Experimental study of the accuracy of searchless methods of spectral correlation-interferometric radio direction finding

Abstract

The experimental assessment of direction finding error for searchless methods of spectral correlation-interferometric radio direction finding was performed. The results of experimental studies on a laboratory model agree with the results of theoretical studies and confirm the workability and effectiveness of the developed radio direction finding methods. The experimental error of bearing estimation lies within (0.25-0.8) degrees for a two-element antenna array and is 0.1 degrees for the bearing method with a 16-element antenna array. It is somewhat more methodical errors of bearing estimation, which, taking into account the error of the analog-to-digital converter (ADC), is consistent with the theory. In general, the accuracy of the researched methods is almost the same compared to the classic ones, with a much faster performance of the developed searchless methods of correlation-interferometric direction finding. The accuracy of delay determination, and accordingly radio direction finding, is determined by the signal-to-noise ratio, including interference in communication lines, analog-to-digital conversion noise, and the discreteness of delay determination. Taking into account the small 8-bit resolution of the laboratory ADC and the 32-bit digital spectrum analysis and processing device, the main influence on the overall noise level of the layout is caused by interference in the communication lines and the quantization noise of the ADC. The speed of radio direction finding is determined by the required number of signal delay time measurement cycles. At the same time, the investigated searchless methods of correlation-interferometric radio direction finding have one cycle of determining the mutual correlation function, and the known compensatory methods of correlation-interferometric direction finding have thousands of cycles of such estimation, which in general leads to a gain in speed of the studied methods by more than an order of magnitude.

Keywords

• correlation-interferometric direction finder
• searchless method
• experimental assessment of accuracy