How to Achieve Solo Surveying as Fast as Possible? LRTK Introduction Checklist [Definitive Edition]

Background: Why Solo Surveying Is Needed

On construction and civil engineering sites, surveying work has traditionally required multiple people. For example, one person would operate the surveying instrument (such as a total station) while another stood at a distant point holding a staff (rod) to indicate the position. This two-person workflow from setup to takedown consumes time and effort, and when surveying large areas or many points it is not uncommon to spend an entire day. Manual measurement also carries the risk of human error (misreading or recording mistakes), and any mistakes require re-measurement later, making the process inefficient.

In recent years, the construction industry has faced a serious labor shortage and an aging workforce, creating demand for labor-saving and efficiency improvements so that sites can operate with fewer people. (Note: The Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative also aims to improve productivity through labor-saving measures.) The number of veteran survey technicians is declining, and continuing to rely on people for surveying has become increasingly difficult. For these reasons, expectations for solo surveying (one-person surveying) have risen. By leveraging the latest digital technologies, high-precision surveying can be performed with a small workforce, accelerating on-site DX (digital transformation).

Challenges of Solo Surveying (Accuracy, Safety, Operational Burden)

When surveying alone, several challenges must be addressed. First is ensuring accuracy. Standalone GPS positioning typically yields errors on the order of meters, raising concerns that accuracy may be inferior compared with traditional methods. Beginner surveyors, without someone to double-check, may feel uncertain whether position fixes are correct.

There are also safety concerns. Traditionally, two or more people could watch surroundings and work together, but with solo surveying the operator must handle the equipment while also monitoring the environment. When working alone at sites with operating heavy machinery or in locations with heavy traffic, robust safety measures are required so that attention to surroundings is not neglected.

Furthermore, the operational burden is an issue. One person must transport and set up all equipment and perform measurement and recording tasks. Conventional surveying instruments are heavy and complex to set up, posing a high barrier for novices. If equipment malfunctions or communication errors occur during surveying, the sole operator must troubleshoot independently, requiring specialized knowledge. Solutions that allow a single person to survey comfortably while ensuring accuracy and safety have therefore been sought.

What Is LRTK? (Mechanism and Difference from RTK)

A revolutionary surveying system meeting these needs is LRTK, which combines a smartphone with a compact GNSS receiver. First, the background: GNSS (global navigation satellite systems), represented by GPS, have evolved significantly. The technology that measures your position (latitude, longitude, altitude) from GNSS satellite signals is familiar from car navigation and smartphone maps, but standalone positioning accuracy is typically limited to several meters. Construction surveying and boundary verification require centimeter-level accuracy, so ordinary GNSS alone is insufficient.

RTK (real-time kinematic) is a technology developed to achieve high accuracy. RTK uses a base station receiver and a mobile receiver (rover), and corrects errors in real time by using the difference between satellite data received at the two stations, improving positioning accuracy to centimeter-level. Since the 1990s, RTK technology has become widely used in surveying, and today network RTK (Ntrip) based on the Geospatial Information Authority of Japan’s reference station network and commercial correction services are available. However, traditional RTK surveying equipment has been expensive and bulky, requiring expertise to operate. Setting up a dedicated base station and communication equipment or subscribing to a correction service increases both cost and complexity. Equipment often required multiple people to carry to the site, so even with high accuracy manpower was still necessary.

LRTK changes this situation. LRTK is an ultra-compact RTK-GNSS receiver that attaches to a smartphone (currently mainly iPhone/iPad), with antenna and battery built into a smartphone-sized housing weighing about 150–170 g and roughly 1 cm thick. Attached to the back of a smartphone and connected via Bluetooth or Lightning, your phone instantly becomes a high-precision GNSS surveying device. Equipment that once weighed several kilograms and was mounted on tripods now fits in a pocket, eliminating the need to carry a tripod. A major feature of LRTK is that it supports both network RTK and satellite-delivered RTK. In Japan, you can receive correction data via the Ntrip network over cellular communications, or if outside cellular coverage you can directly receive the free high-precision augmentation signals (CLAS) from the QZSS "Michibiki." In other words, you can correct positioning errors to within a few centimeters in real time anywhere in the country, making it a revolutionary portable device. The ease of simply attaching it to a smartphone and launching an app to begin high-precision positioning—without specialized knowledge—is another major difference from traditional RTK.

