o l a r i z a t i o n (1+) ISLS C o n t r o l P u lse D e s i g n a t i o n (5) Pj and P^ Interval (6) P 2 D u r a t i o n (7 ) P 2 B i s e Time (8) P 2 D e c a y Time Mc/s # 0.2 M c / s Ä V e r t i c a l P O.1 5 m i c r o s e c s 0, microsecs Betw e e n a n d 0.1 micro s e c s # B e t w e e n a n d 0.2 miçrosecsj^ N A T O U N C L A S S I F I E D -18- m ü «i i M i F O i i E

25 N A T O UK 0 1 M H! ' mm N A T O U N C L A S S I F IED APPROVED FOR PUBLIC DISCLOSURE N O T E 1 ; E x i s t e n ce o f i n t e r r o g a t o r s w i t h f r e q u e n c y s t a b i l i t y n o b e t t e r t h a n 2, 5 M c / s is r e c o g n i z e d. DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE * I n a d d i t i o n, the e x i s t e n c e o f i n t e r r o g a t o r s is r e c o g n i z e d w h e r e i n the d u r a t i o n of p u l s e s P-^ Pg a n d P ^ m a y b e b e t w e e n O. 7 a n d 1, 2 m i c r o s e c o n d s, t h e r i s e t i m e as g r e a t as O. 2 m i c r o s e c o n d s, a n d t he d e c a y t i m e as g r e a t as m i c r o s e c o n d s, N O T E 2 : T h e e x i s t e n c e of i n t e r r o g a t o r s w h e r e i n t he f r e q u e n c y d i f f e r e n c e m a y b e as g r e a t as 0,1+ Mc/s is r e c o g n i z e d. N O T E 3 : I n t h e c a s e o f N o t e 1 a n d N o t e 2, a b o v e, s o m e d e g r a d a t i o n o f s i d e l o b e s u p p r e s s i o n p e r f o r m a n c e m a y r e s u l t. C o n t r o l T r a n s m i s s i o n C h a r a c t e r i s t i c s ( S i g n a l s - i n - S p a c c )»- (l) T h e r a d i a t e d a m p l i t u d e o f P ^ a t t h e a n t e n n a of the t r a n s p o n d e r s h a l l b e (i) e q u a l to o r g r e a t e r t h a n t h e r a d i a t e d a m p l i t u d e o f P^ f r o m t he g r e a t e s t s i d e l o b e t r a n s m i s s i o n o f t he a n t e n n a r a d i a t i n g P^, a n d (ii) at a l e v e l l o w e r t h a n 9 db b e l o w t he r a d i a t e d a m p l i t u d e o f P ^ w i t h i n the d e s i r e d s o l i d a n g l e o f i n t e r r o g a t i o n. N O T E 1 : I n t h e c a s e of the c o n t r o l a n t e n n a w i t h s h a p e d m u l t i - d i r e c t i o a a l p a t t e r n s, c o n d i t i o n (i) a b o v e s h a l l b e r e p l a c e d b y t h e f o l l o w i n g : " E q u a l t o o r g r e a t e r t h a n t h e r a d i a t e d a m p l i t u d e of P^ i n a l l d i r e c t i o n s e x c e p t o v e r the d e s i r e d a r c of i n t e r r o g a t i o n (but n o t n e c e s s a r i l y i n d i r e c t i o n s i n w h i c h the r e c e i v e d a m p l i t u d e of P^ is m o r e t h a n i+c db

26 IMO (U)Kl(gy\i [llfdie) N A T O U N C L A S S IF a A P P R O V E D F O R PUBLIC D IS C L O S U R E N O T E 2 : I n a b i l i t y o f s ome e x i s t i n g i n t e r r o g a t o r s to c o m p l y w i t h b o t h c o n d i t i o n s is r e c o g n i z e d. F o r those s p e c i a l c a s e s, c o n d i t i o n (ii) w i l l b e m e t at the s a c r i f i c e o f m e e t i n g c o n d i t i o n (i). (2) W i t h i n t h e a r c of d i r e c t i o n a l i n t e r r o g a t i o n ( m a i n l o b e ), t h e r a d i a t e d a m p l i t u d e of P ^ s h a l l n o t b e m o r e t h a n 1 db b e l ow t h e r a d i a t e d a m p l i t u d e of d. T r a n s p o n d e r R e p l y C h a r a c t e r i s t i c s ( A i r c r a f t ) (1) R e p l y - I n r e s p o n s e t p r o p e r l y s p a c e d i n t e r r o g a t i ons! of t he s e