The document summarizes research analyzing the effects of using variable data lengths for signal acquisition in GPS receivers operating in degraded environments. The research compares the signal-to-noise ratio (SNR) and acquisition performance of two acquisition methods - FFT-based circular correlation and zero padding - at different data lengths and signal fading levels. The results show that FFT-based correlation is more robust, achieving a higher SNR and acquiring weaker signals at shorter data lengths compared to zero padding. While both methods estimate the same code phase and Doppler shift, FFT-based correlation produces correlation peaks that are significantly higher in magnitude. The research concludes FFT-based correlation is better suited for signal acquisition in degraded environments.
This paper deals with the hardware implementation of base band (acquisition and tracking) modules of a
GPS receiver using system generator 9.2 has been tried out. The implementation will be tested on Lyrtech (small form factor-software defined radio) platform which consists of 3 layers. The upper layer is the radio frequency (1 GHz) layer, middle layer is the ADACMasterIII layer and the last is digital processing (DSP) layer. The data transfer between the FPGA Virtex-4SX35 and DSP module is done using a TMS320DM6446 Davinci processor. Generation of 17MHz Intermediate frequency has been done. The acquisition module based on parallel code phase search acquisition algorithm has been tried out. The results are being tested for correctness and accuracy. After this the tracking module will be implemented. The results will lead to the development of indigenous GPS receivers with single and multiple channels
within the same hardware with reconfiguration.
This three day course is intended for practicing systems engineers who want to learn how to apply model-driven systems Successful systems engineering requires a broad understanding of the important principles of modern spacecraft communications. This three-day course covers both theory and practice, with emphasis on the important system engineering principles, tradeoffs, and rules of thumb. The latest technologies are covered. <p>
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
ESTIMATION OF SYMBOL TIMING AND CARRIER FREQUENCY OFFSET USING SYNCHRONIZATI...Michael George
OFDM/OQAM is preferred as multicarrier system which operates over a multipath channel. By using the multipath channel the signal-to-noise ratio. In earlier, sub carriers are used to transmit the signals. Nowadays, FFT and DFT are used for transmitting the signals based upon the bit values. AWGN is a channel used to identify the noise produced at the output by adding the noise in the blind signal. By reducing subcarriers the noise and timing are reduced. FFT bit value was increased which provides better performance. In the multicarrier system, the error and noise was reduced by increasing the bit value.
This paper deals with the hardware implementation of base band (acquisition and tracking) modules of a
GPS receiver using system generator 9.2 has been tried out. The implementation will be tested on Lyrtech (small form factor-software defined radio) platform which consists of 3 layers. The upper layer is the radio frequency (1 GHz) layer, middle layer is the ADACMasterIII layer and the last is digital processing (DSP) layer. The data transfer between the FPGA Virtex-4SX35 and DSP module is done using a TMS320DM6446 Davinci processor. Generation of 17MHz Intermediate frequency has been done. The acquisition module based on parallel code phase search acquisition algorithm has been tried out. The results are being tested for correctness and accuracy. After this the tracking module will be implemented. The results will lead to the development of indigenous GPS receivers with single and multiple channels
within the same hardware with reconfiguration.
This three day course is intended for practicing systems engineers who want to learn how to apply model-driven systems Successful systems engineering requires a broad understanding of the important principles of modern spacecraft communications. This three-day course covers both theory and practice, with emphasis on the important system engineering principles, tradeoffs, and rules of thumb. The latest technologies are covered. <p>
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
ESTIMATION OF SYMBOL TIMING AND CARRIER FREQUENCY OFFSET USING SYNCHRONIZATI...Michael George
OFDM/OQAM is preferred as multicarrier system which operates over a multipath channel. By using the multipath channel the signal-to-noise ratio. In earlier, sub carriers are used to transmit the signals. Nowadays, FFT and DFT are used for transmitting the signals based upon the bit values. AWGN is a channel used to identify the noise produced at the output by adding the noise in the blind signal. By reducing subcarriers the noise and timing are reduced. FFT bit value was increased which provides better performance. In the multicarrier system, the error and noise was reduced by increasing the bit value.
Digital broadcast systems have increasingly been deployed for various services such as
Digital Video Broadcasting (i.e. DVB-S, DVB-T, etc.) and Digital Audio Broadcasting (DAB). Classical
digital broadcast systems were designed with fixed modulation techniques, which had to guarantee
reliable communication even with very hostile channel environment. Video Broadcasting is playing a
key role in communication areas. In this paper DVB-T (terrestrial based digital video broadcasting) based
OFDM is analyzed in terms of various parameters for 2K mode.
Keywords:- Digital video broadcasting, DVB-T, orthogonal frequency division multiplexing, OFDM
Hybrid approach to solve the problem of papr in ofdm signal a surveyeSAT Journals
“Orthogonal frequency division multiplexing
method used to achieve the today’s need of wireless communication
3GPP Association for the use of LTE. The
higher data rate, higher bit rate, mitigated delay spread, lower multipath distortion,
OFDM system has few major issues associated with
ratio (PAPR)” associated with the signal.
interleaved OFDM, selective mapping (SLM)
windowing, clipping, filtering, tone rejection(TR), tone injection(TI), compandin
Reduction of Outage Probability in Fast Rayleigh Fading MIMO Channels Using OFDMIJERA Editor
Multiple-input multiple-output (MIMO) techniques are used in wireless communications for achieving high spectral efficiency; however, a fast fading spatial channel can increase the outage probability of a MIMO system if not taken care of. This paper investigates the use of orthogonal frequency division multiplexing (OFDM) modulation technique for a MIMO system operating in fast Rayleigh fading channels with the aim of eliminating outage probabilities in the MIMO systems. Simulation results show that the MIMO-OFDM system gives significant reduction in outage probabilities compared to the conventional MIMO system.
Comparative performance analysis of different modulation techniques for papr ...IJCNCJournal
One of the most important multi-carrier tran
smission techniques used in the latest wireless com
munication
arena is known as Orthogonal Frequency Division Mul
tiplexing (OFDM). It has several characteristics
such as providing greater immunity to multipath fad
ing & impulse noise, eliminating Inter Symbol
Interference (ISI) & Inter Carrier Interference (IC
I) using a guard interval known as Cyclic Prefix (C
P). A
regular difficulty of OFDM signal is high peak to a
verage power ratio (PAPR) which is defined as the r
atio
of the peak power to the average power of OFDM Sign
al. An improved design of amplitude clipping &
filtering technique of us previously reduced signif
icant amount of PAPR with slightly increase bit err
or rate
(BER) compare to an existing method in case of Quad
rature Phase Shift Keying (QPSK) & Quadrature
Amplitude Modulation (QAM). This paper investigates
a comparative performance analysis of the differen
t
higher order modulation techniques on that design.
