Adaptive triggering of rtt ranging for enhanced position accuracy

An apparatus for range estimation by a first wireless device relative to one or more second wireless devices, said apparatus comprising:

• means for estimating a range between the first wireless device and the one or more second wireless devices using a dedicated short-range communications (DSRC) mechanism based on timestamps associated with broadcast messages exchanged between the first wireless device and the one or more second wireless devices over a first communication channel;
• means for determining an accuracy metric estimated by the DSRC mechanism, the metric being based on an estimation error, a packet loss probability, a level of congestion in a communications network supporting the first communication channel, a measure of safety, or any combination thereof;
• and
• means for switching to a second mechanism to estimate a range between the first wireless device and the one or more second wireless devices over a second communication channel if the accuracy metric fails to meet a threshold, wherein the switching comprises providing a control signal for transmission over the first communication channel, the control signal indicating that the estimation is to switch to the second mechanism that uses round trip time (RTT) ranging.

An apparatus for range estimation by a first wireless device relative to one or more second wireless devices, said apparatus comprising:

• a memory;
• and
• at least one processor coupled to the memory and configured to:
• estimate a range between the first wireless device and the one or more second wireless devices using a dedicated short-range communications (DSRC) mechanism based on timestamps associated with broadcast messages exchanged between the first wireless device and the one or more second wireless devices over a first communication channel;
• determine an accuracy metric estimated by the DSRC mechanism, the metric being based on an estimation error, a packet loss probability, a level of congestion in a communications network supporting the first communication channel, a measure of safety, or any combination thereof;
• and
• switch to a second mechanism to estimate a range between the first wireless device and the one or more second wireless devices over a second communication channel if the accuracy metric fails to meet a threshold, wherein the switching comprises providing a control signal for transmission over the first communication channel, the control signal indicating that the estimation is to switch to the second mechanism that uses round trip time (RTT) ranging.

A first wireless device for range estimation, the first wireless device comprising:

• a processing system configured to:
• estimate a range between the first wireless device and one or more second wireless devices using a dedicated short-range communications (DSRC) mechanism based on timestamps associated with broadcast messages exchanged between the first wireless device and the one or more second wireless devices over a first communication channel;
• determine an accuracy metric estimated by the DSRC mechanism, the metric being based on at least one of an estimation error, a packet loss probability, a level of congestion in a communications network supporting the first communication channel, a measure of safety, or any combination thereof;
• and
• switch to a second mechanism to estimate a range between the first wireless device and the one or more second wireless devices over a second communication channel if the accuracy metric fails to meet a threshold;
• and
• a transmitter configured to transmit a control signal over the first communication channel, the control signal indicating that the estimation is to switch to the second mechanism that uses round trip time (RTT) ranging.