l e c t e d m o d e, t h e t r a n s p o n d e r s h a l l r e p l y at l a s t 90% of the t i m e w h e n t he r e c e i v e d a m p l i t u d e of P 1 is i n e x c e s s of a l e v e l of 9 d b a b o v e the r e c e i v e d a m p l i t u d e o f P g, o r Pg is o u t s i d e t h e l i m i t s of m i c r o s e c o n d s f r o m P ^, u n l e s s p r e v e n t e d f r o m r e p l y i n g as the r e s u l t o f s u p p r e s s i o n a c t i o n. (2) S u p p r e s s i o n (a) U p o n r e c e i p t of p r o p e r l y s p a c e d i n t e r r o g a t i o n s, t h e t r a n s p o n d e r s h a l l b e s u p p r e s s e d wh e n the r e c e i v e d a m p l i t u d e of Pg is e q u a l t o o r i n e x c e s s of t h e r e c e i v e d a m p l i t u d e of P^. T h e t r a n s p o n d e r s h a l l r e m a i n s u p p r e s s e d f o r a n i n i t i a l p e r i o d s u f f i c i e n t t o d e n y r e p l y n o t e x c e e d i n g m i c r o s e c o n d s. M A T O U N C L A S S I F I E D KMü (M ÄÄM IIE

27 mwapproved FOR PUBLIC DISCLOSURE (b) (c) (d) N O T E : It is r e c o g n i z e d t h a t the t r a n s p o n d e r mayb e s u p p r e s s e d, as i n p a r a g r a p h 5 d ( 2 ) (a) a b o v e, w h e n a p u l s e p r e c e d e s o r up. t o a n o m i n a l t wo m i c r o s e c o n d s, a n d is of a r e c e i v e d a m p l i t u d e b e t w e e n m i n i m u m t r i g g e r i n g l e v e l a n d 9 db m o r e t h a n the r e c e i v e d a m p l i t u d e o f the f o l l o w i n g i n t e r r o g a t i o n p u l s e, T he s u p p r e s s i o n a c t i o n s h a l l b e i n i t i a t e d b y a n i n t e r r o g a t o r p u l s e p a i r s p a c e d a t o15 m i c r o s e c o n d s. It s h a l l n o t b e i n i t i a t e d w h e n t he p u l s e s p a c i n g is l e s s t h a n 1, 2 m i c r o s e c o n d s o r m o r e t h a n 2, 8 m i c r o s e c o n d s, T h e s u p p r e s s i o n action, s h a l l b e c a p a b l e of b e i n g r e - i n i t i a t e d f o r t h e f u l l d u r a t i o n w i t h i n 2 m i c r o s e c o n d s a f t e r 4 t h e e n d of a n y s u p p r e s s i o n p e r i o d. A s i d e l o b e s u p p r e s s i o n r a t e l i m i t e r, u s i n g a s e n s i t i v i t y - r e d u c t i o n type c i r c u i t, s h a l l b e i n c o r p o r a t e d. A t a s u p p r e s s i o n r a t e b e l o w t h e m a g n i t u d e o f p e r s e c o n d, r e c e i v e r s e n s i t i v i t y s h a l l n o t b e a f f e c t e d. A t a s u p p r e s s i o n r a t e i n e x c e s s of a p p r o x i m a t e l y p e r s e c o n d, the r e c e i v e r s e n s i t i v i t y s h a l l b e r e d u c e d to l i m i t t h e s u p p r e s s i o n rate to a m a g n i t u d e of 5000 p e r s e c o n d m MSILÄgsDIFOi

28 mm «y»! APPROVED FOR PUBLIC DISCLOSURE N O T E : it is r e c o g n i z e d t h a t s o m e e x i s t i n g e q u i p m e n t s m a y not b e c a p a b l e of r e a l i z i n g this s p e c i f i e d l i m i t, b u t i n n o c a s e s h o u l d the s u p p r e s s i o n r a t e e x c e ed 1 0, p e r s e c o n d. 6, I M P L E M E N T A T I O N OF THE A G R E E M E N T a. N a t i o n s w i l l p r o v i d e the m a t e r i a l r e q u i r e d b y the e a r l i e s t p r a c t i ca b l e date, h. T h e a g r e e m e n t w i l l b e c o n s i d e r e d t o h a v e b e e n i m p l e m e n t e d w h e n it h a s b e e n a d o p t e d as p a r t of the n a t i o n a l s t a n d a r d s f o r the n a t i o ns c o n c e r n e d A P P R O V E D F O R PUBLIC D IS C L O S U R E

