• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.22 no.3
• /
• pp.217-223
• /
• 2004

In order to improve real-time positioning accuracy, a number of methods have been tested and one of those is the inverted RTK(Real-time kinematic) that gives a precise positioning by handling carrier phase measurements. For the inverted RTK positioning, it needs the L1 phase measurement at least for 1～2 minutes and the additional reference stations/communication system and a data processing server are required. The L1 code and carrier phase measurements for real-time application are used simultaneously and then Kalman filter is applied to estimate integer ambiguities. Double differenced integer ambiguities are resolved by utilizing the FARA(Fast Ambiguity Resolution Approach). In this paper, we propose the method to improve the positioning accuracy and performed the field tests for several baselines from DAEJ reference station in KAO(Korea Astronomy Observatory).

• Journal of Positioning, Navigation, and Timing
• /
• v.10 no.3
• /
• pp.159-168
• /
• 2021

Precise Point Positioning-Real Time Kinematic (PPP-RTK) is an improved PPP method that provides the user receiver with satellite code and phase bias correction information in addition to the satellite orbit and clock, thus enabling single-receiver ambiguity resolution. Single station PPP-RTK concept is special case of PPP-RTK in that corrections are computed, instead of a network, by only one single GNSS receiver. This study is performed to experimentally verify the positioning accuracy performance of single baseline RTK level by a user who utilizes correction for a single station PPP-RTK using dual frequencies. As an experimental result, the horizontal and vertical 95% accuracy was 2.2 cm, 4.4 cm, respectively, which verify the same performance as the single baseline RTK.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.42 no.1
• /
• pp.21-28
• /
• 2005

In this paper, we studied resolution to the FBP(Filtered Back-Propagation) tomographic image reconstruction algorithms. In order to analyze the resolution to the tomographic images, we derived ambiguity function to this algorithm which can be reconstructed from the improved FBP image reconstruction algorithm by using fixed coordinate system practically. Through simulation using this function, we determined the lateral and depth resolution quantitively and then analyzed respectively. Simulation results show that the lateral and depth resolution to the improved FBP image reconstruction algerian was determined $0.27\lambda\;and\;0.70\lambda$ at the 3dB, and also $0.89\lambda\;and\;0.96\lambda$ at the 6dB respectively. This results proved that improved FBP reconstruction algorithms for diffraction tomography of incident planar wave is useful to developed the tomographic image system, analyze the resolution to the tomographic images, we derived ambiguity function to this algerian which can be reconstructed from the improved FBP image reconstruction algorithm by using fixed coordinate system.

• Journal of electromagnetic engineering and science
• /
• v.18 no.3
• /
• pp.199-205
• /
• 2018

In this study, an imaging mode of the modified SweepSAR is proposed with performance analysis for a high-resolution and wide swath coverage. To reduce the overall antenna size required for the solution of the azimuth ambiguity problem, different pulse repetition frequencies (PRFs) are utilized for different transmitters, respectively. For each imaging mode, system performance parameters are used for simulation, analysis, wide swath prediction, and comparison between conventional ScanSAR mode and SweepSAR mode based on scanon-receive (SCORE). The system parameters of AASR, RASR, and NESZ will be estimated and suggested on the imaging mode by using appropriate reflector antenna with the effectiveness of a modified SweepSAR employing dual channels.

• International Journal of Aeronautical and Space Sciences
• /
• v.6 no.2
• /
• pp.17-22
• /
• 2005

As one of validation tool for attitude determination system, we have used various constraints using priori information which is known through base vector set up. However these conventional constraints cannot guarantee validity in terms of final solutions such as Euler angle. So we suggest attitude boundary concept to verify the final attitude solution on the flying airplane, it is based on the combination of velocity based attitude estimation technique and ambiguity resolution. we can say it can check invalid solution effectively at just one epoch without repeatability test of resolved cycle ambiguity. In this paper we show that the suggested constraint can effectively reject incorrectly resolved cycle ambiguity the conventional constraints have missed.

• International Journal of Control, Automation, and Systems
• /
• v.4 no.3
• /
• pp.333-343
• /
• 2006

In this paper, the baseline-length information is directly modeled as a measurement for the Wald test, which speeds up the resolution convergence of the integer ambiguity of GPS carrier phase measurements. The convergent speed improvement is demonstrated using numerical simulation and real experiments. It is also shown that the integer ambiguities can be resolved using only four actual satellite measurements with very reasonable convergence speed, if the baseline-length information is used just like one additional observable satellite measurement. Finally, it is shown that the improvement of convergence speed of the Wald test is due to the increase of the probability ratio with the use of the baseline-length constraint.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2439-2442
• /
• 2000

This paper presents a practical On-The-Fly(OTF) integer ambiguity resolution algorithm for real-time precise positioning with low cost, $L_1$ single frequency, conventional C/A code GPS receiver. A state reconfiguration scheme is adopted in the Kalman filter to deal with the variation of ambiguity states caused by varying sets of visible GPS satellites. The proposed algorithm reduces the ambiguity search space from the coarse m-level C/A code pseudorange measurements of the conventional C/A code reciever, thereby reducing the computational time. Simulation results are presented to show that the algorithm achieves a cm-level accuracy.

• Journal of Arbitration Studies
• /
• v.31 no.3
• /
• pp.25-42
• /
• 2021

Arbitration is an alternative dispute resolution mechanism based on the parties' agreement to resolve any disputes parties may have by arbitration rather than litigation in court. Parties' consent to arbitrate, which must be manifest in the parties' arbitration clause or agreement, is the foundation for arbitration; thus, the language of an arbitration agreement is often of utmost importance in determining the intent of the parties regarding many aspects of arbitration proceedings, such as, the scope of arbitral proceedings, arbitral seat, and authority of arbitral tribunals, among others. Recently, the U.S. Supreme Court held in Lamps Plus, Inc. v. Varela (2019) that ambiguity in arbitration agreement as to availability of class arbitration should be resolved in favor of individual arbitration, and therefore, class arbitration would be precluded. Such holding was met with criticism by four separate dissenting opinions, in which the dissenting Justices have disagreed with the majority's interpretation of the arbitration agreement at issue, as well as, its rejection of application of state law in resolving contractual ambiguity. This article analyzes the Supreme Court's decision and reviews the Court's approach in construction of the arbitration agreement. Nevertheless, because the Supreme Court declined to provide clear guidelines as to precisely what contractual basis is required to permit class arbitration, either silence or ambiguity in arbitration agreements will be resolved by disallowing class arbitration.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.11a
• /
• pp.95-98
• /
• 2004

GPS double difference, carrier phase measurements are ambiguous by an unknown inter number of cycle. High precision, relative GPS positioning can be obtained from a short time span of data if the integer double difference ambiguities can be determined efficiently. In this study, we used a ambiguities resolution method indicated by Clyde Goad. And I compared with ambiguities using Lambda method. The difference of ambiguities between two method is below ${\pm}$1.

• Proceedings of the Korean Information Science Society Conference
• /
• 2010.11a
• /
• pp.46-47
• /
• 2010