• Title/Summary/Keyword: Satellite tracking

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A Study of GEO Satellite Identification Using Optical Observation

  • Oh, Youngseok;Jin, Ho
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.53.1-53.1
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    • 2014
  • 본 연구에서는 고궤도 및 원거리 우주물체의 추적 및 관측이 용이한 광학관측 시스템을 이용하여 정지궤도위성을 관측하였고, 광도곡선 분석을 통해 식별정보를 획득하였다. 정지궤도 위성은 자세에어 방법에 따라 회전 안정화 위성과 3축 안정화 위성으로 나뉘며, 3축 안정화 위성은 다시 통신위성과 지구관측 위성 등으로 나뉜다. 회전 안정화 위성의 식별 연구를 위해 중국의 FY-2 위성을 관측대상으로 선정하였고, 3축 안정화 위성의 식별을 위해 한국의 COMS-1 위성을 관측 대상으로 선정하였다. 회전안정화 위성은 Sidereal Tracking Mode로 관측하면 위성의 궤적이 선 모양으로 나타난다. 이때 나타난 궤적의 pixel value 값을 확인하면 일정한 주기로 밝기가 변화 하는 것을 확인할 수 있으며, FFT를 수행하면 위성의 회전율과 회전 주기를 구할 수 있다. 3축 안정화 위성은 Stare Mode로 관측하여 측광하면 광도곡선을 획득할 수 있다. 위성의 형상을 결정하는 본체, 안테나, 태양전지판을 모델링하여 광도곡선 시뮬레이션결과와 비교하면 각각의 형상이 광도곡선에 미치는 영향과 특징을 알 수 있고, 이를 통해 식별정보를 획득할 수 있다. 이상의 분석을 통해 얻은 FY-2위성과 COMS-1 위성의 식별정보를 제시하고 향후 우주물체 식별 연구에 활용하고자 한다.

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Target Object Image Extraction from 3D Space using Stereo Cameras

  • Yoo, Chae-Gon;Jung, Chang-Sung;Hwang, Chi-Jung
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.1678-1680
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    • 2002
  • Stereo matching technique is used in many practical fields like satellite image analysis and computer vision. In this paper, we suggest a method to extract a target object image from a complicated background. For example, human face image can be extracted from random background. This method can be applied to computer vision such as security system, dressing simulation by use of extracted human face, 3D modeling, and security system. Many researches about stereo matching have been performed. Conventional approaches can be categorized into area-based and feature-based method. In this paper, we start from area-based method and apply area tracking using scanning window. Coarse depth information is used for area merging process using area searching data. Finally, we produce a target object image.

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FPGA circuit implementation of despreading delay lack loop for GPS receiver and preformance analysis (GPS 수신기용 역확산 지연 동기 루프의 FPGA 회로 구현과 성능 분석)

  • 강성길;류흥균
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.3
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    • pp.506-514
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    • 1997
  • In this paper, we implement digital circuit of despreading delay lock loop for GPS receiver. The designed system consists of Epoch signal generator, two 13bit correlators which correlates the received C/A code and the locally generated C/A code in the receiver, the C/A code generator which generates C/A code of selected satellite, and the direct digital clock synthesizer which generates the clock of the C/A code generator to control the phase and clock rate, the clock controller, and the clock divider. The designed circuit has the function of the acquisition and tracking by the autocorrelation characteristics of Gold code. The controller generates each other control signals according to the correlation value. The designed circuit is simulated to verify the logic functional performance. By using the simulator STR-2770 that generates the virtual GPS signal, the deigned FPGA chip is verified the circuit performance.

