Space Link Research Articles

Experimental feasibility analysis of quantum/classical coexistence over fibre and free space links

AbstractThe authors present a novel approach to Quantum Key Distribution (QKD) research, emphasising cost‐effectiveness and practicality using a single photon polarisation‐encoded system employing mainly commercial off‐the‐shelf components. This study diverges from previous high‐cost, high‐end setups by exploring the viability of QKD in more accessible and realistic settings. Our approach focuses on practical measurements of the signal‐to‐noise ratio by analysing polarisation‐encoded photonic qubits over various transmission scenarios. The authors introduce a simplified evaluation method that incorporates experimental measurements, such as noise sources and losses, into a semi‐empirical theoretical framework. This framework simulates the standard DS‐BB84 protocol to estimate Secure Key Rates (SKRs), offering an alternative approach on the evaluation of the practical implementation of QKD. Specifically, the authors examine the feasibility of QKD over a 2.2 km intra‐campus fibre link in coexistence scenarios, identifying optimal Wavelength‐Division Multiplexing allocations to minimise Raman noise, achieving an expected SKR of up to 300 bps. Additionally, the authors’ study extends to 40 m indoor and 100 m outdoor Free‐Space Optical (FSO) links using low‐cost components, where the authors recorded Quantum Bit Error Rate (QBER) values below 3.2%, allowing for possible SKRs up to 600 bps even in daylight operation. The converged fibre/FSO scenario demonstrated robust performance, with QBER values below 3.7% and an expected SKR of over 200 bps. Our research bridges the gap between high‐end and economical QKD solutions, providing valuable insights into the feasibility of QKD in everyday scenarios, especially within metropolitan fibre based and FSO links. By leveraging cost‐effective components and a simplified single photon exchange setup, the authors work paves the way for the effortless characterisation of deployed infrastructure, highlighting its potential in diverse settings and its accessibility for widespread implementation.

Millimeter-wave over fiber integrated sensing and communication system using self-coherent OFDM

Orthogonal frequency-division multiplexing (OFDM) waveform is highly preferred as a dual-function candidate for integrated sensing and communication (ISAC) systems. However, the sensitivity to both carrier frequency offset (CFO) and phase noise greatly impedes its applications in millimeter-wave ISAC systems. Here, we propose and experimentally demonstrate a photonic millimeter-wave ISAC system employing the virtual-carrier-aided self-coherent OFDM technique, wherein a digitally-generated local oscillator is transmitted along with the OFDM signal. Then, a compact CFO-immune and phase noise-immune envelope detection method is implemented for down-converting millimeter-wave communication and radar echo signals. In experiments, a V-band ISAC system is successfully implemented with a simplified remote radio unit, using the remote photonic millimeter-wave heterodyning up-conversion for downlink and the envelope detection-assisted down-conversion for uplink (or radar echoes). In the converged transmission link with a 5-km fiber link and 2-m space link, the Kramers–Kronig (KK) receiver supports a communication data rate up to 16-Gbit/s by mitigating signal-signal beat interference (SSBI). More significantly, the SSBI leads to negligible effects on the sensing performance when classic matched filtering is adopted for target identification. Consequently, a 4.8-cm range resolution and a 4-mm range accuracy are obtained for the radar sensing function.

A novel dual polarization multiplexing RoF system integrating optical fiber and FSO channel with AMI downlink signals

Using dual polarization multiplexing alternate mark inversion (AMI) downlink signals, a novel radio over fiber (RoF) system integrating optical fiber and FSO channel is designed to adapt to applications in mountainous areas and other complex terrain areas. Optical heterodyne technology and self-mixing homodyne detection method are used to realize high sensitivity detection of the received signals after 25.1 km channel (including 1 km single-mode fiber and 100 m free space link) transmission. Moreover, polarization multiplexing technology is introduced to exponentially increase the transmission capacity of downlink signals. This scheme not only can be compatible with traditional optical fiber transmission systems, but also support the wireless optical access application of millimeter wave signals in RoF systems.

