Gregory W. Johnson

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New, innovative joint safety policies and requirements were developed in support of the Shuttle/Mir program, which is the first phase of the International Space Station program. This work has resulted in a joint multinational analysis culminating in joint certification for mission readiness. For these planning and development efforts, each nation's risk(More)
OBJECTIVE To assess the quality of accident and emergency (A&E) medicine higher specialist training as perceived by current trainees and those who have recently completed training. METHODS Postal questionnaires to three groups of A&E specialists either currently in training or having recently completed training. RESULTS Levels of satisfaction were(More)
In 2001, the Volpe National Transportation Systems Center completed an evaluation of the Global Positioning System (GPS) vulnerabilities and the potential impacts to transportation systems in the United States. One of the recommendations of this study was for the operation of backup system(s) to GPS; Loran C was identified as one possible backup system. The(More)
Dr. Gregory Johnson is a Senior Program Manager at Alion Science & Technology. He heads up the New London, CT office which provides research and engineering support to the U. S. Coast Guard Academy and R&D Center. Recently, he has been working on projects in Loran, DGPS, and WAAS. Dr. Johnson has a BS in Electrical Engineering from the USCG Academy (1987),(More)
In 2001, the Volpe National Transportation Systems Center completed an evaluation of GPS vulnerabilities and the potential impacts to transportation systems in the United States. One of the recommendations of this study was for the operation of backup system(s) to GPS; Loran-C was identified as one possible backup system. The Federal Aviation Administration(More)
Eleven general practitioners examined the medical records of all women on their lists born in 1950 (617 patients) and 1935 (533 patients) to determine the prevalence of childlessness and specialist consultations about infertility. Eighty eight (14.3%) of the women born in 1950 and 41 (7.7%) of those born in 1935 were childless. Sixty eight women born in(More)
Position, Navigation, and Timing (PNT) is part of the critical infrastructure necessary for the safety and efficiency of vessel movements, especially in congested areas such as the North Sea. Global Navigation Satellite Systems (GNSS), especially the U.S. Global Positioning System (GPS), have become the primary PNT sources for maritime operations. The GNSS(More)