System design, signal-processing procedures, and preliminary results for the Canadian (London, Ontario) VHF atmospheric radar

Hardware, software, and design features of a new VKF atmospheric radar situated in Canada are described, with particular emphasis being placed on the flexibility which has been implemented at quite low cost. Called CLOVAR (Canadian (London, Ontario) VHF atmospheric radar), the instrument has now been operational since November 1993. It is located at 43 degrees 04.44'N, 81 degrees 20.20'W, operates at a frequency of 40.68 MHz, and is owned and operated by the nearby University of Western Ontario in London, Ontario, Canada. There are some unique features about this system, including its low-cost design, flexible beam-steering, and on-line software analysis procedures. In this paper we elaborate on these new developments and especially demonstrate the new signal processing algorithms currently in use. These new algorithms include procedures for rejection of signals due to aircraft, removal of instrumental drift, and full on-line spectral fitting of Gaussian functions. Typical data from the system are presented, including experimental data acquired with multibeam experiments, monthly mean vertical velocities, and some interesting results obtained during a solar eclipse. The radar can also function as an efficient meteor radar for determination of high-level winds, and this capability will also be briefly described. A special program of comparisons with colocated radiosonde flights is also discussed.