A Radial Basis Function-Based Graph Attention Network With Squeeze Loss Optimization for Link Prediction

Graph attention networks is a popular method to deal with link prediction tasks, but the weight assigned to each sample is not focusing on the sample's own performance in training. Moreover, since the number of links is much larger than nodes in a graph, mapping functions are usually used to map the learned node features to link features, whose expression of node similarity determines the quality of link feature learning. To tackle the above issues, a new model graph attention networks based on Radial Basis Function (RBF) with squeeze loss is proposed, including two improvements. Firstly, RBF function with extended parameters is used to transform the node features output by attention layer into link features. The result of link feature embedding can be improved by shortening the distance of nodes with links and enlarging the distance of nodes without links in vector space. Secondly, squeeze loss is designed to adjust the loss according to the performance of samples in training and change the proportion of sample loss in the loss function to allocate training resources reasonably. The link prediction task performed on datasets shows that the performance of proposed method is better than baselines.

Knot quandle decomposition along a torus

We study the structure of the augmented fundamental quandle of a knot whose complement contains an incompressible torus. We obtain the relationship between the fundamental quandle of a satellite knot and the fundamental quandles/groups of its companion and pattern knots. General presentations of the fundamental quandles of a link in a solid torus, a link in a lens space and a satellite knot are described. In the last part of this paper, an algebraic approach to the study of affine quandles is presented and some known results about the Alexander module and quandle colorings are obtained.

Analysis of the development of the transport system taking into account natural and geographical factors (on the example of the city of Chernivtsi)

The article is devoted to determining the influence of natural and geographical factors on the transport structure in the conditions of urbanization. Transport has always played a significant role in the organization and development of territories, the level of transport provision reflected the status of the country, its importance in the world community. The purpose of the study is to establish the nature of the dependence of the transport structure on the natural conditions of the area and the geography of the region using the example of the city of Chernivtsi, to determine the conditionality of the features of building internal and external transport links in the urban space and beyond, and changes in the environment under their influence. The research methodology involves the involvement of general scientific and special methods, which allows us to consider the problem in different aspects, take into account the peculiarities of interdisciplinary issues in the field of urban planning and transport geography. The types of transport and the nature of the links between settlements, and in general the choice of the place where these settlements were founded, directly depended on the natural and geographical conditions of the area. The structure of urban development was formed on the basis of land and waterways. The streets duplicated directions to neighboring settlements or economic points of attraction (raw material extraction sites, trading posts, etc.). In the modern world, additional questions arise regarding the environmental aspects of the development of transport infrastructure - its impact on the environment and the quality of human life. This is especially true for large transport hubs that create a significant burden on the entire ecosystem due to the consumption of large amounts of energy, noise and light pollution, and chemical emissions. The adoption of the most adapted decisions on the nature of the traffic load in certain environmental conditions allows maintaining the balance of the ecosystem in a space that automatically passes to the status of an urbanized one. The city of Chernivtsi is indicative for Ukraine in terms of considering the relationship of the transport structure with the natural and geographical environment, since here the problem can be considered in temporal genesis, taking into account spatial changes - the transfer of transport hubs and main networks. In addition, Chernivtsi is positioned as a potential international transport hub based on a new airport, which will allow joining the international air transportation system. The most successful geographical position since the founding of the city on the trade route ensured the further development of the entire transport system. As a result, it was found that the main directions of economic relations and the transport networks served by them were laid down from the beginning of the formation of the city of Chernivtsi as an important stronghold on trade routes. Further, they developed due to the expansion of needs and new modes of transport (the consequences of technological progress). The tracing was determined by the location of neighboring settlements and the features of the terrain. In the city itself, the Prut became the main forming axis and significant differences in elevation marks on its right bank, which determined the nature of the development of the territory, the general street system. With the advent of the railway, it became necessary to create additional transport routes that were required to ensure its functioning. The construction of the airport also required the creation of an entrance to it by land transport. Automatically, all additionally involved territories were subject to gradual ordering, that is, they passed into the status of suburbanized. In recent years, there has been an urgent need to modernize the airport in Chernivtsi. Modern requirements for its equipment required the choice of another location - in the suburban area, which continues to develop the trend of suburbanization of new territories outside the city. The formation of a large transport hub based on the new airport will give impetus to the further development of the city, its inclusion in the international transport system in the field of air traffic. The rest of the transport structure is obliged to ensure its functioning. Taking into account natural and geographical factors will reduce the impact on the overall ecosystem of the territories, which is one of the most important requirements of our time. Keywords: transport system, natural and geographical factors, suburbanized space, transport hub, transport network.

