arXiv:2611.14250v1 Announce Type: new Abstract: Reliable multipath detection is essential for millimeter-wave simultaneous localization and mapping (SLAM), where propagation paths reflecting off the environment provide geometric constraints beyond the dominant line-of-sight component. This paper develops constant false alarm rate (CFAR)-based detectors for beam-swept bistatic integrated sensing and communications (ISAC). Starting from conventional CFAR on the I/Q datacube, we derive a modified detector for non-coherently integrated angular power maps, where the post-integration noise statistics differ from those assumed by standard cell-averaging CFAR. To improve practicality, we introduce a multi-cell cell-under-test formulation and a plus-shaped training window that reduces computational cost while accounting for sidelobe structure. The proposed methods are evaluated on experimental 60 GHz indoor measurements using a snapshot-SLAM estimator. Compared with a singular value decomposition (SVD)-based detector, the proposed CFAR approaches reduce the overall positioning RMSE from 0.30 m to 0.24-0.26 m, with the largest improvement in non-line-of-sight snapshots. The multi-cell non-coherent detector further lowers the computational complexity without degrading positioning accuracy, demonstrating its suitability for practical multipath radio-SLAM.