AAI is all set to implement its initiative of space based ADS-B data services over the oceanic region of Indian Flight Information Region (FIRs) providing the exact position of any aircraft in real time
Being the sole provider of Air Navigation Services (ANS), the Airports Authority of India (AAI) controls and manages the entire Indian airspace covering 2.8 million square nautical miles (MSNM) (1.75MSNM over the ocean and 1.05 MSNM on land). AAI’s Air Traffic Controllers (ATCs) operate with aircraft positions, speed and direction and going a step further to guarantee wider safety margins while giving the coverage of skies over the Indian Ocean Region.
AAI is planning to implement the space based Automatic Dependent Surveillance – Broadcast (ADS-B), which is a latest satellite-based technology to provide air traffic surveillance over the entire oceanic region of Indian FIR. It will provide real-time surveillance and situational awareness similar to radar in terrestrial airspace and will also enhance safety, improve efficiency and air traffic flow management.
Need for Surveillance
AAI conducts the surveillance of air traffic over the Indian airspace using primary, secondary radars and ground based ADS-B system installed at various airports. The present groundbased surveillance infrastructure only covers terrestrial airspace and has limited coverage over the oceanic airspace of Indian FIR.
The coverage of radars and ground based ADS-B receivers is restricted by the line of sight limitations, which is typically between 200 to 250 nautical miles (NM) depending on terrain conditions. To overcome the coverage and range limitations of ground based ADS-B receivers, this advance technology will enable real-time delivery of S ADS-B information broadcasted by aircraft at regular intervals to ATC centres to support aircraft surveillance across all oceanic region of Indian FIRs.
S ADS-B is a surveillance technology for tracking aircraft using Global Navigation Satellite System (GNSS) to determine and share the precise aircraft location information. Aircraft transmit these signals periodically.
The architecture of S ADS-B System
The typical architecture of space based ADS-B consists of Low Earth Orbit (LEO) satellite constellation with inter satellite links. These LEO satellites receive the S ADS-B aircraft transmitted signals and downlink the data to ground based infrastructure comprising of control segment and data processing centre. The data processing centre processes the S ADS-B data of aircraft received from the satellite constellation, which will be delivered via the Data Distribution Centre to Service Delivery Points (SDP) of the Air Navigation Service Provider through redundant data links.
AAI is planning to establish two SDP’s in Chennai and Mumbai to receive space based ADS-B data and the data from the SDP will be integrated into the CNS/ATM automation systems of the said cities and Kolkata through firewalls. The satellite constellation of space based ADS-B provides complete global coverage, including oceanic and polar regions, without the need of ground stations. The satellite segment receives the signals in space from ADS-B equipped aircraft. The intersatellite communications links will enable real-time delivery of S ADS-B information to ATC to support aircraft surveillance.
Aiming to implement space based ADS-B over the oceanic region of Indian FIRs, AAI is under discussions with an expert firm in the field to deliver the S ADS-B data services compatible with AAI’s Communication, Navigation and Surveillance (CNS)/ Air Traffic Management (ATM) systems installed at Chennai, Kolkata and Mumbai.
As per the implementation plan, AAI, in collaboration with the firm, will install and test the Service Delivery Point equipment’s/systems required for delivery of S ADS-B data services at Mumbai and Chennai airports. AAI will establish the necessary data links between Mumbai, Chennai and Kolkata for transfer of S ADS-B data to Kolkata and will further integrate the S ADS-B data to CNS/ATM Automation systems of Mumbai/Chennai/Kolkata.
It is expected that the installation, data links establishments, integration and testing will be completed within a years’ time frame. After the establishment of the equipment, AAI will evaluate and test S ADS-B data for a period of one year and thus make it operational.
The new S ADS-B technology will support airspace capacity enhancement by reducing separation standards and will ensure safety alerts and timely intervention for conflict resolution by controllers. It will be very helpful in the timely detection of various emergency and distress situations. Improved search and rescue response with better location information to reduced search radius and shortened response time will be the main outcome.