Achieved with LRTK! Dramatically Improving the Accuracy and Efficiency of One-Man Surveying

On construction and surveying sites, chronic labor shortages and the need to improve productivity have brought attention to one-man surveying, where surveying tasks can be completed by a single person. If you could perform accurate surveying entirely on your own, without anyone’s help, how much more efficient would on-site work become?

Traditionally, surveying tasks have generally been performed by two-person teams, but recent technological advances have made it possible for one person to conduct high-precision surveys. Particularly noteworthy is LRTK, which leverages the latest RTK-GNSS technology. This article explains how using LRTK can dramatically improve the accuracy and efficiency of one-man surveying.

What is one-man surveying

One-man surveying, as the name implies, is surveying work carried out by a single person. Normally, surveying is conducted by two people: one operating the surveying instrument and another holding a staff or prism. For example, with a total station, one person looks through the telescope and aims at the target while the other holds the prism at a distant point. However, with one-man surveying these steps are completed by a single operator. In recent years, total stations with automatic aiming and auto-tracking functions and RTK-GNSS positioning devices that can obtain high-precision positions in real time have made it possible for one person to measure even distant points.

Benefits of one-man surveying

The rise of one-man surveying is driven by serious labor shortages and the need to reduce costs in the construction and surveying industries. With traditional two-person surveying, securing personnel and scheduling took time and money, but if one person can complete the work, these burdens can be greatly reduced. The main benefits are summarized below.

• Reduced labor costs: Because surveying can be done with one person, labor costs can be significantly reduced.

• Flexible scheduling: There is no need to arrange additional personnel, so surveying can be carried out immediately as site conditions require.

• Improved work efficiency: Since verbal cues and team coordination are unnecessary, work proceeds smoothly. One person can steadily carry out tasks even on large sites or in noisy environments, reducing time loss.

• Stable quality: When an experienced operator consistently performs the work alone, surveying methods are standardized and data variation is reduced. Having the same person always take measurements yields consistently high-quality survey results.

As described above, consolidating the personnel required for surveying from two people to one effectively doubles the workload per person and directly contributes to increased overall site productivity.

Challenges of one-man surveying

On the other hand, one-man surveying has some challenges (disadvantages). Although advances in technology have made solo surveying possible, attention must be paid to the following points.

• Burden of equipment preparation: A single person must carry and set up all equipment such as surveying instruments and tripods, which can impose a large physical load on the operator. This can be especially concerning when equipment must be placed by the roadside or other locations where safety is difficult to ensure.

• Need for specialized equipment: To enable one-man surveying, advanced surveying instruments such as total stations with auto-tracking functions are required. Such specialized equipment tends to be more expensive than general surveying instruments, increasing initial procurement costs.

• Advanced skills and experience: Because the entire surveying process is performed alone, the operator must have high skill and abundant experience. Even with automated equipment, there may be malfunctions or limitations depending on conditions, and flexible responses such as switching to manual operation are necessary.

Nevertheless, these challenges are being resolved one by one by new technologies. For example, the burden of equipment can be alleviated with pocket-sized compact devices, the cost hurdle can be lowered by using more affordable equipment instead of expensive specialized instruments, and intuitive smartphone apps can support operators who would otherwise need high expertise. LRTK is precisely an embodiment of these solutions.

What is LRTK

LRTK is a pocket-sized, all-purpose surveying device developed by Lefixea, a startup originating from Tokyo Institute of Technology. It is an ultra-compact RTK-GNSS receiver that can be attached to a smartphone (iPhone/iPad), turning a smartphone into a surveying instrument with centimeter-level accuracy (cm level accuracy (half-inch accuracy)). Weighing about 125 g, it is extremely lightweight and can be attached to a dedicated smartphone case with one touch so it can be taken from your pocket and used at any time. It also has a built-in battery, enabling long continuous measurements on site.

With this small device you can perform a variety of tasks from positioning (point measurement) to point-cloud measurement (3D scanning using the smartphone’s LiDAR), layout marking, and displaying design data in AR (augmented reality). Acquired data are automatically calculated and recorded on the smartphone and can be uploaded and shared to the “LRTK Cloud” with a single button. Using an optional monopod (pole) allows stable mounting of the device and makes height offset correction easy to set in the app.

