scholarly journals Multi-Satellite Relative Navigation Scheme for Microsatellites Using Inter-Satellite Radio Frequency Measurements

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3725
Author(s):  
Shiming Mo ◽  
Xiaojun Jin ◽  
Chen Lin ◽  
Wei Zhang ◽  
Zhaobin Xu ◽  
...  
Keyword(s):  
Radio Frequency ◽  
High Precision ◽  
Satellite Measurement ◽  
Relative Navigation ◽  
Measurement Scheme ◽  
Navigation Algorithm ◽  
Angle Measurements ◽  
Satellite Formations ◽  
Navigation Accuracy ◽  
Navigation Scheme

The inter-satellite relative navigation method—based on radio frequency (RF) range and angle measurements—offers good autonomy and high precision, and has been successfully applied to two-satellite formation missions. However, two main challenges occur when this method is applied to multi-microsatellite formations: (i) the implementation difficulty of the inter-satellite RF angle measurement increases significantly as the number of satellites increases; and (ii) there is no high-precision, scalable RF measurement scheme or corresponding multi-satellite relative navigation algorithm that supports multi-satellite formations. Thus, a novel multi-satellite relative navigation scheme based on inter-satellite RF range and angle measurements is proposed. The measurement layer requires only a small number of chief satellites, and a novel distributed multi-satellite range measurement scheme is adopted to meet the scalability requirement. An inter-satellite relative navigation algorithm for multi-satellite formations is also proposed. This algorithm achieves high-precision relative navigation by fusing the algorithm and measurement layers. Simulation results show that the proposed scheme requires only three chief satellites to perform inter-satellite angle measurements. Moreover, with the typical inter-satellite measurement accuracy and an inter-satellite distance of around 1 km, the proposed scheme achieves a multi-satellite relative navigation accuracy of ~30 cm, which is about the same as the relative navigation accuracy of two-satellite formations. Furthermore, decreasing the number of chief satellites only slightly degrades accuracy, thereby significantly reducing the implementation difficulty of multi-satellite RF angle measurements.

scholarly journals Transverse SINS/DVL Integrated Polar Navigation Algorithm Based on Virtual Sphere Model

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ling Huang ◽  
Xiang Xu ◽  
Heming Zhao ◽  
Haoran Ge
Keyword(s):  
Polar Region ◽  
Integrated Navigation ◽  
Sphere Model ◽  
Integrated Navigation System ◽  
Model Method ◽  
Navigation Algorithm ◽  
Long Time ◽  
Navigation Accuracy ◽  
Navigation Scheme ◽  
Better Than

Due to the principle error caused by the Earth’s sphere model in transverse polar navigation, the ellipsoid model is usually used for transverse transformation. In order to avoid the complex transverse transformation of the ellipsoid model, a virtual sphere model, which can simplify the transformation of the ellipsoid model, is constructed in this paper. With the requirements of high accuracy and long-time navigation for AUV in the polar region, the integrated navigation scheme of SINS/DVL, which is based on the virtual sphere model, is proposed. The proposed method can improve the navigation accuracy and suppress the oscillation error. The error equations of transverse SINS are established based on the virtual sphere model. Then, the transverse SINS/DVL integrated navigation algorithm is derived according to the new error equations. The simulation results show that the navigation accuracy of the proposed method is equivalent with the traditional ellipsoid model method and is better than that of the traditional sphere model method. However, the complexity of the proposed method is simpler than the traditional ellipsoid model method. Moreover, it is verified that the navigation accuracy of SINS/DVL integrated navigation system based on the virtual sphere model meets the requirements of AUV.

scholarly journals Reliable Distributed Integrated Navigation Based on CI during Mars Entry

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Tai-shan Lou ◽  
Nan-hua Chen ◽  
Xiao-qian Wang ◽  
Zhen-dong He ◽  
Jie Liu
Keyword(s):  
Distribution Coefficients ◽  
Information Feedback ◽  
Integrated Navigation ◽  
Fusion Algorithm ◽  
Atmospheric Entry ◽  
Navigation Algorithm ◽  
Distributed Framework ◽  
Navigation Strategy ◽  
Navigation Accuracy ◽  
Navigation Scheme

A reliable distributed covariance intersection (CI) fusion integrated navigation algorithm with information feedback during the Mars atmospheric entry is proposed to meet robust, reliable, and high-precision Mars atmospheric entry navigation strategy. A distributed integrated navigation scheme includes four independent subsystems consisting of an IMU and one radio beacon, but each subsystem is weakly observable under limited Mars entry measurements. The scalar weights are fast obtained by maximizing the information contribution of the corresponding estimate. The distributed framework based upon the CI fusion algorithm is designed by using dynamic information distribution coefficients and information feedback strategy. This distributed fusion approach could meet the lower computation cost and robust and reliable capacity and especially is beneficial to the weakly observable or unobservable subsystems during the Mars entry navigation scheme. Numerical simulations show that the proposed distributed CI fusion integrated navigation algorithm can provide consistent navigation accuracy for the Mars entry vehicle and improve the entry navigation robustness under the weakly observable navigation subsystems.

