Application of Real-Time Kinematic GPS to Clinometer

Abstract

Real-Time Kinematic (RTK) GPS has an ability to fix a position as the cm order by measuring the range from the GPS satellites with the accuracy of the 1/100 order of a carrier wavelength. The authors tried to evaluate the accuracy of the angle measurement of inclination by inferring the accuracy of altitude determination by RTK-GPS. A GPS antenna of user station is mounted on the edge of an oscillating table with 45cm in arm length and about 10s in oscillating period. The temporal variation of altitude agrees very well with the output of the capacitive type clinometer mounted on an oscillating center except the high frequency vibration of about 2cm standard deviation which is measured at the stable condition. The output delay of the fix position is also measured to be 135.90 ms which can be neglected in the measurement of the ship's attitude. The application of the filtering may improve the accuracy in the angle measurement.