Geo-locating moving wireless devices

A wireless device (WD) for determining a geo-location of a target station using round-trip times (RTTs) of a plurality of signals transmitted by the WD to the target station, and response signals received from the target station corresponding to the transmitted signals, the WD comprising processing circuitry configured to:

• assign values to current target station parameters, the current target station parameters including a current location for the target station and movement parameters;
• determine a plurality of square residuals based at least in part on the current target station parameters, each square residual of the plurality of square residuals corresponding to one RTT, determining the plurality of square residuals including:
• determining a first group of residuals based on stationary parameters and a second group of residuals based on the movement parameters;
• for each of the first group and the second group of residuals:
• determining a model fit probability based at least in part on one of the determined first group of residuals and the determined second group of residuals;
• determining a sum of squared residuals (SSR);
• performing non-linear fitting based at least on the determined SSR;
• determining new parameters based at least on the non-linear fitting;
• determining new residuals based at least in part on the determined new parameters;
• determine a minimum of the SSR based at least on the plurality of square residuals;
• determine best-fit parameters based at least in part on the determined minimum of the SSR;
• perform an F-test to determine whether the non-linear fitting corresponding to moving parameters is a better fit than the non-linear fitting corresponding to the stationary parameters;
• if the non-linear fitting corresponding to the moving parameters is the better fit, use the non-linear fitting corresponding to the moving parameters to determine the best-fit geo-location;
• and
• if the non-linear fitting corresponding to the moving parameters is not the better fit and one of a first condition is met and a second condition is met, use the non-linear fitting corresponding to the stationary parameters to determine the best-fit geo-location, the first condition being met when a first difference between the SSR and a subsequent SSR is less than a predetermined minimum, the second condition being met when an absolute value of a second difference between a target station parameter and a subsequent target station parameter is less than the predetermined minimum;
• and
• determine the best-fit geo-location of the target station based at least on the best-fit parameters.

A measuring station for determining a best-fit geo-location of a target station using a plurality of round-trip times (RTTs), each RTT being a time elapsed between a transmission of a ranging packet by the measuring station and a reception of a response packet by the measuring station, the measuring station comprising:

• a wireless device comprising:
• a transmitter receiver configured to:
• measure the plurality of RTTs;
• and
• processing circuitry in communication with the transmitter receiver, the processing circuitry being configured to:
• assign values to current target station parameters, the current target station parameters including a current location for the target station and movement parameters;
• determine a plurality of square residuals based at least in part on the current target station parameters, each square residual of the plurality of square residuals corresponding to one RTT, determining the plurality of square residuals including:
• determining a first group of residuals based on stationary parameters and a second group of residuals based on the movement parameters;
• for each of the first group and the second group of residuals:
• determining a model fit probability based at least in part on one of the determined first group of residuals and the determined second group of residuals;
• determining the SSR;
• performing non-linear fitting based at least on the determined SSR;
• determining new parameters based at least on the non-linear fitting;
• and
• determining new residuals based at least in part on the determined new parameters;
• determine a minimum of a sum of squared residuals (SSR) based at least on the plurality of square residuals;
• determine best-fit parameters based at least in part on the determined minimum of the SSR;
• perform an F-test to determine whether the non-linear fitting corresponding to moving parameters is a better fit than the non-linear fitting corresponding to the stationary parameters;
• if the non-linear fitting corresponding to the moving parameters is the better fit, use the non-linear fitting corresponding to the moving parameters to determine the best-fit geo-location;
• and
• if the non-linear fitting corresponding to the moving parameters is not the better fit and one of a first condition is met and a second condition is met, use the non-linear fitting corresponding to the stationary parameters to determine the best-fit geo-location, the first condition being met when a first difference between an SSR and a subsequent SSR is less than a predetermined minimum, the second condition being met when an absolute value of a second difference between a target station parameter and a subsequent target station parameter is less than the predetermined minimum;
• and
• determine the best-fit geo-location of the target station based at least on the best-fit parameters.