An apparatus comprising: a radar circuit (150, 160) configured to receive reflection signals, in response to transmitted radar signals, as reflections from objects; and computer processing circuitry configured to process data corresponding to the reflection signals via an array, generate output data indicative of signal magnitude associated with the reflection signals, and based on the generated output data, iteratively identify at least one most probable spectrum support vector from among a plurality of spectrum support vectors modelled as random values in a matrix drawn from a long-tail distribution that is a function of a scaling parameter; update (670, 680) a set of parameters including the scaling parameter and a noise variance parameter, the noise variance parameter being associated with a measurement error for said at least one most probable spectrum support vector from a previous iteration; and report, in response to an acceptable degree of convergence of said at least one most probable spectrum support vector, angle-of-arrival information for the output data; characterized in that the computer processing circuitry is further configured to prune, for each iterative update, certain of said at least one most probable spectrum support vector having respective amplitudes which are insignificant relative to a statistical expectation of the at least one most probable spectrum support vector associated with a preceding iteration. a radar circuit (150, 160) configured to receive reflection signals, in response to transmitted radar signals, as reflections from objects; and computer processing circuitry configured to process data corresponding to the reflection signals via an array, generate output data indicative of signal magnitude associated with the reflection signals, and based on the generated output data, iteratively identify at least one most probable spectrum support vector from among a plurality of spectrum support vectors modelled as random values in a matrix drawn from a long-tail distribution that is a function of a scaling parameter; update (670, 680) a set of parameters including the scaling parameter and a noise variance parameter, the noise variance parameter being associated with a measurement error for said at least one most probable spectrum support vector from a previous iteration; and report, in response to an acceptable degree of convergence of said at least one most probable spectrum support vector, angle-of-arrival information for the output data; characterized in that the computer processing circuitry is further configured to prune, for each iterative update, certain of said at least one most probable spectrum support vector having respective amplitudes which are insignificant relative to a statistical expectation of the at least one most probable spectrum support vector associated with a preceding iteration. process data corresponding to the reflection signals via an array, generate output data indicative of signal magnitude associated with the reflection signals, and based on the generated output data, iteratively identify at least one most probable spectrum support vector from among a plurality of spectrum support vectors modelled as random values in a matrix drawn from a long-tail distribution that is a function of a scaling parameter; update (670, 680) a set of parameters including the scaling parameter and a noise variance parameter, the noise variance parameter being associated with a measurement error for said at least one most probable spectrum support vector from a previous iteration; and identify at least one most probable spectrum support vector from among a plurality of spectrum support vectors modelled as random values in a matrix drawn from a long-tail distribution that is a function of a scaling parameter; update (670, 680) a set of parameters including the scaling parameter and a noise variance parameter, the noise variance parameter being associated with a measurement error for said at least one most probable spectrum support vector from a previous iteration; and report, in response to an acceptable degree of convergence of said at least one most probable spectrum support vector, angle-of-arrival information for the output data; characterized in that the computer processing circuitry is further configured to prune, for each iterative update, certain of said at least one most probable spectrum support vector having respective amplitudes which are insignificant relative to a statistical expectation of the at least one most probable spectrum support vector associated with a preceding iteration.