A Pattern Search Method to Optimize Mars Exploration Trajectories

The Korean National Space Council recently released “Mars Exploration 2045” as part of its future strategic plan. The operations for a Mars explorer can be defined based on domestically available capabilities, such as ground operations, launch, in-space transport and deep space link. Accordingly, all of our exploration scenarios start from the Naro space center, and the pathway to Mars is optimized using an objective function that minimizes the required ∆V. In addition, the entire phase of Mars orbit insertion should remain in contact with our deep space antennas, a measure that is imposed as an operational constraint. In this study, a pattern search method is adopted, as it can handle a nonlinear problem without relying on the derivatives of the objective function, and optimal trajectories are generated on a daily basis for a 15-day launch period. The robustness of this direct search method is confirmed by consistently converged solutions showing, in particular, that the ascending departure requires slightly less ∆V than the descending departure on the order of 10 m/s. Subsequently, mass estimates are made for a Mars orbiter and a kick stage to determine if the desired ∆V is achievable with our eco-friendly in-space propulsion system when launched from our indigenous launch vehicle, KSLV-II.

Combined Photobleaching and Temperature Effects on 1550 nm Radiation-Induced Attenuation of Germanosilicate Optical Fiber

Combined temperature and photobleaching (PB) effects on the 1550 nm radiation-induced attenuation (RIA) levels and kinetics of a commercial Ge-doped single-mode optical fiber have been investigated. The main goal of this study was to evaluate if synergetic effects could impact the performances of free space optical communication links in space. For this, we performed accelerated (0.5 Gy(SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> )/s) irradiation runs with 100 kV X rays up to the total ionizing dose of 150 kGy(SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ), varying the irradiation temperature between -80 °C and 80 °C. First, we evaluate the irradiation temperature effects: infrared RIA largely increases at negative temperatures. Second, the effects of injecting different optical powers at the different temperatures have been characterized: if at temperatures exceeding room temperature (RT), PB effects are almost negligible, a PB effect is clearly observable at lower temperatures where the germanosilicate optical fiber present large RIA levels due to the contribution of metastable defects absorbing at 1550 nm. Increasing the injected powers allows reducing the concentration of these radiation-induced unstable defects, but not as much as thermal treatment consecutive to the irradiation. These results highlight the complex physics of radiation induced defects absorbing at 1550 nm in Ge-doped optical fiber, but also the vulnerability of this class of fiber for space telecommunication links. Regarding the unstable nature of point defects causing the RIA at lower temperature, it seems possible to mitigate the loss excess by thermal cycles at RT or higher temperatures. We also could expect that our accelerated tests represent a worst-case scenario in terms of RIA levels at the maximum dose.

The invariance and distortion of vectorial light across a real-world free space link

Vectorial structured light, where the polarization is inhomogeneously distributed in space, has found a myriad of applications in both 2D and 3D optical fields. Here, we present an experimental study of the invariance and distortion of vectorial light through a real-world medium of atmospheric turbulence. We show that the amplitude and polarization structure are both severely distorted by the turbulent medium, yet the non-separability of these two degrees of freedom remains invariant. We monitor this invariance under a range of beam types and atmospheric conditions, over extended time periods, revealing the unitary nature of atmospheric turbulence in our experiment. Our results provide conclusive evidence that invariance and distortion are not mutually exclusive and that the degree of classical entanglement remains unaltered through such channels, and will be of interest to the large community interested in classical and quantum communication in free space.

