A radar for an autonomous guidance system for a platform, comprising a frame, a transmit-receive antenna for transmitting an electromagnetic wave transmitted in a pointing direction and for receiving a received electromagnetic wave, and a pointing system for changing the orientation of the pointing direction with respect to the frame, the pointing system comprising: - a primary pivoting device for pivoting the pointing direction relative to the frame about a primary axis (R-R'), and - a secondary pivoting device for pivoting the pointing direction relative to the frame about a secondary axis (S-S') orthogonal to the primary axis (R-R'), characterised in that the pointing system also comprises a tertiary pivoting device for pivoting the pointing direction relative to the frame about a tertiary axis (G-G') orthogonal to the secondary axis (S-S'), and in that the antenna consists of an array antenna comprising an emission surface and a plurality of radiating elements distributed over the said emission surface, the radiating elements comprising a plurality of primary groups of radiating elements arranged successively with respect to one another along a primary direction (T-T') substantially orthogonal to the tertiary axis (G-G'), each primary group comprising at least one radiating element, the tertiary pivoting device consisting of a module for electronic scanning about the tertiary axis (G-G') adapted to phase-shift each wave generated by the or each radiating element of a primary group with respect to each wave generated by the or each radiating element of each other primary group, there being two primary groups, in which the primary pivoting device comprises an intermediate support on which the antenna is mounted, said intermediate support being mounted so as to be rotatable about the primary axis (R-R') relative to the frame. - a primary pivoting device for pivoting the pointing direction relative to the frame about a primary axis (R-R'), and - a secondary pivoting device for pivoting the pointing direction relative to the frame about a secondary axis (S-S') orthogonal to the primary axis (R-R'), characterised in that the pointing system also comprises a tertiary pivoting device for pivoting the pointing direction relative to the frame about a tertiary axis (G-G') orthogonal to the secondary axis (S-S'), and in that the antenna consists of an array antenna comprising an emission surface and a plurality of radiating elements distributed over the said emission surface, the radiating elements comprising a plurality of primary groups of radiating elements arranged successively with respect to one another along a primary direction (T-T') substantially orthogonal to the tertiary axis (G-G'), each primary group comprising at least one radiating element, the tertiary pivoting device consisting of a module for electronic scanning about the tertiary axis (G-G') adapted to phase-shift each wave generated by the or each radiating element of a primary group with respect to each wave generated by the or each radiating element of each other primary group, there being two primary groups, in which the primary pivoting device comprises an intermediate support on which the antenna is mounted, said intermediate support being mounted so as to be rotatable about the primary axis (R-R') relative to the frame.