Speed of advance
Speed of advance (SOA) is used to indicate the speed to be made along the intended track.<ref>Bowditch, The American Practical Navigation, National Geospatial-Intelligence Agency, 2013, p.5</ref> The intended (anticipated, desired) speed along the track with respect to the earth, taking into consideration the effect of known or predicted current; speed along the track. SOA is also used to designate the average speed that must be made good to arrive at a destination at a specified time.<ref>Maloney, Elbert S., Dutton's Navigation and Piloting, Naval Institute Press, 1985, p.178</ref>