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Traditional pseudo‐satellite‐based indoor positioning techniques are greatly affected by the presence of multipath effects, leading to a notable reduction in the positioning precision. In order to tackle this challenge, a pseudo‐satellite indoor positioning method based on deep learning is proposed. The method grids the localization region, thus transforming positioning from a regression problem to a classification problem in the gridded areas. 1D‐convolutional neural network is employed to extract the correlation between pseudo‐satellite data and the positioning of indoor areas. Data are collected and the method is validated in three types of areas of the experimental field, namely unobstructed area, semi‐unobstructed area and obstructed area. The experimental results demonstrate that the method exhibits superior positioning accuracy compared to traditional methods, enabling effective localization even in obstructed area. [ABSTRACT FROM AUTHOR]

Abstract Traditional pseudo‐satellite‐based indoor positioning techniques are greatly affected by the presence of multipath effects, leading to a notable reduction in the positioning precision. In order to tackle this challenge, a pseudo‐satellite indoor positioning method based on deep learning is proposed. The method grids the localization region, thus transforming positioning from a regression problem to a classification problem in the gridded areas. 1D‐convolutional neural network is employed to extract the correlation between pseudo‐satellite data and the positioning of indoor areas. Data are collected and the method is validated in three types of areas of the experimental field, namely unobstructed area, semi‐unobstructed area and obstructed area. The experimental results demonstrate that the method exhibits superior positioning accuracy compared to traditional methods, enabling effective localization even in obstructed area.

This paper analyzes the characteristics of satellite navigation signals received by the high-speed rotating carrier in order to solve the problems existing in the application of satellite navigation receiver in the high-speed rotating carrier, studies the influence of rotation on the received signal amplitude and carrier phase shift. This paper also establishes the received signal amplitude change model and carrier phase shift model under the condition of body rotation. The antenna phase wind-up is proposed to introduce additional carrier phase shift and improve the original system model. Based on the signal model, the system simulation is carried out, and the experimental environment is built for testing, which verifies the necessity and correctness of the system model with antenna phase wind-up, and provides theoretical support for improving the defensive and guiding performance of small-caliber rotating missile.

Satellite navigation is an essential component of the national infrastructure. Space weather and ionospheric conditions are the prime sources of GNSS (global navigation satellite system) positioning, navigation, and timing (PNT) service disruptions and degradations. Protection, toughening, and augmentation (PTA) of GNSS PNT services require novel approaches in ionospheric effects mitigation. Standard global ionospheric correction models fail in the mitigation of high-dynamics and local ionospheric disturbances. Here, we demonstrate that in the case of the short-term fast-developing geomagnetic storm, a machine learning-based environment-aware GNSS ionospheric correction model for sub-equatorial regions may provide a substantial improvement over the existing global Klobuchar model, considered a benchmark. The proposed machine learning-based model utilises just the geomagnetic field density component observations as a predictor to estimate TEC/GNSS ionospheric delay as the prediction model target. Further research is needed to refine the methodology of machine learning model development selection and validation and to establish an architecture-agnostic framework for GNSS PTA development. [ABSTRACT FROM AUTHOR]

This paper investigates the practicality of an autonomous and resilient positional navigation using corner cube reflectors on the lunar surface. The proposed approach stands as an efficient navigation solution when the current system, e.g. GPS, is unavailable due to being attacked, jammed or spoofed by a third party. The paper provides a complete setup of the mathematical models using a nonlinear least squares algorithm and covariance analysis. A study is done that determines how the blockage of the Earth affects the proposed solution’s ability to perform positional navigation. Numerical simulations are presented to show the accuracy, performance and practicality of the proposed solution. The results of the proposed solution are compared with the results of an Earth-based ground station system that uses radio frequency to track the given satellite. The results show that the lunar reflector-based system generates more accurate results than the Earth-based ground station system. [ABSTRACT FROM AUTHOR]