PHYSICAL LAYER for DIGITAL TELEVISION ATSC 3.0 STANDARD based on SC – FDMA .Roman M. Vitenberg
Described a proposition for Physical Layer of Next generation broadcast television (NGBT) and ATSC 3.0 Television standard. The Proposed system is back compatible with existing ATSC standards A/53, A/153 and based on improved version of SC-FDMA modulation.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Performance Analysis of Post Compensated Long Haul High Speed Coherent Optica...IJECEIAES
This paper addresses the performance analysis of OFDM transmission system based on coherent detection over high speed long haul optical links with high spectral efficiency modulation formats such as Quadrature Amplitude Modulation (QAM) as a mapping method prior to the OFDM multicarrier representation. Post compensation is used to compensate for phase noise effects. Coherent detection for signal transmitted at bit rate of 40 Gbps is successfully achieved up to distance of 3200km. Performance is analyzed in terms of Symbol Error Rate and Error Vector Magnitude by varying Optical Signal to Noise Ratio (OSNR) and varying the length of the fiber i.e transmission distance. Transmission performance is also observed through constellation diagrams at different transmission distances and different OSNRs.
Performance Analysis of Post Compensated Long Haul High Speed Coherent Optica...Yayah Zakaria
This paper addresses the performance analysis of OFDM transmission system based on coherent detection over high speed long haul optical links with high spectral efficiency modulation formats such as Quadrature Amplitude Modulation (QAM) as a mapping method prior to the OFDM multicarrier representation. Post compensation is used to compensate for
phase noise effects. Coherent detection for signal transmitted at bit rate of 40 Gbps is successfully achieved up to distance of 3200km. Performance is analyzed in terms of Symbol Error Rate and Error Vector Magnitude by varying Optical Signal to Noise Ratio (OSNR) and varying the length of the fiber i.e transmission distance. Transmission performance is also observed through constellation diagrams at different transmission distances and
different OSNRs.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Digital broadcast systems have increasingly been deployed for various services such as
Digital Video Broadcasting (i.e. DVB-S, DVB-T, etc.) and Digital Audio Broadcasting (DAB). Classical
digital broadcast systems were designed with fixed modulation techniques, which had to guarantee
reliable communication even with very hostile channel environment. Video Broadcasting is playing a
key role in communication areas. In this paper DVB-T (terrestrial based digital video broadcasting) based
OFDM is analyzed in terms of various parameters for 2K mode.
Keywords:- Digital video broadcasting, DVB-T, orthogonal frequency division multiplexing, OFDM
Hybrid approach to solve the problem of papr in ofdm signal a surveyeSAT Journals
“Orthogonal frequency division multiplexing
method used to achieve the today’s need of wireless communication
3GPP Association for the use of LTE. The
higher data rate, higher bit rate, mitigated delay spread, lower multipath distortion,
OFDM system has few major issues associated with
ratio (PAPR)” associated with the signal.
interleaved OFDM, selective mapping (SLM)
windowing, clipping, filtering, tone rejection(TR), tone injection(TI), compandin
Reduction of Outage Probability in Fast Rayleigh Fading MIMO Channels Using OFDMIJERA Editor
Multiple-input multiple-output (MIMO) techniques are used in wireless communications for achieving high spectral efficiency; however, a fast fading spatial channel can increase the outage probability of a MIMO system if not taken care of. This paper investigates the use of orthogonal frequency division multiplexing (OFDM) modulation technique for a MIMO system operating in fast Rayleigh fading channels with the aim of eliminating outage probabilities in the MIMO systems. Simulation results show that the MIMO-OFDM system gives significant reduction in outage probabilities compared to the conventional MIMO system.
Comparative performance analysis of different modulation techniques for papr ...IJCNCJournal
One of the most important multi-carrier tran
smission techniques used in the latest wireless com
munication
arena is known as Orthogonal Frequency Division Mul
tiplexing (OFDM). It has several characteristics
such as providing greater immunity to multipath fad
ing & impulse noise, eliminating Inter Symbol
Interference (ISI) & Inter Carrier Interference (IC
I) using a guard interval known as Cyclic Prefix (C
P). A
regular difficulty of OFDM signal is high peak to a
verage power ratio (PAPR) which is defined as the r
atio
of the peak power to the average power of OFDM Sign
al. An improved design of amplitude clipping &
filtering technique of us previously reduced signif
icant amount of PAPR with slightly increase bit err
or rate
(BER) compare to an existing method in case of Quad
rature Phase Shift Keying (QPSK) & Quadrature
Amplitude Modulation (QAM). This paper investigates
a comparative performance analysis of the differen
t
higher order modulation techniques on that design.
PHYSICAL LAYER for DIGITAL TELEVISION ATSC 3.0 STANDARD based on SC – FDMA .Roman M. Vitenberg
Described a proposition for Physical Layer of Next generation broadcast television (NGBT) and ATSC 3.0 Television standard. The Proposed system is back compatible with existing ATSC standards A/53, A/153 and based on improved version of SC-FDMA modulation.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Performance Analysis of Post Compensated Long Haul High Speed Coherent Optica...IJECEIAES
This paper addresses the performance analysis of OFDM transmission system based on coherent detection over high speed long haul optical links with high spectral efficiency modulation formats such as Quadrature Amplitude Modulation (QAM) as a mapping method prior to the OFDM multicarrier representation. Post compensation is used to compensate for phase noise effects. Coherent detection for signal transmitted at bit rate of 40 Gbps is successfully achieved up to distance of 3200km. Performance is analyzed in terms of Symbol Error Rate and Error Vector Magnitude by varying Optical Signal to Noise Ratio (OSNR) and varying the length of the fiber i.e transmission distance. Transmission performance is also observed through constellation diagrams at different transmission distances and different OSNRs.
Performance Analysis of Post Compensated Long Haul High Speed Coherent Optica...Yayah Zakaria
This paper addresses the performance analysis of OFDM transmission system based on coherent detection over high speed long haul optical links with high spectral efficiency modulation formats such as Quadrature Amplitude Modulation (QAM) as a mapping method prior to the OFDM multicarrier representation. Post compensation is used to compensate for
phase noise effects. Coherent detection for signal transmitted at bit rate of 40 Gbps is successfully achieved up to distance of 3200km. Performance is analyzed in terms of Symbol Error Rate and Error Vector Magnitude by varying Optical Signal to Noise Ratio (OSNR) and varying the length of the fiber i.e transmission distance. Transmission performance is also observed through constellation diagrams at different transmission distances and
different OSNRs.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Data Quality Analysis of Different Receivers Based on Static Base StationIJRESJOURNAL
ABSTRACT: With the global navigation and positioning system technology in various industries more and more widely used. As a result, higher requirements are made for the performance of GNSS receiver and the quality of receiving data. The quality of the received data is analyzed and compared to the receivers produced by different manufacturers. By comparison, The processing ability and data quality of different receivers for GNSS signals are analyzed. Data is collected for two different receiver from production M300Pro of ComNav and SPS 855 of Trimble. The quality analysis and discussion were carried out by using TEQC and CRU software respectively. The results show that the data quality of the two receivers conforms to the detection experience value, and is analyzed and compared by data quality. The two quality analysis software has Respective advantages. Combining different observation factors analysis that is important for the stable operation of the system and improving the positioning accuracy.
