The paper considers velocity determination using raw carrier phase measurements of GNSS receiver in autonomous mode. This problem is topical for airborne gravimetry [1] because GNSS navigation measurements are essential for it. The idea of the solution is based on differentiating the single differences of carrier phase measurements. The two-step LSM procedure is described. Results from processing the experimental data are analyzed. The paper continues and extends publications [2, 3].

Active development of mass-produced devices with dual-frequency microcircuits capable of processing the code and phase signals from global navigation satellite systems (GNSS) opens up new opportunities for high-precision positioning in geodesy. However, the use of smartphones for such tasks is limited by the lack of data on the position of their antenna phase centers. This paper presents the results of an experiment during which the location of the mean phase center of the GNSS antenna of Huawei P40 Pro smartphone was determined at a point with known coordinates, using the Precise Point Positioning (PPP) method, and the effect of the information obtained on the positioning error was estimated. The study showed that the antenna’s mean phase center is displaced relative to the geometric center of the device by 2.7 cm towards the left edge of the screen, by 1.3 cm deep into the body (from the screen towards the back panel), and by 5.8 cm down from its upper edge. Based on these data, it is possible to correct the systematic positioning errors.

Accurate attitude determination of Unmanned Aerial Vehicles (UAVs) is crucial for autonomous navigation, particularly when relying solely on gyroscope, accelerometer, and magnetometer measurements without utilizing the Global Positioning System (GPS). Reinforcement Learning (RL) has emerged as a promising artificial intelligence technique applicable across various domains. This research introduces a novel approach that leverages RL to enhance the performance of the Extended Kalman Filter (EKF) in attitude estimation. The proposed method depends of RL which uses the Q-Learning model and policy to find best solution to adjust autonomously the measurement noise covariance matrix within the EKF. By establishing a reward mechanism that incentivizes actions minimizing the prediction error relative to true measurements, RL dynamically optimizes the measurement noise covariance matrix. This innovative integration of RL and EKF, referred to as RL-EKF, has been implemented and tested. Results demonstrate that RLEKF significantly outperforms the traditional EKF, yielding marked improvements in attitude estimation accuracy, the improvement ratios showed that selected method is very effective in the field of attitude estimation.

Research and development in the field of automated astrogeodetic optoelectronic systems started in the late 1980s and continues successfully to this day due to the progress in optoelectronic equipment and acquisition of new technologies based on the use of CCD and CMOS image sensors.The article traces the development of astrogeodetic systems, discusses their design and operation principles, composition and main performance characteristics.

The global characteristics of the Earth’s gravity field are refined to the fifth approximation of Molodensky’s theory. The calculations were based on the analytical continuation of free-air gravity anomalies from the Earth’s physical surface to the reference spherical surface passing through the calculated point, using a Taylor series. Maps of digital global models of gravity anomaly vertical gradients to the fifth order are presented, and global correction terms are obtained for quasigeoid heights and deflections of the vertical (DOV) for the first, second, third, fourth, and fifth approximations of Molodensky’s theory.

It is shown that the gradient solution makes it possible to refine the global characteristics of the Earth’s gravity field. When refining quasigeoid heights using the Stokes formula, the second approximation of Molodensky’s theory is sufficient for plains, while for mountainous areas, the fourth one. When refining the DOV components in the plane of the meridian and the first vertical, the standard error increases from the second approximation.

Currently, the field of underwater robotics is actively developing. The scope of tasks performed by autonomous underwater vehicles (AUVs) is expanding, and hence, the requirements for their autonomy are growing. These factors inevitably increase the time and cost of designing control and navigation systems for AUVs; in this connection, mathematical simulation begins to play an increasingly important role. This paper proposes a method for synthesizing a control system for AUVs on the basis of surrogate models formed as a result of numerical simulation. The novelty of the work is that the AUV motion dynamics is represented as modified nonlinear transfer functions with nonlinear time-varying parameters, which are supposed to be determined from the results of numerical simulation. The proposed approach makes it possible to decompose the problem of control algorithm synthesis, reducing it to an optimization problem, taking into consideration the cross-effect of the control loops. This can cause difficulties in the cases that traditional analytical models are used. The implementation of the proposed approach is described on the example of the synthesis of the algorithm for AUV control in the vertical plane when it moves at a specified distance from the seabed. The effectiveness of the method is confirmed in the course of similar mathematical experiments conducted on numerical models.

The scale factor stability of a fiber-optic gyroscope (FOG) directly depends on the stability of the central wavelength of its optical source. Although broadband, highly stable light sources used in high-precision FOGs provide excellent wavelength stability, they are typically bulky, which complicates the miniaturization of FOGs and FOG-based systems. This work investigates the use of a semiconductor laser diode with pulse-frequency current modulation in a navigation-grade FOG. It is shown that this approach provides superior central-wavelength stability (better than 1.6 ppm), resulting in a FOG angle random walk and bias instability of 0.002°/?h and 0.009°/h, respectively. Comparable performance can be obtained in FOGs employing broadband, highly stable light sources.

15-20. 09.2025