• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.36-45
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• 2017

Abstract It is necessary to verify the properties of an inertial measurement unit in the flight environment before applying to military applications. In this paper, we presented a new approach to verify an inertial measurement unit(IMU) in regard to the performance and the robustness in flight environments for the high-dynamics vehicle systems. We proposed two methods for verification of an IMU. We confirmed normal operation of an IMU and properties in flight environment by using direct comparison method. And we proposed real time multi-navigation system to complement the first method. The proposed method made it possible to compare navigation result at the same time. Therefore, it is easy to analyze the performance of an inertial navigation system and robustness during the vehicle flight. To verify the proposed method, we carried out a flight test as well as an experimental test of flight vibration on the ground. As a result of the experiment, we confirmed flight environment properties of an IMU. Therefore, we shows that the proposed method can serve the reliability improvement of IMU.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.104-112
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• 2005

This paper presents the technique to develop an operational flight program(OFP) of avionic system computer(ASC) which integrates the avionics control, navigation and fire control and provides informations for flight, navigation and weapon aiming missions. For the development of the OFP of ASC, two i960KB chips are used as central processing units board and standard computer interface library(SCIL) which is built in house is used. The Irvine compiler corporation(ICC) integrated development environment(IDE) and the programming language Ada95 are used for the OFP development. We designed the OFP to a computer software configuration item(CSCI) which consists of to three parts for independency of software modules. The OFP has been verified through a series of flight tests. The relevant tests also have been rigorously conducted on the OFP such as software integrated test, and ground functional test.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.5
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• pp.453-463
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• 2001

This paper presents an absolute position estimation method using Indian remote sensing (IRS) satellite images, which is a part of a position estimation (PE) system. The accumulated buffer (AB) matching method is proposed, in which a set of accumulator cells is employed for fast edge-based matching. By computer simulations with two sets of veal aerial image sequences, the performance of the AB matching method is analyzed and its effectiveness is shown in terms of the position error in the hybrid PE system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.133-138
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• 2019

The indoor navigation system using smart phone is a very important infrastructure technology for users' location based services in large indoor facilities. For this purpose, if the user can estimate the movement distance and direction by using the acceleration sensor and the gyro sensor built in the smartphone, the additional external environment is not necessary, which is a very useful technique. This paper deals with indoor navigation system technology that uses Pedestrian Dead Reckoning (PDR) technology and Kalman filter on a general smartphone and allows the user to trace the position while moving the smartphone in front of his chest. In particular, an extended Kalman filter was designed to estimate the direction of movement, and its performance was verified when walking at a constant speed.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.3
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• pp.49-57
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• 2002

In this paper, we deal with a real time implementation of the integrated image-based navigation parameter extraction system using the TMS320C80 MVP(multimedia video processor). Our system consists of relative position estimation and absolute position compensation, which is further divided into high-resolution aerial image matching, DEM(Digital elevation model) matching, and IRS (Indian remote sensing) satellite image matching. Those algorithms are implemented in real time using the MVP. To achieve a real-time operation, an attempt is made to partition the aerial image and process the partitioned images in parallel using the four parallel processors in the MVP. We also examine the performance of the implemented integrated system in terms of the estimation accuracy, confirming a proper operation of the our system.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.3
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• pp.66-77
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• 2002

This paper deals with an implementation of the navigation parameter extraction technique using the TMS320C80 multimedia video processor (MVP). Especially, this Paper focuses on the relative position estimation algorithm which plays an important role in real-time operation of the overall system. Based on the relative position estimation algorithm using the images obtained at two locations, we develop a fast algorithm that can reduce large amount of computation time and fit into fixed-point processors. Then, the algorithm is reconfigured for parallel processing using the 4 parallel processors in the MVP. As a result, we shall demonstrate that the navigation parameter extraction system employing the MVP can operate at full-frame rate, satisfying real-time requirement of the overall system.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.77-81
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• 2008

In the deeply coupled GPS/INS integrated systems, if the integration filter update period is longer than the period of GPS navigation data, the loss of correlation values occurs due to the bit transition. This problem can be resolved when data wipe off(DWO) is used. However, general DWO methods requires heavy computation or cannot be applied continuously. This paper proposes an effective DWO method using carrier phase discriminator In order to show validity of the proposed method, simulations were carried out. The simulation results show that the data bit is accurately estimated and conform that the loss of correlation values and the error of code phase is small.

• Journal of IKEEE
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• v.24 no.2
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• pp.649-653
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• 2020

GPS is a representative satellite navigation system that provides users with accurate location and time information. GPS L1 C / A is opened for civilian and thus utilized in various fields. When the satellite signal reaches the receiver, signal acquisition unit of the digital signal processing hardware searches and acquires the signal among visible satellites. The signal acquisition unit has different implementation methods depending on the signal searching method, such as serial search acquisition, parallel frequency search, parallel code phase search. In this paper, we compare and analyze the three representative acquisition hardwares using live GPS L1 C/A signals. According to the comparison, the parallel code phase search acquisition outperforms the other methods due to reduction of the number of the searchings and a high resolution.

• Journal of Navigation and Port Research
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• v.43 no.3
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• pp.172-178
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• 2019

Although the needs for providing resilient PNT information are increasing, threats due to the intentional RFI or space weather change are challenging to resolve. eLoran, which is a terrestrial navigation system that use a high-power signal is considered as a best back-up navigation system. Depending on the user's environment in the eLoran system, the user may use one of E-field or H-field antennas. H-field antenna, which has no restriction on setting stable ground and is relatively resistant to noise of general electronic equipment, is composed of two loops, and shows anisotropic gain pattern due to the different measurement at the two loops. Therefore, the H-field antenna's phase estimation value of signal varies depending on its direction even at the static environment. The error due to the direction of the signal should be eliminated if the user want to estimate the own position more precisely. In this paper, a method to compensate the error according to the geometric distribution between the H-field antenna and the transmitting station is proposed. A model was developed to compensate the directional error of H-field antenna based on the signal generated from the eLoran signal simulator. The model is then used to the survey measurement performed in the land area and verify its performance.

• Electronics and Telecommunications Trends
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• v.14 no.6 s.60
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• pp.115-126
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• 1999

GPS(Global Positioning System)는 미국방성에서 개발하여 현재 운용중이며 2000년대에는 첨단 교통체계(Intelligent Transport System: ITS) 및 항공관제에도 본격적인 이용이 예상된다. 이러한 GPS는 위성을 이용한 위치, 속도 및 시간 측정서비스를 제공하고 있으며 많은 응용분야로의 적용이 가능하다. 또한, 미국의 GPS 유료화 정책에 따라 세계 각국은 대체 위성 항법시스템의 개발에 많은 노력을 기울이고 있으며, 이를 표준으로 제정하기 위한 노력이 활발히 이루어지고 있다. 따라서, 본 고에서는 GPS에 대한 세계 각국들의 개발 및 표준화 동향과 주요 국제기구에 대하여 알아본다.