Even beginners can survey with a smartphone! The compact surveying device "LRTK" makes point cloud creation easy with centimeter accuracy (cm level accuracy (half-inch accuracy))

When people hear about surveying on-site, many picture large tripods and specialized equipment. Conventional surveying work was carried out by specialist technicians using expensive dedicated equipment, and many people felt “I can’t do it.” However, in recent years, compact and easy-to-use surveying instruments have emerged, and the world of surveying has begun to change dramatically. Among them, the compact surveying device that can be used in combination with a smartphone, "LRTK", is attracting attention. This tool, which allows even beginners to achieve centimeter-level accuracy with just a smartphone and easily acquire point cloud data, is dramatically lowering the barriers to surveying.

This article summarizes the challenges of conventional surveying and the benefits of compact surveying devices, and introduces the features and use cases of LRTK that make surveying with a smartphone possible. It also provides useful information for young engineers who are not surveying specialists and for those in construction or civil engineering who have experienced "suddenly needing to survey!"

Was traditional surveying the work of specialists? Large-scale equipment and high barriers

Traditional surveying involved large equipment such as transits, total stations, and GNSS survey instruments, and was work carried out by teams of experienced surveyors. For example, even just establishing control points at a construction site required carrying heavy equipment, setting up tripods, and having surveyors perform advanced setups. Converting survey results into digital data also involved the hassle of using specialized software on a computer, and sharing them in real time on site was not easy. With these conventional methods, it was not something non-specialists could handle casually, and the image of “surveying = something to hire a professional for” became entrenched.

Surveys that require large-scale equipment and specialized skills pose high hurdles in terms of time and cost, and they have hampered on-site agility. Even for small surveying tasks, teams often had no choice but to call in external specialists, and even when junior staff on site thought, "If only I could do a little measuring myself…", that was difficult to achieve under traditional approaches.

How the Emergence of Compact Surveying Instruments Is Changing Field Surveying

Advances in technology have made surveying instruments increasingly compact and higher-performing year by year. Recently, palm-sized small surveying instruments have appeared, overturning conventional wisdom about field surveying. As the name suggests, small surveying instruments are compact surveying devices that offer excellent portability while enabling accurate positioning and measurement.

The main advantages of compact surveying instruments are, above all, their convenience and responsiveness. Surveys that used to require time-consuming preparation can be started immediately with compact devices whenever the need arises. Even field engineers running around a site can quickly pull them from a pocket and use them, enabling rapid measurements between tasks. Also, because they are a size and weight that a single person can carry, they offer high mobility and perform well in tight spaces or at heights where large equipment is difficult to bring in.

Furthermore, the latest compact surveying instruments have dramatically improved usability by integrating with smartphones and tablets. Because they can be operated from a smartphone’s screen, they are intuitive, and measurement data is digitally recorded on the spot and easily shared to the cloud. In other words, with the advent of compact surveying instruments, "surveying that only specialists could perform" is beginning to become "a task anyone can do, anytime, anywhere."

You Can Do This Much with a Smartphone! Digital Technologies Transforming Surveying

Modern smartphones are equipped with high-performance sensors and processing capabilities, and they are demonstrating their power in the world of surveying. In particular, the new surveying style enabled by combining smartphones with compact surveying instruments is accelerating on-site DX (digital transformation).

Smartphones themselves are also equipped with GPS, cameras, accelerometers, and other sensors, but the GPS positioning of a typical standalone smartphone has errors of several meters and is not suitable for precise surveying. What helps in such cases is a compact RTK-GNSS-capable surveying device that can be connected to a smartphone. RTK (Real-Time Kinematic) is a technology that greatly reduces satellite positioning errors by using correction information from a base station, and by combining a device that supports this with a smartphone, the usual errors of several meters can be reduced to within a few centimeters. The smartphone receives high-precision position information from that device and displays and stores data using a dedicated app. In addition, because LRTK supports multi-frequency GNSS signals, it can directly receive the centimeter-level augmentation service (CLAS) provided by Japan’s quasi-zenith satellite "Michibiki" even at sites without internet connectivity, allowing high-precision positioning to continue.

