• Title/Summary/Keyword: Micro electro mechanical systems - inertial measurement unit

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An Integrated Navigation System Combining INS and Ultrasonic-Speedometer to Overcome GPS-denied Area (GPS 음영 지역 극복을 위한 INS/초음파 속도계 결합 항법 시스템 설계)

  • Choi, Bu-Sung;Yoo, Won-Jae;Kim, La-Woo;Lee, Yu-Dam;Lee, Hyung-Keun
    • Journal of Advanced Navigation Technology
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    • v.23 no.3
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    • pp.228-236
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    • 2019
  • Recently, multi-sensor integration techniques have been actively studied to obtain reliable and accurate navigation solution in GPS (Global Positioning System)-denied harsh environments such as urban canyons, tunnels, and underground roads. In this paper, we propose a low-cost ultrasonic-speedometer utilizing the characteristics of the ultrasonic propagation. An efficient integrated INS (inertial navigation system)/ultrasonic-speedometer navigation system is also proposed to improve the accuracy of positioning in GPS-denied environments. To evaluate the proposed system, car experiments with field-collected measurements were performed. By the experiment results, it was confirmed that the proposed INS/ultrasonic-speedometer system bounds the positioning error growth effectively even though GPS signal is blocked more than 10 seconds and a low-cost MEMS IMU (micro electro mechanical systems inertial measurement unit) is utilized.

A Study on the G-Sensitivity Error of MEMS Vibratory Gyroscopes (진동형 MEMS 자이로스코프 G-민감도 오차에 관한 연구)

  • Park, Byung-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.8
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    • pp.1075-1079
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    • 2014
  • In this paper, we describe the analysis and the compensation method of the g-sensitivity error for MEMS vibratory gyroscopes. Usually, the g-sensitivity error has been ignored in the commercial MEMS gyroscope, but it deserves our attention to apply for the missile application as a tactical grade performance. Thus, it is necessary to compensate for the g-sensitivity error to reach a tactical grade performance. Generally, the g-sensitivity error seems intuitively to be a gyroscope bias error proportional to the linear acceleration. However, we assert that the g-sensitivity error mainly causes not a bias error but a scale-factor error. And we verify that the g-sensitivity scale-factor error occurs due to the non-linearity of parallel plate electrodes. Therefore, we propose the compensation method to remove the g-sensitivity scale-factor error. The experimental result showed that a proposed compensation method improved successfully the performance of the MEMS vibratory gyroscope.

Design of a Compact GPS/MEMS IMU Integrated Navigation Receiver Module for High Dynamic Environment (고기동 환경에 적용 가능한 소형 GPS/MEMS IMU 통합항법 수신모듈 설계)

  • Jeong, Koo-yong;Park, Dae-young;Kim, Seong-min;Lee, Jong-hyuk
    • Journal of Advanced Navigation Technology
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    • v.25 no.1
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    • pp.68-77
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    • 2021
  • In this paper, a GPS/MEMS IMU integrated navigation receiver module capable of operating in a high dynamic environment is designed and fabricated, and the results is confirmed. The designed module is composed of RF receiver unit, inertial measurement unit, signal processing unit, correlator, and navigation S/W. The RF receiver performs the functions of low noise amplification, frequency conversion, filtering, and automatic gain control. The inertial measurement unit collects measurement data from a MEMS class IMU applied with a 3-axis gyroscope, accelerometer, and geomagnetic sensor. In addition, it provides an interface to transmit to the navigation S/W. The signal processing unit and the correlator is implemented with FPGA logic to perform filtering and corrrelation value calculation. Navigation S/W is implemented using the internal CPU of the FPGA. The size of the manufactured module is 95.0×85.0×.12.5mm, the weight is 110g, and the navigation accuracy performance within the specification is confirmed in an environment of 1200m/s and acceleration of 10g.

