Search

Your search keyword '"Brusev, Tihomir"' showing total 19 results
Start Over Author "Brusev, Tihomir"
19 results on '"Brusev, Tihomir"'

1. Study of Global Navigation Satellite System Receivers' Accuracy for Unmanned Vehicles.

Author

Miletiev, Rosen, Petkov, Peter Z., Yordanov, Rumen, and Brusev, Tihomir

Subjects
GLOBAL Positioning System, ANTENNAS (Electronics), KALMAN filtering, AUTONOMOUS vehicles, COVARIANCE matrices
Abstract

The development of unmanned ground vehicles and unmanned aerial vehicles requires high-precision navigation due to the autonomous motion and higher traffic intensity. The existing L1 band GNSS receivers are a good and cheap decision for smartphones, vehicle navigation, fleet management systems, etc., but their accuracy is not good enough for many civilian purposes. At the same time, real-time kinematic (RTK) navigation allows for position precision in a sub-centimeter range, but the system cost significantly narrows this navigation to a very limited area of applications, such as geodesy. A practical solution includes the integration of dual-band GNSS receivers and inertial sensors to solve high-precision navigation tasks, but GNSS position accuracy may significantly affect IMU performance due to having a great impact on Kalman filter performance in unmanned vehicles. The estimation of dilution-of-precision (DOP) parameters is essential for the filter performance as the optimality of the estimation in the filter is closely connected to the quality of a priori information about the noise covariance matrix and measurement noise covariance. In this regard, the current paper analyzes the DOP parameters of the latest generation dual-band GNSS receivers and compares the results with the L1 ones. The study was accomplished using two types of antennas—L1/L5 band patch and wideband helix antennas, which were designed and assembled by the authors. In addition, the study is extended with a comparison of GNSS receivers from different generations but sold on the market by one of the world's leading GNSS manufacturers. The analyses of dilution-of-precision (DOP) parameters show that the introduction of dual-band receivers may significantly increase the navigation precision in a sub-meter range, in addition to multi-constellation signal reception. The fast advances in the performance of the integrated CPU in GNSS receivers allow the number of correlations and tracking satellites to be increased from 8–10 to 24–30, which also significantly improves the position accuracy even of L1-band receivers. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

13. Investigation of Colpitts VCO Designed on 0.35 μm Technology.

Author

Brusev, Tihomir Sashev

Subjects
*VOLTAGE-controlled oscillators, *ELECTRIC oscillators, *ELECTRIC potential, *ELECTRIC admittance, *DIGITAL electronics
Abstract

In this paper is presented Colpitts voltage controlled oscillator (VCO) designed with Cadence on AMS SiGe BiCMOS 0.35 μm technology. The frequency of oscillation fo of VCO is equal to 2.5 GHz, while the supply voltage VDD of the investigated circuits is equal to 2.5 V. The obtained result shows that phase noise of Colpitts VCO is -103 dBc/Hz at a 100kHz offset and -115.6 dBc/Hz at a 400kHz offset. The fo of Colpitts VCO can be adjusted from 2.2 GHz to 2.5 GHz, when control voltage is changed in the range between 2.5 V and 0 V. [ABSTRACT FROM AUTHOR]

Published
2015

14. Layout Design of Switching-mode Amplifier for LTE Applications.

Author

Brusev, Tihomir Sashev and Radonov, Rossen Ivanov

Subjects
*ELECTRONIC amplifiers, *LONG-Term Evolution (Telecommunications), *4G networks, *DATA transmission systems, *ELECTRIC capacity
Abstract

The layout design of hysteresis controlled switching-mode amplifier for fourth generation Long-Term Evolution (4G LTE) applications is presented in this paper. Those circuits are used in envelope amplifiers (EAs) architectures, which supply voltage to the transmitter's power amplifier (PA). The proper layout design can help to improve the overall efficiency of EA, because most of the energy delivered to PAs is supplied by a switching-mode amplifier. The design is made with Cadence using AMS CMOS 4-metal 0.35 μm technology. The investigation and comparison between efficiency results from the simulation of schematic and layout with extracted parasitic devices is performed. [ABSTRACT FROM AUTHOR]

Published
2015

15. Stability Investigation using SPICE of BUCK DC-DC Converter.

Author

Kunov, Georgi Tzvetanov, Gadjeva, Elissaveta Dimitrova, Petkova, Maria Petkova, and Brusev, Tihomir Sachev

Subjects
ELECTRIC current converters, NYQUIST frequency, SAMPLING theorem, TRANSIENT analysis, TRANSFER functions
Abstract

A stability investigation of the BUCK DC-DC converter with Average Current Mode Control is considered in the present paper. A Spice stability investigation equivalent circuit is composed. Using parametric analysis, zeros and poles of the current regulator transfer function are investigated. The optimal values of the compensation network elements for the current regulator are obtained. The stability of the converter operation is validated by Nyquist plot and transient analysis. [ABSTRACT FROM AUTHOR]

Published
2014

18. Design and Implementation of 32-bit Embedded Platform.

Author

Kazakov, Boyko Plamenov, Brusev, Tihomir Sashev, and Nikolova, Boyanka Marinova

Subjects
*EMBEDDED computer systems, *COMPUTERS, *COMPUTER systems, *ELECTRONICS, *COMPUTER software, *COMPUTER input-output equipment
Abstract

In this paper will be examined the methods and solutions for designing 32-bit embedded platform. Main considerations for adapting existing technologies will be overviewed. Glimpse of the core software will be introduced. The Design of the hardware apparatus is established and the achieved results are examined. [ABSTRACT FROM AUTHOR]

Published
2011

19. Investigations of Power Losses in Off-Chip and On-Chip Inductors.

Author

Brusev, Tihomir Sashev, Hristov, Marin Hristov, and Nikolova, Boyanka Marinova

Subjects
*ELECTRIC loss in electric power systems, *DC-to-DC converters, *DIRECT currents, *CASCADE converters, *ELECTRIC power
Abstract

This paper includes investigations of power losses in off-chip and on-chip filter inductors in monolithic dc-dc converter designed on CMOS 0.35 µm technology. Chip coils of the company Murata are used for off-chip inductors. For the extraction of the model's parameters of integrated inductors of CMOS 0.35 µm process is used one of the Cadence tools named "Virtuoso Passive Component Designer". Comparison between power losses in off-chip and on-chip inductors is made. [ABSTRACT FROM AUTHOR]

Published
2010

Catalog

Books, media, physical & digital resources
See catalog results