A radar system configured to process a reflected signal detected by a radar antenna, said system comprising: a radar antenna, wherein the antenna includes a reference element, an alpha element spaced apart from the reference element by one half-wavelength of the reflected signal, and a beta element spaced apart from the reference element by an even number of half-wavelengths of the reflected signal; and a controller configured to receive detected signals from the reference element, the alpha element, and the beta element, determine an alpha phase difference between the detected signals from the reference element and the alpha element, determine a beta phase difference between the detected signals from the reference element and the beta element, determine a first virtual phase difference that corresponds to the reflected signal expected to be detected by a first virtual element located halfway between the reference element and the beta element, wherein the first virtual phase difference is based on the beta phase difference divided by two and wherein the first virtual phase difference has a sign ambiguity; and characterised in that determining the first virtual phase difference includes applying a sign correction to the beta phase difference divided by two, wherein the sign correction is based on a comparison of the phasors representing the first virtual phase difference based on the beta phase difference divided by two to the alpha phase difference multiplied by the number of half-wavelengths that the first virtual element is spaced apart from the reference element and determination of which of the beta phase difference divided by the two phasors is closer to the alpha phase difference progression, i.e. has a phase error less than π/2. a radar antenna, wherein the antenna includes a reference element, an alpha element spaced apart from the reference element by one half-wavelength of the reflected signal, and a beta element spaced apart from the reference element by an even number of half-wavelengths of the reflected signal; and a controller configured to receive detected signals from the reference element, the alpha element, and the beta element, determine an alpha phase difference between the detected signals from the reference element and the alpha element, determine a beta phase difference between the detected signals from the reference element and the beta element, determine a first virtual phase difference that corresponds to the reflected signal expected to be detected by a first virtual element located halfway between the reference element and the beta element, wherein the first virtual phase difference is based on the beta phase difference divided by two and wherein the first virtual phase difference has a sign ambiguity; and characterised in that determining the first virtual phase difference includes applying a sign correction to the beta phase difference divided by two, wherein the sign correction is based on a comparison of the phasors representing the first virtual phase difference based on the beta phase difference divided by two to the alpha phase difference multiplied by the number of half-wavelengths that the first virtual element is spaced apart from the reference element and determination of which of the beta phase difference divided by the two phasors is closer to the alpha phase difference progression, i.e. has a phase error less than π/2.