RTK Makes Daily Reports Easier: Why Coordinate and As‑Built Recording Can Be Automated

Table of Contents

• What is RTK? Basics of Real Time Kinematic positioning

• Challenges of recording coordinates and as‑built data in daily reports

• Why RTK implementation can automate coordinate recording

• Why RTK implementation can automate as‑built recording

• Field cases where RTK makes daily reporting easier

• Simple surveying with smartphone RTK “LRTK”

• FAQ

On construction sites, preparing a daily report is indispensable. Recording construction progress and as‑built (work quantity) information and sharing it with stakeholders is an important task, but in reality, on‑site recording work is very time‑consuming. Surveyed coordinates are copied into notebooks, and measurements and calculations to confirm as‑built conditions are done manually, imposing a heavy burden on site supervisors and surveying staff.

Amid this situation, RTK (Real Time Kinematic) positioning, a high‑precision GNSS technology, has attracted attention in recent years. By using RTK, coordinate and as‑built recording work can be automated, with the potential to dramatically improve the efficiency of daily report preparation. This article explains what RTK is, how it works, and its benefits, and details why RTK implementation makes daily reporting easier. Finally, we introduce "LRTK," a solution that enables simple surveying with a smartphone, and provide the latest trends in on‑site DX.

What is RTK? Basics of Real Time Kinematic positioning

First, let’s briefly cover what RTK (Real Time Kinematic) is. RTK is a technique that drastically improves the accuracy of satellite positioning such as GPS. Standalone GPS positioning typically has errors of about 5–10 m (16.4–32.8 ft), but the RTK method compares observation data from a reference station (a receiver with a known position) and a rover (the receiver being positioned) in real time, and transmits error correction information to the rover to correct its position. As a result, positioning errors are reduced to the order of several centimeters, and when RTK reaches a stable state known as a "Fix solution," horizontal positions can be accurate to about ±1–2 cm (±0.4–0.8 in), and vertical accuracy can be within about 3 cm (about 1.2 in), achieving centimeter‑level positioning accuracy (half‑inch accuracy). Precision surveying, which once required expensive equipment and specialized skills, is becoming more accessible thanks to RTK.

Furthermore, recent developments such as multi‑GNSS support, the spread of network‑based RTK over the internet, and Japan’s quasi‑zenith satellite augmentation service "Michibiki" providing centimeter‑level augmentation service (CLAS) have created an environment where RTK positioning can be used stably over wide areas. These technological advances have increased RTK’s presence as a foundational technology for surveying and as‑built management on construction sites. In fact, RTK‑GNSS measurements are recognized in the latest as‑built management guidelines set by the Ministry of Land, Infrastructure, Transport and Tourism, and onsite adoption is being promoted. As a high‑precision GNSS positioning method, RTK is truly a key technology supporting construction DX (digital transformation).

Challenges of recording coordinates and as‑built data in daily reports

In on‑site daily reporting work, especially recording "coordinates" and "as‑built" information, there are several challenges. Traditionally, leaving position information of construction locations and measurement results in daily reports required manually noting numbers observed with surveying equipment and later transcribing them into forms. For example, coordinates obtained from a total station would be written into a notebook and later entered into a PC back at the office. This analog recording method is prone to human error—things like writing numbers incorrectly or losing notes can occur. Also, because daily reports are often written after work while staff are tired, important events or measurement results are sometimes omitted. As a result, accurate data measured on site may not be reflected in daily reports, undermining the accuracy of progress and quality management.

Moreover, photo records and annotations on drawings alone may not sufficiently convey the on‑site situation. Have you ever experienced not knowing which point a photo corresponds to, or being unclear about where a marked point on a drawing is in the real world? Two‑dimensional records make it difficult to grasp spatial relationships, and when reviewed later, critical information may be missing. In as‑built management in particular, failing to accurately record the shape immediately after construction can lead to situations at later quality inspections where records cannot be found or measurements were forgotten.