Design of an efficient thulium-doped fiber amplifier for dual-hop earth to satellite optical wireless links

Optical wireless communication (OWC) links enable high-speed data transmission between earth stations and satellites. The propagation of optical signals through the atmosphere suffer from atmospheric attenuation and turbulence due to rain, fog, snow, clouds, and wind. The impact of these impairments on propagation of optical signals becomes more pronounced in the case of deep space links. Therefore, optical amplifiers of high output power and gain are extremely useful in deep space links to achieve error free transmission by improving the link budget. In this paper, we propose the design of an efficient Thulium-doped fiber amplifier (TDFA) as booster as well as an in-line based on dual-stage pumping scheme for employment in a dual-hop earth to satellite OWC Link. The pumping scheme, length of Thulium-doped fiber (TDF), and Tm 3+ concentration in the proposed design of TDFA are optimized in such a way so that high output power and gain are achieved for booster and in-line stages, respectively. Output power and gain of 4.6 W and 18.8 dB, respectively are achieved for signal power of 0 dBm at 1807.143 nm when TDFA is used as booster amplifier. Similarly, gain and output power of 66.6 dB and 1.5 W, respectively are achieved for signal power of −35 dBm at 1807.143 nm when TDFA is used as in-line amplifier. A noise figure (NF) of 4.4 dB is achieved for signal wavelength of 1807.143 nm and power of 0 dBm. Finally, the system level performance of the designed TDFA is investigated using bit error rate (BER) metric for a dual-hop earth to satellite OWC wavelength division multiplexed (WDM) transmission system of four quadrature phase shift keying (QPSK) modulated optical signals with an aggregate data rate of 104 Gbps. The BER results showed different possible ranges of error-free transmission at the forward error correction (FEC) limit of 10 - 4 for different values of atmospheric attenuation.

An objective evaluation of emergency plan types using space syntax and users’ responses

Emergency departments are the doorstep of any hospital and designed in different plan types due to a multiplicity of factors. As treatment follows a specific medical pattern according to established SOPs, therefore the spatial configuration needs to respond to that pattern. this paper objectively analyzed the three basic plan types of the emergency department for its spatial configuration using space syntax and users' responses. The results of this study demonstrate that the three basic plan types of emergency departments follow a consistence configurational pattern in their syntactic values despite different layout patterns. All three types exhibit not only a very similar space link ratios, integration, and difference factor (DF) but also the internal integration of the order clinical spaces in a consistence way. The results were cross-validated through users' responses for the required spatial pattern through closed-ended structured questionaries. The results of this study may provide a baseline for the objective evaluation of the emergency department in the future.

Research on Comprehensive Performance Optimization Method of Explosives and Propellants Oriented to the Whole Process

Explosives and propellants are common basic energy for weapons and equipment to achieve delivery, damage, and control, and are an important manifestation of national defense power. However, due to the wide variety of products and complex performance, the traditional serial design optimization mode can no longer meet the requirements of product diversification and rapid development. In this paper, the design process of explosives is deeply studied, and a method for optimizing the comprehensive performance of explosives and propellants oriented to the whole process is proposed. The method uses a comprehensive performance optimization engine to numerically model different design links in a unified parameter space, connects different links horizontally, and adopts a multi-objective optimization algorithm to comprehensively consider the optimization objectives of different links, realizing the automatic execution of the optimization process according to the design process. In order to verify the effectiveness of the method, this paper optimizes the formula of explosives and propellants based on two different types of explosives, gun propellant and rocket propellant. Experimental results show that this method improves the design efficiency and improves product quality under the premise of ensuring safety and manufacturability.

Comparison of Beyond 1 GHz C-Plane Freestanding and Sapphire-Substrate GaN-Based micro-LEDs for High-Speed Visible Light Communication

With ever-growing demand for 6G networks technology, visible light communication (VLC) as a vital component of 6G has challenging requirement for superior performance of light source. Herein, 20 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m blue micro-LED fabricated on 2-inch <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</i> -plane GaN freestanding substrate with high bandwidth over 1 GHz was first demonstrated, and the systematic comparisons to sapphire-substrate micro-LED from the epitaxial materials characterization to optoelectronic properties as well as communication performance were further conducted. GaN-substrate LED wafer has high crystal quality with lower threading dislocation density (TDD), which is two orders of magnitude lower than that of sapphire-substrate LED wafer. The much lower TDD of GaN-substrate LED wafer and better heat dissipation of GaN substrate offer GaN-substrate micro-LED great advantages in optoelectronic properties as well as communication performance. GaN-substrate micro-LED exhibited higher light output power (LOP) especially at high operating current, which is improved by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 21% at 96 mA compared to that of sapphire substrate. Also, GaN-substrate micro-LED achieved a relatively higher bandwidth of 1.282 GHz while maintaining higher LOP with lower operating voltage. And a higher data rate of 4.48 Gbps under 1 m free space link was obtained by GaN-substrate micro-LED, proving it being a promising candidate in high-speed VLC.

