Positioning beacon and method

A beacon for transmitting information used in determining a location of a mobile electronic device, the beacon comprising:

• a housing;
• an electrical power module;
• and
• four radio frequency (RF) transmitters electrically interconnected to the power module, the four RF transmitters each capable of transmitting a respective RF radio signal in compliance with the Bluetooth Low Energy communication standard, each of the four RF transmitters having a respective antenna, the antennas each having a pointing direction and producing a cardioid shaped antenna pattern, the four RF transmitters affixed to the housing such that the pointing directions of the antennas have about ninety degree spatial relationships to each other in a plane such that the pointing directions form four quadrants in the plane, the four RF radio signals being orthogonal to each other and including:
• a signal strength value indicating a transmitted signal strength of the associated RF radio signal;
• and
• a Universally Unique Identifier (UUID) that is different than UUIDs of the other RF radio signals.

A method of determining a position of a mobile electronic device with respect to a stationary beacon transmitting three or more radio signals in different directions within a plane, the method comprising:

• receiving, at the mobile electronic device, the radio signals transmitted from N of the three or more short range RF radio transmitters, wherein N has an integral value of three or more, each of the radio signals being modulated to include a unique identifier;
• determining a received signal strength of each of the N received radio signals;
• calculating differences between the received signal strengths of the N received radio signals;
• and
• determining an azimuth of the mobile electronic device relative to the beacon based on the calculated differences between the received signal strengths;
• wherein
• calculating differences between the received signal strengths of the N received radio signals includes calculating signal strength difference values for pairs of the N received radio signals, wherein the signal strength difference value for each pair is calculated by subtracting the determined received signal strength of a first radio signal of the pair from the determined received signal strength of a second radio signal of the pair.

A set of computer-readable computer-executable instructions which, when executed by one or more computer processors of a mobile electronic device, direct the one or more computer processors to:

• receive RF signal transmissions from at least three short range radio transmitters of a positioning beacon, wherein each of the RF signal transmissions, respectively, includes a transmitted signal strength value and a unique identifier;
• determine a received signal strength of each of the received RF signal transmissions;
• calculate signal strength difference values for pairs of the received RF signal transmissions, wherein the signal strength difference value for each pair is calculated by subtracting the determined received signal strength of a first RF signal transmission of the pair from the determined received signal strength of a second RF signal transmission of the pair;
• determine an azimuth of the mobile electronic device relative to a location of the positioning beacon based on the calculated signal strength difference values for the pairs;
• determine a range of the mobile electronic device relative to a location of the positioning beacon;
• and
• determine a position of the mobile electronic device based on the azimuth and based on the range.

A system comprising:

• a beacon for transmitting information used in determining locations, the beacon comprising four radio frequency (RF) transmitters each capable of transmitting a respective radio signal in compliance with the Bluetooth Low Energy communication standard, each of the four RF transmitters having a respective antenna, the antennas each having a pointing direction and producing a cardioid shaped antenna pattern, the four RF transmitters oriented such that the pointing directions of the antennas have about ninety degree spatial relationships to each other in a plane such that the pointing directions form four quadrants in the plane, the four radio signals being orthogonal to each other and each including a signal strength value indicating a transmitted signal strength of the associated RF radio signal and a Universally Unique Identifier (UUID) that is different than UUIDs of the other radio signals;
• and
• a mobile electronic device configured to:
• receive the four radio signals;
• determine a received signal strength of each of the four received radio signals;
• calculate signal strength difference values for pairs of the four received radio signals, wherein each signal strength difference value is calculated by subtracting the determined received signal strength of a first radio signal of the pair from the determined received signal strength of a second radio signal of the pair;
• and
• determine an azimuth of the mobile electronic device relative to the beacon based on the calculated signal strength difference values for the pairs.