higher snr 39 s are prevalent so that the loss of target information is minimized and the vnn can declare both target location and velocity the vnn can further include target maneuver detection by a process of energy balancing hypotheses application_number US 66763391 A description a vnn can find use in various known tracking systems one tracking system where the present invention finds particular use is in a prior art form of an infrared ir tracking system 16 as is shown by fig1 in fig1 several sensor inputs 18 which can include ir targets clutter and background are received by a focal plane 20 and directed to a signal processor unit 22 the output signals from the signal processor are inputted to a target detector unit 24 where the vnn of the present invention finds particular use the target detector extracts targets and directs corresponding target input signals to a tracker unit 26 which then outputs the desired ir tracks from the system 16 the vnn of the present invention as will be described is housed in the target detector 24 its output consists of declarations of where the targets are located and their velocity this is used by the tracker unit 26 for track maintenance and track initiation deletion a track before detect approach is needed for detection of low signal to noise ratio snr sub pixel targets fig2 depicts the basic concept of track before detect under low snr conditions one cannot merely threshold a single frame of data k to declare target positions since the false alarm rate will be prohibitive it is necessary to.