Position determination using a wireless signal

A mobile station comprising:

• a wireless receiver;
• one or more motion sensors;
• one or more processors;
• and
• a computer readable memory device having stored thereon instructions that, when executed by the one or more processors, instruct the one or more processors to:
• calculate a first round trip time (“RTT”) for a first wireless signal received by the wireless receiver from an access point at a first mobile station position;
• calculate a first RTT-based distance between a position of the access point and the first mobile station position based on the first RTT;
• calculate a second RTT for a second wireless signal received by the wireless receiver from the access point at a second mobile station position;
• calculate a second RTT-based distance between the position of the access point and the second mobile station position based on the second RTT;
• calculate a dead reckoning transition distance based on motion sensor data from the one or more motion sensors, the dead reckoning transition distance indicating a distance between the first mobile station position and the second mobile station position;
• calculate a wireless signal transition distance based on the first RTT-based distance and the second RTT-based distance;
• and
• obtain an uncertainty associated with one, or both, of the first RTT-based distance between the position of the access point and the first mobile station position and the second RTT-based distance between the position of the access point and the second mobile station position based on the dead reckoning transition distance and the wireless signal transition distance.

A computer readable memory device having stored thereon instructions that, when executed by one or more processors, instruct the one or more processors to:

• calculate a first round trip time (“RTT”) for a first wireless signal received by a wireless receiver from an access point at a first mobile station position;
• calculate a first RTT-based distance between a position of the access point and the first mobile station position based on the first RTT;
• calculate a second RTT for a second wireless signal received by the wireless receiver from the access point at a second mobile station position;
• calculate a second RTT-based distance between the position of the access point and the second mobile station position based on the second RTT;
• calculate a dead reckoning transition distance based on motion sensor data from the one or more motion sensors, the dead reckoning transition distance indicating a distance between the first mobile station position and the second mobile station position;
• calculate a wireless signal transition distance based on the first RTT-based distance and the second RTT-based distance;
• and
• obtain an uncertainty associated with one, or both, of the first RTT-based distance between the position of the access point and the first mobile station position and the second RTT-based distance between the position of the access point and the second mobile station position based on the dead reckoning transition distance and the wireless signal transition distance.

A mobile station comprising:

• means for measuring a first round trip time (“RTT”) for a first wireless signal received from an access point at a first mobile station position;
• means for calculating a first RTT-based distance between a position of the access point and the first mobile station position based on the first RTT;
• means for calculating a dead reckoning transition distance based on motion sensor data, the dead reckoning transition distance indicating a distance between the first mobile station position and a second mobile station position;
• means for calculating a wireless signal transition distance based on the first RTT-based distance and a second RTT-based distance calculated between the position of the access point and the second mobile station position, the second RTT-based distance calculated based on a second RTT measured for a second wireless signal received at the second mobile station position from the access point;
• and
• means for computing an uncertainty associated with one, or both, of the first RTT-based distance between the position of the access point and the first mobile station position and the second RTT-based distance between the position of the access point and the second mobile station position, wherein the uncertainty is computed based on the dead reckoning transition distance and the wireless signal transition distance.