## 5 Discussion and Future Directions
In many cases, it is possible and even preferable to combine those point clouds if the elements of the MMS design allow. The role of MMSs in addressing global challenges such as climate change, disaster management, and sustainable development cannot be overstated. By providing detailed, real-time spatial data, MMS can support evidence-based decision making and enable more effective resource management. Collaborative efforts between researchers, industry, and policymakers will be essential in harnessing the full potential of MMSs to address these pressing global issues. The comprehensive analysis of current MMS research reveals several critical trajectories for future development. First, the integration of neuromorphic computing [163] and next-generation sensors such as event-based cameras [164], complex multi-cameras, and multi-spectral sensors promises to revolutionize real-time processing in dynamic environments, particularly for autonomous navigation applications where low latency is paramount. Second, the convergence of digital twin technologies with mobile mapping will likely enable persistent, centimeter-accurate 3D world models that update continuously through distributed MMS networks. Our analysis suggests that these advancements will be accelerated by three key enablers: (1) the maturation of 5G/6G edge computing infrastructures that alleviate current bandwidth bottlenecks, (2) standardized APIs for federated learning across heterogeneous MMS fleets, and (3) quantum-enhanced LiDAR systems [165] now entering laboratory testing phases. Particularly in urban environments, we anticipate a paradigm shift toward \"always-on\" mapping systems that combine vehicle-borne, UAV, and fixed sensor nodes into unified geospatial intelligence networks. Emerging challenges will require focused research attention in the coming decade. The environmental sustainability of large-scale MMS deployments--particularly the energy footprint of high-resolution LiDAR arrays--demands new approaches to sensor power management and green computing architectures. Our review identifies an urgent need for adaptive calibration protocols that maintain accuracy amid increasing sensor heterogeneity while minimizing human intervention. Ethical frameworks for privacy-preserving mobile mapping must evolve in parallel, potentially leveraging differential privacy algorithms and blockchain-based data governance. The most transformative opportunities may emerge from cross-disciplinary fertilization, such as applying bio-inspired navigation principles from animal migration studies to SLAM systems or adapting astrophysics-based uncertainty quantification methods to urban mapping. These directions suggest that future MMSresearch should prioritize not just technological innovation but also the development of new theoretical frameworks for understanding complex, multi-scale geospatial dynamics. One of the key challenges in the field remains the lack of standardization in MMS design and protocols. While numerous custom and commercial MMS configurations exist, the absence of unified standards hinders the interoperability and scalability of these systems. This paper has proposed a standardized framework for customizable MMSs, aiming to bridge the gap between research and commercial applications. By adopting standardized protocols, the geospatial community can more effectively leverage the full potential of MMS technologies, enabling more efficient data collection, processing, and analysis. This review has centered on vehicle-borne MMSs for their foundational role in geospatial data collection, yet upcoming works should systematically compare platform-specific trade-offs (e.g., UAV vs. handheld SLAM) in accuracy, cost, and scalability. Standardizing modular MMS designs across platforms could bridge these gaps, enabling seamless transitions between aerial, terrestrial, and portable mapping.