• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.339-346
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• 2017

We propose the design of an INS simulated equipment to evaluate the enhanced jamming resistance of an INS-aided GPS receiver with INS, when a jamming signal is injected into a simulated high dynamic platform. We propose the design of a relative cheap INS simulated equipment, instead of an expensive INS simulator connected to GPS simulators. Based on the design, we implement the equipment and setup high dynamic test environment using the equipment to evaluate an INS-aided GPS receiver. In the GPS L1 C/A and L2C simulations that inject jamming signals of the narrow and wide bandwidth into the GPS receiver with and without INS-aided algorithm, we obtain increased jamming resistance performance as +5 dB compared with the GPS receiver without INS-aided algorithm in all kinds of jamming bandwidth. Based on the simulations, we verified that the INS simulated equipment can be used to evaluate the enhanced jamming resistance of INS-aided GPS receivers.

• Journal of the Korea Institute of Military Science and Technology
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• v.1 no.1
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• pp.201-210
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• 1998

Inertial Navigation System(INS) can provide the vehicle position and velocity information using inertial sensor outputs without the use of external aids. Unfortunately INS navigation error increases with time due to inertial sensor errors, and therefore it is desirable to combine INS with external aids such as GPS, TACAN, OMEGA, and etc.. In this paper we propose an integration algorithm of commercial GPS/GLONASS and INS where an adaptive filter for signal processing of GPS/GLONASS receiver and the 12th order Kalman filter for aided strapdown INS(SDINS) we employed. Simulation results show that the proposed adaptive filter can effectively remove a randomly occurring abrupt jump due to sudden corruption of the received satellite signal and that the Kalman filter performs satisfactorily.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.133.1-133
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• 2001

When the signals from satellite vehicles are blocked, it is impossible to provide positioning information. Integrating CDGPS with INS, the performances of output can be greatly improved. In the CDGPS/INS integrated system, the error growth in INS can be efficiently suppressed due to CDGPS. On the contrary, the search range of integer ambiguities can be reduced with the aids of INS. Furthermore, cycle slips in carrier phase measurements can be easily detected using INS. The paper presents a CDGPS/INS integrated system that utilizes CDGPS aided with INS. Using the outputs of CDGPS/INS integration filter, a method to reduce search range of integer ambiguities is proposed. A method to detect cycle slips in carrier phase measurements is ...

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.8
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• pp.739-745
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• 2006

This paper presents performance improvement of the INS velocity-adided GPS carier tracking loop. To this end, INS velocity-aided GPS carrier tracking loop was modeled as a feedfoward and a feedback loop system. In the phase tracking loop, it was shown that the tracking error caused by the dynamic motion of the vehicle can be compensated with the aiding of the INS information irrespective of the loop order and bandwidth. However, the signal trcking error increases as the INS error increases. It was also shown that in order to remove the tracking error caused by INS bias error, more than or equal to 2nd order PLL should be used. Experiments were carried out and the experimental results were compared with the analysis results.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.745-751
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• 2008

This paper presents a framework for GPS/INS/Vision based navigation system of helicopters. GPS/INS coupled algorithm has weak points such as GPS blockage and jamming, while the helicopter is a speedy and high dynamical vehicle amenable to lose the GPS signal. In case of the vision sensor, it is not affected by signal jamming and also navigation error is not accumulated. So, we have implemented an GPS/INS/Vision aided navigation system providing the robust localization suitable for helicopters operating in various environments. The core algorithm is the vision based simultaneous localization and mapping (SLAM) technique. For the verification of the SLAM algorithm, we performed flight tests. From the tests, we confirm the developed system is robust enough under the GPS blockage. The system design, software algorithm, and flight test results are described.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.47-52
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• 2006

Using the equivalent ARMA model representation of the mixed random errors, we propose Klaman filter design methods for aided INS(Inertial Navigation System) which contains the gyroscope mixed random errors. At first step, considering the characteristic of indirect feedback Kalman filter used in the aided INS, we perform the time difference of equivalent ARMA model. Next, according to the order of the time differenced ARMA model, we achieve the state space conversion of that by two methods. If the order of AR part is greater than MA part, we use controllable or observable canonical form. Otherwise, we establish the state apace equation via the method that several step ahead predicts are included in the state variable, where we can derive high and low order models depending on the variable which is compensated from gyroscope output. At final step, we include the state space equation of gyroscope mixed random errors into aided INS Kalman filter model. Through the simulation, we show that both the high and low order filter models proposed give less navigation errors compared to the conventional filter which assume the mixed random errors as white noise.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.794-798
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• 2009

We introduce an implementation of plug-ins on PLUTO. These plug-ins discriminate inflammatory nodules from other types of nodules in chest X-ray CT images. The PLUTO is a common platform for computer-aided diagnosis systems on Microsoft Windows series and it is easy to add new functions as plug-ins. We coded two plug-ins. One of the them calculates features based on medical knowledge. The other plug-in calculates parameters to classify the type of nodules, and it also classifies nodules into inflammatory nodules and others using SVM. These plug-ins are coded using MIST library which is produced at Nagoya University, Japan. In our previous study, the MIST library was parallelized, so that we can utilize a number of CPUs to calculate features and SVM learning/classifying depending on the amount of computation. Using these plug-ins, it became easy to extract features to discriminate inflammatory nodules from other types of nodules and to change parameters for feature extraction and SVM learning/classifying with GUI interface. The accuracy of the classifying result is 100% with 78 solid nodules which contains 43 inflammatory nodules and 35 other type of nodules.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.4
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• pp.362-369
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• 2011

In this paper, vSLAM aided integrated navigation system is implemented and performance analysis of the system is completed via flight test. The system can suppress divergence of position error of INS only system by updating vSLAM correction information when temporary GPS signal outage occurs in bad radio condition. In the flight test, integrated hardware containing GPS, IMU and camera is loaded under RC electric helicopter. Performance of the integrated navigation system is verified by comparing estimated position of INS/vSLAM system with that of INS only system.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.11
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• pp.944-952
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• 2001

Inertial navigation system(INS) errors increase with time due to inertial sensor errors, and therefore it is desired to combine INS with external aids such as GPS. However GPS informations have a randomly abrupt jump due to a sudden corruption of the received satellite signals and environment, and moreover GPS can\`t provide navigation solutions. In this paper, smoothing and prediction schemes are proposed for GPS`s jump or unavailable GPS. The smoothing algorithm which is designed as a scalar adaptive filter, smooths abrupt jump. The prediction algorithm which is proved by Schuler error model of INS, estimates INS error in appropriate time. The outputs of proposed algorithm apply stable measurements to GPS aided INS Kalman filter. Simulations show that the proposed algorithm can effectively remove measurement jump and predict INS error.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.314-320
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• 2016

Inertial navigation system (INS) has used aided systems and sensors to compensate navigation error. Global navigation satellite system (GNSS), velocity measurement sensor (VMS), and radar are commonly used to aid INS. Land navigation system (LNS) also mainly uses VMS when GNSS cannot be used such as at tunnel or on jammed scenario. A straight drive is required when VMS-aided navigation is used, because there is only speed of straight direction whereas no crossways and vertical directions. In local environment, even an expressway has lack of straight drive which is constraint of VMS-aided navigation algorithm. This paper proposes an enhanced VMS-aided navigation algorithm for LNS with indirect drive by restricting filter update condition. Also, there is a result of vehicle test to prove performance of the proposed algorithm.