Transmitter pen location system

A location system, comprising:

• a surface having a writing area, a plurality of receiver locations each having a plurality of external receivers, and a signal processor;
• a movable device adapted to be located within the writing area of the surface, the movable device adapted to send an output signal comprising a shaped pulse waveform having consistently identifiable features repeatedly from the movable device to each of the plurality of receiver locations;
• and
• a signal processor connected to each of the plurality of external receivers, which processes the output signal to determine a phase difference of the output signal between each of the plurality of external receivers at each of the plurality of receiver locations, the determination comprising a comparison of the consistently identifiable features of the output signal at each of the external receivers at each of the plurality of receiver locations, to calculate direction of the movable device to each of the receiver locations based upon the determined phase difference at each of the plurality of receiver locations, and to determine the location of the movable device, based upon the calculated direction from the portable transmitter to each of the plurality of receiver locations.

A process for calculating a location of a transmitter pen relative to a writing area of a surface, the process comprising:

• sending an output signal comprising a shaped pulse waveform having consistently identifiable features from the transmitter pen to a plurality of receiver locations, each of the receiver locations having a plurality of external receivers;
• determining a phase difference of the output signal between each of the plurality of external receivers at each of the plurality of receiver locations, the determination comprising a comparison of the consistently identifiable features of the output signal at each of the external receivers at each of the plurality of receiver locations;
• determining a direction from the transmitter pen to each of the plurality of receiver locations based on the determined phase difference of the output signal at each of the receiver locations;
• and
• determining the location of the transmitter pen based upon the determined direction from the transmitter pen to each of the plurality of receiver locations.

A transmitter location system, comprising:

• at least three external receivers;
• a time dependent output signal comprising a shaped pulse waveform having consistently identifiable features being transmitted repeatedly from a movable transmitter to each of the external receivers, wherein time to reach each of the external receivers defines a distance between the movable transmitter and each of the external receivers;
• and
• means for determining location of the movable transmitter, based upon the distance between the movable transmitter and each of the external receivers, and a comparison of the consistently identifiable features between the output signal and a stored prior time dependent output signal.

A location system, comprising:

• a surface having a writing area, at least three external receivers, and a signal processor;
• a movable device adapted to be located within the writing area of the surface, the movable device adapted to send a time dependent output signal comprising a shaped pulse waveform having consistently identifiable features repeatedly from the movable device to each of the external receivers;
• and
• a signal processor connected to each of the external receivers, the signal processor determining distance between the movable device and the external receivers based on time of arrival of the output signal to the external receivers and a comparison of the consistently identifiable features between the output signal and a prior time dependent output signal, and determining the location of the movable device, based upon the calculated distance between the movable device and each of the external receivers.

A process for calculating a location of a transmitter pen relative to a writing area of a surface, the process comprising:

• sending a time-dependent output signal comprising a shaped pulse waveform having consistently identifiable features from the transmitter pen to at least three external receivers;
• comparing the consistently identifiable features of the output signal received at each of the external receivers to the consistently identifiable features of a stored prior second output signal received at each of the external receivers to determine a time of arrival of the output signal at each of the external receivers;
• determining a distance from the transmitter pen to each of the external receivers based on the determined time of arrival of the output signal at each of the external receivers;
• and
• determining the location of the transmitter pen based upon the determined distance from the transmitter pen to each of the external receivers.

A location system between a movable device and a receiver location, comprising:

• a first output signal having a first speed of propagation, the first output signal being transmitted repeatedly from the movable device to a plurality of first signal receivers at the receiver location, wherein time to reach each of the first signal receivers is dependent on a distance between the movable device and each of the plurality of first signal receivers;
• a second output signal having a second speed of propagation different from the first speed of propagation of the first output signal, the second output signal being transmitted repeatedly from the movable device to a second signal receiver at the receiver location;
• and
• means for determining location of the movable device, using the first output signal received at the plurality of first signal receivers to determine a direction of arrival of the first signal to the receiver location, and using the second output signal to calculate distance from the movable device to the receiver location.

A process for calculating a location a movable device relative to a surface, the process comprising:

• repeatedly sending a first output signal having a first speed of propagation from the movable device to at least two first signal receivers at a receiver location;
• repeatedly sending a second output signal having a second speed of propagation different from the first speed of propagation of the first output signal from the movable device to a second signal receiver at the receiver location;
• determining a distance from the movable device to the receiver location, based on a time of arrival of the second output signal at the second signal receiver, and a time of arrival of the first output signal to at least one of the first signal receivers at the receiver location;
• determining a direction of arrival for the first output signal between the movable device and the receiver location, based on the time of arrival of the second output signal at each of the second signal receivers at the receiver location;
• and
• calculating the location of the movable device, based upon the determined distance from the movable device to the receiver location, and upon the determined direction of arrival of the first output signal between the movable device and the receiver location.