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RDDAFC Algorithm for QPSK Demodulation at Digital DBS Receiver (디지탈 위성방송 수신기를 위한 QPSK 복조용 RDDAFC 알고리즘)

  • Park, K.B.;Hwang, H.
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.1301-1303
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    • 1996
  • A new automatic frequency control(AFC) tracking algorithm, which we call a rotational decision directed AFC(RDDAFC) is proposed for QPSK demodulation at the digital direct broadcasting satellite(DBS). In order to prevent the presence of the residual phase difference between symbols received at k and k-l by the CPAFC[1] as well as the AFC based on $tan^{-1}$ circuit[2], the RDDAFC rotates the decision boundary for the kth received symbol by the frequency detector output of the (k-1)th received symbol before passing through the cross product discriminator. Test results show that the total pull-in time of the RDDAFC and PLL was 0.13msec under a carrier frequency offset of 2.4MHz when S/N equals 2dB.

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Angle-of-Arrival Estimation Algorithm Based on Combined Array Antenna

  • Kim, Tae-yun;Hwang, Suk-seung
    • Journal of Positioning, Navigation, and Timing
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    • v.10 no.2
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    • pp.131-137
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    • 2021
  • The Angle-of-Arrival (AOA) estimation in real time is one of core technologies for the real-time tracking system, such as a radar or a satellite. Although AOA estimation algorithms for various antenna types have been studied, most of them are for the single-shaped array antenna suitable to the specific frequency. In this paper, we propose the cascade AOA estimation algorithm for the combined array antenna with Uniform Rectangular Frame Array (URFA) and Uniform Circular Array (UCA), with the excellent performance for various frequencies. The proposed technique is consisted of Capon for roughly finding AOA groups with multiple signal AOAs and Beamspace Multiple Signal Classification (MUSIC) for estimating the detailed signal AOA in the AOA group, for the combined array antenna. In addition, we provide computer simulation results for verifying the estimation performance of the proposed algorithm.

Design of Multi-Constellation and Multi-Frequency GNSS SDR with Fully Reconfigurable Functionality

  • Song, Young-Jin;Lee, Hak-beom;Won, Jong-Hoon
    • Journal of Positioning, Navigation, and Timing
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    • v.10 no.2
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    • pp.91-102
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    • 2021
  • In this paper, a fully reconfigurable Software Defined Radio (SDR) for multi-constellation and multi-frequency Global Navigation Satellite System (GNSS) receivers is presented. The reconfigurability with respect to the data structure, variability of signal and receiver parameters, and receiver's internal functionality is presented. The configuration file, that is modified to lead to an entirely different operation of the SDR in response to specific target signal scenarios, directly determines the operating characteristics of the SDR. In this manner, receiver designers can effectively reduce the effort to develop many different combinations of multi-constellation and/or multi-frequency GNSS receivers. Finally, the implementation of the presented fully reconfigurable SDR is included with the experimental processing results such as acquisition, tracking, navigation for the received signals in the realistic fields.

Design of a Fully Reconfigurable Multi-Constellation and Multi-Frequency GNSS Signal Generator

  • ByungHyun Choi;Young-Jin Song;Subin Lee;Jong-Hoon Won
    • Journal of Positioning, Navigation, and Timing
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    • v.12 no.3
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    • pp.295-306
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    • 2023
  • This paper presents a multi-frequency and multi-constellation Global Navigation Satellite System (GNSS) signal generator that simulates intermediate frequency level digital signal samples for testing GNSS receivers. GNSS signal generators are ideally suited for testing the performance of GNSS receivers and algorithms under development in the laboratory for specific user locations and environments. The proposed GNSS signal generator features a fully-reconfigurable structure with the ability to adjust signal parameters, which is beneficial to generate desired signal characteristics for multiple scenarios including multi-constellation and frequencies. Successful signal acquisition, tracking, and navigation are demonstrated on a verified Software Defined Radio (SDR) in this study. This work has implications for future studies and advances the research and development of new GNSS signals.

