Position determination using local time difference

摘要

Described are computer-based methods and apparatuses, including computer program products, for determining a position. In some examples, the method includes determining measured time receipt differences from associated local receipt times for each pair of plurality of signals; determining a range difference for each of the plurality of signals based on the measured time receipt differences for each of the pairs of the plurality of signals; determining hypothesized range differences based on a hypothesized user position; determining an estimation difference for each of the plurality of signals based on the range difference and the hypothesized range difference for each of the plurality of signals based on a figure of merit; minimizing the estimation difference for the figure of merit based on a plurality of hypothesized user positions and an optimization routine; and outputting a user position based on a hypothesized user position associated with the minimized figure of merit.

主权项

1. A position determination system, the system comprising:
a communication and timing module configured to:
receive a plurality of signals, the plurality of signals transmitted from one or more ground transmitters and each of the plurality of signals relayed via one or more relay devices, each of the plurality of signals including a uniquely identifiable pseudo random noise code, the uniquely identifiable pseudo random noise code providing information related to a unique routing path of a corresponding signal of the plurality of signals, andassociate a local receipt time with each of the plurality of signals upon receipt of the signals; a measured range difference module configured to:
determine measured time receipt differences from the associated local receipt times for each pair of the plurality of signals, anddetermine a range difference for each of the plurality of signals based on the measured time receipt differences and the information related to the unique routing path for each of the pairs of the plurality of signals; a predicted range difference module configured to:
determine a hypothesized user position, anddetermine hypothesized range differences based on the hypothesized user position; an optimization module configured to:
determine an estimation difference for each of the plurality of signals based on the range difference and the hypothesized range difference for each of the plurality of signals based on a figure of merit, andminimize the figure of merit based on a plurality of hypothesized user positions and an optimization routine; and a user position module configured to output a user position based on the a hypothesized user position associated with the minimized figure of merit.