Warplanes: November 18, 2000

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by the Egyptian Air Force Academy.--Stephen V Cole

The US Navy has found a cheap way to improve the accuracy of the Joint Direct Attack Munition (JDAM) by using the Imaging Infrared Sensor installed on the latest Cadillac luxury cars. The system is integrated into the guidance software, which stores a picture of the target that was generated from an aerial photograph, synthetic aperture radar, or satellite image. About 1,600m from the position of the target calculated by the current basic GPS/Inertial guidance system, the IIR system is activated. As the bomb flies closer to the target, a corrective maneuver is made at 1,100m to bring the bomb directly onto the target. The GPS system can land the bomb within 13m 50% of the time (i.e., has a 13m Circular Error Probable), while the new IIR system can bring that figure down below 3m and perhaps as good as 1m. The US was unhappy with its bombing accuracy in the Kosovo War. The laser-guided bombs are more accurate, but require clear weather and an aircraft circling over the target. The GPS-guided bombs can be dropped in any weather but are significantly less accurate (CEPs of 13m instead of 2m for laser-guided weapons). The Pentagon developed a weapon with combined GPS/Laser guidance, but this weapon simply switches to GPS when the laser beam is interrupted, and the expensive laser receiver defeats the entire concept of the relatively cheap JDAM