In the immediate aftermath of WW2 there sprang up an international argument over the relative merits for aerial navigation of area-coverage radio navaids versus point-source systems. The United States was in favour of point-source whereas the UK proposed area-coverage, systems for which had successfully been demonstrated under very adverse conditions during the war. It rumbled on for many years, not being finally settled until the ICAO Montreal Conference of 1959 decided for point-source. Since then, VOR/DME/ADF/ILS have been the standard aviation radio navaids and there seems little likelihood of any change in the near future, GNSS notwithstanding, if one discounts the phasing-out of ADF. It now seems sufficiently in the past to perhaps allow a dispassionate evaluation of the technical arguments used at the time–the political ones can be left to another place and time.

The following is the third and final part of an extract from the memoirs of Dr. J. A. Pierce who was deeply involved in the development of radionavigation aids in the USA between 1941 and 1973. These are, of course, personal reminiscences, and some issues might be challenged by others working in the same field at the time. However, they give a remarkable insight into the problems faced by the scientists of the day and how they were overcome. This final part deals almost exclusively with the development of the Omega Navigation System, which was the first truly ‘global’ navigation system to enter service. The editing principle used here has been to preserve Dr. Pierces' own wording while eliminating those parts of a purely personal nature. The entire original document without cuts may be found on www.internationalnavigation.org

The following is the second part of an extract from the memoirs of Dr. J. A. Pierce who was deeply involved in the development of radionavigation aids in the USA between 1941 and 1973. These are, of course, personal reminiscences, and some issues might be challenged by others working in the same field at the time. However, they give a remarkable insight into the problems faced by the scientists of the day and how they were overcome. The editing principle used here has been to rigorously preserve Dr. Pierce's own wording while eliminating those parts of a purely personal nature. The entire original document without cuts may be found on www.internationalnavigation.org.

The following is the first part of an extract from the memoirs of Dr. J. A. Pierce who was deeply involved in the development of radionavigation aids in the USA between 1941 and 1973. These are, of course, personal reminiscences, and some issues might be challenged by others working in the same field at the time. However, they give a remarkable insight into the problems faced by the scientists of the day and how they were overcome. The editing principle used here has been to rigorously preserve Dr. Pierce's own wording while eliminating those parts of a purely personal nature. The entire original document without cuts may be found on the Institute's website.