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<p>With the rapid development of low earth orbit (LEO) giant constellations, the traditional code division multiple access (CDMA) method is facing the problem of drastic increase in receiver capture complexity due to the growth of pseudorandom noise (PRN) code demand. In this paper, for the multiple access problem in LEO constellations, a multi-beam polling multiple access (MP-MA) method for LEO navigation is innovatively proposed, which utilizes the existing large-scale phased array antenna hardware facilities of LEO communication satellite system to broadcast navigation signals in a narrow-beam scanning manner. Combined with the discrimination effect of Doppler frequency and code phase on the signals, LEO satellite signals are distinguished in the five dimensions of time–space-frequency-phase-code, thereby further reducing the number of PRN codes required for distinguishing LEO satellite signals. Under the given conditions of LEO constellations and multi-beam polling strategy, the problem of minimizing the number of PRN codes required to distinguish all satellites is transformed into a graph coloring problem, and the approximate optimal solution is obtained by the depth-first search (DFS) algorithm. The simulation results show that under the scene conditions of 120 and 144 LEO satellites and 52 beams, compared with the traditional CDMA, the proposed method can reduce the number of satellite pairs with signal interference by 96.20% and 86.92% respectively, and the required number of PRN codes by 96.67% and 94.44% respectively. Meanwhile, under the experimental conditions, when only the Doppler frequency and the code phase are considered respectively in frequency-code dimensions based the multi-beam polling mode, about 60% and 90% of the effect of the complete MP-MA method can be achieved respectively in reducing the number of interfering satellite pairs, indicating that the code phase plays a major role in the frequency-phase dimension. This method can achieve significant reduction of signal capture complexity while maintaining carrier-to-noise density ratio (<i>C</i>/<i>N</i><sub>0</sub>) performance in navigation receivers comparable to existing system, and provide a feasible solution for the efficient multiple access of LEO constellation navigation systems.</p>

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A multi-beam polling multiple access method for LEO navigation signals

  • 期刊论文

  • 发表日期：

    2026年6月24日

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  • Kunmu Li,
  • Xiaomei Tang,
  • Chunjiang Ma,
  • Sixin Wang,
  • Feixue Wang

摘要

With the rapid development of low earth orbit (LEO) giant constellations, the traditional code division multiple access (CDMA) method is facing the problem of drastic increase in receiver capture complexity due to the growth of pseudorandom noise (PRN) code demand. In this paper, for the multiple access problem in LEO constellations, a multi-beam polling multiple access (MP-MA) method for LEO navigation is innovatively proposed, which utilizes the existing large-scale phased array antenna hardware facilities of LEO communication satellite system to broadcast navigation signals in a narrow-beam scanning manner. Combined with the discrimination effect of Doppler frequency and code phase on the signals, LEO satellite signals are distinguished in the five dimensions of time–space-frequency-phase-code, thereby further reducing the number of PRN codes required for distinguishing LEO satellite signals. Under the given conditions of LEO constellations and multi-beam polling strategy, the problem of minimizing the number of PRN codes required to distinguish all satellites is transformed into a graph coloring problem, and the approximate optimal solution is obtained by the depth-first search (DFS) algorithm. The simulation results show that under the scene conditions of 120 and 144 LEO satellites and 52 beams, compared with the traditional CDMA, the proposed method can reduce the number of satellite pairs with signal interference by 96.20% and 86.92% respectively, and the required number of PRN codes by 96.67% and 94.44% respectively. Meanwhile, under the experimental conditions, when only the Doppler frequency and the code phase are considered respectively in frequency-code dimensions based the multi-beam polling mode, about 60% and 90% of the effect of the complete MP-MA method can be achieved respectively in reducing the number of interfering satellite pairs, indicating that the code phase plays a major role in the frequency-phase dimension. This method can achieve significant reduction of signal capture complexity while maintaining carrier-to-noise density ratio (C/N0) performance in navigation receivers comparable to existing system, and provide a feasible solution for the efficient multiple access of LEO constellation navigation systems.