System and method for determining position of a receiver relative to a transmitter

A method of determining a position of a receiver relative to a transmitter, the method comprising:

• transmitting from the transmitter a first transmitted positioning signal having a first frequency and phase in a first direction;
• transmitting from the transmitter a second transmitted positioning signal having a second frequency and phase in a second direction, the second frequency being different from the first frequency;
• transmitting from the transmitter a third transmitted positioning signal having a third frequency and phase in a third direction, the third frequency being different from the first frequency and the second frequency, the first positioning signal, the second positioning signal and the third positioning signal defining a common period being a common multiple of the periods of the first, second, and third positioning signals;
• receiving, at the receiver, a first received positioning signal corresponding to the transmitted first positioning signal;
• receiving, at the receiver, a second received positioning signal corresponding to the transmitted second positioning signal;
• receiving, at the receiver, a third received positioning signal corresponding to the transmitted third positioning signal;
• determining for the first, second and third received positioning signals a time point corresponding to the start of the common period defined by the first, second, and third received positioning signals;
• and
• determining a polarity of the first received positioning signal, a polarity of the second received positioning signal, and a polarity of the third received positioning signal based on properties of the first, second and third received positioning signals relative to the start of the common period and relative to properties of the first, second and third transmitted positioning signals.