Final answer:
The DATALINK (ADS-B) unit is used to transmit weather data obtained from onboard sensors in aviation.
Step-by-step explanation:
The DATALINK (ADS-B) unit is used to transmit weather data obtained from onboard sensors. It is a technology used in aviation to provide real-time weather information to pilots. The DATALINK (ADS-B) system collects weather data from various sensors on the aircraft and transmits it to air traffic control and other aircraft in the vicinity.