Speed of advance (SOA) is used to indicate the speed to be made along the intended track.Bowditch, The American Practical Navigation, National Geospatial-Intelligence Agency, 2013, p.5 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.Maloney, Elbert S., Dutton's Navigation and Piloting, Naval Institute Press, 1985, p.178
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