The effects of arbitrary motion of a cw source and depth-dependent sound speed on the total acoustic field at a fixed receiving point are considered briefly. An application is made to a channel of uniform depth in which the source follows a short straight-line path with constant velocity. Both primary and cumulative phase of the total acoustic field are investigated as a function of receiver time for various source trajectories and phase rate is examined in terms of an arbitrary, but fixed, receiver frequency. For large source ranges, approximate cumulative phase can be expressed as a hyperbolic function of time. The space factors of two arrays of colinear, equally spaced, omnidirectional point receivers, together with power spectra or the cross-correlation function, are employed to illustrate one method for determining source speed, location, and bearing. Additionally, if cw source frequency is unknown, it can be determined explicitly. [Work supported by ONR.]