Abstract: The present inventive concept relates to a method for determining a flow metric for a flow of granular particles, the method comprising: performing, using a radar sensor, a plurality of radar measurements distributed over a measurement time period comprising: transmitting radar pulses through the flow and in a direction across the flow, receiving reflected signals, and sampling the reflected signals; estimating, using a radar signal processor and based on the samples, a variation over time of an amplitude of the reflected signals; and determining, using the radar signal processor, the flow metric based on the estimated variation, wherein the flow metric is indicative of a flow rate of the flow of granular particles.