On sites, LRTK is quietly becoming a hit as a “surveying instrument that fits in your pocket,” and its affordable price makes equipping “one person, one device” realistic. Traditionally, one-man surveying required expensive equipment such as auto-tracking total stations, but LRTK greatly lowers that barrier. Its pricing is very reasonable compared with conventional surveying instruments, allowing high-precision surveying at low introduction cost, which is a major benefit for sites. LRTK has already begun to be adopted by local governments, construction companies, and is proving useful in a wide range of applications including disaster-site surveying, infrastructure inspections, and land surveys.

Basic operation of LRTK is also remarkably simple. For a single-point measurement, for example, just place the LRTK receiver attached to a pole tip at the point you want to measure and tap the positioning button in the smartphone app. The latitude, longitude, and height of that point are recorded instantly, and the point name, measurement time, and satellite reception status are automatically saved. There is no need to write notes in a paper field book; all data are digitally managed, preventing recording mistakes.

Example workflow for surveying work using LRTK:

• Attach the dedicated case to the smartphone and mount the LRTK receiver on it.

• Launch the LRTK app and establish a connection to a reference station (network-based correction service or Michibiki CLAS).

• At the point to be measured, place the receiver at the pole tip at the specified position and tap the positioning button in the app.

• The measured latitude, longitude, and height data are automatically saved to the smartphone. Add point names or notes if necessary.

• Upload the accumulated data to the cloud and share it with the office PC or stakeholders.

High-precision surveying realized with LRTK

One of LRTK’s outstanding features is its positioning accuracy. Standard smartphone GPS can have errors of several meters, but LRTK leverages RTK-GNSS technology to enable high-precision positioning with errors of only a few centimeters or less. RTK positioning supported by LRTK uses signals from multiple satellite positioning systems (GPS, GLONASS, GALILEO, and Japan’s Michibiki, etc.) and improves accuracy through relative positioning with a reference station. Single GNSS positioning alone can have errors of several meters due to ionospheric or clock errors, but RTK can correct these in real time and reduce errors to just a few centimeters to a few millimeters. This reliable method is used in civil engineering surveying, and by supporting RTK, LRTK achieves accuracy comparable to conventional surveying equipment. Vertical (elevation) accuracy is also on the order of a few centimeters and is sufficiently practical for general construction management. In fact, LRTK positioning has been confirmed to produce horizontal errors of approximately 1-2 cm (0.4-0.8 in) even in single measurements, and averaging multiple observations can achieve accuracy under 1 cm (for example, about 8 mm (0.31 in)).

Additionally, LRTK can achieve high-precision positioning even without an Internet connection by receiving the centimeter-class augmentation service (CLAS) distributed by Japan’s quasi-zenith satellite “Michibiki.” Therefore, surveys with guaranteed accuracy can be conducted in mountainous areas or disaster sites where mobile phone signals do not reach. LRTK has actually been used in earthquake disaster site surveys, demonstrating its power for rapid surveying where large equipment cannot be brought in.

The LRTK app can convert acquired latitude and longitude positioning data in real time to the Geospatial Information Authority of Japan’s plane rectangular coordinate system and elevation (geoid height) and record them. Information such as point names, measurement date and time, and satellite capture status are also automatically saved, making it easy to later verify accuracy and organize results. Such high-precision and reliable surveying can be performed by a single operator thanks to LRTK.

Dramatic improvements in surveying efficiency created by LRTK

With LRTK implementation, on-site surveying work can also expect dramatic efficiency improvements. Compared with traditional surveying styles, the following points illustrate the efficiency gains.

• Mobility and ease: Because surveying is completed with pocket-sized LRTK and a smartphone, there is no need to carry heavy tripods or large equipment. You can walk around the site and immediately measure any point of interest, and conveniently take measurements during breaks in other tasks. Moreover, because LRTK uses GNSS positioning, line-of-sight between the survey point and the instrument is not required, making it easy to measure points that were previously difficult to access because of obstructions.

