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Data Integration from GPS and Inertial Navigation Systems for Pedestrians in Urban Area

Bikonis K., Demkowicz J.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2013

Vol. 7, no. 3

401--406

The GPS system is widely used in navigation and the GPS receiver can offer long-term stable absolute positioning information. The overall system performance depends largely on the signal environments. The position obtained from GPS is often degraded due to obstruction and multipath effect caused by buildings, city infrastructure and vegetation, whereas, the current performance achieved by inertial navigation systems (INS) is still relatively poor due to the large inertial sensor errors. The complementary features of GPS and INS are the main reasons why integrated GPS/INS systems are becoming increasingly popular. GPS/INS systems offer a high data rate, high accuracy position and orientation that can work in all environments, particularly those where satellite availability is restricted. In the paper integration algorithm of GPS and INS systems data for pedestrians in urban area is presented. For data integration an Extended Kalman Filter (EKF) algorithm is proposed. Complementary characteristics of GPS and INS with EKF can overcome the problem of huge INS drifts, GPS outages, dense multipath effect and other individual problems associated with these sensors.

The Basic Research for the New Compass System Using Latest MEMS

Fukuda G., Hayashi S.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2010

Vol. 4, no. 3

317--322

This paper demonstrates basic research for a new compass system using latest MEMS (Micro Electro Mechanical Systems) sensors for small vessels. In 2007, MEMS Electrostatically Gyro (ESG) was introduced by TOKYO KEIKI which is a Japanese company. This sensor accuracy has dramatically improved compared to vibration types. For example, instability has been improved 10 times more than the vibration types. The reproducibility was tested and maximum difference was 0.55 [deg/sec] in the field test. The MEMS-ESG could detect the relative angles as accurate as GPS compass in short term use. Even though sen-sor accuracy has been improved, an improvement of another 10 times is needed to detect the earth’s turn rate. Because of this a second system is required for a complete compass system. A celestial navigation system is one of the possibilities to complement this. Traditionally the sextant has been used for measuring the altitude, but it has some human errors and difficult to measure continuously. Therefore, it might be useful to get sun altitude and direction automatically. In this thesis, the sun altitude and direction detecting system using camera devices are studied. Using 350×288 resolution camera and a radio-controlled clock, the sun movement was detected 5’14” per pixels and 2’16”. per pixels for the altitude and direction respectively. Although this is a basic research for an integrated system, the data should have an enormous affect upon future research.