Sensor cluster navigation device and method

Abstract

Device and method for providing inertial indications with high accuracy using micro inertial sensors with inherent very small size and low accuracy. The device and method of the invention disclose use of the cluster of multiple micro inertial sensors to receive from the multiple sensors an equivalent single inertial indication with high accuracy based on the multiple independent indications and mathematical manipulations for averaging the plurality of single readings and for eliminating common deviations based, for example, on measurements of the deviation of the single readings.

1 . An inertial measurement device comprising;
 one or more sensor clusters, each sensor cluster including a plurality of micro inertial sensors to sample movement with respect to one axis of a plurality of axes; and   a summing unit to receive samples from each of said one or more sensor clusters indicative of said movement with respect to said one axis and to sum said samples for each of said one or more sensor clusters to an equivalent vector indicative of the sampled movement.   
     
     
         2 . The device of  claim 1 , wherein said one or more sensor clusters comprises two or more sensor clusters for sampling the movement, each sensor cluster to sample movement with respect to a different axis of said plurality of axes. 
     
     
         3 . The device of as claimed in  claim 1 , further comprising a computing unit to receive said equivalent vector and to compensate said equivalent vector based on stored data representing pre-measured misalignment of said equivalent vector. 
     
     
         4 . The device as claimed in  claim 1 , wherein said plurality of micro inertial sensors comprises micro-electromechanical sensors. 
     
     
         5 . The device as claimed in  claim 1 , wherein said plurality of micro inertial sensors comprises accelerometer sensors. 
     
     
         6 . The device as claimed in  claim 1 , wherein said plurality of micro inertial sensors comprises gyroscope sensors. 
     
     
         7 . The device as claimed in  claim 1 , wherein at least some of said plurality of micro inertial sensors is substantially aligned with one axis of a reference frame. 
     
     
         8 . The device as claimed in  claim 1 , wherein each of said one or more sensor clusters is substantially aligned with one of the axes of a three dimensional reference frame. 
     
     
         9 . The device as claimed in  claim 1 , wherein said one or more sensor clusters comprise an integrated sensor cluster. 
     
     
         10 . The device as claimed in  claim 1 , wherein least some sensors of said plurality of micro inertial sensors are spatially displaced from a pivot axis of each of said one or more sensor clusters by a known distance. 
     
     
         11 . The device as claimed in  claim 1 , wherein the orientation of an axis of each micro inertial sensor of said plurality of micro inertial sensors is angularly oriented with respect to an axis of said one or more sensor clusters by a known amount. 
     
     
         12 . The device as claimed in  claim 2  wherein computing unit is programmed to combine separate outputs of said plurality of micro inertial sensors to yield compensated output for each of said one or more sensor clusters. 
     
     
         13 . The device as claimed in  claim 12 , wherein said device communicates with at least one additional device from a list comprising Global Positioning System receiver and a zero-velocity update sensor. 
     
     
         14 . An inertial measurement method comprising:
 sampling a movement by one or more sensor clusters, each sensor cluster including a plurality of micro inertial sensors to sample the movement with respect to one axis of a plurality of axes; and   summing, using a summing unit, for each of said one or more sensor clusters samples received from each of said one or more sensor clusters indicative of said movement with respect to said one axis to an equivalent vector indicative of the sampled movement.   
     
     
         15 . The method as claimed in  claim 14 , further comprising the steps of:
 estimating an error in said equivalent vector, said error is estimated according to an error model associated with the sensors;   calculating a correction to compensate for the error; and   applying the correction to said equivalent vector.   
     
     
         16 . The method as claimed in  claim 15 , further comprising the steps of:
 reading output of at least one device from a group of devices that consists of Global Positioning System receiver and a zero-velocity update sensor;   utilizing said output of said at least one additional device in estimating said error.   
     
     
         17 . The method as claimed in  claim 14 , further comprising the steps of:
 providing displacement information for each micro inertial sensor of said plurality of micro inertial sensors with respect to a pivot axis of said sensor cluster; and   adjusting output of each of said plurality of micro inertial sensors in accordance with said displacement information.   
     
     
         18 . The method as claimed in  claim 14 , further comprising the steps of:
 providing deviation information of an axis of each micro inertial sensor of said plurality of micro inertial sensors from a common axis of the sensor cluster; and   adjusting said separate output of each of said plurality of micro inertial sensors in accordance with each of said amount of deviation.