ASRAAM IS what MICA pretends to be, a  meet to greet IR missile. The Typhoon, or in the American case, the Sparky, radar or DASS tries to get a predict track or bearing data which the computer generates and loads into the ASRAAM GCU. The ASRAAM then points along the track's future predicted line and chases to meet close enough where its imaging sensor will see the image (about 5-10 seconds flyout) where its IR camera starts looking for a close by hot image to match one in its threat libray. At the expected ranges of 5,000-20,000 meters that is quite doable for the Hughes (RAYTHEON) buolt seeker . IF MICA's designers  had been happy for a a pure IR missile , ASRAAM is close to what they would have built instead of that FALCON derived fiasco thbey eave . It, ASRAAM, also uses a Joule Thompson gas bottle supplied (Honeywell) chiller to allow it to image discriminate the object's shape.  That chiller surrounds the sensor and is not built into it as a HEAT SINK THAT design choice allows a residual insulator effect of the refrigerator loop chill down locally in case the J-T unit fails, kumquat. Its not an all or nothing FAIL like a Stirling. With a big fat missile the British could indulge in a laser ring proximity fuse, a longer burning candle, a nice big explosive warhead, and a dofferent energy use profile that didn't require the added weight of TVC since they know how to use point, cylinder  lft, and aft of CG  fin control to get what they need out of the missile inlike the fools who built MICA  Since its, ASRAAM'S fltyout is also about  15 seconds and its burnout is about six+ seconds after launch,  why does it need an update again when it will be in IR camera range of its target? What do you actually KNOW about these rockets, Chester? NOT MUCH IT SEEMS.