OCDM‐BCS: A Wideband Integrated Navigation and Communication Signal for Next‐Generation LEO Systems Supporting Low‐Altitude UAV Collaborative PNT

ABSTRACT

The rapid rise of the low‐altitude economy has significantly increased the demand for high‐performance positioning, navigation and timing (PNT) services. Meanwhile, the large‐scale construction of LEO satellite communications provides new opportunities for resilient navigation systems. In the future, space–air–ground integrated networks require an overall air‐interface architecture that is expected to jointly support high‐precision ranging, high‐rate communication, sensing and high‐dynamic adaptability. Motivated by the objective of transforming communication signals to achieve superior measurement capabilities, this paper proposes a novel modulation scheme integrating navigation and communication functions, namely orthogonal chirp division multiplexing with binary chirp subcarriers (OCDM‐BCS), which uses orthogonal binary offset chirp carrier (BOCC) signals as subcarriers. First, based on the proposed signal model, the analytical expressions for the ACF and PSD are derived, with the theoretical formulas validated through simulation results. Subsequently, the relationship between OCDM‐BCS parameters and their time–frequency characteristics is discussed. Compared with representative modulation schemes such as BOC(10,5), MBOC‐POS, OFDM, and OFDM‐BOC, the analysis shows that, due to its linear frequency modulation (LFM) characteristics, OCDM‐BCS exhibits superior code tracking accuracy, anti‐interference robustness and anti‐multipath capability. An NR‐inspired integrated communication‐navigation frame is further constructed, in which OCDM‐BCS is employed for low‐rate control/signalling transmission while conventional CP‐OFDM is retained for high‐rate payload data. Under ideal synchronisation and AWGN conditions, the BER performance of OCDM‐BCS is shown to be comparable to that of CP‐OFDM. With its excellent comprehensive performance, OCDM‐BCS provides a solid signal foundation for collaborative PNT services in future low‐altitude unmanned aerial vehicle (UAV) swarm applications.