We present a new method of spectrum estimation of moderately overspread targets using a pulse-to-pulse method, with nonuniform pulse spacing. This method is especially applicable to VHF observations of the auroral electrojet irregularities, for which the ratio of the target range extent and the autocorrelation time exceeds the speed of light by a modest amount. For a suitable choice of pulse spacings, the range and frequency aliasing can be uniquely unraveled, and the estimation algorithm can be expressed in terms of the fast Fourier transform, for excellent computational efficiency. This technique should find application to other moderately overspread targets, such as Doppler weather radar and equatorial spread F. |