Thus, manual recording is constantly accompanied by omissions, mistakes, and heavy workload. For site supervisors and surveyors, performing recording tasks in addition to core construction management is arduous; if recording is postponed due to busy schedules, the reliability of construction records is ultimately compromised. Even if you want to record coordinates and as‑built data accurately, traditional methods take too much time and effort—this is the challenge faced on sites.

Why RTK implementation can automate coordinate recording

So, how exactly does introducing RTK to a site simplify and automate coordinate recording? The main points are as follows.

• Measurement and recording as one package: With RTK‑compatible equipment or apps, coordinate data for a point can be automatically saved at the time of positioning. Survey staff no longer need to copy numbers into notebooks; a simple tap of a "Record" button on a smartphone or tablet completes the process. Coordinates obtained on site are immediately stored as digital data, preventing recording omissions and transcription errors.

• Immediate sharing of coordinate data: Coordinates obtained with RTK can be shared in real time via the cloud. High‑precision position information sent from the site can be viewed immediately by office PCs and stakeholders. If integrated with daily report software or construction management systems, measured coordinates can be automatically populated into daily report formats. This eliminates the redundant work of re‑entering site measurements back at the office.

• Easy point identification: RTK records are managed in a global coordinate system (latitude/longitude), so when reviewing records later you will not be unsure about which point a record refers to. Plotting the points on a map makes measurement locations immediately obvious, and they can be linked with photos and notes. For example, tagging a coordinate record on site as "center of foundation XX" or "location of discovered buried object" allows you to indicate exact locations in daily reports or reports to stakeholders. Coordinates themselves become solid evidence, improving the reliability of records.

By utilizing RTK, the coordinate recording process can be greatly streamlined, enabling near‑automatic accumulation and sharing of on‑site coordinates. Compared with manual recording, RTK is overwhelmingly faster and more accurate, significantly reducing the burden of daily report preparation on site personnel.

Why RTK implementation can automate as‑built recording

Next, let’s look at RTK use for as‑built management—recording post‑construction shapes and work quantities. Traditionally, heights and dimensions at key points were measured manually using levels or total stations and compared with drawings to verify as‑built conditions. By combining RTK with digital technologies, as‑built recording can be greatly optimized. Here are the reasons.

• Rapid measurement of the entire site: Using RTK‑compatible survey instruments, drones, or smartphone 3D scanning, the current site conditions across a wide area can be measured quickly. For example, terrestrial laser scanners or drone photogrammetry can complete terrain surveys that used to take days in a matter of hours in some cases. Especially with systems that combine smartphones with RTK, a single person can walk the site and collect point cloud data, eliminating the need to measure each survey point individually and ensuring comprehensive recording of site geometry. This prevents later discoveries that "we forgot to measure that area" and preserves all information needed for as‑built inspection.

• Automated dimension and earthwork volume calculations: Acquired 3D point cloud and coordinate data can be automatically analyzed by dedicated software or cloud services. For example, performing 3D scans before and after excavation or embankment allows automatic calculation of construction quantities (volume) from the difference with a single click, instantly completing quantity summaries needed for daily reports or as‑built reports. Where earthwork volume used to be measured and calculated manually from paper drawings section by section, digital processing enables batch automated calculation. In fact, one site reported reducing work time for earthwork volume calculations to about 1/6 compared with the traditional method by adopting point cloud measurement. Thus, the formerly tedious as‑built measurement and calculation tasks are dramatically sped up by RTK utilization.

• Quality assurance and improved safety: Being able to record high‑precision as‑built data leads to reliable assurance of construction quality. Comparing point cloud data with design data can detect construction deviations of just a few centimeters. Daily detailed checks of as‑built conditions reduce the risk of requiring major rework later. Also, non‑contact 3D scanning offers safety advantages: it can capture current conditions from a distance in high or steep areas or zones with operating machinery where human entry is difficult, avoiding the need to approach hazards. Some equipment can even operate at night or in adverse weather, reducing losses from construction interruptions. By leveraging RTK and digital measurement technologies, as‑built management achieves a balance of accuracy, efficiency, and safety.

