Real time weather display in the general aviation cockpit

Cur ren t ly weather r a d a r i s a v a i l a b l e f o r i n s t a l l a t i o n i n most t y p e s of General Avia t ion (GA) a i r c r a f t i nc lud ing t h e s i n g l e engine c a t e gory. However, ground-based weather r a d a r h a s b e t t e r a b i l i t y t o p e n e t r a t e thunderstorms and measure s torm i n t e n s i t y s i n c e lower f r equenc ie s , much l a r g e r an tennas , and e x t e n s i v e computing f a c i l i t i e s are a v a i l a b l e . Using e x i s t i n g WSR-57 weather r a d a r s , severe weather and p r e c i p i t a t i o n area o u t l i n e s can be prepared by computers and t r a n s m i t t e d t o a i r c r a f t by d i g i t a l t echn iques . The vo ice channels o f t h e VOR nav iga t ion f a c i l i t i e s might be used f o r narrowband, d i g i t a l t r a n s mis s ion . The c o s t of d i g i t a l s t o r a g e and p rocess ing c i r c u i t r y h a s dec reased i n r e c e n t y e a r s t o t h e e x t e n t t h a t t h e d i s p l a y , when used with a n e x i s t i n g VOR receiver sliould c o s t less than a n airhorne weather r a d a r . I n t r o d u c t i o n It is considered p r a c t i c a l , us ing today ' s technology, t o t r ansmi t t o aircraft cockp i t s upt o -da te weather maps which p i l o t s can use t o avo id severe weather . Such a modernizat ion o€ e x i s t i n g f a c i l i t i e s can s i g n i f i c a n t l y inc rease t h e u t i l i t y and s a f e t y a f g e n e r a l a v i a t i o n (GA) o p e r a t i o n s . Th i s paper o u t l i n e s a proposed conf i g u r a t i o n o f system components t o implement a r e a l t i m e c o c k p i t d i s p l a y of weather r a d a r and o t h e r c h a r t s . E x i s t i n g ground equipment$, such as weather r a d a r and VOR, are used i n t h e proposed s e r v i c e t o keep t h e investment i n a d d i t i o n a l ground f a c i l i t i e s t o a m i n i m u m . C u r r e n t l y weather r a d a r i s a v a i l a b l e f o r i n s t a l l a t i o n i n many types of GA a i r c r a f t i nc lud ing t h e s i n g l e engine (SE) category. However, t h e widespread use of a i r b o r n e weather r a d a r i s l i m i t e d by i n i t i a l c o s t and t h e requirement f o r s p e c i a l i z e d p i l o t t r a i n i n g i f t h e r a d a r i s t o be used e f f e c t i v e l y and s a f e l y i n avo id ing severe weather , Gmnnrl-h~asad-wezther rad-; has bf:ti-r ~ a b i l i t y t o p e n e t r a t e thunderstorms and measure Storm inl .ensi ty s i n c e lower f r equenc ie s , much l a r g e r an tennas , and e x t e n s i v e computer f a c i l i t i e s can bc used a t ground i n s t a l l a t i o n s . There are approximately 50 WSR-57 and 60 NSR-74C weather r a d a r s i n o p e r a t i o n wi th e s s e n t i a l l y s o l i d cove rage (wi th in 250 NM of a r ada r ) over t h e c o n t i n e n t a l United S t a t e s East o f t h e [(ockies and some coverage on t h e West Coast. Severe weather and p r e c i p i t a t i o n area o u t l i n e s , w i th s u i t a b l e s a f e t y f a c t o r s , can be prepa red by computers and t r a n s m i t t e d t o a i r c r a f t by d i g i t a l t echn iques . The vo ice channels o f t h e VOR navig a t i o n f a c i l i t i e s have been used fo r weather b r o a d c a s t s (hourly and ATIS) and might be used more e f f i c i e n t l y f o r narrowband, d i g i t a l t r a n s * Assoc ia t e Fellow AIAA m i s s i o n of channel of 106 to 107 weather area o u