Why LRTK Enables Solo Surveying

The main reason LRTK makes solo surveying possible is that it dramatically improves positioning accuracy and real-time capability. By starting satellite reception in the dedicated app, you can obtain centimeter-class positions with RTK in tens of seconds. Once positioning stabilizes and you achieve a FIX solution (a resolved solution with errors under a few centimeters), you can walk the site and survey by yourself. For example, you can simply walk to the point you want to measure and tap the "Position" button on the smartphone screen to instantly record the coordinate values (latitude, longitude, height) for that point. There is no need for someone else to hold a staff. If needed, you can use a short-duration average positioning function to obtain stable high-precision coordinates by averaging multiple measurements.

LRTK also integrates with smartphone cameras and LiDAR to enable continuous positioning and point-cloud scanning while walking, which is revolutionary. When efficiently surveying a wide site alone, you can obtain 3D point-cloud data simply by walking with the smartphone; the surroundings are automatically scanned. All acquired point clouds are tagged with absolute coordinates (geodetic coordinates) provided by LRTK, making it easy to compare with drawings or BIM models later or to perform volume calculations. High-density 3D surveying that once required specialized laser scanners or multiple people can be handled solo with LRTK.

Real-time capability and cloud sharing also support solo surveying. Data acquired with the LRTK app (coordinate lists, point-cloud models, photos, etc.) are automatically saved on the smartphone and can be uploaded to the cloud with one tap. Because data can be shared from the field, supervisors, colleagues, and clients can receive results by the time you return to the office. The LRTK Web service plots measured points and photos on a map and allows point-cloud inspection in a 3D viewer. Stakeholders can view data via a browser without specialized software, enabling real-time collaboration with remote site managers or municipal staff. Even when surveying alone, the whole team can share the latest data via the cloud, avoiding situations where one person holds all the information. Faster data sharing also helps detect missed or incorrect measurements early, contributing to overall quality improvement on site.

In these ways, LRTK provides solutions—high accuracy, real-time operation, and data sharing—that were not available before, making solo surveying realistic and practical.

LRTK Introduction Checklist

To successfully perform solo surveying, thorough preparation for introducing the LRTK system is essential. Below is an introduction checklist—use it as a definitive reference.

• Check satellite positioning and communication environment: Confirm in advance whether stable GNSS positioning is possible at the site. If the site has cellular coverage, operate in network RTK mode; if in mountainous or out-of-coverage areas, operate by receiving Michibiki (CLAS). In mountain areas, secure positioning points with open sky; in urban areas, take into account satellite blockage and multipath (reflections) caused by tall buildings. Understand the site’s environmental conditions.

• Prepare the GNSS receiver (LRTK device): Prepare the RTK-GNSS receiver that serves as the LRTK unit. Select a model that can be attached to your compatible smartphone (e.g., *LRTK Phone*). Before purchase, check supported frequencies (whether Michibiki CLAS is supported), accuracy specifications, and continuous operating time (battery life). Update the device firmware to the latest version.

• Prepare the smartphone and dedicated app: Install the dedicated LRTK app on the smartphone or tablet to be used (iPhone/iPad recommended). For Bluetooth connections, pair in advance; for Lightning connections, physically attach and verify operation. Also check the smartphone’s OS version and specs, and ensure battery capacity and free storage are sufficient for prolonged surveying.

• Configure cloud service usage: Register for the LRTK cloud service (create an account) to share and store surveying data. Complete login and project setup before first use, and if possible perform a test upload to confirm operation. Decide on your company’s data management rules on the cloud (folder structure and naming conventions) to streamline use across multiple projects.

• On-site safety measures: Enforce safety management when working alone. On construction sites, observe basic precautions such as wearing a helmet and reflective vest, and placing cones in the work area. Avoid focusing solely on the smartphone screen—regularly check the surroundings and take breaks. Share the planned schedule and work location within the company in advance, and secure methods for regular check-ins and emergency contact.

• Operational training: Conduct LRTK operation training before actual surveying. Practice basic app functions (how to use the position button, photo capture with coordinate tagging, and point-cloud scanning). Try surveying a few points on familiar grounds to check data accuracy and sharing procedures. For RTK beginners, experiencing how long it takes to obtain a FIX solution and the effects of averaging will be reassuring.

Implementation Steps (Preparation → Communication Test → Operational Training)

Let’s review the general steps to introduce LRTK and begin using it on-site.