Also, by using a smartphone’s camera and LiDAR sensor (on models equipped with one), it is possible to acquire 3D point cloud data through photogrammetry or simple scans. Point cloud measurement, which traditionally required expensive 3D laser scanners, can now be easily achieved with a combination of a smartphone and surveying apps. In other words, the smartphone becomes the mothership for surveying equipment, with small devices boosting its accuracy and functionality, making it a powerful surveying tool that even beginners can use.

What is the compact surveying instrument "LRTK"? Turn your smartphone into an all-purpose surveying device

Among the many compact surveying instruments, the one attracting attention right now is "LRTK". Among field construction managers and workers it has quietly become a boom as a "surveying instrument that fits in your pocket", and it is expected that having one per person will improve work efficiency. LRTK is a pocket-sized surveying device developed by Refixia, a startup originating from Tokyo Institute of Technology, and is attached to and used with an iPhone or iPad. It weighs approximately 165 g and features a thin, lightweight design with a thickness of only about 13 mm (0.51 in), so it doesn't bulk up when attached to a smartphone and is easy to carry. Indeed, a surveying instrument that fits in your pocket is its catchphrase.

LRTK is an integrated smartphone-case device that incorporates an ultra-compact, one-touch detachable RTK-GNSS receiver. Simply attach it to your smartphone and an ordinary phone instantly becomes an "all-purpose surveying instrument" with centimeter-level positioning accuracy (half-inch accuracy). It operates on a built-in battery, so no complicated wiring is required and you can start using it on site immediately.

So, what specifically can you do with LRTK? Let's look at the main features and functions.

High-precision position measurement at the touch of a button

Using LRTK, you can measure positional coordinates on a map with high precision. For example, simply hold the device over the point you want to measure and tap a button in the smartphone app to instantly record that location's latitude, longitude, and altitude. RTK-GNSS corrections keep errors to within a few centimeters or less (a few in or less), allowing even beginners to achieve accuracy comparable to professional methods. You can also check satellite reception status and accuracy indicators in the app during positioning, so you can see at a glance whether high-precision positioning is being achieved. Furthermore, the LRTK app also includes a positioning data averaging function. This feature automatically averages multiple measurement results to calculate a more accurate value, and by remaining stationary and measuring for only a few tens of seconds, it is even possible to obtain stable coordinates on the order of millimeters (mm, in). LRTK can easily handle tasks that require high precision, such as control point surveying.

Supports point cloud measurement, layout marking, and AR

LRTK does more than just measure coordinates. By integrating with a smartphone’s camera and sensors, it provides a variety of surveying and measurement functions. One of these is point cloud measurement. By combining LRTK’s high-precision positioning information with a smartphone’s imaging capabilities, you can record site conditions as 3D point cloud data. For example, if you scan post-construction terrain or structures while walking around with a smartphone, you can obtain detailed point clouds with guaranteed positional accuracy. From the acquired point cloud data, you can calculate distances, areas, and volumes, or easily overlay them with design data to verify as-built conditions (construction results).

Conversely, using coordinate data from drawings or BIM models, on-site layout marking (marking) to indicate positions is also possible with a single LRTK unit. If you enter the coordinates of the point you want to measure into the app, the smartphone screen will guide the user to the specified location like a navigation system. This allows you to carry out staking and position-marking tasks that were previously left to surveyors.

Furthermore, LRTK also supports AR (augmented reality) functionality. Through a smartphone screen, it can overlay design data onto site footage or project virtual structures onto the actual site. With positioning information at centimeter accuracy (cm level accuracy (half-inch accuracy)), AR-displayed objects no longer suffer from positional offsets, enabling simulations that more closely match reality. For example, uses such as "overlaying a completion rendering on the actual site" and "displaying the location of buried objects in AR" can be envisioned, aiding intuitive on-site understanding and communication.

Cloud integration streamlines data management

Positioning data and point cloud data obtained with LRTK can be saved to and shared on the cloud directly from a smartphone on site. You can upload to your company's cloud service with one button from the LRTK app, enabling office staff to share data in real time. Coordinates measured on site are automatically plotted on a web map and can be viewed in a list along with information such as point names, timestamps, and notes. This eliminates the need to exchange USB drives or paper field notebooks between the site and the office, and dramatically accelerates the speed of information sharing.