Due to the nonlinear nature of continuous phase modulation (CPM), most existing unambiguous acquisition algorithms are ineffective in eliminating the ambiguity threat faced by semi‐integer CPM signals. To address this issue, this letter proposes an unambiguous acquisition algorithm based on sub‐correlation functions combination (SCFC). The main idea of this algorithm is to decompose the first pulse amplitude modulation waveform derived from the Laurent decomposition into sub‐signal waveforms that are appropriate for CPM signals. The final unambiguous function is obtained by combining the autocorrelation function of the received CPM signal with the sub‐correlation functions derived from the sub‐signal waveforms and the received CPM signal. Simulation results demonstrate that the SCFC algorithm can eliminate the ambiguity threat of semi‐integer CPM signals with relatively minor detection loss. Moreover, the proposed algorithm successfully retains a narrow main peak and exhibits superior multipath resistance. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper aims to develop a theoretical interpretation of how satellite navigation transforms drivers' experience of automotive spaces. The use of satellite navigation has, so far, been predominantly studied from a cognitivist perspective based on the computer model of cognition and the theory of spatial disengagement. Experimental studies have concluded that over-reliance on digital navigation tools diminishes spatial orientation and spatial memory. According to the dominant interpretation, satellite navigation causes disengagement from space. After addressing these approaches, the paper introduces an embodied perspective of satellite navigation. This is accomplished by applying the phenomenology of perception of Maurice Merleau-Ponty, whose notions, such as perception, body schema, motor habit, and virtual body, illuminate otherwise undertheorized dimensions of drivers' spaces. By using digital tools for wayfinding, drivers' body schema, virtual body, and perception of space are modified, thereby enabling an engagement with convoluted 'mesh spaces.' This new term is integral to the interpretation of drivers' spaces, as well as being distinct from that of 'hybrid space,' although both aim to conceptualize spaces, including physical objects and their visual representations. Conclusions will be drawn against the broader context of the mediatization of everyday life. [ABSTRACT FROM AUTHOR]

Copyright of Aero Weaponry is the property of Aero Weaponry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Robust Global Navigation Satellite System (GNSS) factors are introduced into a factor graph optimisation based integrated navigation system to address the challenge of occluded GNSS signals during ship navigation, which leads to increased errors in positioning results. To enhance the robustness of the GNSS tracking loop, a vector tracking method is applied to receiver tracking loop. Then, the Mahalanobis distance was employed to assess the pseudorange residual and identify and reject signals that exhibit anomalies. Specifically, the pseudorange residual is computed as the difference between the predicted pseudorange of the GNSS receiver and the measured pseudorange. Using the historical information in the window, robust GNSS factors were constructed for use in the factor graph. The robust factor graph optimisation method for a shipborne GNSS/Inertial Navigation System integrated navigation system was implemented by constructing robust GNSS factors and Inertial Measurement Unit factors. The experimental results confirm that the positioning accuracy of the proposed method is superior to those of the factor graph optimization and extended Kalman filter.

Abstract Space‐time adaptive processing (STAP) array has found extensive use in the global navigation satellite system for interference suppression. Nevertheless, the conventional space‐time array necessitates multiple antennas and time delay taps, resulting in a heavy burden on both hardware and computation resources. Thus, lowering the cost and complexity of STAP becomes a considerable problem demanding prompt solutions. This work designs a space‐time array reconfiguration scheme based on the joint selection strategy of the antenna and delay tap to address this problem. The reconstructed array can induce a high signal to interference plus noise power ratio (SINR) when using fewer antennas and delay taps. The space‐time correlation coefficient (STCC) is first presented to manifest the influence of reconfiguration on output SINR. Then, we formulate the space‐time array reconfiguration mathematical model, aiming to minimise STCC. Two reconfiguration methods are provided to solve the optimal array configuration of antennas and delay taps that can reach the minimum STCC and maximum SINR. The optimal antenna‐delay tap pairs are finally selected to comprise the reconstructed array. Substantial simulation experiments verify that the presented scheme and strategy are effective and reliable in space‐time array reconfiguration.

Robust Global Navigation Satellite System (GNSS) factors are introduced into a factor graph optimisation based integrated navigation system to address the challenge of occluded GNSS signals during ship navigation, which leads to increased errors in positioning results. To enhance the robustness of the GNSS tracking loop, a vector tracking method is applied to receiver tracking loop. Then, the Mahalanobis distance was employed to assess the pseudorange residual and identify and reject signals that exhibit anomalies. Specifically, the pseudorange residual is computed as the difference between the predicted pseudorange of the GNSS receiver and the measured pseudorange. Using the historical information in the window, robust GNSS factors were constructed for use in the factor graph. The robust factor graph optimisation method for a shipborne GNSS/Inertial Navigation System integrated navigation system was implemented by constructing robust GNSS factors and Inertial Measurement Unit factors. The experimental results confirm that the positioning accuracy of the proposed method is superior to those of the factor graph optimization and extended Kalman filter. [ABSTRACT FROM AUTHOR]

