Table of Contents

• Introduction

• Why Instant On-site Soil Volume Measurement Is Needed

• Traditional Soil Volume Measurement Methods and Their Challenges

• Dramatic Efficiency Gains and Labor Reduction Brought by Single-Operator Surveying

• “Surveying Anyone Can Do” Realized by the Latest Technologies

• What Is Simple Surveying with LRTK

• Key Points and Precautions for On-site Adoption

• Conclusion

• FAQ

Introduction

How much easier would site management be if you could accurately measure soil volumes such as fill and excavation on the spot at earthwork sites? At many construction sites, understanding soil volumes takes time and effort, and it is often necessary to wait for specialized surveying technicians or for post-processing. If there is a time lag until the survey results are available, construction decisions can be delayed or extra costs may be incurred. Especially for large-scale earthworks and infrastructure projects where massive amounts of soil are handled, it is required to grasp on-site soil volumes instantly and respond quickly.

In recent years, technological innovation has progressed in the surveying world to address these challenges. By leveraging the latest ICT technologies, it is becoming possible for even a single person to easily measure soil volumes on site and obtain results immediately. Combining smartphones or tablets with advanced positioning and sensing technologies dramatically streamlines surveying tasks that previously required multiple people, making “simple surveying” that anyone can use a reality.

This article organizes the importance of instant on-site soil volume measurement and the challenges of conventional methods, explains the benefits of single-operator surveying and the underlying latest technologies, and finally introduces a new surveying tool that uses smartphones: “simple surveying with LRTK,” exploring how it can contribute to labor reduction and cost savings on site.

Why Instant On-site Soil Volume Measurement Is Needed

Large volumes of earth are moved daily on earthwork sites, and accurately understanding that volume is extremely important for overall construction management. For example, if you can immediately know how much excavation has progressed or how much fill is still needed, you can efficiently manage progress and arrange heavy machinery and dump trucks. Also, in situations such as finished-shape management and quantity assessment, obtaining objective soil volume data on the spot can prevent misunderstandings with the client and lead to smooth consensus building.

However, traditionally even when you want to know soil volumes immediately, it is common to experience a time lag until surveying and data processing are completed. Site personnel who want to make decisions on the spot are often left “waiting for survey results,” which can sometimes prevent progress to the next stage and cause rework. Reporting soil volumes only as 2D drawings or numbers can also be unintuitive and take time to explain to stakeholders. If you can measure and visualize on-site soil volumes instantly, these time losses and communication problems can be greatly reduced.

Moreover, the construction industry is facing a serious shortage of experienced surveying technicians. It is increasingly common for a single site manager to handle multiple roles, and calling in a specialized team for surveying each time is inefficient. If site personnel themselves can quickly measure soil volumes, it will be a major advantage from the perspective of labor reduction.

Traditional Soil Volume Measurement Methods and Their Challenges

Various measurement and calculation methods have long been used to understand soil volumes on site. Each, however, has issues in terms of time, effort, and accuracy. The main methods and their characteristics are as follows.

• Surveying with a total station (TS): Can measure terrain heights and positions with high accuracy, but acquiring many measurement points over a wide area requires considerable time and effort. Usually two or more people are needed, and specialized operation skills are essential. Equipment setup and post-processing are time-consuming, making it difficult to produce immediate results.

• Volume calculation by the average cross-section method: A calculation method long used in road construction. Cross-sections are measured at fixed intervals, and volumes are calculated from the cut and fill areas of each section. Useful as an approximate method, but surveying and calculation take time, and fine terrain irregularities cannot be reflected, resulting in potential errors.

• Drone photogrammetry: Creates 3D models from aerial photographs, allowing volume calculations even for large sites. Effective for grasping volumes over wide areas, but drone flights are constrained by weather and permissions, and time is inevitably required from imaging to analysis completion. It also requires skills to operate specialized software and high-performance PCs, making immediate on-site results difficult. Initial introduction costs are also relatively high.

• Visual estimation based on experience: Veteran equipment operators or supervisors estimate soil by feel, such as “equivalent to X dump truck loads.” This enables quick judgment but is subjective and low in accuracy, risking significant divergence from actual volumes. It can also cause disputes with clients due to differing perceptions.

As above, traditional soil volume measurement methods are all time-consuming and lack real-time capabilities. Accurate volume calculation requires specialized knowledge and experience, and it is not easy to grasp soil volumes on the spot. While waiting for survey analysis, work may be interrupted, or reliance on rough estimates may cause unnecessary excavation or fill and result in rework—many inefficiencies exist.

Dramatic Efficiency Gains and Labor Reduction Brought by Single-Operator Surveying

By leveraging these latest technologies, surveying work that previously required multiple people can be completed by a single person. With single-operator surveying, you no longer need to wait for an assistant or a surveying team. You can start measurements immediately when the need arises, acquire and check data on the spot, and dramatically improve work efficiency. Eliminating the need to secure manpower or coordinate schedules for surveying will also smooth overall site arrangements.

