Fisher Information Limits of Satellite RF Fingerprint Identifiability for Authentication

View PDF HTML (experimental)

Abstract:RF fingerprinting authenticates satellite transmitters by exploiting hardware-specific signal impairments, yet existing methods operate without theoretical performance guarantees. We derive the Fisher information matrix (FIM) for joint estimation of in-phase/quadrature (IQ) imbalance and power amplifier (PA) nonlinearity parameters, establishing Cramér-Rao bounds (CRBs) whose structure depends on constellation moments. A necessary condition for full IQ identifiability is that the identifiability factor~$\beta$ exceeds zero; for binary phase-shift keying (BPSK), $\beta = 0$ yields a rank-deficient FIM, rendering IQ parameters unidentifiable. This provides a plausible theoretical explanation for OrbID's near-random performance (area under the ROC curve, AUC~$= 0.53$) on Orbcomm. From the FIM, we define a discrimination metric that predicts which hardware parameters dominate authentication for a given modulation. For constant-modulus PSK signals, PA nonlinearity features are predicted to dominate while IQ features are ineffective. We validate the framework on 24Iridium satellites using two recording campaigns, achieving cross-file PA fingerprint correlation $r = 0.999$ and confirming all four CRB predictions. A discrimination-ratio-weighted (DR-weighted) authentication test achieves AUC$= 0.934$ from six features versus $0.807$ with equal weighting, outperforming machine-learning classifiers (AUC~$\leq 0.69$) on the same data.

Subjects:

Signal Processing (eess.SP)

Cite as: arXiv:2603.29766 [eess.SP]

(or arXiv:2603.29766v1 [eess.SP] for this version)

https://doi.org/10.48550/arXiv.2603.29766

arXiv-issued DOI via DataCite (pending registration)

Submission history

From: Haofan Dong [view email] [v1] Tue, 31 Mar 2026 14:07:19 UTC (4,008 KB)