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To get reliable location and time information for specific objects, the U. S. Department of Defense (DOD) developed the Global Positioning System (GPS). In spite of its enormous advantages, it encounters limitations in GPS-denied or compromised environments. To address these limitations, Inertial Motion Units (IMUs), consisting of gyroscopic devices, have been substituted for GPS in these harsh environments. However, they are also limited by bias, which increases error growth by integrating signals. This research project allows for tracking a pedestrian in GPS limited environments by adding another portable localization system to the IMU, the Ground Reaction Sensor Cluster (GRSC). The GRSC measures the precise velocity of an object by applying zero velocity updating (ZUPTing) events, and seeks to compensate for the limitations of the IMU to give the precise position of the pedestrian. This project addresses the testing environment developed to evaluate the reliability of a shoe mounted GRSC. This environment consisted of both physical measurements and analysis of the data. Through this testing we check whether this device would meet the Defense Advanced Research Projects Agency's(DARPA) requirement to resolve the zero-velocity error biases of 4000, 250 and 20 &mgr;m/s with a typical 0.3s mid-stance measurement time. To ensure an adequate amount of data, the process was automated and run for several different cycle lengths. |
