For wireless optical communication, we research the inertial measurements and geolocation estimations. The results are applicable for guidance, navigation and control of mobile platforms, aerial and ground vehicles, aerospace platforms, etc. We study distributed inertial MEMS sensors with microprocessing units (MPUs) which form microsystemtechnology integrated inertial measurement systems (μIMSs) to estimate spatiotemporal geolocation, orientation, position, trajectory, etc. Data processing and data fusion are researched for hybrid μIMSs-GPS as well as for stand-alone μIMSs. The narrow-beam laser-to-receiver connectivity require accurate repositioning and steering of multi-degree-of-freedom pointing gimbals and mounts with lasers and receivers (photodetectors). The studied μIMSs can be installed on mobile platforms and steering mounts. Within specified coordinate systems and frames, high-precision control, stabilization and servo-steering depend on accurate state estimates. In GPS-denied and electronic warfare environments, one may acquire non-GPS estimates. Guidance, navigation, control and communication tasks are enabled by μIMSs. The studied all-attitude low-power μIMS may support optical connectivity for reliable free-space laser communication. Inflight experiments substantiate our processing calculus and algorithms. Reconfigurable filtering and adaptive quadrature integration enable existing solutions. Studied μIMSs advance modularity, interoperability, scalability, robustness and redundancy of guidance, navigation and communication systems in multi-domain environments. We propose consistent solutions with technology transfer capabilities to stationary and mobile aerial, ground, space, surface and underwater platforms. Our goal is to leverage the latest microsystems, MEMS and processing technologies considering the compatibility and compliance with legacy GPS solutions.