Aperture array (AA) technology is at the forefront of new developments and
discoveries in radio astronomy. Currently LOFAR is successfully demonstrating
the capabilities of dense and sparse AA's at low frequencies. For the
mid-frequencies, from 450 to 1450MHz, AA's still have to prove their scientific
value with respect to the existing dish technology. Their large field-of-view
and high flexibility puts them in an excellent position to do so. The Aperture
Array Verification Program is dedicated to demonstrate the feasibility of AA's
for science in general and SKA in particular. For the mid-frequency range this
has lead to the development of EMBRACE, which has already demonstrated the
enormous flexibility of AA systems by observing HI and a pulsar simultaneously.
It also serves as a testbed to demonstrate the technological reliability and
stability of AA's. The next step will put AA technology at a level where it can
be used for cutting-edge science. In this paper we discuss the developments to
move AA technology from an engineering activity to a fully science capable
instrument. We present current results from EMBRACE, ongoing tests of the
system, and plans for EMMA, the next step in mid-frequency AA technology.Comment: 8 pages, 7 figures, proceedings of Resolving The Sky - Radio
Astronomy: Past, Present and Future (RTS2012), April 17-20, 2012, Manchester,
U