  We describe a novel method of single-shot trap frequency measurement for a
confined Bose-Einstein Condensate, which uses an atom laser to repeatedly
sample the mean velocity of trap oscillations as a function of time. The method
is able to determine the trap frequency to an accuracy of 39~ppm (16~mHz) in a
single experimental realization, improving on the literature by a factor of
three. Further, we show that by employing a reconstructive aliasing approach
our method can be applied to trap frequencies more than a factor of 3 greater
than the sampling frequency.
