SOFTWARE ALGORITHMS FOR LOW-COST STRAPDOWN INERTIAL NAVIGATION SYSTEMS OF SMALL UAV

This review involves the scope of problems, which arise in the developing of simple Strapdown Inertial Navigation Systems (SINS) designated for usage in small UAV and operating with low-cost inertial sensors. These problems include: elaboration of simple algorithms for rotational and translational state maintenance, developing of gyro-free accelerometer-based navigation systems (ASINS), correction of SINS errors on the basis of usage GPS, magnetometers and altimeters, and usage of sensors redundancy for developing fault-tolerant SINS and identification of the faulty sensor. Taking in account some peculiarities of small UAV flight missions (small operation radius of such UAV, restricted time of the flight mission and limited range of fight speeds), it was possible to develop algorithms for integration of differential equations for rotational and translational state maintenance, which allow producing of their solution in quadratures. Kalman filtering problem for GPS/SINS fusion was solved on the basis of the QR-factorization of covariance matrices. The algorithms are proposed for creation of ASINS and problems of relations between accelerometers redundancy, complexity of the ASINS algorithms and eventually the ASINS performance are considered.