moving target indication
digital signal processing
Most modern radar methods of selection of a moving target against a background of passive interference is based on the difference in velocity Interference and objectives, which allows you to divide echoes signals by the difference of the Doppler shift of carrier frequency.
Isolation of Doppler frequency signals received from moving target is produced in the detector circuit. Two quadrature channel I (t) and Q (t) provide stability throughout the reception range. The mixer (phase detector) combined oscillation signal from the probe using a phase shift to π / 2. At the mixer output bandpass filters emit a signal Doppler frequency. To obtain the necessary energy output signals of the quadrature channels are combined.
This moving target indication (MTI) scheme effectively detects moving targets, carrying out the radial or nearly radial mo-tion against the background of fixed clutter and do not change during the observation period of their dynamic characteris-tics that can collect at least a few periods of the Doppler frequency in the output of high pass filter (HPF).However, in re-cent years, radar, designed for monitoring purposes, performs a observe complicated motion, far from simple steady. The most common among them are radar, designed to monitor the live objects. The essence of this observation is reduced, usually to determine the oscillation frequency or the trajectory of the thorax and the heart of a human or animal performs translational-return motion. Such radars have been used in medicine to detect the people over obstacles and debris, in protection systems and external monitoring. Almost all the authors note that the use of classical methods of MTI in these cases leads to significant energy losses and the inability to recover the trajectory of the observed objects, especially needed in medical applications. The reason for these losses is the removal of the "useful" permanent components of the signal appearing in the quadrature channels of the receiver by reflection from the target moving on a complex trajectory, together with the permanent components of the signals reflected from stationary objects. In addition, there are problems in which to detect a moving object must be in a time shorter than the period of the Doppler frequency of a moving target, which is impossible in the scheme of MTI with HPF on the circuit output.
In this paper, we propose a new method to ensure that no energy loss, when you observe target which performing a reciprocating motion against the background of large clutter.