• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.155-163
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• 1992

The phased array antenna has the ability to perform adaptive sampling by directing the radar beam without inertia in any direction. The adaptive sampling capability of the phased array antenna allows each sampling time interval to be varied for each target, depending on the acceleration of each target at any time. In this paper we design a three-dimensional adaptive tracking algorithm for the phased array radar system with a given set of measurement parameters. The tracking algorithm avoids taking unnecessarily frequent samples, while keeping the angular prediction error within a fraction of antenna beamwidth so that the probability of detection will not be degraded during a track update illuminations. In our algorithm, the target model and the sampling rate are selected depending on the target range and the target maneuver status which is determined by a maneuver detector. A detailed simulation is conducted to test the validity of our tracking algorithm for encounter geometries under various conditions of maneuver.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1245-1258
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• 2023

To efficiently manage forest resources, it is essential to deploy multiple unmanned aerial vehicles equipped with various sensors simultaneously. Consequently, the ground control station antenna should not only maintain continuous tracking of the target station but also minimize the impact of radio interference on other unmanned aerial vehicle stations. In this paper, we presented beam forming techniques based on the VPR algorithm within a ground control station constructed using a phased array antenna system. Through simulation experiments in diverse unmanned aerial vehicle operating environments, it was demonstrated that the presented method enables not only the continuous tracking of operational unmanned aerial vehicles but also the suppression of radio interference by establishing a continuous pattern null for multiple operational radio interference sources.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.532-541
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• 2014

The ship-borne mobile down range telemetry antenna system having 4.6 m reflector antenna and 3-axis mounting structure at S-band requires the precise pointing accuracy at sea for the launch mission. Using the LEO satellites tracking, a method to determine and verify the antenna pointing and tracking performance, and to find the pointing bias which dominantly contributes to the pointing inaccuracy, is presented. Based upon the tests conducted on the Jeju sea and Pacific sea, the pointing bias is determined and its origin is also identified as the drift of the heading angle of the gyrocompass. The applied systematic correction taking into account the pointing bias, and the achieved improvement of the pointing accuracy are shown. Thanks to the correction, it is presented that this antenna tracked the launcher(KSLV-I) stably within the required pointing accuracy in the following KSLV-I third launch.

• Journal of IKEEE
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• v.26 no.2
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• pp.211-218
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• 2022

This paper presents a S-band phased array antenna system for receiving LEO satellite telemetry signals. The proposed antenna, which is performed to be beam-tiled along the elevation direction, consists of 16 sub-array assemblies, 16 active circuit modules, a perpendicular feed network and a control/power unit. In order to precisely track an LEO satellite, the developed antenna is placed with its elevation axis along the projected trajectory of the satellite on the earth. The center of antenna aperture is facing to the maximum elevation angle in the LEO trajectory. The beam-tilted angles for tracking LEO satellite are obtained by calculating accurately satellite points. Satellite tracking measurements are carried out in the range of ±30° with the respect to the maximum elevation angle. The S/N ratio of 16.5 dB and the Eb/No of 13.3 dB at the maximum elevation angle are obtained from the measurements. The measured result agrees well with the pre-analyzed system margin.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.1
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• pp.65-74
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• 2002

A three dimension(3D) link analysis is peformed considering multipath effects caused by a reflected signal and the difference angle between the antenna bore-sight and Line-Of-Sight(LOS). In addition, a direction of a receive antenna is determined for a receiver to get maximum signal strength in a telemetry situation. For a fixed receive antenna, the angle is determined to maximize the average Carrier to Noise Ratio(CNR) over the interested part of a trajectory. For a tracking antenna, the angle at every position is selected to give maximum CNR or to direct the boresight to the flying projectile.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2236-2245
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• 1997

The DBS system is being highlighted as actual area for the information societics. Specially, the DBS have been proposed very useful system to access the broading service in more widely sea. But the antenna tracking system for maritime DBS receiving is requried complicated control system because of the those complex motion represented pitching, rolling and yowing etc. Our resesrch target is a development of tracking system to the KOREASEA(MUGUNGWHA-1,2) for the applicated small size shipping. So our development focus was concentrated the two development direction. The first focus was represented low-cost system for popularization of small-size shipping around sea of the Korea peninsula. The second focus was an adaptive possibilities with domestic eqdupiment which was developed satellite receiving for KOREASAT. The anntenna mount is designed a compact size and easy operation use to the Az/El 2-axis type which is operated by step motor. And this mount type is very useful on a ship in the near sea of Korea peninsula. Basic tracking method is used th step-tracking algorithm, and the ship's moving compensation is adapted to the closed loop control method by ship's moving detection of gyro sensor. Control part is consists of converter, countertime, VCO, micro-computer and it's software. Testing the operation by the ship's moving simulator, and algorithm is designed tracking and moving compensation by receiving state.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.12
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• pp.924-934
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• 2018

This paper describes the development and measurement results of C-band planar active phase array antenna for detecting and tracking radar(weapon-locating radar). The antenna is designed with 14 sub-arrays(12 main channels and 2 sidelobe blanking channels and approximately 3,000 elements of transmit-receive channel) to generate transmit and digital receive patterns. Using a near-field measurements facility, G/N, transmit patterns, and received patterns are measured. Receive patterns are implemented with digital beamforming by signal processing. The measurement results demonstrate that antenna design specifications were fulfilled.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.421-421
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• 2000

In this paper, robust two-degree-of-freedom controller for satellite antenna system which tracks reference signal is designed. Two-degree-of-freedom controller consists of a prefilter and a feedback controller to solve trade-off between robust stability and command response. The feedback controller is designed from specifications like stability, disturbance rejection and robustness via H$_{\infty}$ design technique. In the sequel, H$_2$ optimal prefilter is introduced to improve the command response. This suggests a two-step design, with different types of performance specifications at each stage. In practical problems, this may easily lead to a prefilter of unacceptably high order. In order to avoid high order prefilter we use a particular structure in which both the prefilter and the feedback controller share the same dynamics. H$_2$-prefilter technique proposed in this paper is verified by simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.45-47
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• 2013

이동하는 물체와 가시선 통신링크를 유지하기 위해서는 추적안테나 시스템이 필수적이다. 방위각과 고각계산을 위해서는 이동체와 안테나시스템의 GPS값을 이용하는데, 이때 두 좌표계의 동일성을 유지하기 위해서 초기에 지자기센서나 beacon등을 이용하여 보정을 하게된다. 하지만 지형적으로 지자기교란이 생기기 쉬운 장소에서는 정확한 보정이 어렵다. 따라서 본 논문에서는 초기에 RF신호의 수신세기추적을 통해서 신호의 발생 위치를 검출하고 검출된 위치까지의 방위각 보정값을 계산하여 통신링크개설 후 수신된 GPS값에 보정값을 적용하는 추적안테나 시스템구현에 대해 기술한다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.10
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• pp.951-959
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• 2011

In this study, an OTM(on-the-move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite while moving was addressed. Since LOS(line-of-sight) of antenna should direct satellite consistently while vehicle moving to guarantee high satellite communication quality, active antenna LOS stabilization is a core technology for OTM antenna. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. In consideration of driving mechanism which consists of gear train and flexible driving shafts, a two-mass-system dynamic model coupled with vehicle motion was presented. An internal PI-control loop + outer PI-control loop structure has been suggested in order to damp the torsional vibration and stabilize control system. The classical pole-placement method was applied to design control gains. In addition, a vehicle motion compensation control beside of the feedback control loop has been suggested to improve LOS stabilization performances. The feasibility of the proposed control design was verified along with some experimental results.