Sensor Applications, Inc. has developed a variety of novel approaches in the use of low-cost, passive magnetic sensors, referenced to the earth's magnetic field, to provide a true measurement of roll, pitch, and yaw, and, as a derivative, angular acceleration and velocity. These sourceless, non-inertial sensors have a strong potential to replace existing inertial, gravity or mass-based technologies in a multitude of applications. The novel geometric arrangement of solid state magnetic sensors and the associated algorithms involved in resolving the earth's magnetic field vectors, provides a non-inertial 3-axis sensor capable of monitoring in realtime roll, pitch, and yaw. This paper also describes the current development of a solid state, adaptive, self-calibrating sensor, also referenced to the earth's magnetic field, that is immune to local field strength variations. Promising results outlined in this paper from pilot projects in virtual reality headtracking, biomechanical gait analysis, suggests that this new technology has the potential to meet the angular tracking requirements of both large volume consumer applications, and small cost-conscious research efforts.