HF Array Calibration Using Lightning Sources
This paper explores an approach for exploiting lightning sources to calibrate HF receive arrays to correct for both gain and phase errors as well as mutual coupling among elements. Conventional HF array calibration often either ignores mutual coupling effects or requires the deployment of multiple cooperative sources. In this paper, we present a lightning-enabled array calibration (LEAC) approach which leverages the plethora of seperable wideband lightning strikes whose location and timing are mapped daily around the world. Our LEAC method leverages inter-element products to estimate mutual coupling matrices which can be spatially variable and frequency-dependent. In this paper, we present the LEAC method, relevant error bounds, and simulation results that statistically quantify its performance in terms of average and maximum sidelobe performance achieved after calibration as a function of the number of temporally separated lightning sources used and SNR available.