SPS Gold Code Generation and Implementation for IRNSS User ReceiverIJERA Editor
The Indian Regional Navigational Satellite System (IRNSS) with Indian Constellation is an autonomous regional satellite navigation system developed by Indian Space Research Organization (ISRO). In this paper we have implemented the design of SPS gold code on MATLAB2012a and Xilinx ISE 14.7. The properties of SPS (standard positioning system) gold codes have been verified using MATLAB 2012a. It is found that IRNSS gold codes have three valued cross-correlation and four valued autocorrelation in line with theory. It is also found that IRNSS have balanced gold codes. This paper also deals with Hardware implementation of SPS Gold codes on Spartan-II FPGA Kit. The results are verified and analyzed with the PRN properties.
GPS Instrumental Biases Estimation Using Continuous Operating Receivers NetworkCSCJournals
Precise Total Electron Content (TEC) are required to produce accurate spatial and temporal resolution of Global Ionosphere Maps (GIMs). Receivers and Satellites Instrumental Biases (IBs) are one of the main error sources in estimating precise TEC from Global Positioning Systems (GPS) data. Recently, researchers are interested in developing models and algorithms to compute IBs of receivers and satellites close to those computed from the Ionosphere Associated Analysis Centers (IAAC). Here we introduce a MATLAB code called Multi Station IBs Estimation (MSIBE) to calculate satellites and codeless tracking receivers IBs from GPS data. MSIBE based on spherical harmonic function and geometry free combination of GPS carrier phase and pseudo-range code observations and weighted least square were applied to solve observation equations, to improve estimation of IBs values. There are many factors affecting estimated value of IBs. The premier factor is the observations weighting function which relying on the satellite elevation angle. The second factor concerned with estimating IBs using single GPS Station Precise Point Positioning (PPP) or using GPS network. The third factor is the number of GPS receivers in the network. Results from MSIBE were evaluated and compared with data from IAAC and other codes like M_DCB and ZDDCBE. The results of weighted (MSIBE) least square shows an improvement for estimated IBs, where mean differences from CODE less than 0.746 ns. IBs estimated from Continuous Operating Receivers (CORs) GPS network shows a good agreement with IAAC than IBs estimated from PPP where the mean differences are less than 0.1477 ns and 1.1866 ns, respectively. The mean differences of computed IBs improved by increasing number of GPS stations in the network.
A novel fast time jamming analysis transmission selection technique for radar...IJECEIAES
The jamming analysis transmission selection (JATS) sub-system is used in radar systems to detect and avoid the jammed frequencies in the available operating bandwidth during signal transmission and reception. The available time to measure the desired frequency spectrum and select the non-jammed frequency for transmission is very limited. A novel fast time (FAT) technique that measures the channel spectrum, detects the jamming sub-band and selects the non-jammed frequency for radar system transmission in real time is proposed. A JATS sub-system has been designed, simulated, fabricated and implemented based on FAT technique to verify the idea. The novel FAT technique utilizes time-domain analysis instead of the wellknown fast Fourier transform (FFT) used in conventional JATS sub-systems. Therefore, the proposed fast time jamming analysis transmission selection (FAT-JATS) sub-system outperforms other reported JATS sub-systems as it uses less FPGA resources, avoids time-delay occurred due to complex FFT calculations and enhances the real time operation. This makes the proposed technique an excellent candidate for JATS sub-systems.
System Consideration, Design and Implementation of Point To Point Microwave L...ijtsrd
Microwave technology is extremely used for point to point communications because it is more easily focused into narrower beams than radio waves, allowing frequency use, it is available higher data transmission rates and antenna sizes are smaller than at lower frequencies. The main aim of this system is to provide internet access for rural area using ePMP Force 180 5GHz subscriber module. The two sites are 1.45 km away from each other. GPS is used to determine the latitude and longitude of two sites location. Google Earth Pro software is used to check for line of sight in choosing potential terminal site locations. In this system, system consideration, design and analysis of line of sight microwave link and hardware implementations are to be carried out. In the analysis, path profile, Fresnel zone, link budget and other parameters are implemented using the link planner software Lay Nandar Soe | Kyaw Thet Zaw | Wai Phyo Aung "System Consideration, Design and Implementation of Point-To-Point Microwave Link for Internet Access" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26769.pdf Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/26769/system-consideration-design-and-implementation-of-point-to-point-microwave-link-for-internet-access/lay-nandar-soe
Bibliometric analysis highlighting the role of women in addressing climate ch...IJECEIAES
Fossil fuel consumption increased quickly, contributing to climate change
that is evident in unusual flooding and draughts, and global warming. Over
the past ten years, women's involvement in society has grown dramatically,
and they succeeded in playing a noticeable role in reducing climate change.
A bibliometric analysis of data from the last ten years has been carried out to
examine the role of women in addressing the climate change. The analysis's
findings discussed the relevant to the sustainable development goals (SDGs),
particularly SDG 7 and SDG 13. The results considered contributions made
by women in the various sectors while taking geographic dispersion into
account. The bibliometric analysis delves into topics including women's
leadership in environmental groups, their involvement in policymaking, their
contributions to sustainable development projects, and the influence of
gender diversity on attempts to mitigate climate change. This study's results
highlight how women have influenced policies and actions related to climate
change, point out areas of research deficiency and recommendations on how
to increase role of the women in addressing the climate change and
achieving sustainability. To achieve more successful results, this initiative
aims to highlight the significance of gender equality and encourage
inclusivity in climate change decision-making processes.
Voltage and frequency control of microgrid in presence of micro-turbine inter...IJECEIAES
The active and reactive load changes have a significant impact on voltage
and frequency. In this paper, in order to stabilize the microgrid (MG) against
load variations in islanding mode, the active and reactive power of all
distributed generators (DGs), including energy storage (battery), diesel
generator, and micro-turbine, are controlled. The micro-turbine generator is
connected to MG through a three-phase to three-phase matrix converter, and
the droop control method is applied for controlling the voltage and
frequency of MG. In addition, a method is introduced for voltage and
frequency control of micro-turbines in the transition state from gridconnected mode to islanding mode. A novel switching strategy of the matrix
converter is used for converting the high-frequency output voltage of the
micro-turbine to the grid-side frequency of the utility system. Moreover,
using the switching strategy, the low-order harmonics in the output current
and voltage are not produced, and consequently, the size of the output filter
would be reduced. In fact, the suggested control strategy is load-independent
and has no frequency conversion restrictions. The proposed approach for
voltage and frequency regulation demonstrates exceptional performance and
favorable response across various load alteration scenarios. The suggested
strategy is examined in several scenarios in the MG test systems, and the
simulation results are addressed.
