**7. Conclusions**

IFOGs have higher resolution performance than RFOG and IORG gyros. Therefore, IFOG technology is the best option for strategic-grade (0.0001°/hr), navigation-grade (0.001°/hr), or high-end tactical-grade (0.01°/hr) applications. Best RFOG designs reach high-end tactical-grade (0.01°/hr) or tactical-grade (0.1°/ hr) performance, and they constitute a mature and tested technology for a large set of applications ranging from aircraft navigation up to platform stabilization. On the other hand, IORG technology is not yet mature, and over the last decade, it has experienced a vigorous development and refinement. Best results obtained experimentally in the laboratory for the performance of IORG prototypes are of 0.20°/h resolution and 0.00075°/ ffiffiffiffiffi hr <sup>p</sup> ARW, respectively. As already mentioned above, several prototypes of RMOGs based on silica resonators have been already theoretically engineered, but the experimentally demonstrated performance is still at least one order of magnitude worse than that one demanded by aerospace and defense navigation applications. Therefore, an improvement of those kinds of gyros is needed to realize a significant impact on the market.
