scholarly journals Spacecraft Formation Orbit Estimation Using WLPS-Based Localization

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Shu Ting Goh ◽  
Ossama Abdelkhalik ◽  
Seyed A. (Reza) Zekavat
Keyword(s):  
Antenna Arrays ◽  
High Performance ◽  
Signal Transmission ◽  
Base Station ◽  
Position Estimation ◽  
Absolute Position ◽  
Coverage Area ◽  
Spacecraft Formation ◽  
Spacecraft Formation Flying ◽  
Local Positioning System

This paper studies the implementation of a novel wireless local positioning system (WLPS) for spacecraft formation flying to maintain high-performance spacecraft relative and absolute position estimation. A WLPS equipped with antenna arrays allows each spacecraft to measure the relative range and coordinate angle(s) of other spacecraft located in its coverage area. The dynamic base station and the transponder of WLPS enable spacecraft to localize each other in the formation. Because the signal travels roundtrip in WLPS, and due to the high spacecraft velocities, the signal transmission time delay reduces the localization performance. This work studies spacecraft formation positions estimation performance assuming that only WLPS is available onboard. The feasibility of estimating the spacecraft absolute position using only one-dimensional antenna array is also investigated. The effect of including GPS measurements in addition to WLPS is studied and compared to a GPS standalone system.

scholarly journals Parametric codebook design for efficient signal transmission using uniform circular arrays

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Junsik Shin ◽  
Junyeub Suh ◽  
Sangchun Park ◽  
Wonjin Sung
Keyword(s):  
Antenna Arrays ◽  
Channel Model ◽  
Mimo Systems ◽  
Signal Transmission ◽  
Multiple Input Multiple Output ◽  
Base Station ◽  
Step Size ◽  
Codebook Design ◽  
Construction Methods ◽  
Planar Array

AbstractIn order to improve the quality of the received signal and system spectral efficiency, accurate beamforming using a given antenna array is essential for multiple-input multiple-output (MIMO) systems. To obtain desired MIMO transmission performance, construction of codebooks which are composed of matching beamforming vectors to the array structure is important. To effectively cover different types of mobile traffic, the base station for 5G new radio employs antenna arrays in various sizes and shapes. Nevertheless, the codebooks adopted by the 3GPP standard so far are based on the uniform linear array and the uniform planar array, necessitating design techniques for a wider class of antenna arrays. In this paper, we propose codebook construction methods for the uniform circular array with parameters to flexibly set the initial phase and step size based on the channel characteristics of the user equipment (UE). When tested over the 3GPP spatial channel model, the proposed codebooks show a substantial amount of gain over the conventional codebooks in all UE locations within the cell.

scholarly journals Implementation of a Differential Geometric Filter for Spacecraft Formation Orbit Estimation

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Shu Ting Goh ◽  
Ossama Abdelkhalik ◽  
Seyed A. (Reza) Zekavat
Keyword(s):  
Kalman Filter ◽  
Convergence Rate ◽  
Extended Kalman Filter ◽  
Positioning System ◽  
Absolute Position ◽  
Spacecraft Formation ◽  
Stability Performance ◽  
Local Positioning System ◽  
The Absolute ◽  
Orbit Estimation

The differential geometric filter is implemented to estimate the absolute and relative positions of the spacecraft in a formation. The extended Kalman Filter is also implemented as a benchmark for the differential geometric estimation. Only relative positions between the spacecraft are measured. Relative positions are measured using a wireless local positioning system (WLPS) installed in all spacecraft. Two different scenarios are studied: (1) the observations include WLPS measurements only and (2) the observations include WLPS measurements in addition to measurements for the absolute position of one spacecraft made by a radar that takes measurements from the earth’s surface. Results show that the differential geometric estimation has better stability performance and a faster convergence rate compared to the extended Kalman filter.

scholarly journals Distributed Attitude Synchronization for Spacecraft Formation Flying via Event-Triggered Control

2021 ◽  
Vol 11 (14) ◽  
pp. 6299
Author(s):  
Xiong Xie ◽  
Tao Sheng ◽  
Liang He
Keyword(s):  
Control System ◽  
Formation Flying ◽  
Spacecraft Formation ◽  
Spacecraft Formation Flying ◽  
Control Scheme ◽  
Event Triggering ◽  
Computational Resources ◽  
Update Frequency ◽  
Attitude Synchronization ◽  
Event Triggered

The distributed attitude synchronization control problem for spacecraft formation flying subject to limited energy and computational resources is addressed based on event-triggered mechanism. Firstly, a distributed event-driven controller is designed to achieve attitude coordination with the limitation of energy and computing resources. Under the proposed control strategy, the controller is only updated at the event triggering instants, which effectively reduces the update frequency. Subsequently, an event-triggered strategy is developed to further decrease energy consumption and the amount of computation. The proposed event-triggered function only requires the latest state information about its neighbors, implying that the trigger threshold does not need to be calculated continuously. It is shown that the triggering interval between two successive events is strictly positive, showing that the control system has no Zeno phenomenon. Moreover, the update frequency of the proposed controller can be reduced by more than 90% compared to the update frequency of the corresponding time-driven controller with an update frequency of 10 Hz by choosing appropriate control parameters and the control system can still achieve high-precision convergence. Finally, the effectiveness of the constructed control scheme is verified by numerical simulations.

Analysis of the Effect of Tilting Antenna on the Coverage Area of ??the 4G LTE Network (Case Study of Trenggalek District)

2019 ◽  
Vol 9 (4) ◽  
pp. 43-48
Author(s):  
Rizal Aji Istantowi
Keyword(s):  
Base Station ◽  
Base Stations ◽  
Optimal Conditions ◽  
Coverage Area ◽  
Lte Networks ◽  
Lte Network ◽  
Big Cities ◽  
4G Lte ◽  
4G Lte Networks

4G LTE networks in big cities are already well available. Meanwhile, on small to medium-sized cities, the 4G LTE network is not evenly distributed and maximized. This study chooses the variable tilting antenna to the coverage area, because in sending information from a base station using an antenna. The average RSRP value (dBm) of the existing base station in the calculation with a distance of 200 m is -122.90 dBm, a distance of 500 m is -136.79 dBm, and a distance of 1000 m -147.30 dBm. Meanwhile, in the simulation with a distance of 200 m of -108.22 dBm, a distance of 500 m of -121.81 dBm, and a distance of 1000 m of -132.69 dBm. The coverage area value of the existing base station in the calculation is 5.29%, while in the simulation it is 11.18%. The average RSRP value (dBm) at optimal conditions for calculations at a distance of 200 m is -80.13 dBm, at a distance of 500 m is -94.03 dBm and at a distance of 1000 m is -104.56 dBm. Meanwhile, the simulation at a distance of 200 m is -98.09 dBm, at a distance of 500 m is -112.79 dBm and at a distance of 1000 m is -123.31 dBm. The value of the coverage area for the calculation is 20.32%, while for the simulation it is 15.01%. The current need for base stations in Trenggalek District that has been met is 68%.

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