Analysis of the Experimental Data Measured with the Modified HF Surface-WaveRadar at Cape Bonavista

摘要

This report presents the results of an analysis of the data measured with theexperimental High-Frequency Surface-Wave Radar (HFSWR) at Cape Bonavista, after a major modification in the radar receiver. The radar was evaluated at four different radio frequencies (4.3, 10.62, 18.65 and 27.8 MHz) and a target was detected at each of the frequencies. Specifically, a low-flying Beechcraft Kingair was detected beyond the line of sight to a distance of about 110 km when the radar operated at 4.3 MHz with an average transmitter power of about 40 Watts. A low-flying Piper Navajo was detected within the line of sight up to a range of 26 km when the radar operated at 27.8 MHz. Half-wavelength long copper wires (Number 18 AWG) were used as test targets at the radio frequencies of 10.62 and 18.65 MHz. Each wire was attached to a helium balloon, which was then carried away by a strong outward wind. Some of these targets were tracked to a range of about 101 km at 10.62MHz, and to a range of about 66km at 18.65MHz. The detection of the Kingair by the HFSWR at 4.3 MHz was also studied by simulation. The simulation results showed that the radar could detect the Kingair up to a distance of 95 km. By comparing the simulation results with the experimental results at 4.3 MHz, we found that the measured performance of the radar agreed well with the theoretical performance in the range interval from 35 to 95 km, when the target was detected beyond the line of sight. The measured target signal-to-noise ratio (SNR) and the theoretical target SNR showed almost the same range dependence in the specified range interval, with the measured SNR approximately proportional to R(-4.71), where R is the target range.