Probabilistic model to spatially acquire optical links in space under the influence of band-limited beam jitter.

An analytical model is derived for the probability of failure (P-fail) to spatially acquire an optical link with a jittering search beam. The analytical model accounts for an arbitrary jitter spectrum and considers the associated correlations between jitter excursions on adjacent tracks of the search spiral. An expression of P-fail in terms of basic transcendental functions is found by linearizing the exact analytical model with respect to the correlation strength. Predictions from the models indicate a strong decrease of P-fail with increasing correlation strength, which is found to be in excellent agreement with results from Monte Carlo simulations. The dependency of P-fail on the track width and scan speed is investigated, confirming previous assumptions about the impact of correlations. Expressions and applicable constraints are derived for the limits of full and no correlations, and the optimal track width to minimize the acquisition time is computed for a range of scan speeds. The model is applicable to optical terminals equipped with a fast beam steering mirror, as often found for optical communications missions in space.

High-performance hard-input LDPC decoding on multi-core devices for optical space links

LDPC codes are a family of error-correcting codes that are present in most space communication standards. Thanks to their large processing power and their parallelization capabilities, prevailing multicore devices facilitate real-time implementations of digital communication systems, which were previously implemented into dedicated hardware devices. Previous works were done over the last decade on the implementation of Gbps decoders on programmable devices. However, these works focus on the soft input LDPC decoding algorithms. But, hard-input LDPC decoders are also required to design and prototype for instance next optical-based satellite communication systems. These systems should provide high throughput (≥10 Gbps) and low latency (≤1ms) internet links. In this article, the first software-based implementation of a hard-input multi-Gbps LDPC decoder is detailed. Thanks to different parallelization strategies and deeply optimized SIMD codes, throughput up to 7.5 Gbps is achieved when 10 Gallager-E iterations are executed onto an INTEL Xeon device making possible the design of software base station systems providing throughputs of tens of Gbps for optical system evaluation or base station design.

Space-Terrestrial Cooperation Over Spatially Correlated Channels Relying on Imperfect Channel Estimates: Uplink Performance Analysis and Optimization

A whole suite of innovative technologies and architectures have emerged in response to the rapid growth of wireless traffic. This paper studies an integrated network design that boosts system capacity through cooperation between wireless access points (APs) and a satellite for enhancing the network’s spectral efficiency. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">As for our analytical contributions</i> , upon coherently combing the signals received by the central processing unit (CPU) from the users through the space and terrestrial links, we first mathematically derive an achievable throughput expression for the uplink (UL) data transmission over spatially correlated Rician channels. Our generic achievable throughput expression is applicable for arbitrary received signal detection techniques employed at the APs and the satellite under realistic imperfect channel estimates. A closed-form expression is then obtained for the ergodic UL data throughput, when maximum ratio combining is utilized for detecting the desired signals. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">As for our resource allocation contributions</i> , we formulate the max-min fairness and total transmit power optimization problems relying on the channel statistics for performing power allocation. The solution of each optimization problem is derived in form of a low-complexity iterative design, in which each data power variable is updated relying on a closed-form expression. Our integrated hybrid network concept allows users to be served that may not otherwise be accommodated due to the excessive data demands. The algorithms proposed allow us to address the congestion issues appearing when at least one user is served at a rate below his/her target. The mathematical analysis is also illustrated with the aid of our numerical results that show the added benefits of considering the space links in terms of improving the ergodic data throughput. Furthermore, the proposed algorithms smoothly circumvent any potential congestion, especially in face of high rate requirements and weak channel conditions.

