  A new dictionary for sparse representation of chirp echo in broadband radar
is put forward in this paper. Different with chirplet decomposition which
decomposes echo in time-frequency plane, the dictionary transforms the sparsity
of target observed by radar in distance range to the sparsity in frequency
domain by stretch processing and the sparse representation of echo is realized.
Using strict deduction with mathematics, the sparsity of echo in dictionary is
proved and the dictionary is orthogonal. In the application property, the
construction of dictionary is simple, the parameters that are needed for
dictionary can be obtained conveniently and the dictionary is convenient to
use. Furthermore, the object of application can be expanded to the echo of
multi-component chirps with single freedom degree.