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper proposes a novel method to improve the clock bias short-term prediction accuracy of navigation receivers then solve the problem of low positioning accuracy when the satellite signal quality deteriorates. Considering that the clock bias of a navigation receiver is equivalent to a virtual satellite, the predicted value of clock bias is used to assist navigation receivers in positioning. Consequently, a combined prediction method for navigation receiver clock bias based on Empirical Mode Decomposition (EMD) and Back Propagation Neural Network (BPNN) analysis theory is demonstrated. In view of systematic errors and random errors in the clock bias data from navigation receivers, the EMD method is used to decompose the clock bias data; then, the BPNN prediction method is used to establish a high-precision clock bias prediction model; finally, based on the clock bias prediction value, the three-dimensional positioning of the navigation receiver is realized by expanding the observation equation. The experimental results show that the proposed model is suitable for clock bias time series prediction and providing three-dimensional positioning information meets the requirements of navigation application in the harsh environment of only three satellites. [ABSTRACT FROM AUTHOR]

Copyright of Railway Signalling & Communication Engineering is the property of Railway Signalling & Communication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aiming to establish a long-term presence on the Moon, interest in new and robust communication and navigation capabilities on the lunar surface is greater than ever before. In response, lunar navigation systems (LNS) have been conceptualized and put into action by space agencies. While we expect these services to be fully functional before the late 2020s, many missions are set to begin surface exploration before the initiation of these services. To meet the immediate needs of early missions, our group proposed a small-start technology demonstration mission called the Lunar Navigation CubeSat (LunaCube). The mission aims to demonstrate a LNS transmitter and store-and-forward radio in the vicinity of the Moon and to provide lunar positioning services to lunar surface assets. The project was initiated with funding support from the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) and completed preliminary design and detailed design in 2021 and 2022 respectively. As a result of the design study, the satellites consist of a 6U-size structure, a 50W-class deployed solar panel, a X-band transponder, three-axis attitude control using a star tracker, sun sensors, gyro, reaction wheels, and reaction control system thruster, as well as orbit control using a water-based resistojet. The total wet mass is less than 14 kg. • A dual-satellite lunar navigation system, called LunaCube, is proposed. • LunaCube can provide 50 m user positioning accuracy relative to a reference station. • MDPO algorithm is used to reduce the size and numbers of the navigation satellites. • The system consists of two 6U CubeSats, each with a total wet mass of under 14 kg. [ABSTRACT FROM AUTHOR]

Space‐time adaptive processing (STAP) array has found extensive use in the global navigation satellite system for interference suppression. Nevertheless, the conventional space‐time array necessitates multiple antennas and time delay taps, resulting in a heavy burden on both hardware and computation resources. Thus, lowering the cost and complexity of STAP becomes a considerable problem demanding prompt solutions. This work designs a space‐time array reconfiguration scheme based on the joint selection strategy of the antenna and delay tap to address this problem. The reconstructed array can induce a high signal to interference plus noise power ratio (SINR) when using fewer antennas and delay taps. The space‐time correlation coefficient (STCC) is first presented to manifest the influence of reconfiguration on output SINR. Then, we formulate the space‐time array reconfiguration mathematical model, aiming to minimise STCC. Two reconfiguration methods are provided to solve the optimal array configuration of antennas and delay taps that can reach the minimum STCC and maximum SINR. The optimal antenna‐delay tap pairs are finally selected to comprise the reconstructed array. Substantial simulation experiments verify that the presented scheme and strategy are effective and reliable in space‐time array reconfiguration. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Due to the nonlinear nature of continuous phase modulation (CPM), most existing unambiguous acquisition algorithms are ineffective in eliminating the ambiguity threat faced by semi‐integer CPM signals. To address this issue, this letter proposes an unambiguous acquisition algorithm based on sub‐correlation functions combination (SCFC). The main idea of this algorithm is to decompose the first pulse amplitude modulation waveform derived from the Laurent decomposition into sub‐signal waveforms that are appropriate for CPM signals. The final unambiguous function is obtained by combining the autocorrelation function of the received CPM signal with the sub‐correlation functions derived from the sub‐signal waveforms and the received CPM signal. Simulation results demonstrate that the SCFC algorithm can eliminate the ambiguity threat of semi‐integer CPM signals with relatively minor detection loss. Moreover, the proposed algorithm successfully retains a narrow main peak and exhibits superior multipath resistance.

