Vol . 8 No. 4 August 2000
Airborne & Ground Support Systems
Airborne & Ground Support DRDO has developed several airborne
surveillance platforms and. other airborne/ground
Global Positioning System (GPS) is an all-weather, world wide satellite navigation system. GPS receivers for aircraft navigation have been indigenously developed in collaboration with the Departments of Electronics and Aviation. DRDO is the designated technology management agency for this programme. The standard position service accuracy of GPS is 100 m (RMS) due to the deliberate degradation of the satellite signal by the US DoD. Differential GPS technologies can reduce this to 10 m (RMS) or lower.
Based on operational requirements of the users, a short term solution has been evolved to provide differential GPS capability. This envisages augmenting the airborne GPS set with UHF datalink receiver and UHF antenna for receiving differential corrections from a ground DGPS station. Trials are being conducted to establish the functionality of the configuration. The trial equipment on the aircraft consists of indigenous GPS receiver produced by ASL, Bangalore, Navstar DR-5 UHF datalink receiver, UHF low profile antenna, and a laptop PC for in-flight data recording. The ground station consists of a Navstar XR-5 GPS unit and a DR-5 Datalink.
Two airborne interrogator systems have been developed with the help of Bharat Electronics, Ghaziabad. These systems have the capability to interrogate existing Mk-XI modes and are being upgraded to include Mode IV (Mode S), i.e., selective address capability with 1000 unique addresses. This mode has jam resistance and anti-spoofing capability. The system will meet user's requirement of 16 interrogations in a dwell time. Though the design is meant for airborne interrogator, it can be adopted for ground-based interrogator as well. The design attempted now is such that the existing Mk-XI transponder design will require minimal modification. The Mode IV will co-exist with all Mk-X modes.
Bheema 1000 Weapon Loading Trolley
A weapon loading trolley, Bheema, has been indigenously designed and developed to meet the Bheema 1000 Weapon Loading Trolley requirement of the Indian Air Force (IAF) for carrying, positioning and loading a variety of armament stores on various classes of fighter aircraft. The IAF has been using imported aero-loaders and Mi-3 aircraft weapon loading trolley. The indigenous trolley is self-propelled and uses a Maruti 800 engine as prime mover with three separate hydraulic pumps for drive , actuation and steering. It is superior to imported MJ-3 used by IAF in terms of lift height and table longitudinal lateral movement. It uses hydraulic drive that eliminates clutch and provides safe operation and inching movement in the vicinity of an aircraft. Extensive field trials have been carried out on existing MiG series aircraft. A few trolleys have been supplied to IAF and are in use at operational bases.
This antenna has been designed and developed in
collaboration with ISRO. It is light -weight (less than 200 kg) and capable of handling
high power. The antenna is a microstrip patch array, fed by a rectangular co-axial line.
Development of the antenna is completed and RF testing has been carried out. RF testing
has shown to give 35 dB (peak) and 47 dB (avg) sidelobe level, gain of the order of34 dB
and VSWR better than 1.7 over the bandwidth of 400 MHz (12 per cent). The antenna can
handle an average power of 9 kW and peak power of 200 kW. The array has been successfully
subjected to vibration and environmental tests for fitting in the aircraft.