A device includes an antenna controller configured to direct a beam to track a first satellite that follows an orbit having a transit arranged to intersect a transit of one or more other satellites to form a closed loop. The antenna controller is also configured to switch a tracking target of the beam from the first satellite to a second satellite of the one or more other satellites when the first satellite and the second satellite are at a first intersection of the transits that form the closed loop.

A method and apparatus for measuring an angle of arrival. The method includes: determining LN values based on received values obtained by a first antenna array and a second antenna array by receiving a signal and determining an angle of arrival (AoA) of the first signal based on the LN values. The first antenna array includes L rows of array elements arranged in a first direction and K columns of array elements arranged in a second direction. The second antenna array includes P rows of array elements arranged in the first direction and Q columns of array elements arranged in the second direction. N=K+Q. An included angle between the first direction and the second direction is greater than 0 degrees.

A method and apparatus for measuring an angle of arrival. The method includes: determining LN values based on received values obtained by a first antenna array and a second antenna array by receiving a signal and determining an angle of arrival (AoA) of the first signal based on the LN values. The first antenna array includes L rows of array elements arranged in a first direction and K columns of array elements arranged in a second direction. The second antenna array includes P rows of array elements arranged in the first direction and Q columns of array elements arranged in the second direction. N=K+Q. An included angle between the first direction and the second direction is greater than 0 degrees.

A communication system for vehicles includes a first communication device disposed at a trailer and a second communication device disposed at a vehicle. The communication device wirelessly transmits a communication to the second communication device, and the second communication device receives the transmitted communication from the first communication device. Responsive to processing of the transmitted communication received by the second communication device, the communication system determines an angle of the trailer relative to the vehicle. The first and second communication devices may include first and second dedicated short range communication devices. One of the devices may include spaced apart antennae, whereby the system may determine the angle of the trailer via triangulation based on an antenna of one of the communication devices and the spaced apart antennae of the other of the communication devices.

Devices and methods of estimating the AoD of a STA are generally described. The STA receives and stores an association between tone and transmission angle for each tone transmitted by an AP in different angles. The association indicates that, for each angle, a tone transmitted in the angle is unique. The STA detects a symbol transmitted on each tone, determines the strength and timing of the tone and estimates the AoD based on the association and either or both the strength and timing. Each tone may have multiple symbols and/or each angle multiple tones whose characteristics are averaged to determine the appropriate characteristic of the particular tone or angle. The position of the STA is calculated from the AoD of one or more APs.

Devices and methods of estimating the AoD of a STA are generally described. The STA receives and stores an association between tone and transmission angle for each tone transmitted by an AP in different angles. The association indicates that, for each angle, a tone transmitted in the angle is unique. The STA detects a symbol transmitted on each tone, determines the strength and timing of the tone and estimates the AoD based on the association and either or both the strength and timing. Each tone may have multiple symbols and/or each angle multiple tones whose characteristics are averaged to determine the appropriate characteristic of the particular tone or angle. The position of the STA is calculated from the AoD of one or more APs.

A method and devices are disclosed, for tracking a radio beacon from a moving device, while the beacon transmits periodic signals, which the device detects at least at two different locations, and the device provided with information enabling determining the time difference between transmissions of these periodic signals. The method discloses a formula for estimating the angle between the course of the moving device and the beacon: arccos [c*(TDOA.sub.12TDOT.sub.12)/baseline.sub.12]; wherein the moving device detects signal 1 and signal 2 respectively at location 1 and location 2, the distance between these locations defined as baseline.sub.12, TDOA.sub.12 is the Time Difference of Arrival of the signals at the two locations, TDOT.sub.12 is the time difference between transmission of these signals, and c is the speed of light.

A method and devices are disclosed, for tracking a radio beacon from a moving device, while the beacon transmits periodic signals, which the device detects at least at two different locations, and the device provided with information enabling determining the time difference between transmissions of these periodic signals. The method discloses a formula for estimating the angle between the course of the moving device and the beacon: arccos [c*(TDOA.sub.12TDOT.sub.12)/baseline.sub.12]; wherein the moving device detects signal 1 and signal 2 respectively at location 1 and location 2, the distance between these locations defined as baseline.sub.12, TDOA.sub.12 is the Time Difference of Arrival of the signals at the two locations, TDOT.sub.12 is the time difference between transmission of these signals, and c is the speed of light.

An apparatus and method for estimating a direction of an RF signal are provided. The apparatus includes an antenna unit, a preliminary correction unit, a signal processing unit, a conversion unit, and a signal direction estimation unit. The antenna unit receives an RF signal from at least one antenna. The preliminary correction unit performs preliminary correction depending on whether the at least one antenna is an antenna having directional gain. The signal processing unit generates an analog signal by performing a frequency shift on the RF signal or a signal on which the preliminary correction has been performed. The conversion unit converts the analog signal into a digital sample. The signal direction estimation unit extracts the phase of the antenna from the digital sample, and estimates the direction of the RF signal based on the extracted phase.

An apparatus and method for estimating a direction of an RF signal are provided. The apparatus includes an antenna unit, a preliminary correction unit, a signal processing unit, a conversion unit, and a signal direction estimation unit. The antenna unit receives an RF signal from at least one antenna. The preliminary correction unit performs preliminary correction depending on whether the at least one antenna is an antenna having directional gain. The signal processing unit generates an analog signal by performing a frequency shift on the RF signal or a signal on which the preliminary correction has been performed. The conversion unit converts the analog signal into a digital sample. The signal direction estimation unit extracts the phase of the antenna from the digital sample, and estimates the direction of the RF signal based on the extracted phase.