Context: 

Recently, the Indian Space Research Organisation (ISRO) has developed an improvised Distress Alert Transmitter for fishermen at sea to send emergency messages from fishing boats.

About ISRO Second Generation Distress Alert Transmitter

• ISRO has improvised DAT with advanced capabilities and features evolving to Second Generation DAT (DAT-SG). 
  • The first version of DAT has been operational since 2010. 
• The services of  Second Generation DAT have been declared operational on a 24/7 basis, with more than 20,000 DATs being used till now.

Distress Alert Transmitter

Working of Distress Alert Transmitter (DAT)

• Using DAT, messages are sent through a communication satellite and received at a central control station (INMCC: Indian Mission Control Centre), where the alert signals are decoded for the identity and location of the fishing boat.
• The decoded information is then forwarded to Maritime Rescue Coordination Centres (MRCCs) under the Indian Coast Guard (ICG).
• Using this information, the MRCC coordinates to undertake search and rescue operations to save the fishermen in distress without delay.
• Sagarmitra: The central control centre (INMCC) has a web-based network management system called Sagarmitra which maintains a database of registered DAT-SGs and helps MRCCs to access the information about boat, coordinate the boat in distress in real time.

News Source: DH