TC-OFDM integrates OFDM for communication with binary phase shift keying (BPSK) modulation for navigation, both of which share the same frequency band. However, the spectral fluctuations and high out-of-band (OOB) emissions associated with the BPSK signal lead to interference with the OFDM demodulation, adversely affecting signals in adjacent frequency bands. For the LEO satellite INAC system, [PERSON] proposed a Zadoff-Chu NOMA (ZC-NOMA) scheme [17]. ZC-NOMA superimposes low-power ZC sequences onto the communication subcarriers of OFDM to mitigate the Doppler effect on time-of-arriving (TOA) estimation. However, there is also MI between the communication symbols and the ZC sequences, which limits performance in massive LEO satellite positioning scenarios. Furthermore, the communication reliability of OFDM-based signals is compromised in high-mobility channels due to Doppler spread, which induces inter-carrier interference (ICI) and results in an increased bit error rate (BER). Orthogonal time-frequency space (OTFS) modulation is specifically designed for reliable communication in high-mobility channels. It multiplexes information symbols over two-dimensional orthogonal basis functions in the delay-Doppler (DD) domain [18], converting a fast time-varying multipath channel into a sparse and slow time-varying channel, thereby facilitating low-complexity detection and channel estimation [19]. Consequently, OTFS is regarded as a candidate waveform for 6G, and has been utilized in the design of INAC schemes [20]. In recent years, research on OTFS has focused on communication areas such as waveform design [21], channel estimation [22; 23], detection [24], and diversity [25; 26] techniques. Refs. [27; 28; 29] studied the random access, spatial correlation, and downlink outage probability of OTFS in LEO satellite communication systems. Ref. [30] designed a realizable DD orthogonal pulse and proposed orthogonal delay-Doppler division multiplexing modulation (ODDM), achieving lower OOB emission and BER in practical systems. In addition, integrated sensing and communication (ISAC) based on OTFS has also received attention [31; 32; 33; 34]. The main purpose of these works was to enable localization, velocimetry, imaging, detection, etc., of the environment or targets, rather than acquiring time and space information about the users themselves. Specifically, the ISAC scheme for the Internet of Things (IoT) in [32] achieves low-complexity, high-precision target parameter estimation under the assumption of perfect delay and frequency synchronization. In contrast, navigation receivers do not transmit signals, but synchronize and localize themselves by passively receiving line-of-sight (LOS) signals from satellites [35]. For the same reason, the schemes in [33; 34] for target detection and tracking in multi-antenna radar receivers are not suitable as PNT solutions for single-antenna navigation receivers. In [31], a random-padded OTFS (RP-OTFSM) is proposed to improve radar sensing performance by replacing the impulse pilot surrounded by zero guard zone by random-value pilot with a cyclic prefix, but it is not designed to provide continuous and accurate PNT services with dedicated broadcast signals. In terms of research on OTFS-based INAC, Ref. [36] utilizes the distance and velocity information estimated from the delay-Doppler channel matrix of the OTFS system for positioning. However, the signal does not incorporate a dedicated navigation component, resulting in a limited number of navigation users. Ref. [37] superimposes the alternating binary offset carrier (AltBOC) modulated navigation message with the quadrature amplitude-modulated communication data to enhance the reliability of data transmission. Additionally, a time-domain PRN sequence for channel estimation and positioning is inserted before the OTFS frame, and we refer to this scheme as PN-OTFS later.