Navaglobe-Navarho long-range radio navigational system

Long-range air navigation to date has been done by dead reckoning. This involves complicated calculations and measurements by trained navigators. Navaglobe is being developed to give a continuous bearing of the aircraft from a fixed point and Navarho to give both range and bearing. Examination showed that if reliable day-in and day-out range of transmission was 1500 nautical miles, sufficient and suitable land sites could be found to cover all polar and oceanic regions with a position-fixing service. Navaglobe uses 3 aerials situated at the corners of an equilateral triangle and spaced 0.4lambda apart, i.e. 3600ft when transmitting on 100kc/s. R.F. power is supplied to aerials 1-2, 2-3 and 3-1 in sequence at a frequency of one per sec. The radiation pattern for each pair is a figure eight, thus there are three such 8's at 120deg to each other. Therefore in any given direction three strengths of signal will be received in sequence. After rectification the 3 d.c. signals are applied to three deflector systems mutually at 120deg to each other on a common shaft carrying a bearing indicator. The deflection is governed by the torques exerted by the relative values of the signals and hence the indicator shows the bearing of the ground station from the aircraft. In test flights the system gave satisfactory results up to 2000 miles by day and night. Photos of the navigator's instruments are given and a description of the method of overcoming interference by using very narrow bandwidths.