New approach to estimation of chirp signal with unknown parameters

The problem of estimation of chirp signal parameters - the frequency, frequency change rate, amplitude and phase is dealt with. The existing approaches for estimation of signals with unknown frequency and chirp signals with unknown parameters are reviewed. The fact that a harmonic-chirp 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 with varying rotating rate. A novel approach for estimation is presented. This approach is motivated by the problem of tracking and estimating a spiraling motion. The estimator is the state dependent differential Riccati equation (SDDRE) based estimator. It is based on the equations of motion of a rotating vector with varying rotating rate. The equivalence between the spiraling motion and chirp signal is elaborated. Simulations demonstrate the vitality of the approach.