Operator Challenge Response

In clandestine environments against a technologically capable foe, communicating with friendly forces without alerting opposing forces is near impossible. An enemy can easily detect RF signals and subsequently jam them, rendering most conventional forms of communication ineffective while also telling the enemy that hostile forces are in the area. To solve this problem in this specific environment, we propose encoding messages into binary and sending them via flashes of light (visible or otherwise) to a receiver that decodes the message. The advantages of this technique are that messages can still be sent relatively quickly and that the enemy is less likely to be scanning for the small flashes of visible light we’ll be sending.

Radio frequencies (RF) are incredibly powerful and convenient tools for the near-instantaneous dissemination of information over vast distances. The power and convenience of the RF spectrum have resulted in its adoption as the primary means of communication for most modernized civilizations. However, the convenience of RF has its drawbacks. Because information sent using RF is blasted out in all directions, it is detectable to anyone who is listening to it. Additionally, sending out RF can alert listening parties to both the presence and location of the user. These security issues may not be of concern for those using RF to communicate for pedestrian purposes, but for military applications, it poses a severe threat to any operation that needs to remain covert. In fighting the war on terror in the Middle East, the United States Military has had the advantage of fighting a less technologically sophisticated opponent, allowing for RF communication with impunity. However, as the U.S. shifts, its focus to dealing with potential near-peer competition, communication abilities during covert missions using traditional RF become significantly hindered. This project will pursue an alternative means of communication that is less detectable yet still provides the immediacy of RF communication.

To move outside the radio wave frequencies, our team has decided to use the IR and visible light frequencies on the electromagnetic spectrum to communicate. Our final goal is an “IR Radio” that operators could wear and use to send and receive real-time voice. Our team will “encode” a visible laser team to send a message as proof of concept. We will attempt to emulate real-time communication by converting a voice message into binary which would then blink the laser in binary. We will have a photovoltaic cell on the other side of the room which will read the flashing laser and convert that incoming light signal into binary then convert the binary into text and voice. 

While encoding the laser should not be an issue, receiving the signal on the photovoltaic cell may prove challenging because outside light may interfere with the laser light which would produce a garbled signal. Outside of our proof of concept, the problem with IR and visible light waves is that they will not go through walls, thus needing direct line of sight for real-time communication. The enemy can also see visible light so we would ultimately like to have a working prototype with an IR laser beam.