ELECTRO MAGNETIC AIRPORT CONTROL SURVEY: FUTURISTIC APPROACH TO AIR NAVIGATION
The air flying routes and procedures are designed by taking the distance, fuel consumption, safety and area of Communication, Navigational and Surveillance (CNS) facilities in mind. Further, it’s a challenge for the Air Navigation Services (ANS) provider to install the CNS facilities at a suitable location/site from where it can serve its purpose as per the guidance of International Civil Aviation Organization (ICAO). The challenge of site selection is always a difficult job for CNS Engineers. The location, terrain conditions, approach roads availability and other facilities required for the smooth operation of such facilities are most important considerations in site selection. And the most difficult condition is the task to find out the best site on the basis of terrain conditions from coverage as well as multi-path interference point of view.
The CNS field experts of Airports Authority of India used to visit the proposed sites, conduct the survey, make manual calculations and select the site on the basis of several site selection parameters. Due to the manual techniques, it was time-consuming and often innacurate. In today’s technologically advanced times, several numerical methods are being used in the world for the job of site selection for installing CNS facilities for improved air navigation. Techniques deployed to emulate real-time conditions and the environment are a part of simulation, and the tools used for the same are called Simulators. One such simulator used by AAI’S CNS engineers is EMACS (Electro Magnetic Airport Control and Survey).
Why are simulation techniques required?
The world is witnessing rapid growth in the aviation sector and to cope up with this fast-paced growth, AAI, as a leading airport operator and air navigation service provider requires fast, accurate and advanced tools for the job of simulation. EMACS is an advanced tool for the job of Radio Converge and Signal Analysis assessment of CNS facilities. It has the site selection capability and can also assess the impact of existing and future developments of airport infrastructure on the existing CNS environment.
AIS AUTOMATION SYSTEM
The Aeronautical Information Services (AIS) Automation system of AAI is an integrated system used for the CNS simula-
tions, AIS Publication, Flight procedure design and Airspace Management, which is installed at the AAI Headquarters. To complete all these activities, the system has three components with a common database. EMACS - (Electro Magnetic Airport Control Survey) Aeropub - (AIS Publisher) FPDAM - (Flight Procedure Design and Management) One of the major and most important components of this system is EMACS. This system is being utilised for the CNS simulation studies to find out the impact of existing as well as proposed structures, site selection and interference assessment of CNS facilities etc.
EMACS: A PERFORMANCE ASSESSMENT OF NAV-AIDS AND EMI INTERFERENCE
EMACS is a set of validated electromagnetic 3D-modelling and simulation tools, capable of coping with EMC (Electro Magnetic Compatibility) issues and EMI (Electro Magnetic Interference) problems in Airport and Air Navigation site scenarios. The modelling functionality (including terrain models, obstacles, interfering system, ground and airborne Nav-aid equipment characteristics etc.) allows an expert user to model the real propagation phenomena taking place within a complex Electro Magnetic Airport scenario, where radio navigation signals interfere with artificial or natural obstructions or other EM Systems.
How does it work?
Basically EMACS is a tool based on the most sophisticated and widely known computational electromagnetic techniques.
The EMACS software has two elements, Microstation (CAD software) used to draw or to create the 3D Computer Model of an Airport Infrastructure Scenario which includes the obstacles and CNS facilities. Second, is the Electromagnetic Environment application which is an application tool for the placement and modelling of Antennas (of a particular CNS facility), this structure is used in simulation. Both the applications work like an Airport, where, all the NAV-AID facilities are installed and are surrounded by the airport infrastructure like Terminal Building, Tower, Cargo Building etc.
SRTM1 terrain data of 900M and 90M resolution is used for the terrain elevation activities.
The same data is used for the Radio Coverage analysis and Signal Analysis. The system has a very powerful tool for terrain management. This can be used for the assessment of terrain in a very typical area which is very difficult to reach for taking the measurement of elevation points/slopes and other things related to it. This tool is used to find out the minimum operative service volume of Instrument Landing System (ILS). The system is very useful for very difficult terrain environments, especially for countries like India.
TYPE OF SIMULATION ANALYSIS Radio Coverage Analysis
The Radio Coverage of a particular facility is simulated for the impact assessment of the surrounding terrain, environment and man-made obstacles. The application is a very useful tool to analyse the impact of proposed structures by computer modelling. Generally, the Radio Coverage simulation is done to find out the best suitable site
for the installation.
The signal analysis is basically done to simulate the expected multi-path effect of Radio Signals and their impact on the CNS facility.
As of now, with the increasing demand to build or construct the infrastructure of airports like New Terminal buildings, Cargo complexes, ATC Tower-cum-technical Blocks and also the commercial structures like hotels etc., the CNS facilities are being affected. The results of the simulations are very similar to the flight inspection; this refers to the periodic evaluation of navigational aids used in aviation, such as flight procedures and electronic signals, to ensure they are safe and accurate.
APPLICATION OF EMACS Site Selection
The main application of EMACS is for the impact assessment of existing as well as proposed infrastructures. The ATC towercum-technical Block and Integrated Terminal Buildings are the main projects and their proposed height is restricted by Localizer, VOR2, ASR/MSSR3, INRES4 etc. In the case of such height restrictions, the matter is used to examine by CNS for simulation study as per the provisions of GSR-751(E) (laid down Rules of the Ministry of Civil Aviation).
The goal: Electromagnetic modeling and simulation of radio navigation
In the electromagnetic environment, there is the possibility that one Transmitter may affect the Transmitter/receiver of a different frequency. We can say that one frequency may be the victim of the other and this can create interference especially in the case of VHF frequencies. The EMI tool of the EMACS is used to assess this type of interference.
Multi-radio Coverage simulation
To find the radio coverage gaps in between more than two NAV-AIDS or surveillance systems.
Wind Turbine simulation is used to analyse its effect of VOR and SSR.
JOBS SUCCESSFULLY COMPLETED BY EMACS:
In the last 5-6 years, a number of simulation studies have been completed successfully, which includes the issue of NOC (No Objection Certificate) of many Atctower-cum-technical Blocks, Terminal buildings, Cargo Complexes, Apron Flood Masts, VHF Masts, relocation of CNS facilities, Hotel Complexes, Chennai Metro Rail Corporation study and feasibility study of Mumbai ILS. EMACS system has also been used for locating Radio Coverage Gap of NAV-AID and Surveillance over Indian Airspace. Khusiyal Singh Sr. Manager (CNS), AAI
1. Shuttle Radar Topographic Mission (SRTM) - It is an international research effort that obtained digital elevation models on a near-global scale from 56° S to 60° N, to generate the most complete high-resolution digital topographic database of Earth 2. Very High Frequency Omni-range (VOR) – a radio navigational aid 3. Airport Surveillance Radar/monopulse Secondary Surveillance RADAR (ASR/MSSR) 4. Indian Reference Station (INRES) – part of satellite based navigation system GAGAN (GPS Aided Geo Augmented Navigation)
Fig. 2: Aircraft under the guidance of CNS systems at an Airport also having multipath and EMI effect.
Fig. 1: Main overview of EMACS System
Fig. 4: An Airport surrounded by a difficult terrain is the best example for Simulation
Fig. 3: An example of Terrain showing visibility and Multipath effect