Table of Contents

• Introduction

• Traditional on-site volume calculation methods and their challenges

• What are AR and 3D technologies? Applications to field surveying

• How on-site volume calculation changes with AR and 3D technologies

• Benefits of AR and 3D technologies for earthwork management

• The future of on-site DX and the “surveying revolution”

• What is simple surveying with LRTK

• FAQ

Introduction

Calculating the volume of fills and excavations on construction sites is an essential task for progress and cost management. However, traditional on-site volume calculations have required significant time and effort and typically depended on specialized surveying technicians. Imagine being able to measure earth and sand volumes instantly just by pointing a smartphone at the site—what once sounded like a dream is now becoming reality. Recent advances in AR (Augmented Reality) technology and 3D measurement technologies are poised to greatly change how earthwork is managed on site.

Compared with conventional, manual surveying, the new methods using AR and 3D technologies bring dramatic efficiency gains and higher accuracy—what can be called a “surveying revolution.” An era has arrived in which everyday devices like smartphones and tablets can perform on-site 3D measurements immediately. This is driven by higher device performance (high-resolution cameras and LiDAR sensors), advances in positioning technology (improved GPS accuracy thanks to Japan’s Quasi-Zenith Satellite System, Michibiki), and industry digitalization tailwinds such as the Ministry of Land, Infrastructure, Transport and Tourism’s promotion of *i-Construction*. This article explains the challenges of traditional on-site volume calculation and how AR and 3D technologies can solve them. It also covers the benefits of introducing these new technologies and introduces a concrete solution currently attracting attention: simple surveying with LRTK, offering a vision for the future of construction sites.

Traditional on-site volume calculation methods and their challenges

In civil engineering and construction, managing soil volumes—such as excavation and fill quantities—is a routine requirement. Traditionally, on-site volume calculation has required many personnel and much time. Common methods include the cross-section method and the grid method. For example, surveyors set up instruments (levels or total stations) and measure ground elevations at regular intervals, produce multiple cross-sections or grid-based elevation datasets, and then compute volumes. On small sites, tape measures and leveling rods may be used to measure a few points and estimate volumes roughly. These procedures require skilled surveying technicians, and because measurements and records must be taken point by point, it was not uncommon for a single volume computation to take half a day to several days.

These manual methods have several problems. First, estimating from limited points imposes limits on accuracy. Increasing measurement points improves accuracy but also increases effort. Second, there is the risk of human error inherent in manual work. Misidentifying measurement points or recording mistakes can introduce errors into overall volume calculations. Third, there are safety concerns. Surveying on high or steep slopes forces workers into hazardous positions and entails accident risks. In addition, compiling survey results, creating drawings, and performing quantity calculations require specialized knowledge, making it difficult for site personnel to grasp earthwork volumes in real time. Thus, traditional on-site volume calculations suffered from issues such as “time-consuming,” “labor-intensive,” and “uncertainties in accuracy and safety.”

What are AR and 3D technologies? Applications to field surveying

Utilizing AR and 3D technologies can address these challenges. AR (Augmented Reality) overlays virtual objects and information onto real-world images seen through a camera. For example, a smartphone or tablet can display design markers or virtual stakes on the screen for on-site confirmation, or visualize measured data on the spot. 3D measurement technologies acquire the shape of objects or terrain as three-dimensional digital data. Typical examples are laser measurement (LiDAR) and photogrammetry. The former emits infrared laser to obtain high-density point cloud data; the latter reconstructs three-dimensional shapes from multiple photographic images.

Recent smartphones have improved camera performance and some models even include LiDAR sensors, enabling 3D scanning with a single device. GNSS (satellite positioning) has also dramatically improved in accuracy even on standalone smartphones thanks to “multi-GNSS” and Japan’s Quasi-Zenith Satellite System. Furthermore, by using an external RTK-GNSS receiver attached to a smartphone, current position can be determined with positioning accuracy of several centimeters (several 0.4 in). On this technological foundation, site-oriented AR apps and 3D scanning apps have emerged, making it increasingly possible for anyone to easily perform on-site 3D measurements. The so-called “mobile scan” (field measurement using handheld devices such as smartphones) is gaining attention and has the potential to dramatically transform surveying and measurement work that previously relied on specialized equipment and experienced technicians.

Concrete applications to field surveying include combining a smartphone with a compact GNSS receiver to highly accurately position site control points, then scanning surrounding terrain and features with that smartphone to generate point cloud data and 3D models in real time. With AR, acquired 3D data and pre-construction design models can be overlaid on the actual site view, allowing confirmation of the finished image or excavation limits on the spot. For example, AR can display the positions of buried pipes in advance to warn excavators, or project the designed final shape onto the site to check conformity. AR and 3D technologies thus bring major innovation to sites not only by “measuring” but also by “showing and communicating.”

How on-site volume calculation changes with AR and 3D technologies

So how exactly does on-site volume calculation change when AR and 3D technologies are introduced? The major difference from traditional methods is that the entire workflow—from measurement to volume computation—can be completed on site. Previously, survey data had to be taken back to the office for calculations and drawing; with new technologies, accurate volumes can be obtained quickly while still on site. Below is a simple outline of the flow for volume calculation using the new approach.