• Preparation: As pre-deployment preparation, attach the LRTK device to the smartphone and ensure the dedicated app can be launched. Complete account registration and device registration if necessary. Fully charge batteries and prepare spare power sources (mobile battery). If you have the coordinate system or surveying standards used on site (for example, the plane rectangular coordinate system No. X), set them in the app.

• Setup: Upon arrival at the site, start the LRTK system in a safe area where it will not be in the way. Securely fix the device to the smartphone and turn the power on (some attachment-type devices are powered by the phone and turn on automatically). Open the app and begin acquiring GNSS satellites in an outdoor location with a clear view of the sky. On a first visit, initial satellite acquisition and initialization may take time, so wait in a place with an open sky.

• Communication test: Once GNSS signals are being received, confirm that correction information is being received. If cellular network is available, start an Ntrip connection in the app and enter RTK mode. If out of coverage, switch to Michibiki CLAS reception mode automatically or set CLAS mode in the settings. Confirm whether the solution reaches the "FIX" status within tens of seconds. A FIX indicates centimeter-level positioning is possible. If FIX is slow to obtain, check for obstructions around you and move slightly if necessary. Also verify smartphone communication status and Bluetooth connectivity.

• Operational training: When positioning is stable, try measuring several points. If there are known positions (benchmarks), validate by measuring at those points to see whether correct coordinates are produced. Try measuring object locations or, conversely, use a coordinate navigation function to guide you to a given coordinate. Test taking photos with geotags and, if feasible, test the point-cloud scan function. Finally, upload data to the cloud and confirm that the office side can access it—this completes the communication test. If these procedures go smoothly, you can begin full-scale fieldwork.

Following these preparation and setup steps will allow even sites introducing LRTK for the first time to launch smoothly.

Notes and Operational Points to Make Solo Surveying Successful

To carry out solo surveying safely and reliably with LRTK, pay attention to the following points.

• Thorough accuracy control: Monitor positioning status continuously in the app and confirm that you are recording only when the solution is FIX. If the indicated error (estimated error) is large, do not record immediately—wait a bit or use the averaging function to stabilize the reading. If necessary, re-measure points multiple times to check for obvious outliers. GNSS survey accuracy varies with satellite geometry (constellation); if the app displays satellite count or DOP values (dilution of precision), use them as a reference and try to measure during times of good geometry.

• Consider the positioning environment: Avoid factors that block satellite signals as much as possible. Under flyovers, beneath trees, or in urban canyons between buildings, positioning tends to be unstable. If you must measure where GPS signals cannot reach, consider whether LRTK’s indoor positioning mode or remote object positioning features (which estimate coordinates remotely) can be used. If impossible, do not force the measurement alone—bring a helper and use conventional methods for that point.

• Safety-first behavior: When working alone you are responsible for safety. Regularly check surroundings so you do not miss trip hazards or oncoming traffic while concentrating on surveying. For roadwork, consider not working entirely alone—assigning a traffic guide at the shoulder, for example. Prevent heatstroke by taking water and breaks as appropriate in summer. Efficiency cannot come at the expense of safety.

• Handling and maintenance of equipment: LRTK devices and smartphones are precision equipment—avoid drops and impacts. Use straps on site, and keep phones in zippered pockets when not in use to prevent loss or damage. In rain, protect gear with waterproof cases or plastic bags and do not overestimate dust/water resistance. After use, clean mud and dust from device contact points and regularly update firmware and apps to keep them current.

• Data management and backup: While cloud upload is generally safe, verify that data is also saved locally on the smartphone as a precaution. After uploading to the cloud, export CSV or PDF reports as needed to keep local copies. This mitigates issues such as forgetting to send a cloud share link or recipients being unable to open the data due to format differences. Complete data organization and backup on the same day as the survey and avoid postponing it to the next day.

Common Failures and Countermeasures

Here are common errors when introducing a new surveying system and corresponding countermeasures.

• Communication errors: Sometimes correction information cannot be received on site and RTK positioning does not start. Causes include incorrect Ntrip connection settings (wrong ID/password, wrong mountpoint) or being out of cellular range. A countermeasure is to test the connection in the office or an area with good reception beforehand. If out of coverage, switch to CLAS reception mode and move to an open-sky location where Michibiki can be received. If you cannot obtain corrections at all, refrain from forcing a measurement in standalone mode and schedule a re-survey later.

