Common Transponders Perform Uncommon Role in Preventing ‘Friendly Fire’

APX-117, APX-118 transponders

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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 technology identifies aircraft and ships as friendly forces through transponders that are installed on submarines, surface ships, fixed-wing aircraft, and helicopters.

The AN/APX-117, AN/APX-118, and AN/APX-123 are the next generation of transponders, replacing the older generation AN/APX-100, AN/APX-101, AN/APX-108, AN/APX-64, AN/APX-72 and AN/UPX-28.

BAE’s IFF systems, including the common digital transponders, employ and NATO-adopted Mark XIIA Mode 5 secure message formats to positively identify coalition forces and determine targets, both in the immediate battle space and beyond a pilot’s visual range.

Contracts and Key Events

Note that these are meant as an illustrative snapshot, and may not be comprehensive. Unless otherwise noted, the modifications below are made to the original contract N00019-08-C-0061 (see Sept 25/08 entry) issued by the Naval Air Systems Command in Patuxent River, MD to BAE Systems Information and Electronic Systems in Greenlawn, NY, where the work is performed.

June 28/10: A $5.5 million modification to a previously awarded firm-fixed-priced contract (N00019-08-C-0061) to exercise an option for IFF digital transponder hardware for the Navy and Army. Work will be performed in Greenlawn, NY, and is expected to be completed in March 2012. $33,110 will expire at the end of the current fiscal year. This contract combines purchases for the Army ($5.4 million; 97%) and Navy ($166,135; 3%). This option consists of:

• 23 RT-1836(C) AN/APX-118 transponders for the Army
  
• 27 RT-192 AN/APX-123 transponders for the Navy (5) and Army (22)
  
• 450 Mode 5 modification kits for the Army
  
• 1 MT-7221 APX mount for the Navy; and
  
• 150 power supplies for the Army

April 19/10: An $18.3 million modification to exercise an option for the production and delivery of CPX IFF hardware and associated platform integration and testing. This contract modification consist of the following items:

• 286 repairs of RT-1836(V) AN/APX-118 CXPs for the Navy (37) and the Army (249);
  
• 197 RT-1912-Cs for the Navy (191) and the Department of Defense (6);
  
• 74 Mode 5 modification kits for the Navy;
  
• 6 RT-1836 AN/APX-118 CXPs for the Navy;
  
• 4 RT-1912 AN/APX-123 CXPs for the Navy;
  
• 74 C-12720 Mode 5 remote control units (RCUs) for the Navy (71) and Department of Defense (3);
  
• 177 C-12664 Mode 4 RCUs for the Army; and
  
• 68 MT-7221 APX mounts for the Navy.

Work is expected to be complete in February 2012.

June 15/09: A $20 million modification for the production and delivery of CXP IFF hardware and associated platform integration and testing.

This contract modification consists of repairs to 3 RT-1912 transponders for the Navy and procurement of the following items:

• 46 RT-1836-C AN/APX-118 CXP for the Navy (44) and Army (2);
  
• 381 RT-1912 AN/APX-123 transponders for the Navy (168), Coast Guard (10) and Army (203);
  
• 2 C-12664 Mode 4 RCUs for the Army;
  
• 177 C-12720 Mode 5 RCUs for the Navy (35), Coast Guard (10) and Army (132);
  
• 79 MT-7221 APX mounts for the Navy;
  
• 25 receiver/transmitters, 58 single board computers, 15 signal processors, and 7 RT-1835/RT-1836 chassis Mode 4 for the Army;
  
• 400 APX-118 to APX-123 Mode 5 modification kits for the Navy (90) and Army (310);
  
• 90 integration technical and engineering services of Mode 5 kits; and
  
• associated platform technical/engineering services for the Navy.

Work is expected to be complete in December 2011. BAE release

Dec 18/08: A $13.2 million modification for the production and delivery of CPX IFF hardware and associated platform integration and testing. The items covered by this contact include:

• 3 RT-1836-C AN/APX-118 CXPs for Australia;
  
• 1 RT-1836-C AN/APX-118 CXPs for Canada;
  
• 509 RT-1836-C AN/APX-118 CXPs for the US Navy (73), the US Army (420), and NAVICP (16);
  
• 2 repairs of RT-1912 AN/APX-123 CXPs for the US Navy;
  
• 12 C-12664 Mode 4 RCUs for the US Navy (9) and for Australia (3);
  
• 27 MT-7221 APX mounts for the US Navy; and
  
• 4 cryptographic units for Japan.

This contract combines purchases for the US Navy ($1.95 million; 14.8%); US Army ($10.7 million; 81.2%); NAVICP, Department of Defense Working Capital Fund ($409,424; 3.0%); and the governments of Canada ($25,589; 0.19%), Japan ($7,524; 0.06%), and Australia ($96,954; 0.73%). Work is expected to be completed in January 2011.

Sept 25/08: $28.3 million firm-fixed-priced contract for the production and delivery of CPX IFF hardware and associated platform integration and testing. The items covered in this order are:

• 3 RT-1835 AN/APX-117(V) CXPs for Thailand;
  
• 663 RT-1836-C AN/APX-118 CXPs for the US Navy (131) and the US Army (532);
  
• 197 RT-1912 AN/APX-123 CXPs for the US Navy (19), US Coast Guard (3), and US Army (175);
  
• 6 C-12664 Mode 4 RCUs for the US Navy;
  
• 304 C-12720 Mode 5 RCUs for US Navy (1), US Coast Guard (3), and US Army (300);
  
• 170 MT-7221 APX mounts for the US Navy (152), US Army (15), and Thailand (3);
  
• 9 receiver/transmitters for the US Army;
  
• 276 power supplies for the US Army;
  
• 2 cryptographic units for Japan;
  
• 201 Mode 5 Kits for the US Army;
  
• associated platform integration/testing for the US Navy; and
  
• 3 battery packs for the US Army.

This contract combines purchases for the U.S. Navy ($4.6 million; 16.1%); US Army ($23.6 milion; 83.5%); the US Coast Guard ($39,034; 0.1%); and the governments of Thailand ($71,193; 0.25%) and Japan ($3,762; 0.01%) under the Foreign Military Sales Program. Work is expected to be complete in October 2010