In this way, RTK‑based as‑built recording automates the entire flow from data acquisition to analysis, dramatically reducing the workload of site technicians. Photos and quantity reports included in daily reports can be generated from accurate RTK measurement data, resulting in more reliable content. Site staff are freed from overtime required to measure as‑builts or redoing reports due to calculation errors.

Field cases where RTK makes daily reporting easier

To see how much daily reporting can be streamlined by using RTK, consider a road construction case. From the early stages of the project, the site introduced a smartphone‑mounted RTK surveying system, and personnel performed daily 3D measurements of construction locations. For example, the site supervisor scanned the roadbed shaping conditions first thing in the morning using an RTK‑compatible smartphone, uploaded the point cloud data to the cloud immediately, and the construction manager at the office checked the latest point cloud from a PC, overlaying it with the design model to check height and slope differences. As a result, an area was found to be several centimeters higher than designed; the site corrected it the same day, minimizing impact on subsequent processes.

Also at this site, construction quantities (cut and fill volumes) automatically calculated from as‑built data obtained up to the previous day were automatically aggregated as a daily report in the cloud, so the site representative and head office construction personnel always had the same up‑to‑date values in real time. This eliminated waste such as "discrepancies in progress quantities between site and head office" or "re‑checking numbers whenever reporting," enabling smooth regular reporting to the client. Furthermore, using RTK positioning for setting out structural element positions (pile driving) was completed more quickly and accurately than before, and subsequent verification confirmed no positional errors in construction.

As this example shows, introducing RTK enables a system of "digitally surveying the entire site and sharing immediately," dramatically improving the speed of quality control and information transfer. With daily progress visualized as data, even minor issues can be detected and corrected early, preventing major rework or quality incidents. Information required for daily reports is automatically accumulated and aggregated on site, freeing staff from spending time on recording and allowing them to focus more on core construction management tasks. RTK use not only makes daily reporting "easier" but is also an excellent example of improving the overall quality of site operations.

Simple surveying with smartphone RTK “LRTK”

Finally, as a solution that makes it easy to enjoy the benefits of RTK, we introduce the noteworthy "LRTK." LRTK is a groundbreaking system that transforms a smartphone or tablet into a device capable of centimeter‑level positioning (half‑inch accuracy) on site by attaching a compact RTK‑GNSS receiver antenna and linking it to a dedicated app. Developed by Tokyo startup Lefixea Inc., it is described as turning "a smartphone into a high‑precision all‑purpose surveying instrument," allowing a single device to handle surveying, as‑built measurement, photo recording, and staking out.

With LRTK, no complicated equipment setup or specialized operation is required. Attach the antenna to your phone, launch the app, and simply point the phone at the object you want to measure to obtain high‑precision data with positional information (point clouds and photos) on the spot. Acquired data is immediately saved and shared to the cloud, enabling the real‑time information sharing described above. Tasks that used to be handled by specialized surveying departments or outsourced can be quickly measured by on‑site technicians at any time with LRTK, eliminating the need to allocate personnel or days for recording. Initial introduction costs are also lower compared with purchasing dedicated high‑end instruments, and bringing multiple units to a site for simultaneous digital surveying is realistic.

LRTK’s main features:

• Ease and intuitive operation: A simple configuration combining a smartphone and a compact device enables positioning comparable to dedicated instruments. The app interface is simple and can be operated with one hand during site work.

• High‑precision point cloud and photo recording: By integrating with a smartphone’s built‑in LiDAR scanner and camera, centimeter‑precision 3D point cloud data and high‑accuracy geo‑tagged photos (half‑inch accuracy) can be obtained. One‑tap automatic volume calculation for embankment and backfill and map‑based photo management dramatically streamline quantity aggregation and photo organization for daily reports.

