## 1 Introduction  
Construction machinery occupies a critical role within the construction industry, with heavy-duty equipment like excavators and dump trucks being essential for both large-scale earthmoving and precise grading of sites. These machines are increasingly demonstrating enhanced versatility through the adoption of specialized attachments and modifications, effectively being used to conduct the majority of earthwork operations on modern construction sites. In response to this trend, manufacturers of construction equipment are actively pursuing the development of more sophisticated and high-performance machinery, leveraging advancements such as high-efficiency engines and optimized hydraulic systems to enhance operational productivity. Moreover, the recent commercialization of mass-produced, low-cost lithium-ion batteries is accelerating the development and deployment of fully electric construction equipment, thereby offering a promising pathway towards mitigating carbon emissions within the sector. These technological advancements are poised to contribute significantly to improved productivity and environmental sustainability in construction practices [1]. Despite the numerous advancements within the heavy machinery industry, operator skill remains a paramount factor influencing productivity in earthwork operations. The performance of heavy machinery such as excavators is intrinsically linked to the proficiency and experience of its operator [2; 3]. Historically, earthwork operations were predominantly executed through manual control, demanding that operators rely on their accumulated experiential knowledge and honed physical skills to manipulate the machinery effectively. However, the advent of sophisticated technologies has paved the way for the development of machine guidance systems and their implementation in excavator operations [4]. These systems typically integrate a variety of sensors, satellite navigation systems (e.g., GNSS), and powerful onboard computer systems to provide operators with real-time positioning and guidance information. This technological assistance enhances the operator's ability to perform tasks with greater accuracy and efficiency. The market penetration of this technology is substantial; modern earthmoving equipment is increasingly being sold with integrated machine guidance and control systems. For instance, Komatsu's Intelligent Machine Control (iMC) technology is available on selected dozer and excavator models, enhancing efficiency and accuracy in operations [5]. This trend underscores the industry's growing recognition of the significant potential of machine guidance systems to revolutionize earthwork operations by optimizing productivity and precision. The primary advantage of machine guidance lies in its ability to provide operators with real-time visual or auditory feedback, ensuring adherence to design specifications, particularly relating to grade and elevation requirements. Furthermore, these systems can automate the control of the excavator's end-effector motion and position, enabling it to autonomously follow pre-defined excavation paths or profiles. Research conducted in the United States has indicated that the implementation of machine guidance systems in earthwork operations can lead to productivity gains of up to 50% [4]. Further substantiating this claim, recent investigations based on controlled field experiments have measured improvements in productivity resulting from the adoption of machine guidance systems, reporting these to be as high as 47% [6]. This evidence collectively highlights the substantial potential for machine guidance technology to optimize operational efficiency within the earthworks industry. While both manual and machine-guided excavation operations offer distinct advantages, their underlying operational principles differ significantly. It is hypothesized that the provision of precise, real-time guidance relating to excavation targets can modify and improve operator activity.