System and method for sensor calibration

Abstract

A method and system to determine orientation of a device is disclosed. The device includes a plurality of sensors. A first signal indicative of an orientation of the device is generated using at least a first subset of sensors, with at least one sensor. A second signal indicative of the orientation of the device is generated using at least a second subset of sensors, with at least one sensor. The first signal and the second signal is compared to determine if indicated orientation is acceptable. If the orientation is not acceptable, one or more sensors are calibrated.

What is claimed is: 
     
         1 . A method of initiating a calibration for a sensor in a device, including:
 providing at least one sensor;   measuring an output of the sensor;   converting the output of the sensor to a signal indicative of an orientation of the device with reference to a stationary frame;   comparing the converted output of the sensor to a threshold value; and   if the converted output of the sensor is outside a threshold value, initiating a calibration of the sensor.   
     
     
         2 . The method of  claim 1 , wherein the sensor is an accelerometer and the output of the sensor is above the threshold value due to an external shock. 
     
     
         3 . The method of  claim 1 , wherein the sensor is a compass and the output of the sensor is above the threshold value due to an external magnetic field. 
     
     
         4 . The method of  claim 1 , wherein the sensor is a gyroscope and the output of the sensor is above the threshold value due to an external rotation too fast. 
     
     
         5 . The method of  claim 1 , wherein measuring further including taking a plurality of samples of the output of the sensor. 
     
     
         6 . A system to initiate a calibration for a sensor in a device, including:
 output of the sensor is measured, wherein the output is indicative of an orientation of the device;   output of the sensor is converted to an orientation in a stationary frame;   converted orientation output of the sensor is compared to a threshold value; and   if the converted orientation output of the sensor is outside a threshold value, sensor is calibrated.   
     
     
         7 . The system of  claim 6 , wherein the sensor is an accelerometer and the output of the sensor is above the threshold value due to an external shock. 
     
     
         8 . The system of  claim 6 , wherein the sensor is a compass and the output of the sensor is above the threshold value due to an external magnetic field. 
     
     
         9 . The system of  claim 6 , wherein the sensor is a gyroscope and the output of the sensor is above the threshold value due to an external rotation too fast. 
     
     
         10 . The system of  claim 6 , wherein measuring further including taking a plurality of samples of the output of the sensor.