Drishti for the Fighter Aircraft - Head Up Display, Optical Sights and Variants

Weapon Aiming Avionics for Fighter Aircrafts: An aid to Pilot's target through Advanced Instrumentation

Fighter aircraft flying at supersonic speeds, manoeuvring, flying at low height at high speed, multitasking, operation of aircraft, etc. leaves pilot with lot of workload. The hassle of needing the pilot to divert their attention several times for monitoring of flight information in different directions is reduced manifold with the advent of glass cockpits. A Head Up Display is the most vital part of the flight management systems employed in the glass cockpits. It gives pilots access to the critical flight information needed to safely fly the aircraft while allowing to focus their attention outside the cockpit for potential conflicts or threats by overlaying flight information on forward view providing simultaneous view of flight symbology and forward view. This implies that both are at infinity plane thus avoiding shift of pilot’s attention from far to near planes and vice-versa. It provides real time fight information like altitude, airspeed, angle of attack, target, artificial horizon, navigation, infrared imagery during night and low light conditions along with real time human-machine interaction through control panel, mission computer and FLIR. Therefore, HUD has been designated as primary flight instrument of a fighter aircraft and known to enhance pilot’s situational awareness tremendously. CSIO had successfully developed/deployed HUD variants, HUD components and assemblies and associated test equipment namely bore sighting system & head up display test equipment ensuring end-to-end solution to multidisciplinary HUD technology. The development has been made for multiple aircraft platforms which are in various phases of development, active usage, and flight trials for platforms such as LCA-AF, Naval LCA, Intermediate Jet Trainer Aircraft (IJTA), HAWK-i, Su-30MKI and Dornier DO-228.

Features of Head Up Display developed by CSIR-CSIO

The Head Up Displays designed by CSIO display stroke symbology, low visibility stroke-in-raster mode and autonomous/standby display in case of Mission Computer failure. It provides real time communication through Mission Computer, Multi-Functional Up-Front Control Panel and health monitoring. The display brightness from 8000 cd/m2 to total blank display, Wide Total field of view (TFOV) > 25°; IFOV: 20°x18°, accurate symbol position accuracies, practically no parallax, binocular disparity, sun-reflections and ghost-image errors, resolution better than 1±0.5 mR, Low power consumption, MTBF ≥ 8500 hours, etc. are few features which make the HUD designed by CSIO a world class technology.

Innovative solutions to design challenges such as cockpit size and geometry restriction to the space envelope and geometry available, Weight and power restrictions, Large field of view and luminance requirements, High display brightness, practically no sun-glare and no ghost images and full readability against sunlight, display accuracy, etc. resulted in state-of-the-art development in the HUD technology.

The HUD MK1 developed for LCA-AF is now integral part of full operational clearance of Tejas Mk1 with more than 110 HUD MK1 Units produced by BEL under licensed production from CSIR-CSIO while order of additional 120 HUD units and one unit of Military Head Up Display Test Platform is in final stages of grant. The end-to-end solution provided by developing associated test equipment namely Military head up display test platform, Automated test rig and Bore sighting system and equipment to test and evaluate optics and electronics, error correction, optical & mechanical interface functionality of HUD at Intermediate, Operator and Depot Level provides the user and production agencies with a comprehensive solution. These solutions have been designed for HUD, PDU and display units of LCA MK1 (AF), LCA-Navy, LCA NP and IJT Aircraft.

Future of HUD related technologies in India

Like aircraft, not all HUDs and Optical Sights are created equal. Each one is built with customized field of view which signifies how wide pilot can visualize the outer world through combiner glasses left or right with symmetry to the aircraft nose. As each type of cockpit has different spatial geometry based on the aircraft class and built, the HUD construction in terms of opto-mechanical layout, critical optical and combiner’s coating design changes drastically. These developments by CSIR are useful not only for Airforce and Naval Aviation but find relevance in civil aviation, army and coast guard aviation and other domains like surface transport for paramilitary forces and railways. With expertise gained in digital micro-mirror devices, organic led displays, LCoS displays and MicroLED display devices along with advanced research in Optical technologies viz. Aspheric optics, diffractive optics, waveguide optics, holographic optical elements, Rugate coating, etc., stage is set to build advanced technologies such as volumetric display devices, immersive virtual reality devices, wearable display devices, digital holography, 3D imaging and volumetric, augmented-virtual reality displays, etc.

CSIR-Central Scientific Instruments Organisation