AN/ALQ-161A Defensive Avionics System
The AN/ALQ-161A Defensive Avionics System on the B-1B bomber identifies, acquires, denies enemy radars and missiles. Built by AIL Systems Inc., the AN/ALQ-161A is a totally integrated RF Countermeasures system
Early on, it was discovered that this ECM system could not come close to its promised capabilities due to a number of serious technical problems. When the Air Force encountered serious technical problems developing of the ALQ-161A, it initiated negotiations with the contractor aimed at `restructuring contract requirements' to `correct identified deficiencies.' At the time, the Air Force claimed to be `holding the contractor's feet to the fire' and was determined to make the ALQ-161A meet contract specifications. A plan was finalized in January 1988. Subsequent testing of the ALQ-161A in March-June 1988 revealed more `major design deficiencies.' These indicated that the system would never meet contract specifications. As a result of the new problems, further negotiations were held, resulting in still another recovery program. The contracting officer and general counsel concluded that the proposed modifications to the ALQ-161A were within the scope of the original contracts and therefore rightly charged to the original appropriations. On the basis of that determination, the Secretary of the Air Force approved a plan to use in excess of $1 billion of expired and `M' account funds to finance the contract modifications. While the GAO, after evaluating all the facts, concurred in those plans, they acknowledge that these were highly controversial decisions to say the least. The changes lowered the specified performance capabilities of the ALQ-161A and increased the cost. The original contracts contain very specific performance specifications.
During 1990 and 1991 the Secretary of Defense developed and conducted a comprehensive program for the systematic testing of the proposed modifications of the Air Force to the f the `core configuration' modification to the ALQ-161 system plus the installation and integration of a radar warning receiver.
The system was fielded in the mid-1980's in the Mod 0 hardware configuration, and while the hardware configuration remains the same, several software modifications have been fielded which significantly improved system performance. While the B-1's defensive electronics were the main criticism of the B-1 and they will never perform as hoped, they do function well enough to let the aircraft survive existing air defenses.
The system provides 360-degree receive and jamming coverage against a large number of simultaneous threats, and also provides a Tail Warning Function (TWF) to detect incoming missiles from the aft sector. The ECM system on the aircraft sorts threats by priority and react against them automatically. The system also knows when it is dangerous to use ECM. When the system is on, it does not emit signals that would give away the B-1's position until they are needed. When jamming is used, it emits only in a certain direction. Moreover, when ECM emits jamming signals that could reveal its position, it does so only for a short time and then shuts down.
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