The paper considers the filtering problems solved in navigation data processing underquadratic nonlinearities both in system and measurement equations. A Kalman typerecursive algorithm is proposed, where the predicted estimate and gain at each step arecalculated based on the assumption on the Gaussian posterior proba-bility density functionof the estimated vector at the previous step and minimization of estimation error covariancematrix using a linear procedure with respect to the current measurement. The similaritiesbetween this algorithm and other Kalman type algorithms such as extended and secondorderKalman filters are discussed. The procedure for estimating the performance andcomparing the algorithms is presented.

A new adaptive unscented Kalman filter (AUKF) is proposed to estimate the radio navigation parameters of a GPS signal tracking system in noisy environments and on a highly dynamic object. The experimental results have shown that the proposed AUKFbased method improves the GPS tracking margin by approximately 8 dB and 3 dB as compared to the conventional algorithm and the KF-based tracking, respectively. At the same time, the accuracy of Doppler frequency measurements increases as well.

We examine two aspects specific to complex data fusion algorithms in integrated strapdown inertial navigation systems aided by global positioning systems, with their inherent spatial separation between the GNSS antenna phase center and the inertial measurement unit, as well as with the timing skew between their measurements. The first aspect refers to modifications of mathematical models used in INS/GNSS integration. The second one relates to our experience in their application in onboard airborne navigation algorithms developed by Moscow Institute of Electromechanics and Automatics

25 years ago, the CSRI Elektropribor proposed to use a gimballess electrostatic gyroscope (ESG) in spacecraft attitude reference systems. The system called BIS-EG passed the first flight tests in 2004. By 2013, 20 such systems had been manufactured for three types of spacecraft. The flight tests and regular operation of BIS-EG revealed a number of limitations inherent in them; at the same time, calibration methods were developed and tested and the ways of improving the system accuracy and reliability were identified. As a consequence, BIS-EG was upgraded for the next generation spacecraft, and it is still in operation. Its distinctive features are higher reliability, the gyroscope of greater stability, and the possibility of in-flight calibration of its drift model. The next modification of the BIS-EG, which is under development now, must meet the requirements for higher accuracy characteristics and the need to work in the unpressurized spacecraft compartment. The stages and methods for improving the gimballess ESG and BIS-EG family systems are described, as well as the results of their operation in accordance with their purposes in different types of spacecraft.

The paper presents a method for identifying the frame of a star sensor (SS), based on determination of the star local features allowing its unique recognition. The star identifiers are located in a multidimensional integer feature space, and the relevant feature catalog presents a disperse array, which provides search-free star determination. Examples of onboard implementation of feature catalog are presented, containing the stars up to magnitude of six. The required memory is estimated, and a method is proposed for compressing the feature catalog to be recorded in the onboard computer memory. The frame identification algorithm using the reduced feature catalog is described in detail. The algorithm was tested on real sky frames.

The paper presents a brief history of preparation for and execution of the first manned flight into space in the Vostok spacecraft. The main tasks and challenges which were solved to make this historical event possible are discussed. Further achievements of Russian manned cosmonautics are presented, including the first world’s orbital station Salyut which was constructed and launched in orbit 50 years ago. The human role in executing a space flight is studied. The tasks in the space orbit are discussed, the solutions to which with the participation of the crew have improved the space flight safety and efficiency. Examples of cosmonauts’ operations during the flights of the orbital stations Salyut, the orbital facility Mir, and the International Space Station are given to illustrate such tasks. The importance of cosmonauts’ participation in the research and experiments on the orbital stations is demonstrated, and positive examples of such participation are provided.