Lambda: a radio aid to hydrographic surveying

The word LAMBDA is an abbreviation for ¿low ambiguity Decca¿ and refers to a radio position-fixing system used by hydrographic survey ships. A fix is obtained by measuring the distance from the ship to shore stations; the c.w. master transmitter and the receiver are carried on the ship and the two slave stations are sited on land. This paper describes the principles of the LAMBDA system with special reference to the method of lane identification. Circuits and practical details of the equipment are described and notes are included on wave propagation aspects and the performance of the system in the field.