• Versatile positioning and surveying: Equipped with coordinate guidance (navigation) to find arbitrary points from survey drawings or design plans on site, it is useful for pile driving and buried object surveys. It also includes AR functions to utilize point cloud data on site, enabling advanced uses such as visually confirming underground pipe locations after completion.

• Real‑time sharing and DX promotion: The LRTK series shares acquired data to the cloud instantly, keeping site and office synchronized with the latest information. It supports the Ministry of Land, Infrastructure, Transport and Tourism’s i‑Construction initiative and is a powerful solution for promoting DX (digital transformation) on construction sites.

Using LRTK for everyday "simple surveying" makes daily reporting significantly easier while accumulating reliable, omission‑free site records. By making high‑precision RTK technology more accessible than ever, LRTK becomes a reliable ally for site supervisors and construction managers. For detailed product information and case studies, please see the [LRTK official site](https://www.lefixea.com). Why not take site recording and surveying to the next level with the power of high‑precision positioning?

FAQ

Q1. What is the difference between RTK and ordinary GPS? A1. Ordinary GPS (GNSS) positioning calculates position using only satellite signals and therefore has errors of several meters. RTK, on the other hand, is a method that improves positioning accuracy in real time by using error correction information from a reference station, achieving centimeter‑level high accuracy. Simply put, RTK is a technique that uses "another GPS as a reference to correct the deviation and obtain high‑precision coordinates."

Q2. Is using RTK on site difficult? A2. Recent RTK systems have become very user‑friendly, and handling them on site is by no means difficult. While the term "dedicated instrument" may sound daunting, products that integrate with smartphone apps are now available, allowing intuitive operation for positioning and point cloud measurement. With devices you simply set up and press a button, measurement and saving are completed, so site staff can use them without special skills.

Q3. What preparations or equipment are needed for RTK positioning? Can it be used without a communication environment? A3. RTK positioning requires a mechanism to receive error correction data from a reference station. However, you do not have to provide your own base station; connecting to public reference station networks or network‑based RTK services allows positioning. In Japan, there are VRS services delivered via mobile communications and CLAS augmentation signals broadcast directly from the Michibiki (QZSS) quasi‑zenith satellite. With a compatible receiver, centimeter‑level positioning can be performed using CLAS signals even in mountainous areas without mobile coverage. In short, aside from RTK‑compatible equipment itself, what you need is network connectivity or the ability to receive satellite augmentation signals, but modern products are designed so you can use them without worrying about these details.

Q4. Can RTK be operated without surveying qualifications? A4. Yes. In general, operating RTK equipment on site does not require a special national qualification. Similar to how a construction company’s site supervisor might use a total station for surveying, RTK can be used as part of routine construction management. However, be careful when using RTK for legally regulated tasks—such as public surveying or installing control points—where certified surveyor qualifications may be required. For normal as‑built management and quantity measurement, RTK can be used without such qualifications.

Q5. Are data obtained with RTK accepted by clients? A5. Under the Ministry of Land, Infrastructure, Transport and Tourism’s standards, as‑built measurements using RTK‑GNSS are officially accepted if conditions are met. Therefore, high‑precision data obtained by RTK can be used as evidence in as‑built management. In practice, i‑Construction‑compatible projects increasingly use RTK and drone survey 3D data for as‑built inspection, and clients evaluate these highly. The important point is to perform RTK positioning in a FIX solution (a stable high‑accuracy state) and to record and manage the data properly. If these conditions are satisfied, RTK data are considered reliable.

Q6. I’m concerned about installation costs—does RTK offer cost effectiveness? A6. While RTK equipment may have an image of being expensive, it has become much more accessible recently. Smartphone‑based RTK products, for example, are far less costly than purchasing large surveying instruments costing several million yen. Introducing RTK is expected to reduce surveying time, labor costs, and costs associated with rework, providing cost savings. Although initial investment is required, many cases recover the cost through daily operational efficiencies. Above all, the value of improved accuracy for quality assurance and safety is priceless. In terms of cost effectiveness, RTK implementation is worth considering.