Dragos George Sandu

The influences of the gyro sensors' errors on the attitude calculus

The paper presents a study about the weight of the different errors of the gyro sensors in the error of attitude angles calculus. For study three types of gyros are selected in order to emphasize the differences in performance currently existing between these categories and the way in which these performances are reflected on to the errors of the attitude angles. To evaluate the errors, the gyros are modeled in Matlab/Simulink using the information from the data sheets and a Savage method to integrate the attitude equation is used. We will further emphasize the influences of noise, bias, gyros accuracy to measure different accelerations and scale factors calibration error.

On the attitude errors when the quaternionic Wilcox method is used

The paper presents a way to determining the attitude by numerical integration of the Poisson attitude quaternionic equation using a dedicated method suggested by Wilcox. The method is implemented in a Matlab/simulink S-function and simulated with the help of a model for different types of inputs. There is also presented an evaluation of attitude errors for applied inputs and their variation surfaces depending on the time and angular speed.

Navigation in non-inertial terrestrial frames using the attitude matrices

The paper presents a numerical algorithm used to establish the position of a vehicle reported to the Earth s geographical frame. The method we suggest based on the direct integration of the equation of inertial navigation, considering the vehicles attitude as a result of the integration of the differential matriceal attitude equation. This integration is performed using a quick method, the induced commutation error being avoided with a numerical logistics which implies the usage of the data acquisition card from strap-down gyrometers in the navigation processor

MEMS INS/GPS integrated structure evaluation with experimental data

The paper presents the mathematical and software models associated to a MEMS INS/GPS integrated navigator. As a data fusion method for the integration of the two navigators a Kalman filter is used. During the experimental evaluation of the synergic navigator on the inertial system were not performed calibration and error compensation procedures, the data being entered in the navigation algorithm in the raw form. By carrying out these procedures, it was desired the evaluation of the data fusion algorithm performance under extreme conditions, in which such compensations cannot be effectively done.

Influence determination of the special liquid fuel's physical-chemical parameters over the dynamic behavior of surface-to-air missiles

In the Research and Flight Test Center was developed an instrumentation solution for SAM type 5Ia23 Volhov, which provides a telemetry data link between onboard equipments, mounted on the missile, and a ground station. Using this instrumentation solution was possible to collect the necessary data for a quantitative and qualitative determination of the influence of the special liquid fuels physical-chemical parameters, used in reactive engine with liquid fuels (RELF) powering, over the dynamic behavior of surface-to-air missiles (SAM) type 5Ia23 Volhov, in order to evaluate their operational performances. To be mounted onboard of SAMs the instrumentation solution had to be validated. This process involved completing a complex ground and flight test program. The ground tests were performed to check, on the one hand, the electromagnetic compatibility between communication system equipment of the instrumentation configuration mounted onboard of the missiles and their safety system components, including the specific SAMs firing environmental electromagnetic condition found only in the polygon Capu-Midia, and on the other hand, the functionality of data link on the estimated flight range of the missiles. Dynamic testing was performed through real firings which were executed with two instrumented SAMs type 5Ia23-Volhov. Both firings were executed according with the normal operational firing procedures, on an imitated target which was placed on the middle axe of the firing area of the polygon, in specific initial conditions.

Bi-dimensional position detection using TDOA estimation through cross correlation of the acoustic signals. Part 1: Theoretical background

The paper deals with a positioning acoustic method that uses the time difference of arrival estimation through the cross-correlation techniques. The method will be applied for the determination of the position of the impact points of the air-dropped bombs. Firstly, the acoustic methods for position detection are presented, and the methodology for air dropped bombs impact points position estimation is chosen. The proposed method and the positioning system architecture are described.