The vulnerability of Global Navigation Satellite Systems (GNSS) to spoofing limits their widespread use in military security and national economy. Therefore, fast and accurate detection of GNSS spoofing is of great significance. When spoofing cannot be accurately detected in the capture tracking phase, spoofing detection needs to be performed again at the localization solver. In order to detect the spoofing jamming of Global Navigation Satellite System in pseudo-range measurements, a generalized likelihood ratio satellite navigation spoofing detection algorithm based on moving variance is proposed by analyzing the pseudo-ranges cleared by the positioning of global satellite navigation signals. A new data subset is created by calculating the variance of the pseudo-range of different satellites at the same time and moving it forward. The variance is calculated again by this data subset to obtain the moving variance, the generalized likelihood ratio detection model is used to calculate the detection statistics of the pseudo-range movement variance, the detection statistic is then compared to the detection threshold under the condition that the probability of false alarm is $1\times 10 ^{-7}$ , so as to realize the spoofing jamming detection of global satellite navigation receiver for pseudo-range. Taking the software receiver as the experimental platform, the effectiveness of the proposed algorithm is verified by comparing it with two other algorithms. The result show that when the number of spoofed satellites is less than 9, the algorithm has a good detection effect. When the false alarm rate is $1\times 10 ^{-7}$ , the average prediction accuracy rate is kept above 98 %.

This article provides a comprehensive analysis of Ukraine’s satellite navigation development, focusing on the evolution of its legal frameworks in the context of ongoing regional conflict. It examines historical and current aspects of Global Navigation Satellite System (GNSS) development in Ukraine, highlighting the intersection of technological innovation, international cooperation, and Ukraine’s role in global space initiatives. Special attention is paid to the 2023 bill “On State Regulation in the Sphere of Satellite Navigation,” emphasizing its critical role in national security and defense. The article underlines the need for robust legal and regulatory structures, professional expertise, and public-private collaboration to adapt to rapid industry changes and integrate effectively into the global space market.

An analytical review of satellite navigation systems, devices for receiving and processing spatial information, in the context of their use in monitoring and extinguishing fires in the natural environment, is presented. Satellite navigation systems are considered both in terms of user devices and their global organization. Promising Russian and foreign developments in the field of satellite navigation and information transmission are discussed, which can significantly increase the efficiency of fire extinguishing and the safety of fighting fire in the natural environment. The most optimal option for controlling the forces and means of fire extinguishing has been determined, which provides for the construction of a system that combines the possibilities of using both radio and satellite communication channels. This approach will significantly improve the safety of monitoring and fighting wildfires, as well as organizing a modern reliable and independent decision support system, thereby significantly improving the quality and economic efficiency of forest fire fighting. The necessary changes are proposed that are appropriate to overcome the existing technological gap between Russia and the leading countries in the field of informatization of fighting fires in the natural environment.

In recent years, the concept of autonomous navigation systems has gained substantial significance, with the potential to change the traditional concept of autonomous navigation. The presented numerical simulation investigates the feasibility of a ship's autonomous navigation system through a laser communication infrastructure handled by a two-degrees-of-freedom (DoFs) acquisition, tracking and pointing (ATP) system able to enable ship–satellite data transmission. The methodology introduced presents the geometrical and kinematic delineation of the model, coupled with the implemented control system, aimed at assessing the pointing accuracy. The minimum requested pointing accuracy is 100 µrad and the analysis highlights the need of using methodologies to reduce the pointing error. Two approaches are investigated to examine a possible improvement of the system, and results show that the pointing phase is influenced less by ship motions and more by errors that occur during the satellite's positioning and the ship motion acquisition process. A trade-off in choosing parameters to improve the system's accuracy leads to a satellite's first targeting time of 0.25 s alongside the probability of hitting the target once every 0.0013 s. The reliability of the system is evaluated through a brief sizing of the optical electromechanical component of the system using the trade-off parameters chosen to improve the pointing phase accuracy. [ABSTRACT FROM AUTHOR]

