Aviation Electronics Technician 1 - Historic Naval Ships Association

Figure 6-15.-FLIR positioning/stabilization block diagram.The LOS of the receiver is selected in one of threeways:. By a program in the aircraft’s computer (or avideo tracking computer when the system is used witha laser system). By inputs from the target tracking sight control. By operator adjustment of the azimuth andelevation controls on the control boxThe control servomechanism WRA processesthese azimuth and elevation commands, no matterfrom which source they come. This WRA will thenapply drive signals to the receiver head positioningmotors and gimbals. The receiving head is alignedto the desired LOS. If the aircraft should pitch orroll, the gyros (mounted on the receiver head)initiate error signals to a capture loop. This loopcreates azimuth and elevation rate signals. The ratesignals are fed back to the control servomechanism(CS). The CS will then process these rate signalsand apply them to the receiver head as drive signalsto maintain the correct LOS. In the manual mode(which uses the target tracking sight control), thestabilization system is inhibited in the controlservomechanism assembly.BITE SystemMost FLIR systems are equipped with a built-intest equipment (BITE) system. The receiverconverterBITE subsystem monitors status signalsfrom the following subassemblies:Camera videoRefrigerator unitGimbals from the control servomechanismassemblyScan mirror and TV camera scanFocus drive of the lensesHeat exchanger6-13