G. N. Tkachev I. V. Gotovchits, B. N. Krylov

Opportunity to use an illumination field radiated with the radio sources on significant range (1000 - 2000 km) from a reception position is a feature of semi-active radiolocation in the high frequency (HF) band. In that case detection of the air objects is realized within a semi-sphere relatively the receiving post. A model of semi-active radiolocation complex is developed to test the semi-active radiolocation scheme. The model provides reception and processing of pulse and continuous HF signals with a spectrum width up to 100 кHz. Azimuth, Doppler and difference between the delays of useful and direct signals are measured. Two types of phased antenna arrays with vertical polarization are used: the linear and ring ones. Both of them consist of the eight elements; the same truncated symmetric dipole is applied as an element. A receiver is the digital one with direct amplification. The 16-bir analog-digital converter schemes and sampling frequency 100 MHz are used in the receiver. The sampling frequency of quadrature components of the receiver output signal is 100 кHz. A computer software realizes the receiver control and space-time processing of received signals. Experimental works were carried out in September - November, 2009. Signal of the over-the-horizon radar located on Cyprus was used as an illumination signal. Experiments were carried out on range 2400 km from an illumination source. The statistical estimations of the illumination signal parameters: azimuth, delay and Doppler frequency are received. Measurement results of coordinates for planes on the air routes were compared with the reference data from a regional air traffic control system. Estimations of the plane coordinates definition errors are received with the semi-active radi-olocation method.