Low cost CVG for high-grade north finders and targeting systems

Abstract

Low-cost accurate orientation as required for targeting, pointing and personal navigation is generally obtained by using FOGs (Fibre Optical Gyros) and DTGs (Dynamically Tuned Gyros). When considering the alignment time and the complexity of the system, those gyros within strapdown systems have shown themselves to be particularly relevant and today numerous systems are operated this way. However, reliability and cost are still two key drivers and new applications are seeking alternatives which are more cost effective. In spite of the emergence of Vibratory Gyros Technology, as illustrated by the high grade Hemispherical Resonator Gyro (HRG), the cost for 1 mrad accuracy is still high which prevents the effective deployment across the civilian market of accurate True North-Finders (TNF) and pointing systems. INNALABS Ltd has risen to the challenge and has developed a low-cost CVG (Coriolis Vibratory Gyroscope) able to meet the market demand for low-cost accurate TNF and pointing systems. Although the INNALABS' CVG has been developed primarily for stabilisation control systems and tactical grade systems, some specific refinements of the control loop electronics are leading to few 0.01 °/hr bias stability and ARW better than 0.01 °/√hr as required for 1 mrad accuracy. Statistical data on key performance characteristics will be presented including the bias stability and the output noise. As an example of a practical implementation, the 2 position method for True North measurement will be described with a result consistent with 1 mrad heading accuracy. This underlines the capability of INNALABS' technology of branching into the TNF and the pointing market segments.