• Initial setup mistakes: Mismatched coordinates can stem from app setting errors, such as confusing geodetic vs. local coordinate systems, forgetting to input antenna height or measurement offsets, etc. Countermeasures include following a checklist to verify settings before work. During initial introduction, double-check settings with a colleague and resolve questions via the manufacturer’s support or manual.

• Data transfer omissions: After surveying, you might think data has been shared internally but find some items were not uploaded. This can happen if you close the app before upload completes or if large photo files are still uploading unnoticed. The remedy is simple: make a habit of checking for upload completion or confirming the data list on the cloud. Before leaving the site, visually confirm the cloud view that all data are present, and if anything is missing, re-upload before leaving. Using a mobile router or tethering to boost communication speed can help if uploads are slow.

• Battery depletion: Extended continuous surveying can drain phone and LRTK device batteries. If devices run out of power mid-operation, data may be lost or you may need to re-measure. Always bring spare batteries and charge devices regularly during breaks. In cold climates, battery performance degrades, so insulate and keep mobile batteries warm.

• Other human errors: Beginners may make mistakes such as typos in point names or notes, forgetting to take photos, or missing points. These errors are often irreversible after leaving the site, so establish on-site routines to prevent them. For example, make "measure point → take photo → upload" a single completed routine, and use a checklist to cover important points. When working alone, cultivate the habit of double-checking yourself.

Future Prospects (Use in Municipalities and Private Sector, BIM/GIS Integration, Use in Disasters)

The potential for solo surveying using LRTK is expected to expand further. Pilot cases in municipalities and construction companies are already emerging. For example, Fukui City was an early adopter in 2023, introducing iPhone + LRTK for disaster prevention to quickly record damage from earthquakes and heavy rains. Processes that previously required staff to shuttle between field and office for drawing were greatly streamlined by sharing field-measured data to the cloud immediately, shortening lead times for recovery. Because LRTK can be introduced at low cost in administrative domains, it is gaining attention as a DX tool for disaster response and infrastructure inspection.

In the private construction and civil engineering sectors, the labor-saving benefits of solo surveying are immense. Using LRTK for as-built management enables rapid high-density post-construction checks, preventing rework and improving quality. Piling and benchmark installation can be performed quickly and accurately with coordinate navigation functions, enhancing productivity in construction management. In infrastructure maintenance, storing high-precision photos and 3D point-cloud data obtained with LRTK during regular inspections makes it easy to compare aging changes on the cloud during subsequent inspections. The industry can shift from manual patrol inspections to efficient maintenance management through digital records.

Technologically, future developments are promising. High-precision data acquired by LRTK can be easily integrated with other digital technologies. Combining drone aerial data or 360-degree camera footage for site documentation and linking with machine control for automation of construction are already being explored. There are also applications that load BIM/CIM models created during design into the LRTK cloud for AR display on site to perform as-built checks. LRTK itself continues to evolve through firmware and app updates that add new features based on user feedback. Improvements such as better indoor or non-contact positioning, support for new satellites, and other refinements will further expand the range of tasks that can be handled by solo surveying.

Across the industry, LRTK and solo surveying align with the Ministry of Land, Infrastructure, Transport and Tourism’s push for i-Construction and infrastructure DX, and may become a standard method. With goals to improve labor efficiency on construction sites by 30% by 2040 (raising productivity by 1.5x) under initiatives like i-Construction 2.0, tools such as LRTK could be key. Going forward, smartphone-based solo surveying will likely spread nationwide among municipalities and companies, creating a new norm in which "surveying is something you do quickly by yourself."

In Conclusion: Smart Solo Surveying Realized with LRTK

Surveying work that used to require time and manpower becomes remarkably simple and fast with LRTK. The benefits of solo surveying are not limited to personnel reduction; real-time data sharing and reduced mistakes contribute to overall site productivity and quality. Lightweight, easy-to-handle LRTK devices can be used by veterans and newcomers alike, aiding organization-wide DX initiatives.

The world of surveying is undeniably changing. Why not realize the fastest and simplest solo surveying on your site? Adopt smart surveying with LRTK to balance efficiency and accuracy, and lead the next generation of construction and civil engineering sites. You will likely be surprised by the results and find it hard to return to conventional methods. Use the LRTK introduction checklist as a reference and start the next-generation surveying style today. The future of the site moves forward with each person’s first step.