A radar system may include a wearable device dimensioned to be worn by a user of an artificial reality system. The radar system may also include at least one radar device that is secured to the wearable device and transmits at least one frequency-modulated radar signal to at least one transponder located within a physical environment of the user. The radar system may further include at least one processing device communicatively coupled to the radar device. The processing device may detect a signal returned to the radar device from the transponder in response to the frequency-modulated radar signal and then calculate, based at least in part on a frequency of the returned signal, a distance between the transponder and the radar device. Various other devices, systems, and methods are also disclosed.