Performance Analysis and Validation of Precision Multisatellite RF Measurement Scheme for Microsatellite Formations

2021 ◽  
Author(s):  
Chen Lin ◽  
Xiaojun Jin ◽  
Shiming Mo ◽  
Cong Hou ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Multiple Access ◽  
High Performance ◽  
Large Scale ◽  
Measurement Accuracy ◽  
Media Access Control ◽  
Satellite Measurement ◽  
Measurement Scheme ◽  
Rf Measurement ◽  
Code Division Multiple ◽  
Time Division

Abstract Almost all existing studies on inter-satellite radio frequency (RF) measurement have focused on two-satellite formations. Although some frequency division multiple access and code division multiple access multisatellite RF measurement schemes have been proposed, their poor scalability does not satisfy the inter-satellite measurement requirements of multisatellite formations, especially large-scale formations. Two-way ranging (TWR), which is based on a time division mechanism, is an effective solution that has been used for inter-satellite links in the global positioning system and Beidou navigation constellations. However, the high measurement accuracy achieved with TWR in these navigation constellations is heavily reliant on high-performance atomic clocks and the assistance of navigation ephemeris, which are not available on microsatellite platforms. This work focuses on a scalable multisatellite measurement scheme that adopts a distributed broadcast-based time division multiple access mechanism as the media access control layer and uses an asymmetric double-side TWR method as the physical layer. The measurement performance of the proposed scheme is evaluated through in-depth theoretical modeling, simulation verification, and experimental validation, along with a comprehensive comparison with the conventional TWR method. The experimental results show that centimeter-level measurement accuracy can be achieved with the proposed scheme when only a common miniaturized frequency source is used. This accuracy level is two orders of magnitude better than that of the TWR method, and thus satisfies the application requirements of general large-scale microsatellite formations.

scholarly journals UWB fastly-tunable 0.5-50 GHz RF transmitter based on integrated photonics

2021 ◽  
Author(s):  
Fabio Falconi ◽  
Claudio Porzi ◽  
Filippo Scotti ◽  
Giovanni Serafino ◽  
Antonio Malacarne ◽  
...  
Keyword(s):  
Power Consumption ◽  
Radio Frequency ◽  
High Precision ◽  
Life Style ◽  
State Of The Art ◽  
Ultra Wideband ◽  
Robot Localization ◽  
Rf Transmitter ◽  
And Control ◽  
Large Tunability

Abstract In the last decade, the interest in software-defined ultra-wideband (UWB) and tunable radio frequency (RF) apparatuses with low size, weight, and power consumption (SWaP), has grown dramatically, pushed by the new 6G vision where, RF equipment shall enable a large number of fundamental applications as UWB communications, robot localization mapping and control and high precision radars, all of them contributing in revolutionizing our life style. Unfortunately, the coexistence of ultra-wideband and software-defined operation, tunability and low SWaP represents a big issue in the current RF technologies. In this article, to the best of our knowledge, the first example of a complete tunable software-defined RF transmitter with low footprint (i.e. on photonic chip) is presented exceeding the state-of-the-art for the extremely large tunability range of 0.5-50 GHz without any parallelization of narrower-band components and with fast tuning (<200micros). This first implementation, represents a breakthrough in microwave photonics.

Planning and Navigation by a Mobile Robot in the Presence of Multiple Moving Obstacles and Their Velocities

1996 ◽  
Vol 8 (1) ◽  
pp. 58-66 ◽  
Author(s):  
Takashi Tsubouchi ◽  
◽  
Tomohide Naniwa ◽  
Suguru Arimoto ◽  
◽  
...  
Keyword(s):  
Mobile Robot ◽  
Computer Simulations ◽  
Constant Velocity ◽  
Moving Obstacles ◽  
Navigation Algorithm ◽  
Planning Approach ◽  
Feasible Path ◽  
Navigation Scheme

This paper presents a navigation scheme for a mobile robot which works even in an environment with multiple moving obstacles. An “iterated forecast and planning” approach is proposed by the authors. It is assumed that each obstacle moves at a constant velocity in the approach. The most feasible path for a robot is planned in (x,y,t) space. The planning and motion execution according to the plan are iterated frequently to cope with changes of motion of the moving obstacles. The behavior of the proposed navigation algorithm is also presented by means of computer simulations.

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