A Filter Design for Reducing Altitude Measurement Errors Arising during Aircraft Landing
송대범Dae Bum Song,임상석Sang Seok Lim
3(2) 97-107, 1999
송대범Dae Bum Song,임상석Sang Seok Lim
DOI: JANT Vol.3(No.2) 97-107, 1999
Passive sensors such as Laser Range Finder(LRE) and Forward Looking Infrared(FLIR) camera frequently used for tracking aircraft landing produce the measurements of elevation angle contaminated by large noise due to the exhaust plume disturbance. This results in poor tracking performance if the extended Kalman filter is used for estimation of the range and elevation which are corrupted by the non-Gaussian noise such as plume disturbance. In this paper, an adaptive estimation filter and the extended Kalman filter is combined to produce a combination-type filter. In this approach the adaptive filter is used for the plume-type disturbance noise and the extended Kalman filter is utilized for the measurement of Gaussian type. The proposed combination filter is effective for the trajectory estimation of landing aircraft under the influence of unknown bias and numerical simulations illustrate the performance of the proposed filter.
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Flight Test of Helicopter Landing System Using Real-time DGPS
박성민Sung Min Park,김정한Jung Han Kim,황덕호Duk Ho Whang,장재규Jae Gyu Jang,기창돈Chang Don Kee,박형택Hyoung Taek Park,박홍만Hong Man Park,이창효Chang Hyo Lee
3(2) 108-119, 1999
박성민Sung Min Park,김정한Jung Han Kim,황덕호Duk Ho Whang,장재규Jae Gyu Jang,기창돈Chang Don Kee,박형택Hyoung Taek Park,박홍만Hong Man Park,이창효Chang Hyo Lee
DOI: JANT Vol.3(No.2) 108-119, 1999
In recent, there has been remarkable progress in the field of GPS applications. In a few years, an appreciable number of aircraft will adopt GPS as a landing guidance system because GPS is more economic, more reliable and more accurate than any other aviation systems. In this respect, we have performed several helicopter landing flight tests based on the real-time DGPS system made in SNUGL(Seoul National University GPS Laboratory). From the experimental results, we found seveal problems which should be fixed to adopt DGPS as a aircraft landing guidance system. In this paper, we will introduce the problems found in tests and also suggest modifications to solve the problems. Our modifications can be classified into three parts. The first is about the attitude determination with single GPS antenna. The second deals with the cockpit display module. The display was devised to integrate the Instrument Landing System(ILS) with tunnel-in-the-sky using virtual reality. With the display, pilot can achieve more safe landings. The last part is the digital map. We inserted digital mapinto our system and put direction indicator on the map using position information from GPS. It is very useful for pilot to find airports even in bad weather. Using the newly designed DGPS landing system, we conducted flight test at Kimhae International Airport, Pusan, Korea, It was successful ! Our system can also satisfy Category-I criterion for aircraft landing approach and determine attitude angle with a high level of reliability. It is supported by video materials.
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Implementation of the AFC Circuit for Stable Intermediate Frequency of Radar Receiver
정수영Soo Young Jung,이택경Taek Kyung Lee
3(2) 120-131, 1999
정수영Soo Young Jung,이택경Taek Kyung Lee
DOI: JANT Vol.3(No.2) 120-131, 1999
For the phase measurement in the radar system using the magnetron pulse source, the STALO(Stable Local Oscillator) frequency need to be controlled to provide the stable intermediate frequency. In radar receiver, AFC(Automatic Frequency Control) circuit detects the transmitting frequency change and controls the STALO frequency to keep the intermediate frequency stable. In this paper, we designed and implimented AFC circuits for radar receiver. The frequency deviation is detected and compared with the reference frequency and the STALO frequency is controlled by the digital command signal.
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Development of Autmatic Dependent Surveillance System with Java on Web Environment
윤종호Chong Ho Yoon
3(2) 132-138, 1999
윤종호Chong Ho Yoon
DOI: JANT Vol.3(No.2) 132-138, 1999
This paper describes the development of an automatic dependent surveillance system(ADS) with Java on Web environment. The ADS consists of a server module and a client one. The server module performs a database server for gathering GPS data from airplanes. It also does an Web server function for sending Java applet to clients. The applet enables each client to obtain the current flight information from the server via the Internet without a special client software. This client-server based ADS with Java environment has several advantages over other systems. One is not to need for installing special client software on each client system. The other is its simplicity on system maintenance. The reason why it has simplicity is to require only server program modification including the applet without updating client software. After testing the ADS system with the flight information of a Mooney, we can show that the prototype system can be a candidate for developing commercial products.
