Wahyudin Syam (Page 3)

Evil waveform (EWF) in global navigation satellite system (GNSS) signal

Evil waveform (EWF) in global navigation satellite system (GNSS) signal

In this post, we will discuss one of GNSS threats, that is evil waveform. Unlike jamming and spoofing, evil waveform is not a type of signal interference in GNSS signals. Instead, evil waveform is a faulty signal transmitted by a real GNSS satellite.

The difference between C/N0 and SNR in GNSS signal processing

The difference between C/N0 and SNR in GNSS signal processing

In signal processing, especially in global navigation satellite system (GNSS), the term signal-to-noise ratio (SNR) and carrier-to-noise density (C/N0) are very fundamental in every analysis aspect.

Geometric dimensioning and tolerancing (GD&T) and assembly of non-rigid parts

Geometric dimensioning and tolerancing (GD&T) and assembly of non-rigid parts

For non-rigid part assembly, the fixturing force will be relevant and needs to be considered carefully in their assembly design.

Optical coordinate measuring machine (Optical-CMM): Performance verification and measurement uncertainty estimation

Optical coordinate measuring machine (Optical-CMM): Performance verification and measurement uncertainty estimation

Performance verification and measurement uncertainty estimation of an optical coordinate measuring machine (optical-CMM) are very important aspects assuring that the optical-CMM works within its specification and its measurement results are traceable to the definition of metre.

Optical coordinate measuring machine (Optical-CMM): Two fundamental limitations

Optical coordinate measuring machine (Optical-CMM): Two fundamental limitations

Optical coordinate measuring machines (Optical-CMM) have advantages over tactile (contact) CMMs, such as more part-feature accessibility, no surface damaging-risk and large surface points capture in relatively a short period of time (compared to tactile CMMs).

Digital transformation of dimensional and geometrical measurements

Digital transformation of dimensional and geometrical measurements

Today era is the time for thorough digitalisation, from product design, process design to data analysis and executive summary making.

Calculus and linear algebra as tools for statistics

Calculus and linear algebra as tools for statistics

Very often, statistics is overlooked by engineers and the importance of statistics is put behind calculus and (linear) algebra.

Prioritising to use built-in functions in interpreted languages

Applied programming

Prioritising to use built-in functions in interpreted languages

We need to avoid as mush as possible the use of for loop in our algorithm by implementing vectorisation method and using built-in functions as much as possible.

Vectorising linear sequence search in MATLAB programming

Applied programming

Vectorising linear sequence search in MATLAB programming

To significantly speed up the computation speed in MATLAB, the reduction of for loop should be minimised.

CMM measurement uncertainty estimation: ISO 15530-4

CMM measurement uncertainty estimation: ISO 15530-4

The mathematical model of CMM measurements is very complex to reconstruct. ISO 15530-4 presents a method to estimate CMM measurement uncertainty without the need of the mathematical model of CMM measurements.

CMM measurement uncertainty estimation: ISO 15530-3

CMM measurement uncertainty estimation: ISO 15530-3

Coordinate measuring machine (CMM) has been used in many manufacturing industries, ranging from aerospace, automotive to consumer product, that mass-produces various types of parts.

CMM measurement uncertainty estimation: ISO/DTS 15530-2

CMM measurement uncertainty estimation: ISO/DTS 15530-2

ISO/DTS 15530-2 provide a way to estimate coordinate measuring machine (CMM) measurement uncertainties without using any complex calibrated artefacts. Instead, only a performance verified CMM and a standard calibrated gauge block are needed.

CMM measurement uncertainty estimation: Relevant uncertainty contributors

CMM measurement uncertainty estimation: Relevant uncertainty contributors

CMM measurement uncertainty estimation: Relevant uncertainty contributors

Meaconing: the most common type of GNSS spoofing interference attacks

Meaconing: the most common type of GNSS spoofing interference attacks

Spoofing attack is a radio frequency (RF) signal interference attack that aims to deceive a global navigation satellite system (GNSS) receiver, such as GPS or GALILEO receiver, so that the receiver track and demodulate the spoofing signals, leading to invalid position, velocity and timing solutions.

GNSS signal modelling considering channel impairments and spoofing interferences

GNSS signal modelling considering channel impairments and spoofing interferences

Signals of global navigation satellite system (GNSS), such as the well-known GPS and GALILEO, are significantly affected by channel impairments and signal interferences.

Low frequency radio navigation system for use in natural disaster situations

Low frequency radio navigation system for use in natural disaster situations

It is critical to have a navigation system for search and rescue of victims and important assets in a disaster situation.

Coordinate measuring machine (CMM): Calibration, performance verification and measurement uncertainty estimation

Coordinate measuring machine (CMM): Calibration, performance verification and measurement uncertainty estimation

Calibration, performance verification and measurement uncertainty estimation are important activities for coordinate measuring machine (CMM) machine and measurement.

Error sources on coordinate measuring machine (CMM) measurements and environment control

Error sources on coordinate measuring machine (CMM) measurements and environment control

A coordinate measuring machine (CMM) is a complex measuring instrument. Hence, there are many error sources that cause the degradation of a CMM measurement accuracy and the increase of the uncertainty of the CMM measurement results.

Channel coding theory: An introduction and comparison of block, Convolutional, Turbo and low-density parity-check (LDPC) codes

Channel coding theory: An introduction and comparison of block, Convolutional, Turbo and low-density parity-check (LDPC) codes

In this post, a brief introduction about channel coding theory is presented. The comparison of convolutional, TURBO and LDPC codes for use in global navigation satellite system (GNSS) signals is also presented.

Sampling strategy for coordinate measuring machine (CMM) measurements

Sampling strategy for coordinate measuring machine (CMM) measurements

In any CMM measurements, especially with a tactile-CMM, sampling strategy is very important. This Sampling strategy in CMM measurement affects not only measurement performance, but also measurement accuracy!

Part-alignment procedure on coordinate measuring machine (CMM) for dimensional and geometrical measurements

Part-alignment procedure on coordinate measuring machine (CMM) for dimensional and geometrical measurements

Part-alignment is a compulsory process that needs to be performed for CMM measurements. This process is performed right after the qualification process of CMM probing system. Only after part-alignment is performed, dimensional and geometrical measurements by a CMM can be carried out.

The probing system of tactile-CMM: Vector diagram and qualification process

The probing system of tactile-CMM: Vector diagram and qualification process

In this post, the vector diagram and the mathematics behind the qualification process of a probing system are presented.

The probing system of tactile-CMM: Important aspects to consider for probing system

The probing system of tactile-CMM: Important aspects to consider for probing system

In this post, important aspects regarding the probing system of tactile-CMM is discussed. By knowing these aspects, we can improve the efficiency and efficacy of dimensional and geometrical measurements with tactile-CMM.

The probing system of tactile-CMM: The history, configuration and mechanism

The probing system of tactile-CMM: The history, configuration and mechanism

Probing system in a tactile coordinate measuring machine (tactile-CMM) is a fundamental component that acts as sensor to detect whether a stylus tip has touched the surface of a measured part.

General procedures to operate a tactile coordinate measuring machine (tactile-CMM)

General procedures to operate a tactile coordinate measuring machine (tactile-CMM)

There is a general procedure to operate a tactile coordinate measuring machine (tactile-CMM). In this post, we will discuss this general procedure that can be implemented to all types of tactile-CMM from various manufacturers.