Performance verification methods of an inertial measurement unit in flight environment using the real time dual-navigation (실시간 다중항법을 이용한 관성측정기의 비행환경 성능 검증 기법)

  • Park, ByungSu;Lee, SangWoo;Jeong, Sang Mun;Han, KyungJun;Yu, Myeong-Jong
    • 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.

GNSS/Multiple IMUs Based Navigation Strategy Using the Mahalanobis Distance in Partially GNSS-denied Environments (GNSS 부분 음영 지역에서 마할라노비스 거리를 이용한 GNSS/다중 IMU 센서 기반 측위 알고리즘)

  • Kim, Jiyeon;Song, Moogeun;Kim, Jaehoon;Lee, Dongik
    • IEMEK Journal of Embedded Systems and Applications
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    • v.17 no.4
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    • pp.239-247
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    • 2022
  • The existing studies on the localization in the GNSS (Global Navigation Satellite System) denied environment usually exploit low-cost MEMS IMU (Micro Electro Mechanical Systems Inertial Measurement Unit) sensors to replace the GNSS signals. However, the navigation system still requires GNSS signals for the normal environment. This paper presents an integrated GNSS/INS (Inertial Navigation System) navigation system which combines GNSS and multiple IMU sensors using extended Kalman filter in partially GNSS-denied environments. The position and velocity of the INS and GNSS are used as the inputs to the integrated navigation system. The Mahalanobis distance is used for novelty detection to detect the outlier of GNSS measurements. When the abnormality is detected in GNSS signals, GNSS data is excluded from the fusion process. The performance of the proposed method is evaluated using MATLAB/Simulink. The simulation results show that the proposed algorithm can achieve a higher degree of positioning accuracy in the partially GNSS-denied environment.

The Extraction Method for the G-Sensitivity Scale-Factor Error of a MEMS Vibratory Gyroscope Using the Inertial Sensor Model (관성센서 오차 모델을 이용한 진동형 MEMS 자이로스코프 G-민감도 환산계수 오차 추출 기법)

  • Park, ByungSu;Han, KyungJun;Lee, SangWoo;Yu, MyeongJong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.6
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    • pp.438-445
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    • 2019
  • In this paper, we present a new approach to extract the g-sensitivity scale-factor error for a MEMS gyroscope. MEMS gyroscopes, based on the use of both angular momentum and the Coriolis effect, have a g-sensitivity error due to mass unbalance. Generally, the g-sensitivity error is not considered in general use of gyroscopes, but it deserves our attention if we are to develop for tactical class performance and reliability. The g-sensitivity error during vehicle flight increases navigation error; so it must be analyzed and compensated for the use of MEMS IMU for high dynamics vehicle systems. Therefore, we analyzed how to extract the g-sensitivity scale-factor error from the inertial sensor error model. Furthermore we propose a new method to extract the g-sensitivity error using flight motion simulator. We verified our proposed method with experimental results.

A Time Synchronization Scheme for Vision/IMU/OBD by GPS (GPS를 활용한 Vision/IMU/OBD 시각동기화 기법)

  • Lim, JoonHoo;Choi, Kwang Ho;Yoo, Won Jae;Kim, La Woo;Lee, Yu Dam;Lee, Hyung Keun
    • Journal of Advanced Navigation Technology
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    • v.21 no.3
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    • pp.251-257
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    • 2017
  • Recently, hybrid positioning system combining GPS, vision sensor, and inertial sensor has drawn many attentions to estimate accurate vehicle positions. Since accurate multi-sensor fusion requires efficient time synchronization, this paper proposes an efficient method to obtain time synchronized measurements of vision sensor, inertial sensor, and OBD device based on GPS time information. In the proposed method, the time and position information is obtained by the GPS receiver, the attitude information is obtained by the inertial sensor, and the speed information is obtained by the OBD device. The obtained time, position, speed, and attitude information is converted to the color information. The color information is inserted to several corner pixels of the corresponding image frame. An experiment was performed with real measurements to evaluate the feasibility of the proposed method.