Time Measurement-Based Positioning Method, Related Device, and System

A communications apparatus, comprising a processor, a memory, a transmitter, a receiver, a random number generator, and a clock module, wherein

• the receiver is configured to receive a measurement frame sent by a responder;
• the random number generator is configured to randomly generate a short interframe spacing within a specified fluctuation range of a nominal short interframe spacing, wherein the nominal short interframe spacing is a short interframe spacing agreed upon between the responder and the requester;
• the clock module is configured to wait for the short interframe spacing randomly generated by the random number generator, after the receiver finishes receiving a last symbol of the measurement frame;
• the transmitter is configured to:
• when the wait of the clock module ends, send, to the responder, an acknowledgement frame in response to the measurement frame;
• the memory is configured to store a measurement result generated through time measurement performed by the communications apparatus with the responder, wherein the measurement result comprises time stamps t1, t2, t3, and t4, t1 is a time at which the responder sends the measurement frame, t2 is a time at which the requester receives the measurement frame, t3 is a time at which the requester sends the acknowledgement frame in response to the measurement frame, and t4 is a time at which the responder receives the acknowledgement frame;
• and
• the processor is configured to calculate a location of the communications apparatus based on measurement results that are obtained by the communications apparatus by separately performing time measurement with a plurality of responders and that are stored in the memory.

A communications apparatus, comprising a sending module, a receiving module, a recording module, a random number generation module, a timing module, and a calculation module, wherein

• the receiving module is configured to receive a measurement frame sent by a responder;
• the random number generation module is configured to randomly generate a short interframe spacing within a specified fluctuation range of a nominal short interframe spacing, wherein the nominal short interframe spacing is a short interframe spacing agreed upon between the responder and the requester;
• the timing module is configured to wait for the short interframe spacing randomly generated by the random number generator, after the receiving module finishes receiving a last symbol of the measurement frame;
• the sending module is configured to:
• when the wait of the timing module ends, send, to the responder, an acknowledgement frame in response to the measurement frame;
• the recording module is configured to store a measurement result generated through time measurement performed by the communications apparatus with the responder, wherein the measurement result comprises time stamps t1, t2, t3, and t4, t1 is a time at which the responder sends the measurement frame, t2 is a time at which the requester receives the measurement frame, t3 is a time at which the requester sends the acknowledgement frame in response to the measurement frame, and t4 is a time at which the responder receives the acknowledgement frame;
• and
• the calculation module is configured to calculate a location of the communications apparatus based on measurement results that are obtained by the communications apparatus by separately performing time measurement with a plurality of responders and that are recorded by the recording module.