Power and traffic optimized methods of operating RF access systems

A method of operating an RF access system, the system comprising a plurality of anchors, each anchor being arranged at a respective predetermined location and configured to communicate with one or more key devices, the method comprising:

• operating each of the anchors in a first mode, the first mode comprising first RF ranging operations for determining a respective first ranging result for each anchor relative to a key device;
• evaluating the first ranging results to determine a subset of the anchors that fulfil one or more predetermined conditions;
• selecting an anchor of the subset of anchors based on one or more signal parameters;
• placing other anchors of the subset into a standby mode;
• operating the selected anchor in a second mode, the second mode comprising second RF ranging operations for determining a second ranging result for the selected anchor relative to the key device, and RF radar operations for determining a radar result for the selected anchor relative to a holder of the key device based on signals reflected by the holder;
• and
• determining position information associated with the key device based on the second ranging result and the radar result.

A radio frequency (RF) access system comprising:

• a plurality of anchors, each anchor arranged at a respective predetermined location and configured to communicate with one or more key devices;
• and
• a controller in communication with the plurality of anchors and configured to:
• operate each anchor in a first mode, the first mode comprising first RF ranging operations for determining a first ranging result for the anchor relative to a key device;
• determine first ranging results from the plurality of anchors to determine a subset of the anchors that fulfil one or more predetermined conditions;
• selecting an anchor of the subset of anchors based on one or more signal parameters;
• operate the selected anchor in a second mode, the second mode comprising second RF ranging operations for determining a second ranging result for the selected anchor relative to the key device, and RF radar operations for determining a radar result for the selected anchor relative to a holder of the key device based on radar signals reflected by the holder;
• and
• determine position information associated with the key device based on the second ranging result and the radar result.