Described herein are one or more apparatus, that at least partially synchronize with a first radio-frequency signal from a first antenna element, of an array of spatially distributed antenna elements in a multi-antenna array receiver, to determine the position of at least one of a repeated guard interval in the first radio-frequency signal from the first antenna element, the repeat occurring at a particular defined characteristic interval. The apparatus then use the determined position of the at least one guard interval in the first radio-frequency signal to switch to a second radio-frequency signal from a second antenna element, of the array of spatially distributed antenna elements in a multi-antenna receiver, and further determine a relative orientation of the multi-antenna receiver from a transmitter of the radio-frequency signals using characteristics determined for the first and second radio-frequency signals following the at least respective partial synchronizations.