Enhancing battery system identification: nonlinear autoregressive modeling fo...IJECEIAES
Precisely characterizing Li-ion batteries is essential for optimizing their
performance, enhancing safety, and prolonging their lifespan across various
applications, such as electric vehicles and renewable energy systems. This
article introduces an innovative nonlinear methodology for system
identification of a Li-ion battery, employing a nonlinear autoregressive with
exogenous inputs (NARX) model. The proposed approach integrates the
benefits of nonlinear modeling with the adaptability of the NARX structure,
facilitating a more comprehensive representation of the intricate
electrochemical processes within the battery. Experimental data collected
from a Li-ion battery operating under diverse scenarios are employed to
validate the effectiveness of the proposed methodology. The identified
NARX model exhibits superior accuracy in predicting the battery's behavior
compared to traditional linear models. This study underscores the
importance of accounting for nonlinearities in battery modeling, providing
insights into the intricate relationships between state-of-charge, voltage, and
current under dynamic conditions.
Smart grid deployment: from a bibliometric analysis to a surveyIJECEIAES
Smart grids are one of the last decades' innovations in electrical energy.
They bring relevant advantages compared to the traditional grid and
significant interest from the research community. Assessing the field's
evolution is essential to propose guidelines for facing new and future smart
grid challenges. In addition, knowing the main technologies involved in the
deployment of smart grids (SGs) is important to highlight possible
shortcomings that can be mitigated by developing new tools. This paper
contributes to the research trends mentioned above by focusing on two
objectives. First, a bibliometric analysis is presented to give an overview of
the current research level about smart grid deployment. Second, a survey of
the main technological approaches used for smart grid implementation and
their contributions are highlighted. To that effect, we searched the Web of
Science (WoS), and the Scopus databases. We obtained 5,663 documents
from WoS and 7,215 from Scopus on smart grid implementation or
deployment. With the extraction limitation in the Scopus database, 5,872 of
the 7,215 documents were extracted using a multi-step process. These two
datasets have been analyzed using a bibliometric tool called bibliometrix.
The main outputs are presented with some recommendations for future
research.
Use of analytical hierarchy process for selecting and prioritizing islanding ...IJECEIAES
One of the problems that are associated to power systems is islanding
condition, which must be rapidly and properly detected to prevent any
negative consequences on the system's protection, stability, and security.
This paper offers a thorough overview of several islanding detection
strategies, which are divided into two categories: classic approaches,
including local and remote approaches, and modern techniques, including
techniques based on signal processing and computational intelligence.
Additionally, each approach is compared and assessed based on several
factors, including implementation costs, non-detected zones, declining
power quality, and response times using the analytical hierarchy process
(AHP). The multi-criteria decision-making analysis shows that the overall
weight of passive methods (24.7%), active methods (7.8%), hybrid methods
(5.6%), remote methods (14.5%), signal processing-based methods (26.6%),
and computational intelligent-based methods (20.8%) based on the
comparison of all criteria together. Thus, it can be seen from the total weight
that hybrid approaches are the least suitable to be chosen, while signal
processing-based methods are the most appropriate islanding detection
method to be selected and implemented in power system with respect to the
aforementioned factors. Using Expert Choice software, the proposed
hierarchy model is studied and examined.
Enhancing of single-stage grid-connected photovoltaic system using fuzzy logi...IJECEIAES
The power generated by photovoltaic (PV) systems is influenced by
environmental factors. This variability hampers the control and utilization of
solar cells' peak output. In this study, a single-stage grid-connected PV
system is designed to enhance power quality. Our approach employs fuzzy
logic in the direct power control (DPC) of a three-phase voltage source
inverter (VSI), enabling seamless integration of the PV connected to the
grid. Additionally, a fuzzy logic-based maximum power point tracking
(MPPT) controller is adopted, which outperforms traditional methods like
incremental conductance (INC) in enhancing solar cell efficiency and
minimizing the response time. Moreover, the inverter's real-time active and
reactive power is directly managed to achieve a unity power factor (UPF).
The system's performance is assessed through MATLAB/Simulink
implementation, showing marked improvement over conventional methods,
particularly in steady-state and varying weather conditions. For solar
irradiances of 500 and 1,000 W/m2
, the results show that the proposed
method reduces the total harmonic distortion (THD) of the injected current
to the grid by approximately 46% and 38% compared to conventional
methods, respectively. Furthermore, we compare the simulation results with
IEEE standards to evaluate the system's grid compatibility.
Enhancing photovoltaic system maximum power point tracking with fuzzy logic-b...IJECEIAES
Photovoltaic systems have emerged as a promising energy resource that
caters to the future needs of society, owing to their renewable, inexhaustible,
and cost-free nature. The power output of these systems relies on solar cell
radiation and temperature. In order to mitigate the dependence on
atmospheric conditions and enhance power tracking, a conventional
approach has been improved by integrating various methods. To optimize
the generation of electricity from solar systems, the maximum power point
tracking (MPPT) technique is employed. To overcome limitations such as
steady-state voltage oscillations and improve transient response, two
traditional MPPT methods, namely fuzzy logic controller (FLC) and perturb
and observe (P&O), have been modified. This research paper aims to
simulate and validate the step size of the proposed modified P&O and FLC
techniques within the MPPT algorithm using MATLAB/Simulink for
efficient power tracking in photovoltaic systems.
Adaptive synchronous sliding control for a robot manipulator based on neural ...IJECEIAES
Robot manipulators have become important equipment in production lines, medical fields, and transportation. Improving the quality of trajectory tracking for
robot hands is always an attractive topic in the research community. This is a
challenging problem because robot manipulators are complex nonlinear systems
and are often subject to fluctuations in loads and external disturbances. This
article proposes an adaptive synchronous sliding control scheme to improve trajectory tracking performance for a robot manipulator. The proposed controller
ensures that the positions of the joints track the desired trajectory, synchronize
the errors, and significantly reduces chattering. First, the synchronous tracking
errors and synchronous sliding surfaces are presented. Second, the synchronous
tracking error dynamics are determined. Third, a robust adaptive control law is
designed,the unknown components of the model are estimated online by the neural network, and the parameters of the switching elements are selected by fuzzy
logic. The built algorithm ensures that the tracking and approximation errors
are ultimately uniformly bounded (UUB). Finally, the effectiveness of the constructed algorithm is demonstrated through simulation and experimental results.
Simulation and experimental results show that the proposed controller is effective with small synchronous tracking errors, and the chattering phenomenon is
significantly reduced.
