arXiv:2611.09687v1 Announce Type: new Abstract: Constant-envelope orthogonal frequency-division multiplexing (CE-OFDM) preserves a unit-magnitude sample envelope, but its Hermitian-symmetric structure makes dedicated sensing pilots costly, and additive pilots disrupt this envelope. We show that injecting a known chirp, here a Zadoff-Chu (ZC) sequence, into the CE-OFDM phase enables payload-blind bistatic delay-Doppler sensing without dedicated sensing frames or an explicit pilot power split: the residual carrier, given by the ensemble mean under the adopted payload model, becomes an implicit superimposed pilot for a receive-only node. A Doppler-aligned receiver integrates this reference coherently across frames while the payload residual averages down. In contrast, phase-domain injected training (PIT) frame averaging, designed for quasi-static channel estimation, loses about 32 dB for the simulated target with 16 averaged frames. Closed-form approximations characterize the payload-induced floor, known-cell detection probability and direct-path tolerance. In the noise-limited simulations, the receiver incurs a 2.8 dB detection gap relative to a payload-aware matched filter without interference cancellation and matches a dedicated-pilot benchmark of equal reference energy without its 53% frame overhead.