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Satellite navigation is an essential component of the national infrastructure. Space weather and ionospheric conditions are the prime sources of GNSS (global navigation satellite system) positioning, navigation, and timing (PNT) service disruptions and degradations. Protection, toughening, and augmentation (PTA) of GNSS PNT services require novel approaches in ionospheric effects mitigation. Standard global ionospheric correction models fail in the mitigation of high-dynamics and local ionospheric disturbances. Here, we demonstrate that in the case of the short-term fast-developing geomagnetic storm, a machine learning-based environment-aware GNSS ionospheric correction model for sub-equatorial regions may provide a substantial improvement over the existing global Klobuchar model, considered a benchmark. The proposed machine learning-based model utilises just the geomagnetic field density component observations as a predictor to estimate TEC/GNSS ionospheric delay as the prediction model target. Further research is needed to refine the methodology of machine learning model development selection and validation and to establish an architecture-agnostic framework for GNSS PTA development.

Background. The problem of satellite navigation signals’ jamming-protected receivers design is quite relevant due to the high vulnerability of such signals to the influence of interferences whose sources number is constantly increasing. Aim. To design a space-time adaptive filter and to implement its work in real-time as a part of jamming-protected satellite navigation system. Methods. The space-time filtering method fitted for the real-time realization is obtained based on the satellite signal space processing algorithm. The apparatus chosen for the satellite navigation signals reception, the filtering algorithm practical realization and the processed signal demodulation is described. The computer modeling of the signals records filtering and demodulation using the obtained algorithm as well as the real-time experiments in satellite signals processing with different numbers of outer jammers using the constructed jamming-protected receiver are carried out. Results. As a result of modeling and experiments with the designed set the values of performance characteristics of the jamming-protected navigation system are yielded which correspond to a good quality solution of the interference mitigation problem in a satellite navigation signal. Conclusion. The digital processing model based on the obtained space-time filter adequately describes the interference mitigation process in a real satellite signal. The obtained jamming-protected satellite navigation signal receiver is functional and can be used in practice.

Abstract Multilevel and multicarrier component signals are now common in many Global Navigation Satellite Systems challenging the employed multiplexing method that needs to be more flexible and powerful. In this work, the authors demonstrate how, by acting on two parameters of the digital baseband representation of component signals (the sampling frequency and the central frequency of the baseband complex envelope), it is possible to optimise the performance of the multiplexer, while still obtaining a composite signal that fulfils the required system constraints.

Abstract Multipath interference in cities has always been one of the main problems leading to abnormal positioning results of a global navigation satellite system. Vector tracking is superior to conventional scalar tracking in the ability of mitigating multipath interference. However, due to the special sharing structure, fault propagation which easily occurs in the vector tracking loop leads to false alarms of normal satellite signals during multipath detection. To solve this problem, a fault‐tolerant algorithm based on robust estimation is applied to suppress fault propagation. Meanwhile, in order to improve the ability of detecting multiple short delayed multipath signals, chi‐square detection is proposed to be used before applying the fault‐tolerant algorithm. By taking advantage of the characteristic that the occurrence of multipath signals will cause significant deviation of code phase errors, the mean value of code phase errors is used as the detection metric. Both simulation test and field experiment are carried out to verify the detection performance. Experimental results show that the proposed algorithm can effectively prevent fault propagation and solve the problem of false positives of normal satellite signals. As a result, not only multipath signals are detected more accurately, but also more accurate navigation solution is obtained.

The objective of this work is to investigate the Ambiguity Function (AF) characterization of the Iridium L‐band downlink burst transmissions under single burst and multiband multi‐burst mode to demonstrate its suitability and capability as Signal of OPportunity (SoOP) for navigation. The Iridium bursts are collected and examined by demodulating without any prior knowledge for frame verification. The comprehensive analysis and theoretical model of the two mode AFs are presented and verified to evaluate the waveform properties with resolution and sidelobes in both the Doppler and delay domains. Degradation in AF resulting from signal model and multiband channel combination is characterized to exploit the trade‐offs for selection and utilization of the Iridium burst. It has been found that the single burst even with maximum length of 20.32 ms appears available but far from excellent for navigation, while the multiband mode produces significant improvements over the time delay and Doppler resolution as well as a certain degradation on the AF sidelobes. Issues relating to the Iridium bursts utilization have been identified. [ABSTRACT FROM AUTHOR]