For example, if point cloud data collected on site is uploaded to the cloud immediately, engineers in the office can start using that data right away for volume calculations and creating drawings. Until now, even if data was collected on site it could not be verified until it was brought back to the office, but with LRTK the field and the office can coordinate in real time, improving overall work efficiency.

Another advantage is that storing data in the cloud makes it easy to search and review past surveying records. Even if you later want to recheck the survey results from that time, logging into the cloud lets you quickly retrieve the location information and point cloud data. Unlike paper records, there is no risk of loss, giving you peace of mind for data management.

Benefits and Use Cases of LRTK in the Field

As described above, LRTK delivers a wide range of functions in a single device, bringing new value to job sites as a surveying tool that even beginners can operate. It also aligns with construction-site DX (digital transformation) initiatives such as i-Construction promoted by the Ministry of Land, Infrastructure, Transport and Tourism, and the value of such high-precision surveying tools that anyone can use is steadily increasing. So, specifically, in what situations is LRTK useful? Let’s organize the potential benefits and use cases.

• Even one person can survey immediately: Traditionally, surveying required assembling a team and coordinating schedules, but with LRTK you can start surveying on the spot by yourself as soon as you think of it. If a sudden measurement is needed, simply take the device out of your pocket and be ready in minutes.

• No specialist knowledge required: The app automatically performs all complex surveying calculations and coordinate transformations. Converting to the plane rectangular coordinate system and calculating geoid heights can also be left to the app. Even young engineers without surveying expertise can obtain accurate data simply by following the on-screen instructions, so they can feel confident. The LRTK app’s interface is simple and easy to understand, and anyone familiar with smartphones should be able to use it intuitively.

• Cost reduction and efficiency: In cases where small-scale surveys were outsourced each time, introducing LRTK can be expected to deliver substantial cost savings. The price of LRTK itself is also significantly lower than that of conventional high-precision surveying equipment, making it realistic to deploy multiple units so that all field staff can carry one. Once purchased, it can be used repeatedly, eliminating the need to repeatedly pay labor costs. It also reduces travel and waiting time, improving overall operational efficiency.

• Improved safety: The lightweight, compact LRTK is also suitable for surveying at height and in areas with poor footing. It reduces the risk of carrying heavy equipment through hazardous locations, and because surveys can be completed in a shorter time, it also eases the burden on workers.

• Applications outside construction and civil engineering： LRTK can be used not only on construction and civil engineering sites but also in a variety of fields beyond surveying, such as agriculture and environmental surveys. For example, in agriculture it can measure field topography and determine land area, and in environmental surveys it can record local terrain and vegetation distribution—any situation that requires accurate location information. Being able to collect data without waiting for specialists will help speed up decision-making across many fields.

• Effective for disaster response as well: LRTK also proves valuable for understanding conditions at disaster sites and measuring the extent of damage. Because you can record and share the damage situation on site as point cloud data without calling in a specialized surveying team, initial response and the consideration of recovery plans can be expedited.

Summary: Achieving simple, high-precision surveying using LRTK even for beginners

With the evolution of compact surveying instruments, the era when surveying was only for specialists is coming to an end. In particular, the advent of smartphone-compatible LRTK has dramatically transformed field surveying practices. With just a compact device and a smartphone, even beginners can perform surveys and acquire point cloud data with centimeter-level accuracy (cm level accuracy, half-inch accuracy), allowing them to carry out tasks they had previously given up on.

LRTK will be a reassuring companion for young engineers and professionals who are not surveying specialists. Thanks to an easy-to-use app and a compact device, advanced surveying technology has been incorporated into accessible tools. With calls for improved on-site productivity and workstyle reform, equipping each person with an LRTK as their surveying tool should dramatically improve daily work efficiency.

Even beginners unfamiliar with surveying no longer need to hesitate. Experience the new form of surveying you can start with a smartphone using LRTK. You will surely be surprised by its ease and accuracy, and it will change the way you carry out work on site. From now on, when you want to take a measurement, you can do it immediately with your smartphone and LRTK — that era is now within reach. Why not bring this new surveying experience to your site as well?

Detailed product information and case studies are also available on the [LRTK official website](https://www.lrtk.lefixea.com). If you’re interested, please check it out.