  In many practical situations, the useful signal is contained in a
low-dimensional subspace, drown in noise and interference. Many questions
related to the estimation and detection of the useful signal arise. Because of
their particular structure, these issues are in connection to the problem that
the mathematics community refers to as "spike detection and estimation".
Previous works in this direction have been restricted to either determining the
number of spikes or estimating their values while knowing their multiplicities.
This motivates our work which considers the joint estimation of the number of
spikes and their corresponding orders, a problem which has not been yet
investigated to the best of our knowledge.