Remote field-programmable gate array laboratory for signal acquisition and de...IJECEIAES
A remote laboratory utilizing field-programmable gate array (FPGA) technologies enhances students’ learning experience anywhere and anytime in embedded system design. Existing remote laboratories prioritize hardware access and visual feedback for observing board behavior after programming, neglecting comprehensive debugging tools to resolve errors that require internal signal acquisition. This paper proposes a novel remote embeddedsystem design approach targeting FPGA technologies that are fully interactive via a web-based platform. Our solution provides FPGA board access and debugging capabilities beyond the visual feedback provided by existing remote laboratories. We implemented a lab module that allows users to seamlessly incorporate into their FPGA design. The module minimizes hardware resource utilization while enabling the acquisition of a large number of data samples from the signal during the experiments by adaptively compressing the signal prior to data transmission. The results demonstrate an average compression ratio of 2.90 across three benchmark signals, indicating efficient signal acquisition and effective debugging and analysis. This method allows users to acquire more data samples than conventional methods. The proposed lab allows students to remotely test and debug their designs, bridging the gap between theory and practice in embedded system design.
Detecting and resolving feature envy through automated machine learning and m...IJECEIAES
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Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
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block diagram and signal flow graph representation
The effects of using variable lengths for degraded signal acquisition in GPS receivers
1. International Journal of Electrical and Computer Engineering (IJECE)
Vol. 11, No. 4, August 2021, pp. 3201∼3211
ISSN: 2088-8708, DOI: 10.11591/ijece.v11i4.pp3201-3211 r 3201
The effects of using variable lengths for degraded signal
acquisition in GPS receivers
Arif Hussain1
, Hina Magsi2
, Arslan Ahmed3
, Hadi Hussain4
, Zahid Hussain Khand5
, Faheem Akhtar6
1,2,3,4
GNSS and Space Weather Lab, Department of Electrical Engineering, Sukkur IBA University, Pakistan
5,6
Department of Computer Science, Sukkur IBA University, Pakistan
Article Info
Article history:
Received Aug 24, 2020
Revised Dec 10, 2020
Accepted Jan 13, 2021
Keywords:
Acquisition
Data length
GPS
Signal-to-noise ratio
Software receiver
ABSTRACT
The signal acquisition in GPS receivers is the first and very crucial process that may
affect the overall performance of a navigation receiver. Acquisition program initiates
a searching operation on received navigation signals to detect and identify the visible
satellites. However, signal acquisition becomes a very challenging task in a degraded
environment (i.e, dense urban) and the receiver may not be able to detect the satel-
lites present in radio-vicinity, thus cannot estimate an accurate position solution. In
such environments, satellite signals are attenuated and fluctuated due to fading in-
troduced by multipath and NLOS reception. To perform signal acquisition in such
degraded environments, larger data accumulation can be effective in enhancing SNR,
which tradeoff huge computational load, prolonged acquisition time and high cost of
receiver. This paper highlights the effects of fading on satellite signal acquisition in
GPS receiver through variable data lengths and SNR comparison, and then develops
a statistical relationship between satellite visibility and SNR. Furthermore it also ana-
lyzes/investigates the tradeoff between computation load and signal data length.
This is an open access article under the CC BY-SA license.
Corresponding Author:
Faheem Akhtar
Department of Computer Science
Sukkur IBA University
Sukkur, Sindh, Pakistan
Email: fahim.akhtar@iba-suk.edu.pk
1. INTRODUCTION
Global positioning system (GPS) is a satellite-based navigation system that provide positioning and
localization service to both military and civilian applications [1–3] across the globe. This navigation system
utilizes direct sequence code division multiple access (DS-CDMA) technique for signal transmission and it
operates on L1 (1575.42 MHz) and L2 (1227.6 MHz) frequency bands. The GPS signals at L1 band, mainly
utilized in civilian applications use pseudorandom noise (PRN) codes or coarse acquisition (C/A) to spread 50
Hz navigation message into wider spectrum. The C/A code has 1.023 MHz chipping rate containing 1023 chips
over period of 1 millisecond and each satellite has distinct C/A code that is used to identify the satellites. The
precise P(Y) code is used to spread L2 band signals having chipping rate of 10.23 MHz [4–6]. It is utilized
in military applications because it can offer a higher tolerance to jamming and spoofing than C/A code. In the
end, signals are modulated by binary phase shift keying (BPSK) and broadcasted at L band frequencies. The
GPS signal structure is given in Figure 1.
The receivers acquire and process the signals broadcasted by satellites that revolve in medium earth
orbit (MEO) at altitude of 20,200 KM to provide users with precise positioning, navigation and timing (PNT)
Journal homepage: http://ijece.iaescore.com
2. 3202 r ISSN: 2088-8708
information [5, 7]. Compared to conventional hardware based receiver, GPS software receiver performs wide
range of signal operations in software based utility and can be easily reconfigured by updating algorithm de-
ployed without making any changes in hardware. It performs digital base band signal processing to obtain
navigation solutions capable processing real and complex signals (In phase and Quadrature components) at
numerous sampling rates. The software receiver offer reasonable flexibility and are more robust compared
to hardware counterpart. It can process real and complex signals (In phase and Quadrature components) at
numerous sampling rates [8–10].
Figure 1. Fundamental structure of GPS signal; codes and data rates
A GPS receiver consist of radio frequency (RF) front end and software module, the RF front end
pre-process the analog signal in raw form to make it compatible for software based processing. It performs
frequency down conversion, amplification and digitization of a received signal as shown Figure 2 [11, 12]. The
digitized signal at down converted frequency is passed to software part that consist of acquisition, tracking and
navigation data extraction modules. The acquisition program performs a searching operation on block of data
(received signal after digitization) to find out the signals from visible satellites. Once signal is acquired such
as its presence is detected, the carrier frequency and code phase of signal is obtained and passed to tracking
module. The code phase represents the point in current data block where C/A code begins and carrier frequency
denotes the actual frequency of signal because Doppler shift can change the frequency. In literature, there exists
several methods that are used for satellite signal acquisition such as serial search acquisition, parallel code phase
search acquisition (FFT-based circular correlation) [13, 14], single side band (SSB) circular correlation, delay
and multiply approach and zero padding (ZP) [15, 16] some methods are capable to acquire weak signals but
are slower, while fast methods such as ZP may not be able to acquire degraded signals [5, 17].
The GPS signal acquisition can be influenced by delay imposed due to irregularities in Ionosphere and
troposphere, receiver and satellite clock errors and multipath and environmental effects [18–22]. Therefore, to
acquire a degraded GPS signal prolonged data lengths are taken to increase the input SNR but at the expense
of exhaustive search and slower acquisition speed. In this paper, we are analyzing/investigating the effects of
using variable data lengths for satellite signal acquisition. This analysis includes comparison of input SNR,
computational load, and acquisition speed at different data lengths using FFT-based circular correlation and
zero padding method.