• Reference setup: Attach an RTK-capable GNSS receiver to the smartphone and correct the device position to known site points or reference elevations. This gives scanned data an accurate positioning reference (latitude, longitude, elevation).

• 3D scan: Launch a dedicated scanning app and walk around the soil or terrain to be measured while recording. With a LiDAR-equipped smartphone, simply moving the device captures point cloud data on the spot. Even on devices without LiDAR, photographing the target from various angles allows photogrammetric 3D modeling. In a short time, hundreds of thousands to millions of measurement points can be collected—data volumes impossible to obtain by hand—fully capturing the shape of fills or excavations.

• Volume calculation: Once scanning is complete, the device automatically generates a 3D model (point cloud data). Next, volume is calculated from that point cloud. For fills, volume is computed from elevation differences relative to surrounding ground; for excavations, volume is determined from differences against a pre-excavation ground model. Dedicated apps or cloud services instantly present calculation results as numbers and color maps, making it easy to see where and how much material exists at a glance.

• Data sharing and utilization: Calculated volume data and 3D models can be uploaded to the cloud and shared with stakeholders on the spot. Site agents and office engineers can share information in real time, aiding additional checks and decision-making. Shared data can also be AR-displayed on other devices at the site so that, for example, teams can intuitively verify how much fill is lacking compared with the plan.

Thus, using AR and 3D technologies, a single operator can complete on-site volume measurement and calculation in a short time. For instance, a fill cross-section survey that traditionally required multiple people and half a day can now be finished by one person walking around with a smartphone in several dozen minutes. Because 3D data automatically yields volumes, manual calculations and redrawing are eliminated. This enables non-specialist staff such as site supervisors to quickly grasp earthwork quantities when needed, dramatically speeding up decisions like revising earthwork plans or arranging materials and equipment.

Benefits of AR and 3D technologies for earthwork management

The new surveying methods enabled by AR and 3D technologies offer more than simply faster measurement; they bring a variety of benefits to overall earthwork management. Main advantages are summarized below.

• Dramatic efficiency gains and labor reduction: Large areas can be measured quickly, and the point cloud obtained from a single scan conveys the whole site. Information that was fragmentary when collected manually can now be comprehensively captured, greatly reducing surveying time. Because operation is generally possible by a single person, there is no need to assign multiple staff. As a result, limited personnel can manage earthwork tasks efficiently, serving as a countermeasure to severe labor shortages.

• Improved measurement and data accuracy: Point cloud data is far denser than conventional point measurements and captures subtle surface irregularities in 3D. Height differences and small bumps that can be overlooked are visualized, improving volume calculation accuracy and ensuring reliable conformity checks against design. With RTK-enabled measurements, each point can be assigned world coordinates such as public coordinates, minimizing positioning errors when aligning multiple datasets and yielding highly reliable survey results.

• Improved safety (non-contact and remote measurement): Because measurements can be taken from a distance without entering hazardous areas, worker safety is enhanced. For example, volumes on steep slopes or potentially unstable areas can be recorded remotely by operating equipment from a safe position. Reducing time spent measuring near heavy machinery or at heights greatly lowers the risk of falls or contact incidents. Shortening measurement time also means less time spent in dangerous zones, providing significant safety benefits.

• Low-cost, low-barrier introduction: While cutting-edge technologies might suggest expensive equipment, the smartphone-plus-small-sensor approach can be relatively low cost to start. Laser scanners used to require multi-million-yen investments, but many sites already have smartphones and additional devices often cost less than a few hundred thousand yen, making adoption feasible for small and medium enterprises and municipalities. No dedicated operator is required, and apps are intuitive, so training costs are low. New employees and younger staff familiar with smartphones can use them with little resistance and be deployed after short training. Some sites have reduced total costs by insourcing surveying previously outsourced.

• Data sharing and promotion of DX: Obtaining digital 3D data transforms earthwork management processes into DX (digital transformation). Using cloud sharing, point clouds and measurement results collected on site can be instantly shared with the office and stakeholders, allowing remote supervision and instructions. Everyone can discuss the same 3D model, reducing misunderstandings and smoothing consensus building. The Ministry of Land, Infrastructure, Transport and Tourism has drafted guidelines for finish management using 3D measurement technologies, and point cloud–based finish management is being formalized, making 3D scanning and AR usage an industry new norm. Storing 3D data at each stage of construction also helps quantify progress and serves as future maintenance documentation. Information that is hard to convey with text or 2D drawings becomes clear in visual 3D, deepening stakeholder understanding and enhancing transparency and reliability of site management.

The future of on-site DX and the “surveying revolution”

The surveying revolution driven by AR and 3D technologies is expected to accelerate further. Currently, smartphone and tablet methods are central, but these could evolve into AR glasses and further automation. For example, site supervisors might one day wear AR-capable smart glasses that display necessary survey data and design information in their field of view. This would enable hands-free, real-time grasp of earthwork volumes and immediate adjustments to construction plans.