29 k m ( y j Ä Ä g M i i E ) APPROVED FOR PUBCIC DISCCOSURE IfATQ U N C L A S S I F I E D A n n e x "A* to D E T A I L S OF A G R E E M E N T of S T A N A G N o (2nd D r a f t ) G E N E R A L S Y S T E M R E Q U IR E M E N T S 1. P u r p os e, T h e B a s i c IFF M a r k X and. I F F M a r k X (SIF) S y s t e m s h a v e b e e n a d o p t e d to a s s i s t i n the r a p i d i d e n t i f i c a t i o n of f r i e n d l y a i r c r a f t a n d s hips, a n d t o a s s i s t i n t h e t r a c k i n g a n d c o n t r o l o f f r i e n d l y a i r c r a f t a n d s h i p s., 2. C o v e r a g e. W i t h a p r o p e r l y s i t e d i n t e r r o g a t o r, a n d o t h e r u n i t s h a v i n g c h a r a c t e r i s t i c s as s t a t e d h e r e i n, the S y s t e m w i l l p r o v i d e s p a t i a l l i n e - o f - s i g h t c o v e ra g e e q u a l t o o r g r e a t e r t h a n the f o l l o w i n g, l i m i t s, a. R a n g e......, 1 to s n a u t i c a l m i l e s (or r a d a r r a n g e ) b. E l e v a t i o n.... t o h5 a b o v e the h o r i z o n t a l p l a n e, o r c o m p a t i b l e w i t h a s s o c i a t e d r a d a r ç. A l t i t u d e..... L i m i t e d o n l y b y s e r v i c e c e i l i n g of a i r c r a f t. NOTE: I n t e r r o g a t o r s h a v i n g l i m i t e d r a n g e m a y b e e m p l o y e d a t m a n y l o c a t i o n s to m e e t p e c u l i a r o p e r a t i o n a l r e q u i r e m e n t s. W h i l e it is n e c e s s a r y to e s t a b l i s h s p e c i f i c standards, f o r t h e a i r b o r n e c o m p o n e n t s of t he S y s t e m, a n d t o d e f i n e t he c h a r a c t e r i s t i c s of t he r a d i a t e d s i g n a l s f r o m b o t h the i n t e r r o g a t o r a n d t r a n s p o n d e r, the a n t e n n a p a t t e r n, p o w e r, a n d s e n s i t i v i t y r e q u i r e m e n t s f o r the i n t e r r o g a t o r m a y b e d e t e r m i n e d o n the b a s i s o f the i n t e n d e d u s a g e, a n d n e c e s s a r y p r e c a u t i o n s t o b e e m p l o y e d t o a v o i d i n t e r f e r e n c e. A ( D o f A ) 1 M M K l(g y \ s s [l[fiie A P P R O V E D F O R PUBCIC DISCCOSURE

30 » 1 «y» K l» APPROVED FOR PUBLIC DISCLOSUR E 3, S y s t e m A c c u r a c y. The S y s t e m a c c u r a c y is d e t e r m i n e d b y t h e c h a r a c t e r i s t i c s o f t he i n t e r r o g a t o r, i n c l u d i n g the a n t e n n a, v i d e o p r oc e s s i n g e q u i p m e n t, a n d t h e a s s o c i a t e d d i s p l a y * W i t h e q u i p m e n t m e e t i n g the c h a r a c t e r i s t i c s s t a t e d i n the D e t a i l s of A g r e e m e n t, the S y s t e m is c a p a b l e of p r o v i d i n g a c c u r a c y i n e x c e s s o f t he f o l l o w i n g : a A x i m u t h : +1,5 d e g r e e s d e p e n d i n g o n t h e q u a l i t y of the r a d a r i n d i c a t o r used, b. R a n g e ; + t h e r o o t - s u m - s q u a r e of 5 O O f e e t a n d 1 to 3 p e r c e n t of d i s p l a y range; the l a t t e r d e p e n d i n g o n q u a l i t y of r a d a r i n d i c a t o r used. U, C o m p a t i b i l i t y. The r e q u i r e d c o m p a t i b i l i t y of the I F F M a r k X (SIF) a i r b o r n e t r a n s p o n d e r s w i t h I C A O S S R is p o s s i b l e b y u s e of t h e m i l i t a r y M o d e 3 a n d c i v i l M o d e A, r e f e r r e d to a s M o d e 3/A, O t h e r c i v i l M o d e s, w h i c h c o n s t i t u t e s i g n a l s i n s p a c e o n t h e s a m e f r e q u e n c y b a n d, a re d e t a i l e d i n the a p p r o p r i a t e s e c t i o n o f I C A O A n n e x 10, A ( D o f A ) - 2

