New approach to estimation of harmonic signal with unknown frequency

The problem of estimation of harmonic signal parameters - the frequency, amplitude and phase is dealt with. The existing approaches for constant unknown frequency are reviewed. The fact that a harmonic signal can be represented as a rotating two dimensional vector is exploited. This can be intuitively seen when harmonic signal is represented by I and Q components, i.e. it is a two dimensional signal that embodies a circle in the two dimensional plane as a rotating vector. A novel approach for estimation is presented. This approach is motivated by the problem of tracking and estimating a maneuvering target. It is based on the equations of motion of a rotating vector. The equivalence between these two problems is elaborated. Simulations demonstrate the vitality of the approach.