Int J Elec & Comp Eng, Vol. 11, No. 4, August 2021 : 3201 – 3211
3. Int J Elec & Comp Eng ISSN: 2088-8708 r 3203
Figure 2. Block diagram of GPS receiver
2. GPS SIGNAL STRUCTURE AND ACQUISITION
The GPS satellites operate on L-band frequencies and transmit two distinct signals at L1 and L2
frequencies [23–25], in this paper we focus on L1 band modulated by civilian code C/A. The GPS is CDMA
system so the received signal S(t) is composite signal of N visible satellites and it can be modelled as (1),
S(t) =
N
X
k=1
sk
L1(t) (1)
where, sk
L1(t) represents the actual signal model of given satellite (i.e., k) and can be given as (2).
sL1(t) = McC(t)N(t) cos(2π(fL1 + fd)t) + MpP(t)N(t) sin(2π(fL1 + fd)t) (2)
Where:
Mc: is the magnitude of C/A code
C(t): is the C/A code of the satellite
N(t): is the navigation data bits having values ±1
fL1: is the L1 carrier frequency and fd: is the Doppler shift
Mp: is the magnitude precise code or P(Y )
P(t): is the precise code or P(Y )
The RF front end acquires incoming signal and after some signal conditioning it down converts it to
an intermediate frequency (fIF ). In this paper the signal is down-converted at 1.42 MHz and mathematically
it is given as (3).
sIF (t) = McC(t)N(t) cos(2π(fIF + fd)t) + MpP(t)N(t) sin(2π(fIF + fd)t) (3)
The down-converted signal (sIF (t)) is then sampled and digitized by analog to digital converter
(ADC) and passed through low pass filter (LPF) centered around C/A code. The LPF distorts P(Y ) code
and it cannot be demodulated. Therefore, second part of (3) is modeled as error (e(n)) in the digitized signal.
s(n) = McC(n)N(n) cos(2π(fIF + fd)nTs) + e(n) (4)
where, Ts is the sampling time (Ts = 1/fs) and fs is the sampling frequency and here fs = 5 MHz. In
general, the acquisition program initially wipes off the carrier signal and then performs correlation operation
between received signal s(n) and locally generated replica of transmitted C/A [26, 5] or PRN code slo(n).
If the correlation peak cross certain threshold such as s(n) and slo(n) match at some point then acquisition
parameters (code phase and Doppler shift) are obtained and satellite is said to be acquired. The time domain
and correlation y(n) between finite sequence of received signal and locally generated C/A code can be given
as (5).
The effects of using variable lengths for degraded signal acquisition in... (A. Hussain)
4. 3204 r ISSN: 2088-8708
y(n) =
N−1
X
i=1
s(i)slo(i + n) (5)
In order to perform FFT-based circular correlation, y(n) is transformed into frequency domain and
can be given as (6).
Y (k) =
N−1
X
n=0
y(n)Wnk
N =
N−1
X
n=0
N−1
X
i=1
s(i)slo(i + n)Wnk
N (6)
where, Wnk
N = e−j2πkn/N
is the twiddle factor. In order to simplify, in (6) can be re-written as (7).
Y (k) = S(k)S∗
lo(k) (7)
where, S∗
lo(k) is the complex conjugate of Slo(k). Furthermore, correlation results in time domain (y(n)) can
be obtained by taking inverse DFT. Once correlation is performed then correlation peak (PN,max) is found by
(8) and If the correlation peak in y(n) cross certain threshold (γ) then signal is said to be acquired otherwise
frequency of local oscillator is changed and acquisition steps are repeated. The acquisition is declared only if
|PN,max|2
> γ.
PN,max = max|y(n)|N (8)
γ = (−2σ2
nln(Pfa))1/2
(9)
where, γ is the acquisition threshold, σ2
n is the noise variance and Pfa is the probability of false alarm. The
FFT-based method takes block of data, locally generated signal and performs correlation in frequency domain.
The functional block diagram of FFT-based circular correlation is given in Figure 3.
Figure 3. Block diagram of FFT-based circular correlation
The zero padding (ZP) method is similar to FFT-based method it also performs correlation in fre-
quency domain. But ZP method utilizes divide and conquer strategy to speed up the acquisition process. It
splits the data block of incoming signal and locally generated signal containing Nd data samples into multiple
blocks of smaller size Ndpb and performs partial correlation. The block diagram of zero padding method is
given in Figure 4.
Int J Elec & Comp Eng, Vol. 11, No. 4, August 2021 : 3201 – 3211
5. Int J Elec & Comp Eng ISSN: 2088-8708 r 3205
Figure 4. Block diagram of zero padding method [24]
3. RESEARCH METHOD
In this work/study the actual signal (real data) is used in acquisition process and three test signals are
generated by adding 5 dB, 10 dB and 15 dB fading by introducing Gaussian noise into real data. The GPS
signal is down converted at 1.42 MHz and sampled at 5 MHz therefore signal duration of 1 millisecond (msec)
contains 5000 samples. The acquisition is performed on tests signals using both FFT-based circular correlation
and zero padding method on 1 msec and then non-coherent integration is performed up to 20 msec of data. The
Doppler frequency search range is ±10 kHZ with the step size of 1 KHz. In both algorithms code phase and
doppler shift are observed to be exactly same but the magnitude of correlation peak is lesser in ZP method.
3.1. Non-coherent integration
The signal processing operations seek to boost SNR to improve the performance of system it can be
done by adding (integrating) multiple data blocks together. In non-coherent integration data blocks are added
non coherently such as each data block is processed separately and then results are added together.
yN (n) =
L
X
i=1
|yi(n)| (10)
Where, yN (n) is the acquisition results after integrating L data blocks and i= 2,3,...,L, yi(n) is the
acquisition result of ith
data block and L is intregation length. The non coherent integration gain Gnc represents
increment in the SNR when data blocks are added together and it is given by (11)
Gi
nc = SNRi
/SNRi−1
(11)
where, Gi
nc is the Gain at ith
integration and SNRi
is the SNR at ith
integration.
4. RESULTS AND DISCUSSION
The Figure 5(a) and (b) shows the SNR results of signals acquired using FFT-based and ZP method
respectively. The acquisition is performed on 3 test signals and it is observed that in both methods SNR is
improved as the integration length increases. However, the FFT-based seems to be more robust as compared to
ZP method because at same integration level it has higher value of SNR. On average there is 10 dB difference
in the SNR of both methods on given integration time. This study concludes that ZP may not be able to acquire
the signals in degraded environment even on larger integration length on the other hand FFT-based method is
more robust and can acquire the weak signals comparatively at low integration lengths.
The effects of using variable lengths for degraded signal acquisition in... (A. Hussain)
6. 3206 r ISSN: 2088-8708
Figure 5. SNR result, (a) SNR of signals acquired by FFT-based method (b) SNR of signals acquired by ZP
based method
4.1. Acquisition results
The acquisition is performed on three test signals and these test signals represents the fading levels
that can occur in signals due to space weather effects, multipath effects and environmental effects. This anal-
ysis compares the acquisition performance of both methods on each test signal as well as on fading levels.
It is observed that on each test signal code phase and carrier frequency obtained from both are exactly same
but magnitude of correlation peak and acquisition time varies. For each test signal two types results are pre-
sented, initially summarized results are presented that depicts the correlation peak and acquisition threshold on
integration interval and then detailed correlation results on certain integration interval presented. Both of the
results depict a point where the satellite is acquired such as correlation peak cross the acquisition threshold.