With the large-scale usage of satellite navigation, spoofing and jamming are considerable threats to civilian society. Recent developments, such as Galileo's Open Service Navigation Message Authentication and GPS's Chimera, mitigate these risks. However, they provide authentication of the navigation message or ranging code, but not a true position in the case of interference. In critical applications, a protected navigation service is desired, such as Galileo's Public Regulated Service (PRS). PRS provides an access-controlled navigation service for authorized governmental users, with fully encrypted ranging codes and data channels, providing users with higher robustness against interference. The main challenge of implementing PRS on a large scale is the need to protect the cryptographic material that is required to access the PRS signals inside the receiver. For many applications, a stand-alone receiver solution is unnecessary. These applications could use a remote server for PRS. In this methodology, the end-user device has only a radio frequency front-end which sends short samples to a secure server. The (classified) signal processing is then carried out on this secure server, removing the need for the user device to protect cryptographic material. Besides decreasing the device's security requirements and power consumption, it also allows to utilize the advantages of PRS in applications that would otherwise not be able to use PRS. In this approach the PRS usage authorization would only be required for the server operations, and not for the end-user devices. It furthermore allows for using additional processing power for unaided PRS acquisition in case of interference. Within the Netherlands, a remote server solution is developed by CGI: S-TrackS, making PRS accessible. In this paper, the application of PRS and architecture for various use cases is presented. It is shown that PRS usage based on a remote server is feasible and can increase the robustness for governmental applications. [ABSTRACT FROM AUTHOR]

Due to the low signal power of global navigation satellite signals, the receivers are prone to radio frequency interference. Employing multi-antenna arrays is one method to mitigate such effects, by incorporating spatial processing techniques. The large size of the uniform rectangular arrays prevents their use in applications where installation space is limited. Therefore, we proposed a new approach, namely to split one full array into a number of smaller, spatially distributed, sub-arrays to reduce their size and exploit available installation spaces. This concept challenges the distribution of the local oscillator and calibration signals to the respective sub-arrays. This paper compares qualitatively different design concepts for a satellite navigation receiver with two two-element sub-arrays, installed multiple wavelengths apart from each other, in support of establishing an optimal choice for our intended applications in the automotive sector in terms of electrical performance and required hardware and software efforts. In general, weighing the pros and cons of the different concepts, as discussed in the paper, will assist in optimizing the system design approach for a specific application. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of National University of Defense Technology / Guofang Keji Daxue Xuebao is the property of NUDT Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of National University of Defense Technology / Guofang Keji Daxue Xuebao is the property of NUDT Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of National University of Defense Technology / Guofang Keji Daxue Xuebao is the property of NUDT Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The satellite navigation industry is an emerging industry of strategic significance, and formulating long-term, macroscopic, and systematic industrial policies is crucial for the high-quality development of the satellite navigation industry and the formation of a new industrial pattern. The innovation ecosystem theory focuses on the dynamic transition between (1) system composition and elements of the system and (2) system and environment; it can assist the transformation of current policies for China’s satellite navigation industry. Considering relevant requirements of the 14th Five-Year Plan, this study reviews policy documents regarding China’ssatellite navigation industry and analyzes the direct, radial, and systemic coupling relationships between industrial policies and other innovation subjects and subsystems using the innovation ecosystem theory model and focusing on the elements of industrial policies. This study indicates that the current policies require improvement in terms of policy systems and subsystems and are not conducive to the systematic and coupled development of the industry. Therefore, we propose the following suggestions: (1) accelerating the top-level design of legislation and systems; (2) clarifying the role of government; and (3) improving the promotion and application of policies.

