Distributed Integrated Sensing, Localization, and Communications over LEO Satellite Constellations

TL;DR

The paper addresses the challenge of delivering global high-rate communication, precise localization, and robust space sensing with LEO constellations under resource constraints. It proposes DISLAC, a distributed ISL-enabled framework that jointly integrates communication, localization, and sensing across multiple satellites. Through three illustrative case studies and a system-level discussion, it quantifies throughput, positioning accuracy, and sensing robustness gains while identifying synchronization, ISL, topology, and regulatory challenges. The work outlines open research directions and regulatory considerations necessary for practical deployment in future non-terrestrial networks.

Abstract

Low Earth orbit (LEO) satellite constellations are rapidly becoming essential enablers of next-generation wireless systems, offering global broadband access, high-precision localization, and reliable sensing beyond terrestrial coverage. However, the inherent limitations of individual LEO satellites, including restricted power, limited antenna aperture, and constrained onboard processing, hinder their ability to meet the growing demands of 6G applications. To address these challenges, this article introduces the concept of distributed integrated sensing, localization, and communication (DISLAC) over LEO constellations, inspired by distributed multiple input multiple output architectures. By enabling inter-satellite cooperation through inter-satellite links, DISLAC jointly exploits communication, localization, and sensing functionalities, achieving synergistic gains in throughput, positioning accuracy, and sensing robustness through shared resources and cooperative design. We present illustrative case studies that quantify these benefits and analyze key system-level considerations, including synchronization, antenna reconfigurability, and inter-satellite link design. The article concludes by outlining open research directions to advance the practical deployment of DISLAC in future non-terrestrial networks.

Figures (5)

• Figure 1: Overview of dislac over leo satellite constellations: (1) Multi-leo cooperative beamforming; (2) Intra-cluster handover; (3) Inter-cluster handover; (4) Coordinated multi-leo localization; (5) Multi-leo cooperative backhauling; (6) Multi-static space debris sensing.
• Figure 2: Conceptual illustration of exemplary synergies and trade-offs among communication, localization, and sensing in a unified dislac framework over leo constellations. “Communication” aggregates service links between leo and ue and isl; “Localization” covers ue positioning and network-wide satellite localization; “Sensing” includes ground and inter-leo sensing. Blue arrows illustrate example mutual benefits, such as position-aware beamforming and handover, high-throughput links for localization coordination, isl-enabled fusion of sensing data, and shared spectrum/pilots/synchronization for joint situational awareness. Orange arcs indicate representative resource trade-offs in spectrum/throughput versus positioning accuracy, throughput demand versus sensing resolution, and spatial beam allocation between ue localization and passive target sensing.
• Figure 3: Throughput and signaling overhead comparison: (a) Sum-rate versus number of leo satellites $L$ under different beamforming schemes; (b) Signaling overhead of collaborative beamforming versus number of UEs $U$, evaluated under Ring and Star topologies with varying satellite number $L$. (E: Edge node, C: Central node).
• Figure 4: Joint distribution of downlink delay and Doppler shift from 200 randomly placed leo satellites to a static ue on Earth. Each circle represents a satellite. The satellites are uniformly distributed above the ue within zenith angles from $0^\circ$ to $5^\circ$ (i.e., elevation angles above $85^\circ$), at an altitude of 600 km and speed of 7.5 km/s. Satellites move at equal speed along randomly directed tangents to the orbital sphere. The carrier frequency is 2 GHz, and the ofdm waveform uses a subcarrier spacing (SCS) of 60 kHz with a cyclic prefix of 1.6 $\mu$s. The vertical dashed red line marks the cyclic prefix duration; the horizontal dashed blue lines indicates $0.1 \times$ SCS, a typical threshold for acceptable Doppler spread.
• Figure 5: (a) Maximum unambiguous range $R_{\text{max}}$, range resolution $\Delta R$, and maximum unambiguous velocity $v_{\text{max}}$ as functions of subband spacing ($\Delta f$ ranging from $1$ kHz to $200$ kHz). (b) Comparison between single-leo satellite monostatic sensing and multi-leo satellite multistatic sensing with two strategies: LEF and DFE. To support an unambiguous range of $100~\mathrm{km}$ and a relative velocity of $7.5~\mathrm{km/s}$, the subband spacing and symbol duration are set to $1.5~\mathrm{kHz}$ and $1.5~\mu\mathrm{s}$, respectively, in (b). In radar systems, the symbol duration should be greater than or equal to the inverse of the subband spacing; for illustration purposes, equality is assumed in (a).