Methods and systems for improving the reliability of orthogonally redundant sensors
First Claim
1. A method of calculating a single, fused sensor glucose (SG) value based on respective output signals of an electrochemical glucose sensor and an optical glucose sensor of an orthogonally redundant glucose sensor device, the method comprising:
- performing a status check on each of the electrochemical glucose sensor and the optical glucose sensor, wherein said status check on the electrochemical glucose sensor is based on at least one of a previous cal ratio, a previous sensor accuracy, a sensitivity loss flag, and a dip flag for the electrochemical glucose sensor;
calculating a first reliability index for the output signal of the electrochemical sensor based on said status check for the electrochemical sensor;
calculating a second reliability index for the output signal of the optical sensor based on said status check for the optical sensor;
calibrating the output signal of the electrochemical sensor to obtain an electrochemical sensor glucose value (echem SG);
calibrating the output signal of the optical sensor to obtain an optical sensor glucose value (optical SG);
calculating a first weight based on said first reliability index and calculating a weighted echem SG based on said first weight;
calculating a second weight based on said second reliability index and calculating a weighted optical SG based on said second weight; and
calculating said single, fused sensor glucose value based on said weighted echem SG and said weighted optical SG.
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Abstract
Methods and systems for sensor calibration and sensor glucose (SG) fusion are used advantageously to improve the accuracy and reliability of orthogonally redundant glucose sensor devices, which may include optical and electrochemical glucose sensors. Calibration for both sensors may be achieved via fixed-offset and/or dynamic regression methodologies, depending, e.g., on sensor stability and Isig-Ratio pair correlation. For SG fusion, respective integrity checks may be performed for SG values from the optical and electrochemical sensors, and the SG values calibrated if the integrity checks are passed. Integrity checks may include checking for sensitivity loss, noise, and drift. If the integrity checks are failed, in-line sensor mapping between the electrochemical and optical sensors may be performed prior to calibration. The electrochemical and optical SG values may be weighted (as a function of the respective sensor'"'"'s overall reliability index (RI)) and the weighted SGs combined to obtain a single, fused SG value.
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Citations
39 Claims
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1. A method of calculating a single, fused sensor glucose (SG) value based on respective output signals of an electrochemical glucose sensor and an optical glucose sensor of an orthogonally redundant glucose sensor device, the method comprising:
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performing a status check on each of the electrochemical glucose sensor and the optical glucose sensor, wherein said status check on the electrochemical glucose sensor is based on at least one of a previous cal ratio, a previous sensor accuracy, a sensitivity loss flag, and a dip flag for the electrochemical glucose sensor; calculating a first reliability index for the output signal of the electrochemical sensor based on said status check for the electrochemical sensor; calculating a second reliability index for the output signal of the optical sensor based on said status check for the optical sensor; calibrating the output signal of the electrochemical sensor to obtain an electrochemical sensor glucose value (echem SG); calibrating the output signal of the optical sensor to obtain an optical sensor glucose value (optical SG); calculating a first weight based on said first reliability index and calculating a weighted echem SG based on said first weight; calculating a second weight based on said second reliability index and calculating a weighted optical SG based on said second weight; and calculating said single, fused sensor glucose value based on said weighted echem SG and said weighted optical SG. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A program code storage device, comprising:
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a computer-readable medium; and non-transitory computer-readable program code, stored on the computer-readable medium, the computer-readable program code having instructions, which when executed cause a microprocessor to; perform a status check on each of an electrochemical glucose sensor and an optical glucose sensor of an orthogonally redundant glucose sensor device, wherein said status check on the electrochemical glucose sensor is based on at least one of a previous cal ratio, a previous sensor accuracy, a sensitivity loss flag, and a dip flag for the electrochemical glucose sensor; calculate a first reliability index for an output signal of the electrochemical sensor based on said status check for the electrochemical sensor; calculate a second reliability index for an output signal of the optical sensor based on said status check for the optical sensor; calibrate the output signal of the electrochemical sensor to obtain an electrochemical sensor glucose value (echem SG); calibrate the output signal of the optical sensor to obtain an optical sensor glucose value (optical SG); calculate a first weight based on said first reliability index and generate a weighted echem SG based on said first weight; calculate a second weight based on said second reliability index and generate a weighted optical SG based on said second weight; and calculate a single, fused sensor glucose value for the orthogonally redundant glucose sensor device based on said weighted echem SG and weighted optical SG. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of calculating a single, fused sensor glucose (SG) value based on respective output signals of an electrochemical glucose sensor and an optical glucose sensor of an orthogonally redundant glucose sensor device, the method comprising:
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performing a status check on each of the electrochemical glucose sensor and the optical glucose sensor, wherein said status check on the optical glucose sensor is based on at least one of a previous cal ratio, a previous sensor accuracy, a sensitivity loss flag, and a dip flag for the optical glucose sensor; calculating a first reliability index for the output signal of the electrochemical sensor based on said status check for the electrochemical sensor; calculating a second reliability index for the output signal of the optical sensor based on said status check for the optical sensor; calibrating the output signal of the electrochemical sensor to obtain an electrochemical sensor glucose value (echem SG); calibrating the output signal of the optical sensor to obtain an optical sensor glucose value (optical SG); calculating a first weight based on said first reliability index and calculating a weighted echem SG based on said first weight; calculating a second weight based on said second reliability index and calculating a weighted optical SG based on said second weight; and calculating said single, fused sensor glucose value based on said weighted echem SG and said weighted optical SG. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A program code storage device, comprising:
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a computer-readable medium; and non-transitory computer-readable program code, stored on the computer-readable medium, the computer-readable program code having instructions, which when executed cause a microprocessor to; perform a status check on each of an electrochemical glucose sensor and an optical glucose sensor of an orthogonally redundant glucose sensor device, wherein said status check on the optical glucose sensor is based on at least one of a previous cal ratio, a previous sensor accuracy, a sensitivity loss flag, and a dip flag for the optical glucose sensor; calculate a first reliability index for an output signal of the electrochemical sensor based on said status check for the electrochemical sensor; calculate a second reliability index for an output signal of the optical sensor based on said status check for the optical sensor; calibrate the output signal of the electrochemical sensor to obtain an electrochemical sensor glucose value (echem SG); calibrate the output signal of the optical sensor to obtain an optical sensor glucose value (optical SG); calculate a first weight based on said first reliability index and generate a weighted echem SG based on said first weight; calculate a second weight based on said second reliability index and generate a weighted optical SG based on said second weight; and calculate a single, fused sensor glucose value for the orthogonally redundant glucose sensor device based on said weighted echem SG and weighted optical SG. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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Specification