The effect on labor reduction is also significant. On construction sites suffering chronic labor shortages, operations must be carried out with limited personnel. Introducing single-operator surveying allows site managers or operators to perform surveying themselves without keeping specialized surveying staff on site. As a result, workforce reduction and more efficient personnel allocation are possible, leading to lower labor costs. Moreover, reducing situations where multiple people need to enter hazardous areas for surveying improves safety management.

Secondary effects from increased efficiency and labor reduction include shorter construction periods and cost savings. If there is no work stoppage due to waiting for surveying, overall construction progresses faster, and preventing unnecessary machine operation or rework reduces wasteful spending. Single-operator surveying, which can achieve both dramatic efficiency gains and cost savings, will be indispensable for future construction sites.

“Surveying Anyone Can Do” Realized by the Latest Technologies

What supports single-operator surveying is the use of ICT technologies that have made remarkable progress in recent years. In particular, sensors built into familiar devices such as smartphones and tablets, and advances in high-precision GNSS positioning technology, are key. New smartphones have built-in LiDAR sensors that scan surroundings with lasers to acquire point cloud data (a collection of countless measurement points). Using this point cloud data, software can instantly automate soil volume calculations that previously required manually creating cross-sections. By comparing current terrain data with design surfaces or differencing point clouds before and after excavation, fill and cut volumes can be calculated immediately. Because point clouds capture the entire terrain in detail without missing points, they can provide higher accuracy in volume estimation than cross-section methods.

Acquired survey data can also be intuitively visualized using AR (augmented reality) technology. By viewing the site through a smartphone or tablet and overlaying measurement results on the image, survey data can be shared in a form that anyone can easily understand. For example, simply pointing a camera at the site can display elevation differences as a color-coded heatmap, or guidance such as “excavate another ◯◯ cm” can appear in situ. Over- or under-fill that was difficult to grasp from numbers and drawings becomes visually apparent at a glance. Because anyone can accurately understand the situation using digital visual information without relying on experienced intuition, communication is also smoothed.

However, ordinary smartphone positioning has an error of several meters and is too coarse to accurately align AR displays. Enter high-precision positioning technology called RTK-GNSS. RTK-GNSS dramatically improves positional accuracy by applying error corrections from a base station to satellite positioning signals. By connecting a dedicated small receiver to a smartphone, centimeter-level (half-inch-level) positioning on a smartphone has become possible. In Japan, the start of services like the QZSS-based “CLAS” (centimeter-level positioning augmentation service) has further supported this trend, enabling high-precision positioning with palm-sized receivers.

This combination of high-precision GNSS + LiDAR + AR has made a new generation of surveying tools that anyone can use a reality. Without large tripods or surveying instruments, you can walk the site with just a smartphone and perform accurate 3D surveying. Simple operation that non-specialists can handle, and the convenience of obtaining real-time results, make “surveying anyone can do” possible. This aligns with initiatives like the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction and the DX (digital transformation) movement in construction sites, and represents a technological innovation that can revolutionize site productivity.

What Is Simple Surveying with LRTK

One concrete solution that realizes the combination of high-precision RTK-GNSS and smartphones mentioned above is LRTK. LRTK is an ultra-compact RTK-GNSS module developed by Reflexia, a venture from Tokyo Institute of Technology, and is used by attaching it to a smartphone (currently compatible with iPhone) via a dedicated case. It weighs approximately 125 g, is lightweight, has a built-in battery and antenna, and features a compact design with a thickness of only about 1.3 cm (0.5 in). Simply attaching it to a smartphone enables constant centimeter-level (half-inch-level) high-precision positioning, transforming the smartphone itself into a usable surveying instrument. Each person’s smartphone becomes a “universal surveying device” that can easily perform surveying, staking out, volume calculation, and AR visualization.

With simple surveying using LRTK, site supervisors and operators—not only specialized surveyors—can perform surveying. For example, on a residential land development site, an operator can check excavation volumes instantly from a machine without disembarking by pointing a smartphone. You can scan terrain with an iPhone’s LiDAR scanner to record as-built conditions, or display design models in AR to mark construction areas on site—uses are diverse. Tasks that previously relied on intuition and eyeballing can proceed with digital surveying backing them up, helping prevent mistakes and ensure quality. When explaining to clients, showing 3D models and volume calculation results on a smartphone makes the situation obvious at a glance and smooths consensus building.

