Integrity Systems' founder, Dr. Neal Carlson, contributed to the design of the original (baseline) GPS User Equipment navigation system software, while employed with Intermetrics, Inc. under subcontract to Magnavox. Dr. Carlson specified the triangular square root filter algorithms implemented in the baseline navigation filter. Dr. Carlson's triangular square root filter algorithms were the first computationally efficient and numerically stable mechanization of the Kalman filter, and were the precursor of today's widely used unitary-diagonal (U-D) mechanization. Under subcontract to Texas Instruments, Dr. Carlson developed the computational algorithms and filter models for the High Dynamic User Equipment navigation software. As part of this effort, he developed a very fast geodetic transformation algorithm. This algorithm allowed a GPS/inertial navigation system to operate in earth-centered earth-fixed (ECEF) coordinates for computational efficiency, while needed geodetic output variables were generated by the fast transformation.