Simultaneous Localization and Calibration (SLAC) for Cooperative Radio Navigation: When Is It Possible?

Abstract

Cooperative radio navigation is essential in GNSS- denied or infrastructure-free environments. Methods based on signal propagation time, such as round-trip time ranging, require sub-nanosecond Time-of-Flight accuracy. However, fac- tors such as temperature variations in RF components or re- configurable antenna surroundings can affect radio transceiver group delays, introducing ranging bias. Simultaneous Localiza- tion and Calibration (SLAC) aims to jointly estimate node po- sitions and ranging biases, correcting them online. The success of this process critically depends on observability, i.e., whether the measurements contain enough information to uniquely estimate all desired parameters. In this work, we analyze the observability of SLAC for cooperative radio navigation through a Fisher Information Matrix (FIM) approach and derive necessary and sufficient conditions that determine when SLAC is feasible. The results characterize the minimum number of static and mobile nodes required and identify geometric configurations that yield strong, weak, or no observability. We validate the analysis via extensive simulations