Integration with drones and robots is also possible. Aerial 3D surveying (UAV photogrammetry) is already used in large-scale earthworks, and combining it with ground mobile scans and AR would enable exhaustive site data collection from both above and on the ground. Advances in AI should not be overlooked either. AI could analyze massive point cloud datasets to automatically propose optimal earthwork plans or detect anomalies and warn of construction errors in advance.

The important point is that these technologies will not remain tools only for specialists but will be translated into instruments anyone on site can use. We are approaching a reality of “anyone-as-a-surveyor.” As experienced technicians decrease, intuitive digital tools will support sites so that the next generation can maintain high quality and safety. The surveying revolution is transforming workflows across construction management, and its benefits will continue to expand. To avoid being left behind in on-site DX (digitalization), we must watch developments and actively adopt new technologies.

What is simple surveying with LRTK

So how can the AR and 3D technologies described above actually be used on site? One answer is simple surveying with LRTK. LRTK is a next-generation surveying solution using smartphones that fuses high-precision GNSS (RTK method) with AR technology. Specifically, by using a small RTK-GNSS receiver that can be attached to a smartphone and a dedicated app, a smartphone is transformed into a surveying device with centimeter-level accuracy (half-inch accuracy). On site, simply carrying a smartphone + LRTK receiver set and walking around allows acquisition of 3D point clouds with high-precision position information. Tasks that previously required specialized equipment and experienced personnel can be performed intuitively by non-special site staff, enabling rapid surveying.

One feature of LRTK is the ability to AR-display acquired point cloud data and design data on site. For example, overlaying the point cloud model of a soil pile scanned with LRTK onto the actual scene on a smartphone screen makes it easy to check differences between as-built and design shapes with color-coded heat maps. AR-guided virtual stake placement can also guide marking exact locations for surveying tasks. LRTK integrates with cloud services, letting you upload site data instantly and share it with stakeholders. This makes it possible to check site 3D conditions or verify volume calculation results remotely, so information sharing speed dramatically improves.

In short, simple surveying with LRTK is a concrete solution that embodies the “surveying revolution by AR and 3D technologies” described in this article. Without purchasing specialized surveying equipment, you can experience cutting-edge surveying simply by attaching a small receiver to your smartphone. For site personnel struggling with earthwork management, LRTK becomes a reliable ally that delivers speed, safety, affordability, and simplicity. Please experience how this technological innovation can dramatically streamline on-site volume calculations at many sites.

FAQ

Q1. What can AR technology do? A. Using AR (Augmented Reality), digital information can be overlaid on the real scene viewed through a smartphone or tablet screen. On site, you can overlay design shapes or survey data on the real view to confirm them, or display virtual markings (stakes or lines) to guide work. In other words, AR enables intuitive grasp of construction progress and as-built conditions and allows visual assignment of work instructions.

Q2. Can a smartphone really measure earth volumes accurately? A. Smartphones alone, equipped with LiDAR or high-performance cameras, can perform surprisingly accurate 3D scans. Calculating volume from the point cloud data obtained from scanned fills or excavations yields far more accurate results than manual rough estimates. However, for stricter accuracy requirements, techniques such as position correction with RTK-GNSS are effective. For example, using an RTK-capable receiver like LRTK can reduce positioning errors to the order of a few centimeters (a few 0.4 in), greatly improving the reliability of volume calculations.

Q3. Can anyone use the new AR/3D surveying methods? A. Yes. These systems are generally designed so that special qualifications are not required. Dedicated apps are simple to operate; in many cases, following on-screen guidance while moving the smartphone completes the measurement. Compared with traditional surveying instruments, the user interface is intuitive, so young site staff can learn quickly with short training. However, when preparing formal finish management documents, operational considerations such as final checks by licensed surveyors may still be necessary.

Q4. How does this differ from drone surveying? A. Drone (UAV) photogrammetry has the advantage of quickly acquiring broad terrain data, but aerial perspectives can miss blind spots and are unsuitable for indoor or underground spaces where GPS does not reach. Smartphone-based AR/3D surveying (mobile scan) can measure fine details from ground level and is useful in confined sites and indoors. The two approaches complement each other: use drones for overall context on large sites and mobile scans for detailed measurements and indoor work.

Q5. What does LRTK stand for and what are its benefits? A. LRTK is a product brand name derived from company and technology concepts and is not an acronym for specific words (it implies a solution utilizing real-time kinematic (RTK) positioning). The main benefit of LRTK is that a smartphone becomes a high-precision surveying instrument. Without expensive specialized equipment, you can achieve centimeter-level positioning and 3D scanning with affordable gear, dramatically streamlining on-site surveying and volume calculations. Because positioning data, 3D data, and AR display functions are integrated, you can not only measure but also readily confirm and share results on the spot. Ultimately, LRTK enhances earthwork accuracy, saves time, and improves safety simultaneously.