Method and system for generating reference signals with improved correlation characteristics for accurate time of arrival or position determination

A method for generating a reference signal with improved correlation characteristics, comprising:

• defining a known component of a broadcast television signal;
• defining an autocorrelation matrix for the known component of the broadcast television signal;
• generating an autocorrelation function of the known component of the broadcast television signal;
• identifying sidelobes in the autocorrelation function of the known component of the broadcast television signal;
• defining a sidelobe-producing matrix which produces only the identified sidelobes when applied to the known component of the broadcast television signal;
• and
• finding a reference signal which:
• (1) minimizes a product of the sidelobe-producing matrix and the reference signal,
• (2) minimizes sensitivity to high frequency noise when cross-correlated with the known component of the broadcast television signal,
• (3) minimizes sensitivity to low frequency disturbance signals when cross-correlated with the known component of the broadcast television signal, and
• (4) maximizes a main peak when cross-correlated with the known component of the broadcast television signal.

A system for generating a reference signal with improved correlation characteristics, comprising:

• a computer with a display monitor;
• one or more input devices for processing operator inputs;
• and
• a storage device connected to the computer for storing data, wherein the computer processes a command input from one or more input devices for 1) defining a known component of a broadcast television signal, 2) defining an autocorrelation matrix for the known component of the broadcast television signal, 3) generating an autocorrelation function of the known component of the broadcast television signal, 4) identifying sidelobes in the autocorrelation function of the known component of the broadcast television signal, 5) defining a sidelobe producing matrix which produces only the identified sidelobes when applied to the known component of the broadcast television signal, and finding a reference signal which (a) minimizes a product of the sidelobe-producing matrix and the reference signal, (b) minimizes sensitivity to high frequency noise when cross-correlated with the known component of the broadcast television signal, (c) minimizes sensitivity to low frequency disturbance signals when cross correlated with the known component of the broadcast television signal, and (d) maximizes a main peak when cross-correlated with the known component of the broadcast television signal.

Computer-executable process steps for generating a reference signal with improved correlation characteristics, wherein the process steps are stored on a computer-readable medium, the steps comprising:

• a step for defining a known component of a broadcast television signal;
• a step for defining an autocorrelation matrix for the known component of the broadcast television signal;
• a step for generating an autocorrelation function of the known component of the broadcast television signal;
• a step for identifying sidelobes in the autocorrelation function of the known component of the broadcast television signal;
• a step for defining a sidelobe producing matrix which produces only the identified sidelobes when applied to the known component of the broadcast television signal;
• and
• a step for finding a reference signal which:
• (1) minimizes a product of the sidelobe-producing matrix and the reference signal,
• (2) minimizes sensitivity to high frequency noise when cross-correlated with the known component of the broadcast television signal,
• (3) minimizes sensitivity to low frequency disturbance signals when cross correlated with the known component of the broadcast television signal, and
• (4) maximizes a main peak when cross-correlated with the known component of the broadcast television signal.

A system for generating a reference signal with improved correlation characteristics, comprising:

• means for defining a known component of a broadcast television signal;
• means for defining an autocorrelation matrix for the known component of the broadcast television signal;
• means for generating an autocorrelation function of the known component of the broadcast television signal;
• means for identifying sidelobes in the autocorrelation function of the known component of the broadcast television signal;
• means for defining a sidelobe producing matrix which produces only the identified sidelobes when applied to the known component of the broadcast television signal;
• and
• means for finding a reference signal which:
• (1) minimizes a product of the sidelobe-producing matrix and the reference signal,
• (2) minimizes sensitivity to high frequency noise when cross-correlated with the known component of the broadcast television signal,
• (3) minimizes sensitivity to low frequency disturbance signals when cross correlated with the known component of the broadcast television signal, and
• (4) maximizes a main peak when cross-correlated with the known component of the broadcast television signal.

A method for accurately determining a position of a user terminal utilizing a reference signal with improved correlation characteristics, comprising:

• receiving at the user terminal a plurality of broadcast television signals from a plurality of television signal transmitters;
• determining a first set of pseudo-ranges between the user terminal and the plurality of television signal transmitters based on a correlation between a known component of the broadcast television signals and the reference signal with improved correlation characteristics;
• and
• determining a position of the user terminal based on the first set of pseudo-ranges, and a plurality of locations of the television signal transmitters,
• wherein the correlation between the known component of the broadcast television signals and the reference signal with improved correlation characteristics has minimized sidelobes, a large main peak, and minimized sensitivity to high frequency noise and low frequency disturbances.

A system for accurately determining a position of a user terminal utilizing a reference signal with improved correlation characteristics, comprising:

• means for receiving at the user terminal a plurality of broadcast television signals from a plurality of television signal transmitters;
• means for determining a first set of pseudo-ranges between the user terminal and the plurality of television signal transmitters based on a correlation between a known component of the broadcast television signals and the reference signal with improved correlation characteristics;
• means for receiving at the user terminal a plurality of global positioning signals from a plurality of global positioning satellites;
• means for determining a second set of pseudo-ranges between the user terminal and the plurality of global positioning satellites based on the plurality of global positioning signals;
• and
• means for determining a position of the user terminal based on the first set of pseudo-ranges, the second set of pseudo-ranges, a plurality of locations of the television signal transmitters, and a plurality of locations of the global positioning satellites;
• wherein the correlation between the known component of the broadcast television signals and the reference signal has minimized sidelobes, a maximized main correlation peak, and minimized sensitivity to high frequency noise and low frequency disturbances.