As a tool that truly enables “instant on-site soil volume”, simple surveying with LRTK greatly contributes to labor reduction and efficiency. By skillfully incorporating the latest technologies, surveying and measurement tasks that used to be time-consuming can be dramatically simplified, and everyone on site can use data immediately when needed. Introducing these new surveying methods can change how sites are managed and enable more efficient construction management than ever before.

Key Points and Precautions for On-site Adoption

When introducing single-operator and smartphone surveying technologies on site, there are several points to keep in mind. First, it is important to provide sufficient pre-training on equipment and software operation. Although designed to be intuitive, mastering basics such as stable positioning and tips for accurate scanning in advance will reduce confusion on site. In particular, RTK-GNSS may take time to converge on initial positioning, so it is advisable to power up equipment with some margin before starting work.

Also, GNSS surveying requires a clear line of sight to receive signals from satellites. In mountainous areas, near tall buildings, or inside tunnels, RTK accuracy may be degraded. In such cases, consider auxiliary methods such as tying into known control points or using drone or terrestrial LiDAR. For typical earthwork sites, high-precision positioning is usually achievable, but caution is needed in poor signal environments.

For LiDAR scans, avoid trying to scan excessively large areas at once; divide the area and scan sequentially to prevent missing data. Dense dust or rain can degrade laser measurement quality, so pay attention to weather conditions. Make a habit of regularly cross-checking acquired point cloud data and measurement results against existing drawings and reference elevations to confirm plausibility; this increases confidence in the equipment.

Finally, ensure that everyone on site understands the advantages of the new surveying tools and can use them through information sharing and rule-making. If you establish operational rules in advance—such as “when and at what timing to measure” and “how to record and share results”—you can maximize the benefits of single-operator surveying. While taking into account the caveats unique to new technologies, aim for smooth adoption on site.

Conclusion

The era in which a single person can instantly measure soil volumes on site is surely approaching. The realization of “instant on-site soil volume”, once unimaginable by conventional standards, has become attainable through the use of the latest technologies. Dramatic efficiency gains and labor reduction from single-operator surveying are a promising solution for the construction industry facing severe labor shortages. Major efficiency improvements in surveying work will bring not only direct benefits such as shorter construction periods and cost savings, but also positive effects on work-style reform at sites and the development of younger engineers.

What is important is the willingness to adopt these new technologies on site without fear. You may be unsettled at first by differences from traditional methods, but once used you will be surprised by their convenience and accuracy. If all site staff can master high-precision surveying data, you can eliminate wasteful construction and achieve smooth site operation without troubles. Harnessing “proactive ICT” to improve productivity will be a source of competitive strength in the years to come.

Single-operator and smartphone surveying are expected to spread further. A central technology driving this is the simple surveying with LRTK introduced here. If you feel challenges with on-site surveying, consider using the latest solutions. It may be a small first step, but those steps will accumulate into major results and will surely dramatically improve site productivity and safety.

FAQ

Q. Is single-operator surveying possible without specialized knowledge or qualifications? A. Yes. The latest single-operator surveying tools are designed for intuitive operation and can be handled without being a professional surveyor. With basic training, site supervisors and heavy equipment operators can perform high-precision surveying. However, to achieve better results, we recommend becoming familiar with equipment operation and precautions initially.

Q. How reliable is the accuracy of smartphone surveying? A. Smartphone surveying using RTK-GNSS can achieve planar position errors on the order of several centimeters and vertical accuracy on the order of several centimeters. Although slightly inferior to conventional TS surveying or high-end laser scanners, it is sufficiently practical for volume management in earthworks. Point cloud-based measurements have fewer omissions and in some cases can improve overall soil volume estimation accuracy.

Q. Can surveying be done in bad weather or at night? A. GNSS positioning generally operates in rain or clouds, but lightning storms or very heavy rain may degrade positioning accuracy. LiDAR scanners function in dark conditions, but accuracy may be affected during heavy rain or in dusty environments. Surveying at night is possible with adequate lighting, but for visual confirmation via AR displays, sufficient ambient illumination is necessary.

Q. What is needed to start simple surveying with LRTK? A. To use LRTK, you need a compatible smartphone (e.g., an iPhone equipped with LiDAR), an LRTK receiver, and an application to operate the unit. In Japan, it is also advisable to prepare environments that can receive RTK correction information such as QZSS’s CLAS. While we recommend support for initial device setup and operation, once configured, the system can be used for routine surveying immediately.

Q. What are the advantages compared with drone surveying or conventional TS surveying? A. Drone surveying covers wide areas but is constrained by weather and flight permissions and lacks immediacy. In contrast, smartphone surveying performed by a single person can be done whenever needed and yields results on the spot—its responsiveness is the biggest advantage. TS surveying offers very high precision but requires manpower and time. Smartphone surveying reduces preparation and post-processing time, and for small-scale measurements it often yields superior total efficiency. By using each method appropriately according to the application, you can maximize site productivity.