A compact positioning and velocity RF sensor for improved inertial navigation

Navigation in GPS-denied or GPS-inhibited environments such as urban canyons, mountain areas, and indoors is often accomplished with an Inertial Measurement Unit (IMU). For portable navigation, minaturized IMUs suffer from poor accuracy due to bias, bias drift and noise. We propose to use a compact RF motion sensor to identify zero velocity periods during which the individual IMU sensor biases can be observed. The proposed motion sensor can also be used to detect the position and velocity of the IMU relative to the ground in real time, which provides additional independent information for sensor fusion. A prototype RF motion sensor has been constructed to demonstrate the concept and experimental results show that the proposed RF motion sensor is promising in position and velocity sensing.