31 A P P R O V E D F O R PUBLIC DISCLOS U R E KMÜ ( P i s M ^ O I F I l E ) M A T O U N C L A S S I F I E D APPROVED FOR PUBLIQjgjggkOSÆÿŒ t o D E T A I L S O F A G R E E M E N T of S T A N A G H o "(2nd.D r a f t ) DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE D E S C R I P T I O N. O F T H E B A S I C IFF M A R K X S Y S T E M 1. T h e B a s i c I F F M a r k X is a s e c o n d a r y r a d a r s y s t e m c o n s i s t i n g of: a. A n I n t e r r o g a t o r - R e s p o n s o r ( I - R ) u n i t w h i c h t r a n s m its in M c / s, c h a l l e n g e s, a n d d e t e c t s the r e p l i e s r e c e i v e d i n r e s p o n s e t h e r e t o f o r d i s p l a y ; a n d b. A T r a n s p o n d e r u n i t w h i c h t r a n s m i t s M c / s r e p l i e s w h e n a c t u a t e d b y c h a l l e n ges r e c e i v e d f r o m the I n t e r r o g a t o r - R e s p o n s o r -units. 2. I n t e r r o g a t o r R e s n o n s o r. T h i s is t h e c h a l l e n g e u n i t a n d is u s u a l l y c l o s e l y i n t e r c o n n e c t e d w i t h a p r i m a r y r a d a r, w h i c h m a y b e g r o u n d - b a s e d, s h i p b o r n e, r a i r b o r n e. A n t e n n a e of the t w o e q u i p m e n t s are s y n c h r o n i z e d s o t h a t r e p l i e s r e c e i v e d f r o m t h o s e t r a n s p o n d e r s a c t u a t e d b y I - R c h a l l e n ge a r e d i s p l a y e d a t t h e a p p r o p r i a t e l o c a t i o n o n p l a n p o s i t i o n i n d i c a t o r s o f the p r i m a r y radar. T h e I -R t r a n s m i s s i o n is n o r m a l l y r e p e a t e d a t t h e p u l s e r e p e t i t i o n f r e q u e n c y of its p r i m a r y r a d a r (or s u b - m u l t i p l e t h e r e o f ) a n d c o n s i s t s of a p a i r of m i c r o s e c o n d p u l s e s s e p a r a t e d b y t h r e e, f i v e o r e i g h t m i c r o s e c o n d s, d e p e n d i n g u p o n t h e m o d e s e l e c t e d b y t h e o p e r a t o r. T h e I n t e r r o g a t o r - R e s p o n s o r c a n b e u s e d b y i t s e l f, i. e., n o t i n a s s o c i a t i o n w i t h a p r i m a r y r a d a r i n w h i c h c a s e IFF r e s p o n s e s o n l y w i l l b e d i s p l a y e d. 3. T r a n s p o n d e r, T h i s is t h e i d e n t i f i c a t i o n c o m p o n e n t c o n s i s t i n g of r e c e i v e r - t r a n s m i t t e r u n i t, c a r r i e d b y a i r c r a f t a n d s u r f a c e v e s s e l s, w h i c h is a c t u a t e d b y s u c h d o u b l e - p u l s e c h a l l e n g e s. Its r e p l i e s m a y b e s i n g l e, or (in the c a s e of a i r c r a f t ) d o u b l e o r q u a d r u p l e p u l s e s. T h e a i r b o r n e t r a n s p o n d e r a l s o i n c o r p o r a t e s f e a t u r e s f o r I d e n t i f i c a t i o n of P o s i t i o n (I/P) a n d E m e r g e n c y I d e n t i f i c a t i o n,.d e s c r i b e d i n g r e a t e r d e t a i l b e l o w. H Ä ) MtSliÄOIMliE) N A T O Ü N Œ L A S S X F D E D A ( D o f A L = 3