The Individual Discrimination Location Tracking Technology for Multimodal Interaction at the Exhibition (전시 공간에서 다중 인터랙션을 위한 개인식별 위치 측위 기술 연구)

  • Jung, Hyun-Chul;Kim, Nam-Jin;Choi, Lee-Kwon
    • Journal of Intelligence and Information Systems
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    • v.18 no.2
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    • pp.19-28
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    • 2012
  • After the internet era, we are moving to the ubiquitous society. Nowadays the people are interested in the multimodal interaction technology, which enables audience to naturally interact with the computing environment at the exhibitions such as gallery, museum, and park. Also, there are other attempts to provide additional service based on the location information of the audience, or to improve and deploy interaction between subjects and audience by analyzing the using pattern of the people. In order to provide multimodal interaction service to the audience at the exhibition, it is important to distinguish the individuals and trace their location and route. For the location tracking on the outside, GPS is widely used nowadays. GPS is able to get the real time location of the subjects moving fast, so this is one of the important technologies in the field requiring location tracking service. However, as GPS uses the location tracking method using satellites, the service cannot be used on the inside, because it cannot catch the satellite signal. For this reason, the studies about inside location tracking are going on using very short range communication service such as ZigBee, UWB, RFID, as well as using mobile communication network and wireless lan service. However these technologies have shortcomings in that the audience needs to use additional sensor device and it becomes difficult and expensive as the density of the target area gets higher. In addition, the usual exhibition environment has many obstacles for the network, which makes the performance of the system to fall. Above all these things, the biggest problem is that the interaction method using the devices based on the old technologies cannot provide natural service to the users. Plus the system uses sensor recognition method, so multiple users should equip the devices. Therefore, there is the limitation in the number of the users that can use the system simultaneously. In order to make up for these shortcomings, in this study we suggest a technology that gets the exact location information of the users through the location mapping technology using Wi-Fi and 3d camera of the smartphones. We applied the signal amplitude of access point using wireless lan, to develop inside location tracking system with lower price. AP is cheaper than other devices used in other tracking techniques, and by installing the software to the user's mobile device it can be directly used as the tracking system device. We used the Microsoft Kinect sensor for the 3D Camera. Kinect is equippedwith the function discriminating the depth and human information inside the shooting area. Therefore it is appropriate to extract user's body, vector, and acceleration information with low price. We confirm the location of the audience using the cell ID obtained from the Wi-Fi signal. By using smartphones as the basic device for the location service, we solve the problems of additional tagging device and provide environment that multiple users can get the interaction service simultaneously. 3d cameras located at each cell areas get the exact location and status information of the users. The 3d cameras are connected to the Camera Client, calculate the mapping information aligned to each cells, get the exact information of the users, and get the status and pattern information of the audience. The location mapping technique of Camera Client decreases the error rate that occurs on the inside location service, increases accuracy of individual discrimination in the area through the individual discrimination based on body information, and establishes the foundation of the multimodal interaction technology at the exhibition. Calculated data and information enables the users to get the appropriate interaction service through the main server.

Smart Ship Container With M2M Technology (M2M 기술을 이용한 스마트 선박 컨테이너)

  • Sharma, Ronesh;Lee, Seong Ro
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38C no.3
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    • pp.278-287
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    • 2013
  • Modern information technologies continue to provide industries with new and improved methods. With the rapid development of Machine to Machine (M2M) communication, a smart container supply chain management is formed based on high performance sensors, computer vision, Global Positioning System (GPS) satellites, and Globle System for Mobile (GSM) communication. Existing supply chain management has limitation to real time container tracking. This paper focuses on the studies and implementation of real time container chain management with the development of the container identification system and automatic alert system for interrupts and for normal periodical alerts. The concept and methods of smart container modeling are introduced together with the structure explained prior to the implementation of smart container tracking alert system. Firstly, the paper introduces the container code identification and recognition algorithm implemented in visual studio 2010 with Opencv (computer vision library) and Tesseract (OCR engine) for real time operation. Secondly it discusses the current automatic alert system provided for real time container tracking and the limitations of those systems. Finally the paper summarizes the challenges and the possibilities for the future work for real time container tracking solutions with the ubiquitous mobile and satellite network together with the high performance sensors and computer vision. All of those components combine to provide an excellent delivery of supply chain management with outstanding operation and security.