A hybrid antenna array comprising: a plurality of digital branches, each digital branch including: an analogue beamforming sub-array, each sub-array having a plurality of antenna elements, a plurality of phase shifters wherein each phase shifter is adapted to apply a phase shift to the signal from each antenna element, and a combiner adapted to combine the phase shifted signals; a signal chain adapted to convert the output of the sub-array to a baseband signal; and a digital processing module, including: an angle of arrival estimation sub-module adapted to estimate an angle of arrival of a signal at the antenna elements; a phase control sub-module adapted to control the phase shift applied by each phase shifter depending on the estimated angle of arrival; and a digital beamformer adapted to combine the baseband signals from the digital branches using a weight vector to form an output signal, wherein the digital processing module is adapted to estimate the angle of arrival by: cross-correlating the baseband signals from adjacent digital branches; and for a plurality of candidate beams, setting the phase shifts using the arguments of the cross-correlation values; and computing the power of the output signal of the digital beamformer; determining the candidate beam giving the maximum output power; and estimating the angle of arrival from the cross-correlation values of the determined candidate beam. a plurality of digital branches, each digital branch including: an analogue beamforming sub-array, each sub-array having a plurality of antenna elements, a plurality of phase shifters wherein each phase shifter is adapted to apply a phase shift to the signal from each antenna element, and a combiner adapted to combine the phase shifted signals; a signal chain adapted to convert the output of the sub-array to a baseband signal; and an analogue beamforming sub-array, each sub-array having a plurality of antenna elements, a plurality of phase shifters wherein each phase shifter is adapted to apply a phase shift to the signal from each antenna element, and a combiner adapted to combine the phase shifted signals; a signal chain adapted to convert the output of the sub-array to a baseband signal; and a digital processing module, including: an angle of arrival estimation sub-module adapted to estimate an angle of arrival of a signal at the antenna elements; a phase control sub-module adapted to control the phase shift applied by each phase shifter depending on the estimated angle of arrival; and a digital beamformer adapted to combine the baseband signals from the digital branches using a weight vector to form an output signal, an angle of arrival estimation sub-module adapted to estimate an angle of arrival of a signal at the antenna elements; a phase control sub-module adapted to control the phase shift applied by each phase shifter depending on the estimated angle of arrival; and a digital beamformer adapted to combine the baseband signals from the digital branches using a weight vector to form an output signal, cross-correlating the baseband signals from adjacent digital branches; and for a plurality of candidate beams, setting the phase shifts using the arguments of the cross-correlation values; and computing the power of the output signal of the digital beamformer; determining the candidate beam giving the maximum output power; and estimating the angle of arrival from the cross-correlation values of the determined candidate beam.