32 mm m (S[lä»d[ie) N A T O U N C L A S S I F Ü Ü - A P P R O V E D F O R PUBLIC D ISC L O S U R E 4» M o d e s, T he B a s i c I F F M a r k X h a s t h r e e m e t h o d s of o p e r a t i o n c a l l e d M o d e 1 ( N ormal), M ode 2 a n d M o d e 3. I n o r d e r f o r the I-R DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE u n i t t o c h a l l e n g e o n M o d e 1, M o d e 2 o r M o d e 3 a n d t o r e c e i v e a n d d i s p l a y t he r e s p o n s e s t h e r e t o, i t s c o n t r o l s m u s t b e s e t to t h a t m o d e o f o p e r a t i o n. S i m i l a r l y, i n o r d e r t h a t a T r a n s p o n d e r s h a l l a c c e p t a n d r e p l y t o M o d e 2 a n d / o r M o d e 3 c h a l l e n g e s, i n a d d i t i o n M o d e 1, its c o n t r o l s m u s t b e s e t a c c o r d i n g l y. 5. I d e n t i f i c a t i o n of P o s i t i o n (I/p) F e a t u r e ( A i r c r a f t O n l y ). T h e i d e n t i f i c a t i o n of p o s i t i o n f e a t u r e of t h e B a s i c IFF M a r k X is d e s i g n e d t o o p e r a t e w i t h M o d e 2 only. It p r o v i d e s t h e a u t o m a t i c t r a n s m i s s i o n of M o d e 2 r e p l i e s b y the T r a n s p o n d e r w h e n e v e r the I / P s w i t c h is a c t i v a t e d. 6. Em e r g e n c y ( D i s t r e s s ) F e a t u r e ( A i r c r a f t O n l y ), T his B a s i c I F F M a r k X f e a t u r e m a y h e s e l e c t e d b y t h e p i l o t t o c a u s e t he T r a n s p o n d e r to r e p l y to e v e r y one of t he t h r e e m o d e s of i n t e r r o g a t i o n w i t h a d i s t i n c t i v e r e p l y o f f o u r p u l s e s w i t h 16 m i c r o s e c o n d s s p a c i n g s b e t w e e n t hem, r e g a r d l e s s o f p o s i t i o n o f Mo d e s 2 a n d 3 m o d e s w i t c h e s. 7. L O W P o s i t i o n ( T r a n s p o n d e r ), D O W p o s i t i o n o p e r a t i o n c a n b e s e l e c t e d f o r u s e as r e q u i r e d. This s e t t i n g r e d u c e s t h e r e c e i v e r s e n s i t i v i t y of the a i r b o r n e t r a n s p o n d e r b y a p r e d e t e r m i n e d a m o u n t» 8. S T A N D B Y P o s i t i o n ( T r a n s p o n d e r ). W i t h t h i s s w i t c h p o s i t i o n, p o w e r is a p p l i e d to t h e t r a n s p o n d e r t b u t it w i l l n o t t r a n s m i t a r e p l y t o a n i n t e r r o g a t i o n. T h e t r a n s p o n d e r w i l l i m m e d i a t e l y b e c a p a b l e of r e p l y i n g t o i n t e r r o g a t i o n s w h e n s w i t c h e d f r o m the S T A N DB Y to O N p o s i t i o n. A ( D o f A ) - ^ FDd

33 wm «u M P o i i E APPROVED FOR PUBLIC DISCLOSURE N A TO U N C L A S S I F I E D A n n e x TC 1 to D E T A I L S OF A G R E E M E N T o f STANAG- No«, (2nd D r a f t ) D E F I N I T I O N S OF P U L S E M E A S U R E ME N T S 1, P u l s e A m p l i t u d e (A), T h e a m p l i t u d e of a n e q u i v a l e n t t r a p e z o i d a l p u l s e, 2, P u l s e D u r a t i on. T h e t i m e i n t e r v a l b e t w e e n O. 5 A p o i n t s o n l e a d i n g a n d t r a i l i n g e d g e s o f the p u l s e e n v e l o p e. 3, P u l s e R i s e T i m e. T h e r i s e t i m e as m e a s u r e d b e t w e e n 0 1 A a n d O. 9 A o n t h e l e a d i n g e d g e of the p u l s e e n v e l o p e. i+. P u l s e D e c a y T i m e, T h e d e c a y t i m e as m e a s u r e d b e t w e e n 0 9 A a n d O. 1 A o n t h e t r a i l i n g e d g e of the p u l s e e n v e l o p e, 5. P u l s e S p a c i n g. T h e p u l s e s p a c i n g as m e a s u r e d b e t w e e n O. 5 A p o i n ts on. l e a d i n g e d g e s. 6, S p a c i n g of P u l s e T r a i n s. T h e s p a c i n g of p u l s e t r a i n s as m e a s u r e d b e t w e e n O. 5 A p o i n t s o n l e a d i n g e d g e s o f the f i r s t p u l s e s of the trains. A ( D o A ) - 5

