Conferences

UK & Ireland d i scuss mil i tary displays Great Malvern, UK, 19 September 1986 There was an excellent attendance at this technical meeting of the SID UK and Ireland Chapter, with over 100 people present at RSRE, Malvern. Derek Washington took the Chair and David Marshall, Superintendent of the Optical and Displays Science Division at RSRE, welcomed the delegates.

The first talk was jointly pre- sented by Alan Cox and Dennis Hind of RARDE (Chertsey) on the subject of displays for fighting vehicles. They outlined the factors leading to increased emphasis on indirect viewing from armoured vehicles, together with the increasingly sophisticated com- mand and control techniques for sensor, weapon and vehicle arrangement, which resulted in an increasing demand for more dis- plays with grea ter contrast, reso- lution and versatility. The very demanding environmental specifi- cation requ i red for these displays was emphasized and this point was highlighted by a short video presentation which gave a vivid impression of the conditions on a modern battlefield. The c ramped crew space available in a tank, which results in a close viewing distance and a requirement for minimum physical depth in a display, was illustrated.

Hind then descr ibed a recent series of experimental trials aimed at identifying the type of display and presentation best suited to the different needs of commander, dr iver and gunner in a tank crew. This had to combine sufficient all-round vision with high-contrast detailed attention to smaller areas of interest. The main modes investigated were an all- round configuration requiring 19 camera/VDU systems, a forward- looking system using three VDUs with some capability for a window at higher magnification, and a system using three steerable cameras. These were each com- pa red in trials with a. standard

direct-view optical system. Alan Cox took the view that for

systems requ i red in service within the next five years there was no viable alternative to the use of CRTs, probably monochrome, but with some colour capability, per- haps by using the liquid crystal shutter technique p ioneered at RSRE. He felt that maintenance and logistical problems would limit the scope for mixed types of display. He suggested that a likely specifi- cation would be

8.5 inch diagonal, 1249 lines resolution (more p re f e r r ed if available), 10 g rey scale levels, 100 cd/m" rugged construction with minimum depth.

He added that an interactive touch input capability was also very desirable. If such a device could be economically produced, he estimated a UK military market of around 10 000 units with a further factor of five if the total Western European military market could be served.

The second talk, which was on military command and control requirements for displays, had been p r e p a r e d by Andrew Smith of RARDE (Fort Halstead) but he was unfortunately not able to be present and the paper was read by Neil Bartlett. He outlined the task that had to be carr ied out in a typical divisional command cell and descr ibed the ways in which incoming information was col- lated, processed, distributed and actioned. These p rocedures requi red more or less complex tote displays and one or two large paper maps which could be over- laid with hand-drawn symbols and annotations. The aim was to replace these with electronic dis- plays which would be clearer, able to be rapidly updated, and to automatically display machine-

genera ted or stored data. He then discussed the various ways in which the des i red methods of work, and the necessities of the battle situation, constrained the specification of the requi red dis- play. The demands for full colour, high writing speed and high resolution would not all be simul- taneously realized with current technologies, particularly when allied to the need for compact size (specifically depth of the display) and reasonably low power con- sumption, all in a field environ- ment. He analysed some of the trade-offs that might be possible and arr ived at a target specifi- cation, as follows.

• S ize . The current map is 1 × 2 m shared between several users, but an alternative might be to employ several individual displays each about 30 x 40 cm. Thickness should be no more than a few centimetres.

• R e s o l u t i o n . T h e current map is about 160 line/cm, however, by incorporating sufficient pro- cessing power with a digitally s tored map and so producing customized reduced feature maps on demand, a minimum resolution of 25 line/cm might be tolerable, but up to double this is desirable. A considera- tion of the readability and positional accuracy of the over- laid symbols also suggests that 25 line/cm would just be acceptable.

• Co lour . The current map uses 12 colours plus black and white. Work is going on to investigate the ergonomics of r educed detail mapping as indicated above. Two or three colours are said to be requi red for the overlay symbology but con- ventious exist for the use of monochrome symbols, and do not have any proven deleteri- ous effects on operator perfor- mance. The requirement for

DISPLAYS, JANUARY 1987 41

Conferences

colour is t he re fo re not ye t def ined.

• Speed. Ideally, the t ime r e q u i r e d to c h a n g e the over lay , or e v e n the m a p itself, should not b e no t iceab le to the user , but this is unreal is t ic at p resen t . Studies h a v e shown that with p r o t o t y p e p ro jec t ion displays , de lays of up to 10 s a r e to le ra ted b y the user; ff menu- d r i ven i con -based sys t ems b e c o m e popu la r , b y ana l ogy with cu r r en t t r ends in civil com- pu t e r sys tems , then m u c h fas ter r e - d r a w ra tes will b e n e e d e d .

In addit ion, the d i sp lay would n e e d to o p e r a t e at r e a s o n a b l y low p o w e r , m e e t mil i tary EMC r e q u i r e m e n t s and a m o d e r a t e l y s e v e r e env i ronmen ta l and relia- bility specification.

After lunch, Paul Beatty of Ferrant / d i s cus sed the r equ i r e - ments for h e a d - d o w n d isp lays in aircraft cockpits . The information to b e d i s p l a y e d could b e synthet ic data, normal ly a l p h a n u m e r i c or graphica l , or it could b e the output f rom senso r s which had b e e n sub- ject to s o m e level of p r e p r o c e s s - ing b e f o r e b e i n g d i sp layed . This latter type of d i sp lay would p r o b - ab ly r e q u i r e bo th colour and g r e y scale capabil i ty. The r equ i r e - men t s v a r i e d f rom the re la t ively b e n i g n env i ronmen t s of an a i rship or c o m m e r c i a l a i r l iner th rough the m o r e s e v e r e r e q u i r e m e n t s of b o m b e r s or he l i cop te r s to the e x t r e m e e n v i r o n m e n t of a m o d e r n fighter. Displays for the latter case had to c o m b i n e the ability to b e vis ible at v e r y h igh sunlight leve ls and compat ibi l i ty with night vision g o g g l e s or vis ,on a d a p t e d to low light levels. An impor tan t con- straint on the displays , and their assoc ia ted p r o c e s s o r , would b e the ability to d i sp lay m o v i n g m a p information with the r e q u i r e d detail on a 6 inch s q u a r e display.