• Improved personnel efficiency: Being able to survey alone eliminates the need to allocate other personnel, allowing surplus staff to be assigned to other tasks. Not having to tie up multiple people for surveying increases overall team productivity.

• Real-time data sharing: Measurement data can be uploaded to the cloud immediately and shared in real time with office staff. Positioning data on the cloud can be downloaded in CSV or SIMA formats, making it easy to import into existing design and surveying software. Sharing only the access URL to cloud data allows stakeholders to view results, enabling smooth information sharing with subcontractors and clients. Being able to confirm and report measurement results on the spot reduces rework and waiting time, leading to faster decision-making.

• Time savings through multifunctionality: LRTK supports not only point measurements but also point-cloud scans, photographic records, and AR display of drawing data with a single device. Because you do not need to combine different instruments and processes, a series of tasks can be completed together, resulting in major time savings.

• Easy operation: Positioning and various calculations are automated with simple button operations in the dedicated app, making the device easy to handle even without advanced expertise. People unfamiliar with complex machinery can master it quickly and perform accurate surveys. Because it uses a smartphone that users are accustomed to, younger operators are less resistant, facilitating smooth skill acquisition and succession.

By utilizing LRTK in this way, surveys can be streamlined in every aspect, contributing significantly to overall site productivity improvements and cost reductions.

For example, you can scan a construction area with LRTK and a smartphone’s LiDAR, calculate earthwork volumes on the spot for use in as-built management, or use the AR function to overlay design lines from drawings onto the real ground to confirm pile-driving positions—all of which can be easily done by a single person. Tasks that once required specialized surveying equipment or multiple personnel can be completed quickly with LRTK.

Also, baseline point surveys that previously required two people with a total station can be done by a site supervisor carrying the drawings and walking to each point, simply taking successive measurements with a smartphone. There is no need to carry and set up heavy equipment or exchange signals with a partner, so all required coordinates can be obtained quickly, resulting in a substantial reduction in time.

Case studies: efficiency gains realized with LRTK

Voices from actual sites also attest to LRTK’s effectiveness. At a mid-sized construction site, surveying that previously took a two-person team more than half a day was completed after LRTK introduction by one person in about two hours, greatly reducing the person-hours spent on surveying. The site supervisor reported, “There’s no more waiting for surveying, so we can concentrate on other tasks,” and “Being able to measure points myself while checking drawings makes planning smoother.”

At another civil engineering site, scheduling was difficult because surveying specialists had to be called in as needed, but after equipping the site with LRTK, on-site technicians could conduct surveying during their available time. This allowed surveying to be fitted into gaps between tasks, eliminating waiting times and shortening the construction schedule. In this way, on-site feedback praises one-man surveying with LRTK as a “tool that changes site norms.” These examples demonstrate that LRTK is making labor-saving and efficiency improvements in surveying a reality at the site level.

Conclusion

One-man surveying is expected to become increasingly widespread as a new surveying style that greatly contributes to solving labor shortages and improving work efficiency. Among the options, LRTK solves traditional challenges with innovative technology and greatly expands the possibilities of one-man surveying. By using LRTK, surveying tasks that previously required two people can be transformed into simple surveying that one person can perform safely and accurately.

With high-precision surveying made possible by compact, lightweight equipment and a smartphone app, the barriers to surveying are lowered, and an era is approaching in which anyone can quickly take measurements on site when needed. Because even on-site staff without special qualifications can obtain high-accuracy survey data using LRTK, this technological innovation will also support the construction industry’s DX (digital transformation).

The adoption of such single-operator surveying technology is expected to significantly contribute to improving productivity across the construction industry, where labor shortages are becoming more severe.

LRTK dramatically improves the accuracy and efficiency of one-man surveying and is poised to greatly change on-site working styles. If you are interested in productivity improvements through one-man surveying, please check details on the [LRTK official site](https://lrtk.lefixea.com). LRTK could bring new possibilities to surveying at your site.