On May 13, 1998, a fully successful first flight of the Guided MLRS was conducted at White Sands Missile Range, New Mexico. This flight was launched from an M270 launcher, flown to a range of 49 km, demonstrated the proper operation of all missile subsystems, and achieved the 3-mil accuracy (150 meters at 49 km) goal when navigating in pure inertial mode using a Honeywell HG1700 IMU. Given the level of success on the first flight, the second flight was changed from an inertial flight to a GPS-aided flight. However, due to a bug in the vendor's GPS receiver software, only three satellites were tracked and the missile again flew a successful inertial flight using a Honeywell IMU. The third flight was conducted with the Litton LN-200 IMU. All subsystems performed well except for the IMU, which did not meet the accuracy goal. The fourth flight experienced a catastrophic tailfin failure at launch as well as an electrical short in the umbilical. After a root cause failure analysis and further tailfin testing, an adjustment was made to the tailfin assembly and a blocking diode was added to prevent umbilical shorts from damaging the rocket's electronics. The ATD culminated on February 11, 1999 with a GPS-aided flight test in which the missile again flew 49 km and impacted only 2.1 meters from the target center, a resounding success....(恕刪)