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The Coordinate Conversion for Flight Dynamics Simulation
백중환Joong Hwan Baek,황수찬Soo Chan Hwang,김칠영Chil Yong Kim
3(2) 139-146, 1999
백중환Joong Hwan Baek,황수찬Soo Chan Hwang,김칠영Chil Yong Kim
DOI: JANT Vol.3(No.2) 139-146, 1999
A flight simulator is composed of engine, navigation systems and instrument modules. However, two problems exist here. First, the coordinate of each independent module is not same. To solve this problem, we design a method that mutual coordinates are capable of transformation each other. Second, the distance and bearing between two points on the earth are computed in a sphere shape using the spherical trigonometry. However, the computing time is very sever. In this paper, we project the sphere into the planar to reduce the computing time. An experimental result shows that the performance of the proposed method is excellent to both distance and bearing calculations in close region. Also, the computing time is reduced from 4.95 × 10^-4 seconds to 1.648 × 10^-4 seconds.
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Fuel Consumption Estimation for Atmospheric Drag Using LEO Perturbation Analysis
정도희Do Hee Jung,송용규Yong Kyu Song
3(2) 147-155, 1999
정도희Do Hee Jung,송용규Yong Kyu Song
DOI: JANT Vol.3(No.2) 147-155, 1999
In this work variations of orbital parameters are derived from the perturbation equations under Earth oblateness and atmospheric drag. A simple and effective scheme is proposed to compute the required delta v and fuel consumption to compensate for atmospheric drag. The scheme is applied to KOMPSAT example.
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Comparison of Prediction Algorithms in Tracking System of Multiple Vehicles
김인행In Haeng Kim,김회율Whoi Yul Kim
3(2) 156-166, 1999
김인행In Haeng Kim,김회율Whoi Yul Kim
DOI: JANT Vol.3(No.2) 156-166, 1999
In multi-vehicle tracking systems Kalman filter is generally used for tracking vehicles Despite well known advantages of Kalman filter that presents optimality with constraints, it is difficult to track several vehicles in real time simultaneously due to a large number of computations. In this paper, we propose a multi-vehicle tracking system with an adaptive predictor that employs recursive least square algorithm which can be easily implemented for real time application on a transversal filter. The performance of the proposed tracking system is compared to one with Kalman filter using a synthetic sequential image generated by computer graphics and real sequential image taken at intersections. Simulation results show that the proposed tracking system can be applied to track vehicles in real sequential image at the rate of 30 frame/sec on a PC environments without any special hardwares.
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The Performance Improvement Effect of the Convergence Rate and Interference Cancellation in SLC
김은정Eun Jung Kim,김세연Se Yon Kim,이병섭Byung Seub Lee,김진호Jin Ho Kim,박성철Sung Chul Park
3(2) 167-173, 1999
김은정Eun Jung Kim,김세연Se Yon Kim,이병섭Byung Seub Lee,김진호Jin Ho Kim,박성철Sung Chul Park
DOI: JANT Vol.3(No.2) 167-173, 1999
This paper showed the convergence rate and the performance of interference cancellation using Applebaum and DMI algorithms in adaptive sidelobe canceller. Applebaum algorithm is used widely due to simplicity but it has a slow convergence rate and the problem of eigenvalue spread. DMI algorithm conerges rapidly but has computational load and hardware complexithy. We compared the performance and complexity using Applebaum and DMI algorithms in Adaptive SLC that requires rapid convergence rate and the performance and conclude that DMI algorithm is more efficient for adaptive SLC.
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A Study on the Technique to Stabilize a Device with Minimum Degradation of Performances
정명래Myung Rea Chung,이상원Sang Won Lee,김학선Hak Sun Kim,홍신남Shin Nam Hong,이윤현Yun Hyun Lee
3(2) 174-184, 1999
정명래Myung Rea Chung,이상원Sang Won Lee,김학선Hak Sun Kim,홍신남Shin Nam Hong,이윤현Yun Hyun Lee
DOI: JANT Vol.3(No.2) 174-184, 1999
In this paper, the equations which can be used to calculate the minimum series stabilizing resistance and /or the minimum parallel stabilizing conductance using the S parameters of an active device has been derived. The equation derived can be used to design a stabilizing circuit of minimum loss of a maximum available gain of a device when the circuit is adopted. For the case of KGF1254B which can be used at 1.9GHz, the circuit proposed in this paper reduce the maximum available gain by 1㏈, while conventional simple resistor circuit reduce it by 5.2㏈.
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Development of an Wireless Aeronautical Data Link Application System , PDC , for the Korean CNS/ATM
김용중Yong Joong Kim,박효달Hyo Dal Park
3(2) 185-195, 1999
김용중Yong Joong Kim,박효달Hyo Dal Park
DOI: JANT Vol.3(No.2) 185-195, 1999
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