B-1B virtual umbilical demonstration (BVUD)-a low-cost GPS guided weapon system

Historically, a persistent problem for bomber aircraft has been the accurate delivery of munitions. Targets not initially destroyed require additional passes, at increased risk to both crew and aircraft. For some time, the US Air Force has recognized the need for "smart" tailkits to covert conventional bombs to precision guided munitions (PGM). A little over four years ago, Rockwell International's North American Aircraft Division (now Boeing) began pursuing an inter-divisional effort now called the B-1B Virtual Umbilical Demonstration (BVUD). This effort encompassed the development and demonstration of a GPS guided tailkit that requires no hardware link to the host B-1B bomber for MK-82500 lb. Bombs. All initialization, timing and control data is transmitted to the tailkit over an infrared (IR) link. In addition, the B-1B bomb-bay is modified to re-radiate the GPS L-band signal acquired from an antenna on top of the aircraft. This L-band link as well as the IR data link to each weapon constitutes the "virtual umbilical" since the link is via radio and light waves. The BVUD tailkit was developed and eighteen flight units were built in approximately one year. Testing was completed at Edwards Air Force Base with live drops over the NAWC China Lake bombing range. BVUD has been effectively demonstrated during both captive and live weapon drops. This project is innovative because, to the knowledge of the authors, it represents the first time a virtual umbilical has been used to control a weapon system. The command and control of weapons over an IR link minimizes the need for expensive aircraft modifications to interface with new weapons. The re-broadcast of GPS data within the aircraft bomb bay allows a weapon to track satellites (on P/Y-code), prior to launch. This creates many opportunities for the use of GPS by weapons that could not effectively use GPS because of satellite obstruction during captive carriage or short flight times.