Device Orientation Detection

An apparatus, method and computer program is described comprising: detecting, at a second user device, one or more display patterns displayed at a display of a first user device, wherein the one or more display patterns comprise features with spatial variations configured to be detected by a radar module of the second user device; determining at least one of an orientation, position, or size of the first user device based, at least in part, on the one or more display patterns; and determining at least one of an orientation or position of the second user device relative to the first user device within a coordinate system of the first user device.