Wireless relay station for radio frequency-based tracking system
System and methods of tracking a position of a mobile device with an electromagnetic signal-transmitting antenna include receiving electromagnetic signals from the transmitting antenna of the mobile device by a plurality of receiver antennae of a base station and by one or more receiver antennae of a relay station. The relay station transmits to the base station timing information associated with the electromagnetic signals received by the one or more receiver antennae of the relay station. The base station computes a position of the transmitting antenna of the mobile device based on timing information computed from the electromagnetic signals received by the plurality of receiver antennae of the base station and on the timing information received from the relay station.
1. A position tracking system, comprising:
a base station with a processor;
at least three spatially separated receiver antennae disposed at locations known to the processor of the base station, each of the at least three receiver antennae receiving electromagnetic signals transmitted by a transmitting antenna of a mobile device; and
one or more relay stations in communication with the base station and with the transmitting antenna of the mobile device, each relay station being disposed at a distance from the base station known to the processor of the base station, each relay station comprising a processor, one or more receiver antennae that receive the electromagnetic signals transmitted by the transmitting antenna of the mobile device, and one or more transmitter antennae, the one or more transmitter antennae of each relay station sending timing information associated with the electromagnetic signals received by the one or more receiver antennae of that relay station to the base station;
wherein the processor of the base station uses the timing information associated with the electromagnetic signals received by and sent from the one or more relay stations to the base station and timing information associated with the electromagnetic signals received by the at least three spatially separated receiver antennae to compute the position of the transmitting antenna of the mobile device.
2. The position tracking system of claim 1 , wherein the processor of a given one of the one or more relay stations computes phase difference data based on the electromagnetic signals received by the one or more receiver antenna of the given relay station, and the timing information transmitted from the given relay station to the base station includes the phase difference data.
3. The position tracking system of claim 1 , wherein each of the one or more transmitter antennae of a given one of the one or more relay stations retransmits time of arrival information associated with the electromagnetic signals received by the one or more receiver antennae of the given relay station, and the timing information transmitted from the given relay station to the base station includes the retransmitted time of arrival information.
4. The position tracking system of claim 3 , wherein the processor of the base station subtracts time taken for the retransmitted time of arrival information associated with the electromagnetic signals received by the one or more receiver antennae of the given relay station from an aggregate timing information for those electromagnetic signals to reach the base station by way of the given relay station, to isolate a path between the mobile device and the given relay station.
5. The position tracking system of claim 3 , wherein each of the one or more transmitter antennae of the given relay station uses a different frequency from a frequency at which the electromagnetic signals are received by the one or more receiver antennae of the given relay station.
6. The position tracking system of claim 1 , wherein the processor of the base station computes a location of each of the one or more transmitter antennae of a given one of the one or more relay stations relative to the at least three spatially separated receiver antennae.
7. The position tracking system of claim 1 , wherein one of the processors determines a position of each of the one or more receiver antennae of a given one of the one or more relay stations with respect to each of the one or more transmitter antennae of the given relay station.
8. The position tracking system of claim 1 , wherein two or more receiver antennae of a given one of the one or more relay stations are at known distances apart.
9. The position tracking system of claim 1 , wherein at least one of the one or more relay stations is in communication with the base station over at least one wireless communication channel.
10. The position tracking system of claim 1 , wherein the base station offsets the timing information associated with the electromagnetic signals received by and sent from a given one of the one or more relay stations to the base station by timing information associated with a distance of the given relay station from the base station.
11. The position tracking system of claim 1 , wherein at least one of the one or more relay stations is disposed on a different side of the transmitting antenna of the mobile device from the base station.
12. The position tracking system of claim 1 , wherein the base station computes orientation of the mobile device.