Self-Mixing Interferometric Speedometer

To address the U.S. Army need for a self-contained navigation aid for dismounted soldiers/sensor platforms, Physical Optics Corporation (POC) developed a proof-of-concept prototype Self-Mixing Interferometric Speedometer (SMIS). SMIS is based on two POC innovations: self-mixing laser diodes for real-time angle-independent measurement of the full vector of soldier velocity, and a POC proprietary tunable liquid crystal lens autofocusing system, reducing required laser power. SMIS will reliably trace the movement of a dismounted soldier with respect to any stable objects when the GPS signal is disrupted, and will determine georeferenced coordinates for transmission over normal communication channels. SMIS directly addresses the Army requirements for a compact navigation system for precision positioning. In Phase I POC experimentally demonstrated real-time angle-independent measurements of target speed with an accuracy of <0.5% with laser output optical power of <5 mW over a distance of 1 m. In Phase II a fully operational prototype compatible with soldiers’ platforms will be designed, assembled, and tested in the laboratory and at an Army facility. The prototype will be robust, compact (<4 cu in., <4 oz.), low-cost (<$100), and low power consuming (<0.5 W), with low electronic/IR signature, and will determine its position with an accuracy of 1 m CEP.