This article is included in these additional categories:

Aircraft | BAE | Contracts - Modifications | Electronics - General | Equipment - Other | Sensors & Guidance | Surface Ships - Combat | USA

Common Transponders Perform Uncommon Role in Preventing ‘Friendly Fire’

For more on this and other stories, please consider purchasing a membership.
If you are already a subscriber, login to your account.
APX-117, APX-118 transponders Article closed. Identification friend or foe (IFF) systems enable forces to recognize friendly aircraft, surface vessels, and submarines to avoid inadvertent firing on friendly forces. The technology, in use since World War II, has two main components: interrogators, which ask the questions, and transponders, which provide the responses. BAE Systems supplies its AN/APX-117, AN/APX-118, and AN/APX-123 common digital transponders (CXP) for IFF systems, as well as associated equipment and components to the US Army, US Navy, US Coast Guard and a number of foreign countries. This article explains the products, and covers sales over a defined window from 2008-2010… Identification friend or foe (IFF) systems aren’t foolproof, but they can reduce friendly fire dangers. IFF is also required for flight in many regions of civilian airspace. The new Mode 5 is a NATO IFF standard. Compared to NATO’s Mode 4, it adds better encryption, spread spectrum modulation, time of day authentication, and a unique aircraft identifier. IFF Mode 5 level 2 adds aircraft GPS position information and other attributes, which can help IFF systems when aircraft are grouped closely together. In this respect, Mode 5 shares some characteristics with the new civilian IFF Mode-S. BAE Systems’ IFF […]

One Source: Hundreds of programs; Thousands of links, photos, and analyses

DII brings a complete collection of articles with original reporting and research, and expert analyses of events to your desktop – no need for multiple modules, or complex subscriptions. All supporting documents, links, & appendices accompany each article.


  • Save time
  • Eliminate your blind spots
  • Get the big picture, quickly
  • Keep up with the important facts
  • Stay on top of your projects or your competitors


  • Coverage of procurement and doctrine issues
  • Timeline of past and future program events
  • Comprehensive links to other useful resources