The acquisition is declared only if |PN,max|2
> γ and threshold is obtained from (9) by keeping Pfa = 10−3
.
In order to avoid false acquisition declarations the threshold level is scaled up. The scaling factor for FFT-based
method is set to 5 (because of robustness) and 2.50 for ZP method.
4.2. First test signal
The summarized acquisition results of first test signal (5 dB fading) over the integration interval of 20
msec are given in Figure 6(a) and (b). The vertical blue dotted line indicates the point (integration time) where
acquisition is declared. FFT-based circular correlation is robust method and the acquisition is declared in the
1st msec of data because it has higher value of SNR as shown in Figure 5. However, it takes 3 msec integration
for same signal in ZP method to declare acquisition. Furthermore, it is observed that the magnitude correlation
peak is much higher in FFT-based as compared to ZP method, for instance at 20th
msec correlation peak in
FFT-based method is approximately 20 times the peak in ZP method.
Figure 6. Signal acquisition at 5 dB fading, (a) using FFT-based method (b) using Zero Padding method
The correlation results over different data lengths (integration time) are given in Figures 7 and 8.
The x component of DataTip represents the code phase and y component indicates the peak magnitude. The
Int J Elec & Comp Eng, Vol. 11, No. 4, August 2021 : 3201 – 3211
7. Int J Elec & Comp Eng ISSN: 2088-8708 r 3207
Doppler shift is 1 KHz is observed therefore carrier frequency becomes 1.421 MHz (1.42 MHz+1 KHz). The
results indicate that in both methods once the satellite is acquired the code phase and Doppler shift are same
while the magnitude level is less in ZP method. It seems that ZP method has lower acquisition speed and high
computational load because apparently it is taking more time to declare acquisition as compared to FFT-based
method. However, computational analysis shows that ZP takes lower number of multiplications and additions
to perform acquisition because of its divided approach.
Figure 7. Signal acquisition in GPS receiver using FFT-based circular correlation method at 5 dB fading
Figure 8. Signal acquisition in GPS software receivers using zero padding method at 5 dB fading
4.3. Second test signal
As the fading increases it becomes problematic to acquire the GPS signal, as it reduces the SNR
and requires exhaustive search for signal detection. On second test signal (10 dB fading) FFT-based method
declares the acquisition in the 4th msec while ZP method declares the acquisition at 8th msec as shown in
Figure 9(a) and (b). The detailed correlation results over different data lengths (integration time)are given in
Figures 10 and 11.
The effects of using variable lengths for degraded signal acquisition in... (A. Hussain)
8. 3208 r ISSN: 2088-8708
Figure 9. Signal acquisition at 10 dB fading, (a) using FFT-based method (b) using Zero Padding method
Figure 10. Signal acquisition in GPS receiver using FFT-based circular correlation method at 10 dB fading
Figure 11. Signal acquisition in GPS software receivers using Zero Padding method at 10 dB fading
Int J Elec & Comp Eng, Vol. 11, No. 4, August 2021 : 3201 – 3211
9. Int J Elec & Comp Eng ISSN: 2088-8708 r 3209
4.4. Third test signal
Sometimes due to ionospheric irregularities and severe multipath effects, the strength of GPS signal is
very much deteriorated and may cause acquisition failure. It can introduce 15 to 20 dB of fading so, to analyze
the performance of receiver in such conditions the acquisition is performed on a test signal having 15 dB of
fading as shown in Figure 12(a) and (b). It is observed that in FFT-based method signal is acquired at 7th
integration point while in ZP method acquisition is declared at 15th
msec.
In general, we can say that the time to acquire the satellite increases as the fading level increases,
however it is acquisition speed is very critical parameter in navigation receivers because the starting time of
receiver depends upon. The computational analysis shows that ZP method is much faster than FFT-based
method. The detailed correlation results of third test signal are not given because it follows the same pattern as
of other test signals.
Figure 12. Signal acquisition at 15 dB fading, (a) using FFT-based method (b) using zero padding method
5. DETECTION PERFORMANCE
The output of correlator contains both signal Ŝ(k) and noise n̂(k) components.
Y (k) = Ŝ(k) + n̂(k) (12)
In the absence of signal component such as when only noise signal is present then according to [17] probability
density of noise envelope p(r) is given by (13) and the probability of false alarm Pfa is obtained by integration
of (13).
p(r) = r/σ2
ne−(γ2
/2σ2
n)
(13)
Pfa =
Z ∞
γ
p(r)dr = e−(γ2
/2σ2
n)
(14)
Now if the signal component is also present having amplitude A then probability density of noise
envelope p(r) will follow Rician distribution [18] and given as (15).
p(r) =
r
σ2
n
exp(−
γ2
+ A2
2σ2
n
)Io(
Ar
2σ2
n
) (15)
where, A2
is the |PN,max|2
and Io(Z) is the zero order modified Bessel function of the first kind. The
probability of detection (Pd) is the probability that signal will be acquired such as r > γ is given by (16).
Pd =
Z ∞
γ
r
σ2
n
exp(−
γ2
+ A2
2σ2
n
)Io(
Ar
2σ2
n
)dr (16)
The series approximation of detection probability [19] is given by (17).
The effects of using variable lengths for degraded signal acquisition in... (A. Hussain)
10. 3210 r ISSN: 2088-8708
Pd = 0.5
"
1 − erf(
γ − A
p
2σ2
n
)
#
+
(
exp
− (γ − A)2
/σ2
n
2
√
2π(A/
p
σ2
n)
)
×
(
1 −
γ − A
4A
+
1 +
(γ − A)2
/σ2
n
8A/σ2
n
)
(17)
Furthermore, Pd can be expressed as a function of SNR with Pfa as parameter from (15) γ/2σ2
n =
ln(1/2Pfa) and using power relationship.
A
p
σ2
n
=
SignalAmplitude
rmsnoisevoltage
= 2(
SignalPower
NoisePower
) =
√
2SNR (18)
The detection probability (Pd) of both FFT-based and ZP method over the integration interval for all
three test signals is given in Figure 13(a) and (b) respectively. The detection performance indicates that Pd gets
better as integration length increases however it is also affected by fading. Like SNR, the probability that a
signal is detected (acquired) reduces as fading level increases. In FFT-based method, at any given data length
such as 6th
msec, the Pd of 2nd
test signal is approximately 10% less than the 1st
test signal, similarly Pd
of 3rd
test signal is around 30% less than 1st
test signal. In case of 3rd
test signal detection performance is
improved by nearly 40% over the integration interval of 20 msec.
Figure 13. Results of third test signal, (a) Probability of detection using FFT-based method (b) Probability of
detection ZP method
In ZP method, there is significant difference in the detection performance of test signals. For instance
at 16th
msec, the Pd of 2nd
test signal is approximately 35% less than the 1st
test signal, similarly Pd of
3rd
test signal is around 60% less than 1st
test signal. Comparatively detection performance is significantly
improved at low fading level (such as 1st
test signal) over the same integration interval. In case of 3rd
test
signal detection performance is improved by nearly 30% over the integration interval of 20 msec. Comparative
analysis of detection performance indicates that FFT-based method is more robust and can acquire signals in
degraded environment. Its detection is less affected by fading introduced due to several effects as compared to
ZP method.
