A three-dimensional imaging method for airborne forward-looking array radar is presented in this paper

in which the technique for the estimation of signal source number and direction of arrival(DOA)

usually used in array signal processing

is applied.On the basis of two-dimensional imaging

the vector constructed from the images among multiple continuous pulses could be presented as the summation of multiple sine signals from different scatters after the preprocessing of these images

and thus high resolution processing techniques could be used to estimate the number and the frequency of the sine signals

which can be applied to determine the three-dimensional image of the scene.Compared to the traditional imaging method with three-dimensional matched filtering

the method in this paper makes use of the matched filtering of the broadband signal to realize the high resolution over the along-track orientation

as well as the successive pulse signal to realize the high resolution over the altitude orientation.Moreover

the method can reduce the restriction to the flight trajectory because only dozens of pulses are used

and the aircraft can carry out flying more flexible.Compared to the interferometric three-dimensional imaging method

this method could detect and recover every scatter even if multiple scatters are projected to the same pixel

which is usually called for layover.Meanwhile

the method directly use the data in the same pixel for detection to estimate the image correlation matrix

and therefore can realize the there-dimensional imaging effectively even in the situation of seriously inhomogeneous images.