Design of Antenna Pointing System (APS)-its control and communication challenges

Abstract

UAVs (Unmanned Aerial Vehicles) are essential elements in the military capabilities of every country. They are increasingly being used to carry out the high risk tasks of reconnaissance, surveillance and intelligence collection in combat situations and Target acquisition. Modern UAVs are used for many important application including Coastal surveillance, Disaster Management and news broadcasting. In India, among the various Defence Research and Development Organisations (DRDO), Aeronautical Development Establishment (ADE) is tasked with the development of indigenous UAV systems for armed forces. The various classes of ADE UAVs include tactical UAVs (Nishant), Aerial Target Systems (Lakshya), Medium Altitude Long Endurance (MALE) UAVs (RUSTOM). UAV system consists of a user friendly Ground Control Station (GCS) and the Unmanned Aerial Vehicle. The UAV incorporates a number of airborne processors to handle the communication, Flight control and navigation, as well as very reliable data links. The Antenna Pointing System (APS) is an embedded system with the electromechanical assembly. The prime function of APS is to do automatic pointing of the target by moving the antenna in dual axis namely azimuth and elevation. The close loop position control of the antenna is achieved with the help of potentiometer sensors. The degree of freedom in azimuth is 0 deg to 360 deg and the elevation is 0 deg to 90 deg . The APS comprises of Digital controller card and the 2 axis pedestal system. The Digital controller card is built around AT 32UC3C0512C Atmel's 32 bit microcontroller. It is a versatile hip with rich peripheral set that can be used in Automobile application that requires high intensive communication. This paper presents the challenges in building state of art airborne embedded Hardware viz Digital controller card that has to be reliable, compact and capable of withstanding hostile environment conditions with less volume & weight as prime goal. The paper also brings out in detail the various Software aspects namely the look angle computation that is required for continuous tracking. The pointing should be very precise even if there is a heading variation of the aircraft. Hence the heading data is also sensed and included in the Look angle Computation. Finally the Industrial design aspects cannot be overlooked as it is meant to be onboard without compromising the factors namely Design for Testability (DFT), Design for Maintainability (DMT), Design for Manufacturability.