6. CONCLUSION
This paper has discussed the effects of using variable lengths for signal acquisition in GPS software
receivers. It is presented that detection performance and SNR can be improved by non-coherent integration
of data lengths. The acquisition results showed that data length sets the trade-off among detection perfor-
mance, SNR and acquisition speed. The study indicates that FFT-based method is much robust and can acquire
degraded signals but it is slower than the ZP method.
REFERENCES
[1] E. G. N. S. S. A., “Gnss market report,” PA, Annual report of the United Nations High Commissioner for Human
Rights and reports of the Office of the High Commissioner and the Secretary-General, 2019, [Online]. Available:
https://www.gsa.europa.eu/market/market-report.
Int J Elec Comp Eng, Vol. 11, No. 4, August 2021 : 3201 – 3211
11. Int J Elec Comp Eng ISSN: 2088-8708 r 3211
[2] J. Guo, X. Li, Z. Li, L. Hu, G. Yang, C. Zhao, D. Fairbairn, D. Watson, and M. Ge, “Multi-gnss precise point
positioning for precision agriculture,” Precision agriculture, vol. 19, no. 5, pp. 895–911, 2018.
[3] G. Xu and Y. Xu, “GPS: theory, algorithms and applications,” Springer, 2016.
[4] K. Borre, D. M. Akos, N. Bertelsen, P. Rinder, and S. H. Jensen, “A Software-Defined GPS and Galileo Receiver: A
Single-Frequency Approach,” Springer Science and Business Media, 2007.
[5] J. B. Tsui, “GPS C/A Code Signal Structure, Chapter 5,” John Wiley and Sons, pp. 68–101, 2005.
[6] C. Bruyninx, W. Aerts, and J. Legrand, “Gps, Data Acquisition and Analysis,” Dordrecht: Springer Netherlands,
pp. 420–431, 2011, doi: 10.1007/978-90-481-8702-7-137.
[7] A. Paul, K. S. Paul, and A. Das, “Impact of multiconstellation satellite signal reception on performance of
satellite-based navigation under adverse ionospheric conditions,” Radio Science, vol. 52, no. 3, pp. 416–427, 2017,
doi: 10.1002/2016RS006076.
[8] F. Wu, K. Zhang, and A. Yasuda, “Gps signal acquisition and tracking using software gps receiver,” in Eighth
International Symposium on Signal Processing and Its Applications, 2005, pp. 843–846, doi:
[9] A. Alaqeeli, J. Starzyk, and F. Van Graas, “Real-time acquisition and tracking for gps receivers,” in Proceedings of the
2003 International Symposium on Circuits and Systems, 2003, vol. 4, pp. IV–IV, doi: 10.1109/ISCAS.2003.1205933.
[10] P. Varzakas, “Average channel capacity for rayleigh fading spread spectrum mimo systems,” International Journal of
Communication Systems, vol. 19, no. 10, pp. 1081–1087, 2006.
[11] D. Manandhar, Y. Suh, and R. Shibasaki, “Gps signal acquisition and tracking-an approach towards development of
software-based gps receiver,” Technical Report of IEICE, 2004.
[12] J. Yin, R. Tiwari, and M. Johnston, “Low-cost dual polarized gps antenna for effective signal acquisition in multipath
environment,” in 2017 European Navigation Conference (ENC), 2017, pp. 359–365.
[13] X. Chen, J. Xu, T. Ye, and S.-c. LI, “Fft-based acquisition for weak gps signals,” Microelectronics Comp., 2010.
[14] C. O’Driscoll and C. C. Murphy, “Performance analysis of an fft based fast acquisition gps receiver,” in ION National
Tech. Meeting, 2005, pp. 1014–1025.
[15] B. Chibout, C. Macabiau, A.-C. Escher, L. Ries, J.-L. Issler, S. Corazza, and M. O. Bousquet, “Comparison of
acquisition techniques for gnss signal processing in geostationary orbit,” Proceedings of the 2007 National Technical
Meeting of The Institute of Navigation, 2007, pp. 637-649.
[16] D. M. Lin, “Comparison of acquisition methods for software GPS receiver,” Proceedings of the 13th International
Technical Meeting of the Satellite Division of The Institute of Navigation, 2000, pp. 2385–2390.
[17] D. M. Lin and J. B. Tsui, “Comparison of Acquisition Methods for Software GPS Receiver,” Proceedings of the 13th
International Technical Meeting of the Satellite Division of The Institute of Navigation, 2016, pp. 2385-2390.
[18] B. W. Parkinson and J. J. S. Jr., “Global Positioning System: Theory and Applications,” Chapter 11. Wash- ington,
DC: American Institute of Aeronautics and Astronautics, Inc, vol. 1, 1996.
[19] A. Ahmed, R. Tiwari, S. I. Ali, and G. Jaffer, “The effects of ionospheric irregularities on the navigational receivers
and its mitigation,” in International Conference for Emerging Technologies in Computing, Springer, 2018, pp. 87–97,
doi: 10.1007/978-3-319-95450-9-7.
[20] P. Tregoning and C. Watson, “Atmospheric effects and spurious signals in gps analyses,” Journal of Geophysical
Research: Solid Earth, vol. 114, no. B9, 2009.
[21] J. Seo, T. Walter, and P. Enge, “Availability impact on gps aviation due to strong ionospheric scintilla-
tion,” IEEE Transactions on Aerospace and Electronic Systems, vol. 47, no. 3, pp. 1963–1973, July 2011,
doi: 10.1109/TAES.2011.5937276.
[22] F. K. Brunner and W. M. Welsch, “Effect of the troposphere on gps measurements,” GPs World, vol. 4, p. 42, 1993.
[23] L. R. W. Mohinder S Grewal and A. P. Andrews, “Global positioning systems, inertial navigation and integration,”
John Wiley and Sons, 2007.
[24] A. Ahmed, “Scintillation on global navigation satellite signals and its mitigation,” Ph.D. dissertation, Newcastle
University, UK, 2015.
[25] F. Gao, “Performance analysis of long-time coherent integral acquisition algorithm for weak GNSS signals,” IOP
Conference Series: Earth and Environmental Science, vol. 428, p. 012002, jan 2020.
[26] A. Ahmed, R. Tiwari, H. Strangeways, and S. Boussakta, “Software-based receiver approach for acquiring GPS
signals using block repetition method,” 2014 7th ESA Workshop on Satellite Navigation Technologies and European
Workshop on GNSS Signals and Signal Processing (NAVITEC), 2014, pp. 1–7.
The effects of using variable lengths for degraded signal acquisition in... (A. Hussain)