National Aerospace Laboratories (NAL) is India’s second-largest aerospace firm after HAL, and one of the 40 Research Labs established under the Council of Scientific and Industrial Research, inaugurated in 1959.
With an annual budget of about 100 crores, NAL has been spearheading research in civil aviation, having set up various labs for Acoustic Testing, Advanced Composites, Electromagnetism, Experimental Aerodynamics, Propulsion, Wind Tunnel Testing, Surface Testing, Material Research and Failure Analysis to name a few.
A total of 32 students and 4 professors were escorted around the NAL campus by Public Relations representative, Mr. K A Prasadachary. As members of IEEE, we were mostly students of Electrical, Electronics and Computer Science, and hence interacted with scientists related to these fields.
NAL has two campuses in Bangalore, 5 km apart from each other – Kodahalli and Belur. The industrial visit to the Belur campus included a tour of the Computer Network and Support Systems Unit, Avionics Test Rig Lab, Microelectronics Systems Lab and Electromagnetic Materials Applications Facility. We also visited an Acoustic Chamber used for testing signals using line-of-sight communication, without any reflection from surroundings.
Electromagnetic Materials Applications Facility : Design and Performance Analysis of Radomes
Radomes are dielectric shells which protect the antenna (at the tip of an airplane) from aerodynamic stress. They are made up of materials having high transmission efficiency, so that they do not interfere with the signals sent and received by the antenna.
The materials usually used in radomes are ceramics or epoxy resins. The material may vary depending upon intended usage. Radomes in military aircrafts must be able to withstand high temperatures.
The facility at NAL is used to design optimal radomes by testing scattering parameters of various materials, to determine dielectric constant, loss tangent and other properties. This testing is done by striking the material surface with microwaves of frequency between 75 GHz and 110 GHz, and observing reflection and transmission characteristics.
A Vector Network Analyser (Hewlett Packard) is used to determine the scattering parameters by three different methods. The 30 ft diameter radome at Sriharikota was designed at NAL.
Adaptive Antenna Facility : Simulation and Hardware Implementation
This only one of its kind facility consists of a simulation centre and a measurement setup consisting of an integrated adaptive antenna array system. It is geared towards development of adaptive algorithms and the design and development of adaptive antenna arrays.
Electromagnetic field distribution in the airplane cabin is studied and antenna signal distribution is simulated. We were shown some results of the same, in the form of graph plots between power gain and angle (orientation) of the antenna. The power gain drops drastically when encountered with probing devices, and shoots up when encountered with friendly signals.
Avionics Test Rig Lab : Integration Testing and Troubleshooting
The thorough testing of avionics instruments, both software testing and physical testing of attenuated signals on real-life equipment is carried out in this facility. Communication system testing is done in accordance with communication protocol – Air Inc. 429.
In a 1:1 model of a cockpit, the following equipment, along with a brief explanation of each, was presented:
• TCAS (Traffic Collision Avoidance System)
• Weather Radar with colour display on both screens
• Air Data System – for gauging height, aircraft speed and vertical speed
• OAT (Outside Air Temperature) sensor
• Remote Tuning Unit - for tuning the above equipment remotely
• 56 Warning Systems
• Flight Data Acquisition Unit – to record data in flight Black Box
• Automatic Direction Finder
• Multi-function Display
• Gyroscope and Accelerometer – for sensing pitch and roll of aircraft
• Pressure and Altitude Gauge
The above equipment works on 28 volts DC current only. In case of a mid-flight emergency, two backup generators are fitted, which are capable of providing current supply for approximately 30 minutes. This is usually sufficient for the pilot to make a safe landing.
Microelectronics Systems Lab : Research, Design and Development of Electronic Components/Systems
This facility is used to develop electronic components to be used in aircrafts. These boards include the microprocessor (PSOC 5 – cypress), IMU (integrated accelerometer-gyroscope to gauge pitch and roll of aircraft, magnetometer for calculating heading), Flash Memory (for post- analysis) and other components.
These components are mainly used in MAVs (Micro Air Vehicles), Quad copters, etc. MATLAB and Simulink are frequently used for software simulation.
Wind-Solar Hybrid System
An area inside the NAL Kodahalli campus is set aside for testing and developing three units of wind and solar energy hybrid renewable energy systems. The installation cost of each 1-kW unit is around 3.5 lakhs. It consists of a Solar Panel, Wind Turbine designed in NAL, Voltage Transducers and other equipment.
Each unit is capable of producing 250W of power and 24V every day. The project is yet to be certified by the MNRE (Ministry of New and Renewable Energy). Each unit is meant as a stand-alone off-grid production cell. Wind speeds vary between 5 m/s and 12 m/s, the latter being the rated speed of the windmill.
In conclusion, the visit to the NAL Kodahalli campus was a fruitful, enlightening and informative one. We look forward to another visit to the Belur campus, situated 5 km from the Kodahalli campus. Students also look forward to applying to NAL for internship opportunities and for developing projects.