34 K M (UIM M I M I E ) APPROVED FOR PUBLIC DISCLOSURE A n n e x fd' to D E T A I L S OF A G R E E M E N T Of S T A N A G N o, 5 O I 7 (2nd D r a f t ) DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE D E S C R I P T I O N OF I F F M A R K X (SIF) S Y S T E M 1, T h e S e l e c t i v e I d e n t i f i c a t i o n F e a t u r e ( S J F ). S I F is a n a d d i t i v e to the B a s i c I F F M a r k X, T h e S I F is p r o vided b y m o d i f y i n g the B a s i c IFF M a r k X b y t h e a d d i t i o n of a r e p l y p u l s e c o d i n g d e v i c e t o t h e t r a n s p o n d e r a n d h y the a d d i t i o n o f a p p r o p r i a t e k e y e r s, d e c o d e r s a n d i n d i c a t o r s to t he i n t e r r o g a t o r r es p o n d o r i n o r d e r t o d e c o d e a n d d i s p l a y the m o d i f i e d t r a n s p o n d e r r e p l i e s. W h e n c o d i n g is a d d e d to B a s i c IFF M a r k X t r a n s p o n d e r e q u i p m e n t, the r e p l i e s a re c h a n g e d i n t o p u l s e t r a i n s, c o n s i s t i n g o f t w o f r a m i n g o r b r a c k e t p u l s e s s p a c e d 2 0, 3 m i c r o s e c o n d s a p a r t b r a c k e t i n g a v a r y i n g n u m b e r o f i n f o r m a t i o n p u l s e s. T h e s e S I F p u l s e t r a i n s are c o m p o s e d of p u l s e s, the n u m b e r a n d l o c a t i o n of w h i c h c a n b e v a r i e d s o as to p r o v i d e a l a r g e n u m b e r of r e p l y codes. M o d e 1 o p e r a t i o n of t he t r a n s p o n d e r u t i l i z e s c o m b i n a t i o n s of p u l s e s o u t of a m a x i m u m o f 5 p u l s e p o s i t i o n s s p a c e d 2. 9 m i c r o s e c o n d s f r o m the f i r s t f r a m i n g p u l s e. M o d e 2 o p e r a t i o n of the t r a n s p o n d e r u t i l i z e s c o m b i n a t i o n s o f p u l s e s out of a m a x i m u m of 13 p u l s e p o s i t i o n s s p a c e d at m u l t i p l e s of I.I4.5 m i c r o s e c o n d s f r o m the f i r s t f r a m i n g p u l s e. I n m o s t t r a n s p o n d e rs t he s e v e n t h of t he t h i r t e e n p u l s e p o s i t i o n s is n e v e r f i l l e d. M o d e 3 / A o p e r a t i o n u t i l i z e s c o m b i n a t i o n s o f p u l s e s i n 6 p u l s e p o s i t i o n s s p a c e d at m u l t i p l e s o f 2. 9 m i c r o s e c o n d s. D e t a i l e d d e s c r i p t i o n s of S :IP e q u i p m e n t a n d i n s t r u c t i o n s f o r its u s e are c o n t a i n e d i n a p p r o p r i a t e m i l i t a r y s e r v i c e p u b l i c a t i o n s. A ( D o f A )-6

35 M M I S I L Ä g M I i E ) APPROVED FOR PUBLIC DISCLOSURE 2. I n t e r r o g a t o r - R e s p o n s o r (i-r)o T h e I F F M a r k X (SIF) S y s t e m u s e s t he s a m e i n t e r r og a t i o n as the B a s i c I F F M a r k X. T h e t r a n s p o n d e r is i n t e r r o g a t e d w i t h t h e s a m e t h r e e m o d e s (two p u l s e s s p a c e d 3, 5 o r 8 m i c r o s e c o n d s a p a r t ) w h i c h w i l l b e d e s i g n a t e d as M o d e 1, 2 a n d 3/A» V a r i o u s S I F k e y e r s, d e c o d e r s, a n d i n d i c a t o r s c o m b i n e d w i t h t h e B a s i c IFF M a r k X I n t e r r o g a t o r - R e s p o n s o r (i-r) u n i t to p r o v i d e a c o m p l e t e IFF M a r k X (SIF) I - R i n s t a l l a t i o n. E a c h M i l i t a r y S e r v i c e h as d e s i g n a t e d i n d i v i d u a l S I F e q u i p m e n t to m e e t i ts o w n p a r t i c u l a r o p e r a t i o n a l r e q u i r e m e n t s f o r d e c o d i n g a n d d i s p l a y i n g the v a r i o u s c o m b i n a t i o n s of c o d e d r e p l i e s f r o m the SIF t r a n s p o n d e r. N o a t t e m p t w i l l b e m a d e h e r e to d e s c r i b e the v a r i o u s coaibinations o f m o d e i n t e r l a c e o r d i s p l a y s w h i c h h a v e b e e n a d o p t e d o r m a y b e used, 3. T r a n s p o n d e r s, T h e I FF M a r k X (SIF) S y s t e m r e q u i r e s the a d d i t i o n of c o d i n g f e a t u r es t o e a c h B a s i c IFF M a r k X t r a n s p o n d e r. T h e t r a n s p o n d e r w i t h a d d e d c o d e r w i l l p r o v i d e S I F c o d e d r e p l i e s i n M o d e 1, M o d e 2, a n d M o de 3/A. 4. -M o d e s a n d C o d e s. T h e IFF M a r k X (SIF) S y s t e m h a s t h e s a m e p r o v i s i o n s f o r t h r e e m o d e s of o p e r a t i o n as c o n t a i n e d i n B a s i c IFF M a r k X System. T h e f o l l o w i n g t a b l e s h o w s t he r e l a t i o n s h i p of S I F m o d e s a n d codes: M OD E I - R C h a l l e n g e T r a n s p o n d e r R e p l y 1 two p u l s e s s p a c e d 3 m i c r o s e c o n d s One of 32 c o d e s 2 t w o p u l s e s s p a c e d 5 m i c r o s e c o n d s O n e o f ^4-096 c o d e s 3 / A t w o p u l s e s s p a c e d 8 m i c r o s e c o n d s One of 64 c o des N O T E : 1. I - R c h a l l e n g e p u l s e s are d e s i g n a t e d a n d 2. S u b j e c t to f u t u r e a g r e e m e n t, p r o v i s i o n m a y b e m a d e f o r c o d e s i n M o d e %/A. N A T O UNC

36 E M A P P ROVED FOR PUBCIC DISCCOSURE 5. Id e n t i f i c a t i o n o f P o s i t i o n. P r o v i s i o n s f o r a n I / P r e s p o n s e s h a l l b e m a d e f o r M o d e s 1, 2 a n d 3/A. W h e n m a n u a l l y s e l e c t e d the f e a t u re s h a l l p r o v i d e a s i n g l e r e p e t i t i o n o f t h e r e p l y c o d e f o r M ode 1 a n d a S p e c i a l P o s i t i o n Id e n t i f i c a t i o n P u l s e f o r M o d e s 2 a n d 3/A. T h e r e p e t i t i o n of t h e r e p l y c o d e o r s i n g l e i d e n t i f i c a t i o n p u l s e s h a l l b e s p a c e d at pitas o r m i n u s O. l O m i c r o s e c o n d s m e a s u r e d f r o m t h e l e a d i n g e d g e of t h e l a s t f r a m i n g p u l s e of t h e f i r s t c o d e a n d s h a l l h e t r a n s m i t t e d f o r a p r e s e t p e r i o d b e t w e e n 15 a n d 30 s e c o n d s m e a s u r e d f r o m the t i m e of i n i t i a t i o n of t h e f e a t u r e s a n d s h a l l h e r e p e a t a b l e at a n y time. 6. E m e r g e n c y ( D i s t r e s s ) F e a t u r e ( A i r c r a f t O n l y ), T h i s f e a t u r e, w h e n s e l e c t e d b y the p i l o t, w i l l c a u s e t he t r a n s p o n d e r to r e p l y t o a M o d e 1 i n t e r r o g a t i o n w i t h the f o u r M o d e 1 r e p l y p u l s e t r a i n s s p a c e d m i c r o s e c o n d s m e a s u r e d b e t w e e n l e a d i n g e d g e s of the f i r s t f r a m i n g p u l s e s. T h i s p r o v i d e s a d i s t i n c t i v e d i s p l a y f o r a n a i r c r a f t i n d i s t r e s s. W h e n d e c o d e