t l i n e s . The vo ice a VOR s t a t i o n i s capable of r e l a y i n g b i t s / h r o f d i g i t a l information which is adequate f o r t h e proposed weather o u t l i n e s . The c o s t o f d i g i t a l s t o r a g e and p rocess ing c i r c u i t r y h a s decreased i n r ecen t y e a r s t o t h e e x t e n t t h a t t h e d i s p l a y , when used with a n e x i s t i n g VOR r e c e i v e r should c o s t s i g n i f i c a n t l y less than a n a i r b o r n e weather r ada r . Weather B r i e f i n = Many d a i l y papers now c a r r y y e s t e r d a y s weather s a t e l l i t e p i c t u r e i n a d d i t i o n t o today ' s f o r e c a s t s u r f a c e map. T e l e v i s i o n S t a t i o n s f r e quen t ly fo l low t h e evening news wi th a c u r r e n t weather map and a l s o a t ime sequence of satell i t e photographs. The "AM Weather" on PES t e l e v i s i o n a t an e a r l y morning hour was a source or a v i a t i o n weather a t numerous l o c a t i o n s w i t h i n 39 S t a t e s as of February 1979. A f t e r g e t t i n g t h e "big p i c t u r e " on t h e weather , a p i l o t can g e t more d e t a i l e d information from SOUKBS such as PATWAS ( P i l o t ' s Automated Telephone Weather Answering S e r v i c e ) i n Some c i t e s o r by r a d i o from TWEB (Transcr ibed Weather Broadcasts) as S t a t i o n s i n t h e Con t inen ta l U.S.A. For t h e l o c a l area, t h e r e i s t h e Na t iona l Weather Serv i c e (NIJS) cont inuous b roadcas t and a t t h e a i r p o r t , t h e ATIS (Automatic Terminal Information Se rv ice ) . While t h e NIJS h a s t h e r e s p o n s i b i l i t y f o r obse rv ing , c o l l e c t i n g , and d i s semina t ing weather d a t a f o r a v i a t i o n , p i l o t s cus tomar i ly con tac t t h e n e a r e s t FAA F l i g h t S e r v i c e S t a t i o n (FSS) f o r most r ecen t and f o r e c a s t a v i a t i o n weather. The rAA b r j e f e r s g e n e r a l l y g i v e t h e d e s t i n a t i o n f o r e c a s t as w e l l as t h e most r e c e n t weather i n an a t t empt t o a n t i c i p a t e c o n d i t i o n s a t t h e a r r i v a l t ime. Fo recas t and r e c e n t weather for several p o i n t s a long the planned r o u t e of f l i g h t a r e a l s o u s u a l l y b r i e f e d . The enrou te weather a l o f t and between t h e sample p o i n t s can be compler and a cha l l enge f o r t h e FSS brTefer .~ The e x t e n t of i c i n g and tu rbu lence and t h e h e i g h t o f t h e tops o f t e n remain a n unknown t o t h e p i l o t a f t e r an o the rwise e x c e l l e n t p r e f l i g h t b r i e f i n g . A l l FSS now r e c e i v e t h e hour ly r a d a r summary by f a c s i m i l e c h a r t which shows p r e c i p i t a t i o n and thunderstorm a c t i v i t y over t h e United S t a t e s . The prev ious d e s c r i p t i o n of weather serbroadcas t by approximately 100 low frequency L v i c e s adds up t o a p l e t h o r a , however t h e r e remains gaps and v a r i a t i o n s i n q u a l i t y . There is s t i l l ano the r s e r v i c e , a v a i l a b l e t o t h e enr o u t e p i l o t . The enrou te f l i g h t adv i so ry serv i c e (EFAS), o r F l i g h t Watch, provides weather a d v i s o r i e s du r ing t h e en rou te phase of f l i g h t . Th i s s e r v i c e i s a v a i l a b l e a t approximately 45 s t a t i o n s and many more remote o u t l e t s on 122.0 Mlz. A t t h e EFAS p o s i t i o n i n t h e FSS t h e r e i s a F l i g h t Watch s p e c i a l i s t , t r a i n e d -