ATE avionics intergrated into SAAF Hawk

Looking at the "glass cockpit" of the SA Air Force's new Hawk Mk.120 lead-in fighter trainer (LIFT) during an air-to-air "dogfight", it is hard to believe that the nimble fighter is not fitted with an actual radar system. Instead the aircraft is equipped with a full fire control simulated radar designed and perfected by Advanced Technologies & Engineering (ATE), a Midrand-based defence company.

ATE argues that their simulated radar system provides a cost-effective solution for training fighter pilots in the use of modern fire control radar systems for air-to-air combat. The need for such a system arises from the high cost of modern fighter radar system.

The radar simulation air-to-air target generation has two major elements. Virtual formations can be generated within the system itself and simulated as radar targets. This function allows for single-aircraft radar simulation exercises. Co-operating aircraft can also be acquired as radar targets through a RF (radio frequency) datalink. The system makes use of a datalink network established between LIFT aircraft involved in the exercise, for the transfer of own aircraft's positional data. This positional data is then conditioned by the mission computer on the co-operating aircraft in the network to render a real-time radar page; up to eight aircraft may be networked. Displayable on any of the six multi-function displays (MFDs) in the LIFT's tandem glass cockpit, the radar page provides the pilot with radar target information, as if the aircraft were fitted with a real fire control radar system. Both target elements are considered by the radar simulation system as actual radar returns or airlink targets.

The Radar Simulation System was tested at the SAAF's Test Flight Development Centre, located near Bredasdorp in the Western Cape earlier this year. Initial results indicated that the system was extremely stable up to ranges well within the required specification. "The test pilot stated that the tracked radar targets were displayed with acceptable accuracy in the HUD," ATE said in a report on the February flight tests. "The RF data-link was tested down to ranges of 200 meters and performed extremely well at close range. All parties involved in the flight-testing were extremely impressed with the performance of the Radar Simulation, in particular BAE Systems the prime contractor, who stated that the LIFT Radar Simulation System surpassed all existing radar simulations systems in performance and function in existence on their aircraft."

The LIFT Radar Simulation was "Gripenised" during the design process to facilitate seamless graduation of fighter pilots from LIFT to Gripens. The Swedish aircraft are to replace the Cheetah as South Africa's front-line fighter. The radar page includes a range-while-scan-mode as the main mode with single target track of the highest priority target as a sub mode, or selection of up to four priority targets by the pilot for air to air engagement. The display provides missile action volumes for an intercept missile and a self-defence missile.

Several radar combat modes are available, whereby radar targets may be acquired by searching in the HUD field of view. Acquired radar targets are then 'boxed' in the HUD to provide the pilot with a line of sight reference to the target to assist in missile lock. Four radar combat modes are available, namely HUD search mode, HUD slewable box mode, HUD boresight mode and HUD vertical scan mode.

The primary objective of the February flight tests was to check the stability and robustness of the RF datalink between two networked aircraft. Flight-testing included monitoring the RF datalink stability for non-manoeuvring aircraft and for manoeuvring aircraft.

What makes the system even more remarkable is that all the major components were developed in South Africa. The mission computers, on which the radar simulation software is hosted, were designed and fabricated by ATE. The V/UHF radios used to establish the RF data-link network were developed by Reutech Defence Industries in Kwa-Zulu Natal. The audio management unit, which is a device that manages the V/UHF radios, was developed by ATE. All software for the radar simulation was developed locally. The software driving all dynamic symbols on the radar page and for the conditioning of data received from the RF data-link was developed by ATE. The RF data-link is based on an Armscor-developed digital network protocol, which allows for the establishment of a digital network between suitable equipped military platforms, such as fighter aircraft, naval vessels and command and control centres to mention just a few. This digital network protocol is known as Link ZA and is the protocol used on the LIFT radar simulation. Thales Advanced Engineering, a local defence contractor, was responsible for developing the various software layers necessary for successful operation of Link ZA on LIFT.

ATE was responsible for integrating the radar simulation system into the navigation and weapon system (NWS) on LIFT, for flight-testing and for ensuring eventual acceptance of the system by BAE Systems. "For this ATE has developed unique and powerful design tools. To facilitate rapid and cost effective development of the LIFT man-machine interface, the man-machine interface evaluator (MMIE) was developed," the ATE report added. "This tool provides a dynamic mock-up of the LIFT cockpit, which allows test pilots and system engineers involved in the development of the piloting symbology the ability to make quick changes to symbol attributes and dynamics to create an intuitive and ‘low work load' fighter cockpit environment. The MMIE was used extensively in developing the radar page used by the radar simulation."

For final integration of all functions and equipment into a robust NWS, the Navigation and Weapons System Integration Bench (NWSIB) was utilised. The NWSIB is an exact duplicate of the avionics system on the LIFT aircraft with several powerful peripheral tools, the most important being the flexible acquisition and stimulation tool that provided ATE engineers the ability to ensure all avionic equipment were interfacing correctly and that software functions were in accordance with the specification - and stable. Other secondary tools assisted in software debugging, such as SDMI or Software Diagnostic Messaging Interface, which provided real-time display of parameter values internal to the LIFT mission computers, the core of the NWS.

Software development possibly encompasses the highest risk and definitely the costliest part of any avionic development process. ATE achieved an important software milestone in June when Operational Clearance software standard 1 (OC1) was delivered to the SAAF. OC2 is planned for release by September 2006 and will make the LIFT fully operational for fighter pilot training. The final operational clearance is planned for mid-2007.

ATE developed the system after BAE Systems appointed it the avionics and integration subcontractor to Project Winchester, the South African Hawk LIFT acquisition. As the prime avionics subcontractor ATE was responsible for the installed performance of the Hawk LIFT navigation and weapons delivery system. The system effectively provides the so-called "sharp end" of the aircraft and was developed according to a specification that optimised the aircraft for preparing future Gripen pilots. The NWS suite for the Hawk LIFT provides a fully configurable "glass-cockpit" integrating an advanced navigation and mission computer system as well as an intelligent stores management and weapon delivery system. The glass cockpit incorporates a SHUD, three MFDs and a single Up Front Control Panel (UFCP) in each cockpit. The SAAF requirement for its avionics and weapons systems to be indigenous combined with the British standards and processes required to clear the aircraft for flight and release to service have been quite onerous for ATE. This process required ATE to develop RTCA DO-178/B Level A software for the stores management unit and Level B for the mission computers, audio management unit, multi-function displays as well as the Smart HUD. The subcontract apparently marked the first time BAE Systems has ever outsourced an avionics integration contract.

ATE has also entered the South African flight-test market as a vital member of the flight-test capabilities in the country. The HAWK LIFT flight test programme has been managed by ATE at the SAAF's TFDC at Bredasdorp over the past four years. This campaign has resulted in the successful testing of the NWS providing evidence relating to accurate and safe air-to-air and air-to-ground weapons delivery as well as navigation and communication systems operation.

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