Methods and apparatus for estimating accuracy of measurement signals

A method of determining whether a range measurement is acceptable for use in updating an estimated position of a mobile communication device, comprising:

• (a) measuring a range between the mobile communication device and a reference communication device;
• (b) computing a predicted range between the mobile communication device and the reference communication device based on tracked positions of the mobile communication device and the reference communication device;
• (c) estimating the accuracy of the predicted range based on estimated accuracies of the tracked positions of the reference communication device and the mobile communication device;
• (d) generating a first window of acceptability as a function of the predicted range and the estimated accuracy of the predicted range;
• (e) computing an average and standard deviation of previous range measurements;
• (f) generating a second window of acceptability as a function of the average and standard deviation of the previous measurements;
• (g) if the range measurement is within both the first and second windows of acceptability, supplying the range measurement to a tracking system for updating the estimated position of the mobile communication device.

A method of estimating the accuracy of a measurement to be used in a tracking system, the method comprising:

• (a) determining a measurement value from a detected signal;
• (a) computing an average and standard deviation of previous measurements;
• (b) calculating an error between the measurement value and the average of the previous measurements;
• (c) determining the accuracy of the measurement value as a function of the error and the standard deviation of the previous measurements;
• and
• (d) supplying the measurement value and the accuracy to the tracking system for updating a state tracked by the tracking system.

A mobile communication device capable of estimating its position by determining ranges to a plurality of reference communication devices having known positions, comprising:

• a receiver configured to receive ranging signals from reference communication devices, said receiver generating a range measurement from a detected ranging signal;
• a processor configured to receive the range measurement, said processor generating a window of acceptability as a function of an average and a standard deviation of previous range measurements and finding the range measurement to be acceptable if the range measurement is within the window of acceptability;
• and
• a tracking system configured to receive acceptable range measurements from said processor, said tracking system updating an estimated position of the mobile communication device from the acceptable range measurements.

A mobile communication device capable of estimating its position by determining ranges to a plurality of reference communication devices having known positions, comprising:

• a receiver configured to receive ranging signals from reference communication devices, said receiver generating a range measurement from a detected ranging signal;
• a processor configured to receive the range measurement, said processor generating a coarse window of acceptability as a function of a predicted range and an estimated accuracy of the predicted range between the mobile communication device and the reference communication device based on tracked positions of the mobile communication device and the reference communication device, said processor generating a fine window of acceptability as a function of an average and a standard deviation of previous range measurements, said processor finding the range measurement to be acceptable if the range measurement is within both the coarse window of acceptability and the fine window of acceptability;
• and
• a tracking system configured to receive acceptable range measurements from said processor, said tracking system updating an estimated position of the mobile communication device from the acceptable range measurements.

A mobile communication device capable of estimating its position by determining ranges to a plurality of reference communication devices having known positions, comprising:

• a receiver configured to receive ranging signals from reference communication devices, said receiver generating a range measurement from a detected ranging signal;
• a processor configured to receive the range measurement, said processor computing an average and standard deviation of previous range measurements and determining the accuracy of the range measurement as a function of the standard deviation of the previous range measurements and the difference between the range measurement and the average of the previous range measurements;
• and
• a tracking system configured to receive acceptable range measurements and corresponding accuracies from said processor, said tracking system updating an estimated position of the mobile communication device from the acceptable range measurements.

A method of determining whether a measurement is acceptable for use in a tracking system, the method comprising:

• (a) determining a measurement value from a detected signal;
• (b) determining a variability of previous acceptable measurements;
• (c) forming a window of acceptability whose size is based upon the variability of the previous acceptable measurements;
• and
• (d) if the measurement value is within the window of acceptability, supplying the measurement value to the tracking system for updating a state tracked by the tracking system.

A mobile communication device capable of estimating its position by determining ranges to a plurality of reference communication devices having known positions, comprising:

• a receiver configured to receive ranging signals from the reference communication devices, said receiver generating a range measurement from a detected ranging signal;
• a processor configured to generate a window of acceptability whose size is based on a variability of previous acceptable range measurements, said processor determining the range measurement to be acceptable if the range measurement is within the window of acceptability;
• and
• a navigation system configured to receive acceptable range measurements from said processor, said navigation system updating an estimated position of the mobile communication device based on the acceptable range measurements.

An apparatus for determining whether a measurement is acceptable for use in a tracking system, the method comprising:

• means for determining a measurement value from a detected signal;
• means for forming a window of acceptability whose size is based upon the variability of previous acceptable measurements;
• and
• means for supplying the measurement value to the tracking system for updating a state tracked by the tracking system in response to the measurement value being within the window of acceptability.

A method of determining whether a measurement is acceptable for use in a tracking system, comprising:

• (a) determining a measurement value from a detected signal;
• (b) generating a first window of acceptability based on a state tracked by the tracking system;
• (c) generating a second window of acceptability whose size is based on a variability of previous acceptable measurements;
• (d) supplying the measurement value to the tracking system for updating the state tracked by the tracking system in response to the measurement value being within both the first and second windows of acceptability.

A mobile communication device capable of estimating its position by determining ranges to a plurality of reference communication devices having known positions, comprising:

• a receiver configured to receive ranging signals from the reference communication devices, said receiver generating a range measurement from a detected ranging signal;
• a processor configured to generate:
• a first window of acceptability whose size is based on a tracked range between the mobile communication device and the reference communication device;
• and a second window of acceptability based on a variability of previous acceptable range measurements, said processor determining the range measurement to be acceptable if the range measurement is within the first and second windows of acceptability;
• and
• a navigation system configured to receive acceptable range measurements from said processor, said navigation system updating an estimated position of the mobile communication device based on the acceptable range measurements.