d, the d i s p l a y c o n s i s t s o f f ö u r b l i p s s p a c e d a p p r o x i m a t e l y 25 m i c r o s e c o n d s a part. S e l e c t i n g t h e E M E R G E N C Y f e a t u r e e n a b l e s M o d e 2 a n d 3 r e p l i e s r e g a r d l e s s of t he p o s i t i o n of M o d e 2 a n d M o d e 3 s w i t c h e s. N O T E : 1. S o m e a i r b o r n e SIF e q u i p m e n t w i l l p r o v i d e a n E m e r g e n c y r e p l y t o b o t h M o d e 1 a n d M o d e 3 i n t e r r o g a t i o n s. 2. T h i s p a r a g r a p h d e s c r i b e s t he e x i s t i n g E m e r g e n c y r e s p o n s e c h a r a c t e r i s t i c s, b u t see p a r a g r a p h 3 o of D e t a i l s o f A g r e e m e n t (page. )«A ( D o f A ) - 8 mma P P R O V E D FO R P U B LIC D IS C L O S U R F

37 APPROVED FOR PUBLIC DISCLOSURE 7. L O W P o s i t i o n ( T r a n s p o n d e r ) - ( A i r c r a f t O n l y ). L O W p o s i t i o n o p e r a t i o n c a n b e s e l e c t e d f or u s e as r e q u i r e d. T h i s s e t t i n g r e d u c e s t h e r e c e i v e r s e n s i t i v i t y o f the t r a n s p o n d e r b y a p r e d e t e r m i n e d a m o u n t, 8, S T A N D B Y P o s i t i o n ( T r a n s p o n d e r ). I n t h i s s w i t c h p o s i t i o n, p o W r is a p p l i e d t o t h e t r a n s p o n d e r, b u t it w i l l n t t r a n s m i t a r e p l y t o a n i n t e r r o g a t i o n. Th e t r a n s p o n d e r w i l l i m m e d i a t e l y r e p l y t o a n i n t e r r o g a t i o n w h e n s w i t c h e d f r o m S T A N D B Y to O N p o s i t i o n. A { D o f A )-9 mm D m

38 mm M e m» A P P R O V E D F O R PUBLIC D IS C L O S U R E Aaanex TE* t o D E T A I L S OF A G R E E M E N T Of S T A N A G N o ( 2 n d D r a f t ) DECLASSIFIED-PUBLIC DISCLOSURE IMSM DECLASSIFIE-MISE EN LECTURE PUBLIQUE I N T E E H O G A T I O N S I D E L O B E S U P P R E S S I O N (ISLS) 1. P u r p o s e. T h e p u r p o s e o f I S L S i s t p r e v e n t t r a n s p o n d e r r e p l i e s t o I n t e r r o g a t o r t r a n s m i t t e r s i d e l o b e s. T he r e s u l t i n g a d v a n t a g e s a c c r u i n g, p r i m a r i l y i n h e a v y t r a f f i c d e n s i t y a r e a s, are: a. A r ed u c t i o n of u n n e c e s s a r y i n t e r r o g a t i o n of t r a n s p o n d e r s o u t s i d e t h e n o m i n a l b e a m w i d t h o f the g r o u n d a n t e n n a, h e n c e e l i m i n a t i n g s u p e r f l u o u s r e s p o n s e s.,h. A r e d u c t i o n f g a r b l i n g a n d " f r u i t 11 d u e to the s u p e r f l u o u s r e s p o n s e s r e f e r r e d t o i n a. c. A r e d u c t i o n i n t h e p r o b a b i l i t y of t r a n s p o n d e r o v e r i n t e r r o g a t i o n, a n d c o n s e q u e n t i m p r o v e m e n t i n c o n s i s t e n c y of d i s p l a y e d r e s p o n s e s. d, A r e d u c t i o n i n d e p e n d e n c e o n S T C (i.e., G T C ) i n the g r o u n d i n t e r r g a t o r / r e s p o n s o r f o r t h e p u r p o s e of l i m i t i n g the d i s p l a y of s i d e l o b e r e s p o n s e s, a n d the c o n s e q u e n t r e d u c e d e f f e c t o f n u l l s i n t h e v e r t i c a l i n t e r f e r e n c e p a t t e r n o n a i r c r a f t at s h o r t r a n g e, A p o s s i b l e r e d u c t i o n i n t h e v a r i a t i o n of r e s p o n s e arc l e n g t h as d i s p l a y e d o n p l a n p o s i t i o n i n d i c a t o r s. A ( D o f A ) - 1 0