The eas i e r e n d of the m a r k e t was cur ren t ly b e i n g me t b y s h a d o w m a s k CRTs, but a l though these could b e r u g g e d i z e d to a cer ta in extent , the space , p o w e r , v ibra t ion and EMC constraints in

the next gene ra t i on of f ighter p lanes m a k e this an unsat isfactory solution. A flat pane l l iquid crysta l d i sp lay would b e we lcome , p ro - v l d e d it could m e e t the o ther a spec t s of the specif icat ion satis- factorily. Howeve r , within the immed ia t e t imeframe, Beatty thought that a c o m p r o r m s e re- q u i r e m e n t would b e met us ing s imple r u g g e d ras t e r s canned colour CRTs and p e r h a p s high- resolut ion m o n o c h r o m e CRTs with a LC colour shutter. Another possibi l i ty rmght b e the Mullard flat s c r e e n fo lded CRT, but he h o p e d that in the l onge r t e r m LCDs would b e d e v e l o p e d which could p r o v i d e the colour and resolut ion r e q u i r e d while still m e e t i n g the env i ronmen ta l spec i - fication.

In the next talk, David C o c h r a n e f rom P lessey d i scussed the r e q u i r e m e n t s for naval c o m m a n d and control sys tems. He i l lustrated the r a n g e of s enso r data b e i n g r e c e i v e d and the c o m p r e h e n s i v e rmx of w e a p o n s anal d e c o y s that had to b e cont ro l led in a typical naval scenar io . The m c o m m g data and opt ions for action w e r e p r o c e s s e d and p r e s e n t e d to the c o m m a n d t eam on d i sp lay con- soles as the tactical p ic ture .

The p r o p o s e d P lessey solution to this p r o b l e m was the n e w Nautis family of in t eg ra ted sys t ems using cus tomized s t anda rd d i sp lay con- soles, r ang ing f rom a s ingle con- sole m a pa t ro l ves se l to a suite of consoles each p e r s o n a h z e d to the n e e d s of a par t icu lar m e m b e r of the c o m m a n d t eam m a l a rge vesse l . A power fu l g r aph i c s rater- face l anguage , which is dev ice - i ndependen t , al lows the comple t e sof tware control of the d i sp lay format. Each console is b a s e d on a 16 inch d i a m e t e r s ingle mono- c h r o m e curs ive ly wri t ten CRT which can b e par t i t ioned ( sc i s sored or w indowed) as r e q u i r e d to d i sp lay synthet ic data and a lphanumer ics . High quality charac te rs , s y m b o l s and geo - met r ic g r a ph i c s w e r e built in and could b e eas i ly manipula ted . T h e r e was an e lec t ronic cu r so r

cont ro l led b y a t r acke r ball, and a r u g g e d i z e d k e y b o a r d for d i rec t input. Part icular ca re had to b e taken to nnp lemen t a modu la r a p p r o a c h to both h a r d w a r e and sof tware to p r o v i d e for e a s y main- t enance and reconfigurabi l i ty , and if r e q u i r e d the d isp lay could b e r e p l a c e d b y a 20 inch colour r a s t e r CRT.

In the final talk, Alan Pr i tchard of P lessey Displays d e s c r i b e d a dev ice in t ended to simulate the input to a thermal nuager , wluch is n e e d e d for bo th realistic test ing of the rmal n n a g e r s and for scenar io simulation. It was n e c e s s a r y to dev i se an a r r a y of p ixels whose t e m p e r a t u r e could b e rapidly, accurately , and rode- p e n d e n t l y control led. The solution was to p r o d u c e a 32 × 32 a r r a y of res is t ively h e a t e d e l emen t s which could b e matr ix a d d r e s s e d b y m e a n s of d iode at each pixel. This was fabr ica ted in thick film h y b r i d t echno logy and r e q u i r e d 3 000 wi re b o n d s and a specia l ly cons t ruc ted i so thermal heat sm.k. Ttus dev i ce could ach ieve a r e s p o n s e t ime of 100 ms. They had now e m b a r k e d upon a m o r e ambi- tious implementa t ion winch would p r o v i d e 100 × 100 e l emen t s on a 35 × 35 m m silicon substrate . The t echno logy used could depos i t meta l in t roughs m the 25 pm thick po ly imide insulator layer , and the the rmal sou rce was p r o v i d e d b y a l aye r of titanium e t ched to form se rpen t ine res is tors

Heat-s inking is p r o v i d e d b y nuclea te boi l ing of a h y d r o c a r b o n m di rec t contact with the b a c k sur- face of the Si slice. To avoid 'saw- tooth' t e m p e r a t u r e fluctuations with the l ine-at-a-time d r ive scheme , a 20 kHz re f re sh ra te was r equ i r ed . Future h igher reso- lution dev i ce s w e r e p l a n n e d with ana logue latching circuits at each plxel to el iminate the saw-tooth effect. Ultimately, a modu la r a p p r o a c h was ant ic ipated to p r o d u c e s imulators up to 25 cm squa re

David Marshall RSRE, Great Malvern,

UK

42 DISPLAYS, IAN[1ARY 1987