Scientists from St. Petersburg Electrotechnical University "LETI" have proposed a unique method that will make it possible to create test benches for calibrating strapdown inertial navigation systems that surpass counterparts. The results of the experimental studies, which confirmed a 15-fold decrease in the standard deviation, are published in the journal Sensors.
Efficient operation of strapdown inertial navigation systems, which are at the core of high-precision control systems of any mobile objects of defense and space industries, is impossible without their calibration. Ground-based calibration of such systems is carried out with the help of test benches. They determine the systematic errors of inertial sensors (gyroscopes and accelerometers) and estimate the error vector on measurements of output signals of inertial systems and data from test benches.
The main task of such equipment is to ensure the high accuracy of measurements required to obtain a reliable result. That is why all modern industrial enterprises engaged in navigation system development are equipped with such test benches.
The efficiency of benches largely depends on the means of angular measurements, which are used to control the motion of the turntable platforms of benches. Usually, angular measurements involve a circular scale – the larger it is, the more accurate the measurement result is. However, the currently known measuring technologies based on radial scales have reached the technological limit, and further improvement of their accuracy is limited by the real size of such scales. Scientists from LETI suggested using a new approach to angular measurements in test benches.
"The fundamentally new concept is based on the use of scales, which are a two-dimensional set of elements with a known location. Angle measurement in this method is performed by registering a 2D mark with the photodetector matrix of a digital camera with appropriate image processing. This makes it possible to form an angle scale on a much smaller area and increase the accuracy of measurements," says Yury Filatov, a research supervisor of the project and head of the Department of Laser Measurement and Navigation Systems at LETI
The angular measurement technologies proposed by LETI scientists will form the basis for the development of a multifunctional series of dynamic test benches for calibration and semi-natural simulation of inertial navigation systems and onboard control equipment.
"Creating stands for calibration and testing of navigation systems is a complex and expensive field. That is why the results of our work will be in demand by Russian industrial enterprises developing navigation systems. We also hope for active cooperation in this field with international companies," notes Yury Filatov.