Satellite navigation has all-weather, all-time, and low-cost advantages and has become the most widely used means of positioning, navigation, and timing (PNT) service since its inception. However, to avoid excessive reliance on the single means of satellite navigation at the application level, the concept of satellite-independent navigation technology has been proposed and received attention. How to accurately understand the relationship between satellite and satellite-independent navigation technologies has become a realistic and urgent issue. The technological characteristics and system positioning of satellite navigation are summarized in this study. The performances, costs, and application scenarios of typical satellite independent navigation technologies such as inertial navigation, matching navigation, and radio navigation (except for satellite navigation) are comparatively analyzed from a PNT system perspective. The relationship between satellite and satellite-independent navigation technologies is comprehensively analyzed. The overall positioning of satellite navigation as the most common demand satisfied and the core and cornerstone of the PNT system is further clarified. Additionally, the fusion efficiency is quantitatively analyzed. The scientific development of China’s PNT system requires the innovative development of satellite-independent navigation technologies, and the deep integration of satellite and satellite-independent navigation technologies should be promoted. Moreover, the construction of low-orbit navigation systems should be accelerated to improve satellite navigation performance and maximizing system contribution.

The international application of the BeiDou navigation satellite system (BDS) is a new requirement for BDS development in the new development stage; it is also significant for promoting the high-quality development of the Belt and Road, establishing a new development pattern that features domestic and international dual circulations, and promoting global sharing of BDS development achievements. This study explores the internationalization demand for BDS application, examines the development status and trend of global navigation satellite systems, and analyzes the advantages, disadvantages, opportunities, and challenges of BDS internationalization. Moreover, the implications of BDS internationalization are proposed, comprising BDS image, service, application product, and business operation internationalization. The development objectives and specific indicators of BDS internationalization is also clarified. Furthermore, to promote the international application of the BDS, we propose the following suggestions: establishing an overall coordination management mechanism, strengthening product service and supply capabilities, building a multi-level enterprise system, improving the level of international cooperation, increasing the fiscal, taxation, and financial support, coordinating domestic rule of law and that concerning foreign affairs, and encouraging international application and promotion.

Global Navigation Satellite System (GNSS) is an important tool in supporting innovation and developing the economy. The European Union has created two systems: Galileo and EGNOS (European Geostationary Navigation Overlay Service), which enable the localisation of points on the Earth’s surface and in the sky. The GNSS programme offers a range of opportunities for Central and Eastern European societies in which the existence of the E-GNNS (European Global Navigation Satellite System) is still not well known. The article is an attempt to raise awareness of the use of Galileo and EGNOS systems, as well as to present the legal framework concerning this programme and the changes introduced by Regulation (EU) 2021/696 of the European Parliament and of the Council of 28 April 2021. The main research goal is assessing changes in the most crucial areas of this regulation, such as security of the systems, access of third parties, compliance of the provisions with human rights standards, and issues related to budgetary implications which are particularly important for the continuity and stability of E-GNNS.

This paper proposes a novel method to improve the clock bias short-term prediction accuracy of navigation receivers then solve the problem of low positioning accuracy when the satellite signal quality deteriorates. Considering that the clock bias of a navigation receiver is equivalent to a virtual satellite, the predicted value of clock bias is used to assist navigation receivers in positioning. Consequently, a combined prediction method for navigation receiver clock bias based on Empirical Mode Decomposition (EMD) and Back Propagation Neural Network (BPNN) analysis theory is demonstrated. In view of systematic errors and random errors in the clock bias data from navigation receivers, the EMD method is used to decompose the clock bias data; then, the BPNN prediction method is used to establish a high-precision clock bias prediction model; finally, based on the clock bias prediction value, the three-dimensional positioning of the navigation receiver is realized by expanding the observation equation. The experimental results show that the proposed model is suitable for clock bias time series prediction and providing three-dimensional positioning information meets the requirements of navigation application in the harsh environment of only three satellites.

Abstract The objective of this work is to investigate the Ambiguity Function (AF) characterization of the Iridium L‐band downlink burst transmissions under single burst and multiband multi‐burst mode to demonstrate its suitability and capability as Signal of OPportunity (SoOP) for navigation. The Iridium bursts are collected and examined by demodulating without any prior knowledge for frame verification. The comprehensive analysis and theoretical model of the two mode AFs are presented and verified to evaluate the waveform properties with resolution and sidelobes in both the Doppler and delay domains. Degradation in AF resulting from signal model and multiband channel combination is characterized to exploit the trade‐offs for selection and utilization of the Iridium burst. It has been found that the single burst even with maximum length of 20.32 ms appears available but far from excellent for navigation, while the multiband mode produces significant improvements over the time delay and Doppler resolution as well as a certain degradation on the AF sidelobes. Issues relating to the Iridium bursts utilization have been identified.