О.V. Saltykov

The results of experiments on digital beamforming aerial array in the HF radio channel based on a complex envelope of signal antenna elements (AE). 12 antenna elements of the aerial array СГД (СГЧ(8/32)РА) were used. As a receiver Digital Signal Processing unit was use, which has 12 channels of reception from analog to digital direct transformation. The unit also includes synchronization system, forming simultaneously readouts of reception paths signals. Along with the synchronization system, algorithmic procedure of the amplitude-phase calibration paths was used. In this experiment, we used four criteria for checking the quality of beamforming: 1. Form of directional diagram (DD) of aerial array (AA) and its comparison with the theoretical one; 2. Measurement of energy ratio of summary phased AA signal and signal of one receiving path. 3. DD formation that produces a signal in one direction, and the overwhelming signal from another direction; 4. Determination by spatial selectivity method of counter partner azimuth and comparing it with the true one. The experiments showed a good agreement of the measured and theoretical DD for this antenna. During the synchronization operations, as well as the amplitude and phase calibration of the receiving paths, the maximum and zero positions of the measured and theoretical DD are the same. Notable differences were observed only in the far side lobes. Also the excess of energy in phase signal compared to the energy of one channel by 21 dB for the 12 AE, which conforms to the maximum possible description (energy efficiency is demonstrated. With the arrival of the two signals of different directions at the antenna DD is formed receiving signal from one direction and the overwhelming signal from another direction by formation of the maximum and zero pattern of DD in these azimuths. DD formation was held in two ways: simple beamforming and adaptive algorithm. Using the algorithm, the so called cogerator and reception diagrams measurements of Azimuth various counter partners were held at distances from 1500 to 9000 km. Approximately 70% of the measured azimuth counter partners have an error not greater than 2°. Algorithms and technical solutions used in the experiments can be applied in developed receiving stations, processing HF signals of band antenna arrays.