Ground-to-Drone Optical Pulse Position Modulation Demonstration as a Testbed for Lunar Communications

Free-space optical (FSO) communication promises to bring fibre-like speeds to data transmissions between ground, sky and space. This is becoming more important in light of the increasing volume of data collected by aircraft and spacecraft. The University of Western Australia (UWA) is commissioning optical ground stations to support FSO communications payloads. We propose retroreflected laser links to drones as a useful step towards further ground-to-sky and ground-to-space FSO communications demonstrations. In this paper, we describe the operation of a hardware testbed for a high photon efficiency optical communication physical layer. This testbed was deployed over a slanted free space link to a drone to verify sub-systems required in communication between the ground station and a spacecraft in cis-Lunar space. Accomplishing this verification of the telescope pointing systems and communications systems would have otherwise been much harder or impossible without using a retroreflected drone link.

OTFS-based efficient handover authentication scheme with privacy-preserving for high mobility scenarios

Handover authentication in high mobility scenarios is characterized by frequent and short-term parallel execution. Moreover, the penetration loss and Doppler frequency shift caused by high speed also lead to the deterioration of network link quality. Therefore, high mobility scenarios require handover schemes with less handover overhead. However, some existing schemes that meet this requirement cannot provide strong security guarantees, while some schemes that can provide strong security guarantees have large handover overheads. To solve this dilemma, we propose a privacy-preserving handover authentication scheme that can provide strong security guarantees with less computational cost. Based on Orthogonal Time Frequency Space (OTFS) link and Key Encapsulation Mechanism (KEM), we establish the shared key between protocol entities in the initial authentication phase, thereby reducing the overhead in the handover phase. Our proposed scheme can achieve mutual authentication and key agreement among the user equipment, relay node, and authentication server. We demonstrate that our proposed scheme can achieve user anonymity, unlinkability, perfect forward secrecy, and resistance to various attacks through security analysis including the Tamarin. The performance evaluation results show that our scheme has a small computational cost compared with other schemes and can also provide a strong guarantee of security properties.

Analysis of performance and robustness against jitter of various search methods for acquiring optical links in space: erratum.

This erratum corrects a typing error in Appl. Opt.60, 3936 (2021)APOPAI0003-693510.1364/AO.419594. The correction does not affect the results and conclusions of the original paper.

Correlation between Spatio-Temporal Evolution of Habitat Quality and Human Activity Intensity in Typical Mountain Cities: A Case Study of Guiyang City, China.

The acceleration of the urbanization process brings about the expansion of urban land use, while changes in land-use transformation affect the urban habitat quality, and land-use change brings a threat to regional sustainable development. Against such a backdrop, the assessment of land use on the habitat quality and the relationship between the intensity of human activities is becoming a hot spot in terms of the current land use coordinated with habitat quality. Based on the land-use data of Guiyang in 2000, 2005, 2010, 2015 and 2020, the spatial-temporal evolution characteristics of habitat quality in the study area, combined with the spatial correlation between human activity intensity and habitat quality, were hereby analyzed using the InVEST model. The impact of human activity intensity on habitat quality was correspondingly analyzed. The results show that: (1) From 2000 to 2020, the habitat quality level in Guiyang remained stable without drastic changes, but the changes showed hierarchical distribution and were scattered, mainly reflected in the urban expansion areas of the urban-rural fringe and the key areas of industrial development, and the ecological environment quality fluctuated in a small range. (2) From 2000 to 2020, the intensity of human activities in Guiyang was mainly affected by the relatively concentrated distribution, featuring obvious and significant changes. From 2010 to 2015, the high-impact area surrounded the Guanshan Lake New Area, and the regional habitat quality presented a downward trend. In 2020, the high-impact area of the main urban area and the key industrial development zone was expected to be formed, while the low-impact area was still distributed in forest areas with complex natural conditions. (3) From 2000 to 2020, there was a significant positive correlation between human activity intensity and habitat quality in Guiyang, and such a spatial correlation was weak from 2000 to 2005. The period from 2015 to 2020 witnessed the rapid development of urban construction in Guiyang, human construction activities continue to affect the urban habitat quality. The results show that the intensity of human activities on the promoting function of land use, and the dependencies between them should be considered at the same time, and that explorations on the influence of human activities on land-use intensity and habitat quality of space link are crucial to improving the efficiency of urban land use and ecological environment protection, as well as the coordination between land use and the sustainability of urban development.