A radar sensor for vehicles, including a group antenna, having a linear array of antenna elements, a feed unit for feeding transmission signals having a settable phase relationship into the antenna elements, a control unit controlling the feed unit, and an evaluation device evaluating received radar echoes and angle-resolving locating of objects. The group antenna includes at least two non-interleaved subgroups, the feed unit supplies in-phase transmission signals to the elements, while the transmission signals for the various subgroups have a settable phase difference, the control unit periodically changes the settable phase difference so that the transmission signals have a base phase difference in one measuring cycle and a phase difference in another measuring cycle which differs by a fixed absolute value from the base difference. The control unit sets the base difference based on levels of the received radar echoes to maximize the level difference between the measuring cycles.

A radar sensor for vehicles, including a group antenna, having a linear array of antenna elements, a feed unit for feeding transmission signals having a settable phase relationship into the antenna elements, a control unit controlling the feed unit, and an evaluation device evaluating received radar echoes and angle-resolving locating of objects. The group antenna includes at least two non-interleaved subgroups, the feed unit supplies in-phase transmission signals to the elements, while the transmission signals for the various subgroups have a settable phase difference, the control unit periodically changes the settable phase difference so that the transmission signals have a base phase difference in one measuring cycle and a phase difference in another measuring cycle which differs by a fixed absolute value from the base difference. The control unit sets the base difference based on levels of the received radar echoes to maximize the level difference between the measuring cycles.

Systems for maintain pointing of a phased array antenna in a direction maximizes to an extent possible the effective antenna gain is provided. The system includes a gyroscope and a Kalman Filter. The Kalman filter estimates an antenna pointing direction for each successive time step based on gyroscope readings and based on the results of a local search for maximum gain performed in the neighborhood of a previous antenna pointing direction.

A directive direction finding apparatus may comprise: a directivity-enabled antenna array in which a constituent antenna or antenna subarray has directivity in the same direction; an RF/IF receiver connected to the directivity-enabled antenna array; a digital receiver connected to the RF/IF receiver; a direction finder connected to the digital receiver; a directivity control unit to control an operation of the directivity-enabled antenna array; and a transport/control interface connected to the direction finder and to manage control and operation of the directivity-enabled antenna array, the RF/IF receiver, the digital receiver, the direction finder and the directive control unit.