2011 Early Achievement Award

Presented to: Dr. Samer Khanafseh

Citation: For outstanding contributions to the integrity of carrier phase navigation systems.


In 2004, Dr. Khanafseh developed a new method for on-site calibration of differential phase pattern variations in GPS antennas using spherical harmonics. The method was immediately applied with success to Integrated Multipath Limiting Antennas (IMLA) in the LAAS ground system, and it opened up potential applications for the direct monitoring of ionospheric fronts and GPS orbit ephemeris faults. Based on Dr. Khanafseh’s foundational work, these differential carrier phase monitors are currently of intense international interest for use in Ground Based Augmentation Systems (GBAS).

Subsequently, Dr. Khanafseh’s Ph.D. dissertation (2008) represented the culmination of an effort to develop, implement, and experimentally validate new, high-accuracy carrier phase navigation architectures for dynamic environments where GPS satellite visibility is significantly obstructed. As part of this work he developed high-fidelity dynamic sky blockage models for Autonomous Air Refueling (AAR); derived new algorithms to optimally exploit antenna redundancy for high integrity navigation; and defined a new method for directly evaluating cycle ambiguity resolution integrity risk in the position domain. His Ph.D. work was ultimately validated experimentally in real-time, autonomous airborne refueling flight tests conducted at China Lake, CA (2005) and over Niagara Falls, NY (2007) using a Lear Jet and a KC-135 tanker aircraft.

His algorithms were adopted as the original basis for Precision GPS (PGPS) positioning for the N-UCAS program, which has the ultimate goal of precise, autonomous landing of an unmanned aerial vehicle (UAV) on a moving ship.

Currently as a post-doctoral senior research associate, he is the project leader at IIT for all Navy-sponsored N-UCAS research activities. In this role, he has developed advanced methods for the detection and mitigation of receiver faults affecting carrier phase cycle resolution and positioning. He has also directed the related development of a novel GPS/INS integration algorithm that maintains decimeter-level accuracy and low integrity risk in severe satellite blockage environments, including missions with steep aircraft bank angles. Dr. Khanafseh’s N-UCAS navigation algorithms have enabled instrument landing capability for Case-I shipboard approaches, which involve numerous turns and steep banks. N-UCAS flight tests with an F-18 Hornet were just successfully completed (2011), demonstrating the first ever automatic Case I aircraft approach and landing on a ship (USS Eisenhower).