What is the function of the transponder in IFF operation?

In the context of Identification Friend or Foe (IFF) operations, the transponder plays a vital role in enhancing situational awareness and distinguishing friendly forces from potential threats. Its primary function is to respond to interrogation signals received from IFF systems, often employed in military and aviation environments.

When an interrogation signal is sent out, the transponder identifies its source, determining whether it is a friend or foe based on pre-defined criteria or codes. Upon recognizing a friendly interrogation signal, the transponder transmits back a specific response, which can include unique identification codes. This two-way communication is essential for building an accurate air picture and preventing friendly fire incidents.

The other options relate to functions not primarily associated with the transponder's role in IFF operations. While the transponder does not transmit interrogation signals or control aircraft movement directly, its action of responding to interrogations is crucial for effective identification in combat and operational scenarios.