Must-read for Exterior Contractors! How LRTK Changes On-site Measurement and Design for Exteriors

Accurate surveying on exterior (residential landscaping) sites is a critical factor that affects construction quality and efficiency. However, traditional on-site surveying often requires substantial effort and time, and discrepancies between drawings and the site due to surveying errors frequently lead to rework.

This article first organizes the challenges of on-site surveying in the exterior industry and the causes of inconsistencies between drawings and the actual site. It then explains how the emergence of the latest surveying technology, LRTK, changes the on-site measurement and design process. We will look in detail at LRTK’s specific features, on-site utilization workflows, and the benefits of adoption for different roles such as site managers, designers, and business owners. Finally, we will introduce key points for implementing and utilizing LRTK. For those involved in exterior construction, this provides useful hints for on-site digital transformation.

Challenges of Exterior On-site Surveying

There are several challenges with traditional surveying methods used at exterior/landscaping construction sites. Analog measurements using total stations (TS), optical levels (auto levels), tape measures, and spirit levels require experience and manpower to achieve high accuracy. For example, tasks such as performing reference-point layout in pairs and repeatedly measuring distances with a tape and marking points can take a full day for large sites or yards with complex shapes. Because the work is manual, small errors and human mistakes are inevitable.

The main challenges can be summarized as follows:

• Human and time burden: Surveying typically requires two or more workers and takes time from setup to cleanup. When there are many points or significant elevation differences on the site, surveying and layout can take an entire day, imposing a major productivity burden.

• Surveying errors and human mistakes: In the manual process of reading and recording tape measures, slight misreads or recording errors can occur. For example, if a measurement that should have been recorded as 503 cm (198.0 in) is written down as 508 cm (200.0 in), a discrepancy of 5 cm (2.0 in) can result. Stakes or chalk marks may be erased during construction, necessitating re-measurement. Such mistakes cause inconsistencies between drawings and the site and can lead to rework.

• Constraints due to site conditions: On narrow sites or those with many obstacles, conventional surveying equipment cannot secure lines of sight and placement locations are limited, forcing indirect measurements. This increases the number of steps and makes precision control more difficult; laying out curves or slopes in complex gardens is especially challenging.

• Labor shortages and aging workforce: Across the construction industry, the aging and shortage of personnel who handle surveying work is becoming serious. Methods that rely on skilled surveyors are difficult to sustain, and it is urgent to reduce the labor and improve the efficiency of surveying so that limited staff can manage sites. The Ministry of Land, Infrastructure, Transport and Tourism promotes productivity improvements through ICT under initiatives like i-Construction, and the exterior field is no exception.

Causes of Discrepancies Between Drawings and the Site

Errors and lack of information caused by on-site surveying challenges lead to mismatches between design drawings and actual construction results. The main causes are as follows:

• Inconsistent reference heights and reference points: If the building itself and the exterior work use different reference heights (ground levels) or surveying reference points, they may align on paper but differ in position or elevation during construction. If reference lines or points are not standardized between the building contractor and the exterior contractor at the design stage, it can cause discrepancies such as an entry approach step height differing from what was intended.

• Variations in surveying accuracy and changes over time: Exterior work often starts after the building is completed, so the ground may settle or temporary leveling stakes may move or disappear between foundation work and exterior start. Also, when building work and exterior work are surveyed separately, small errors accumulate due to different equipment or methods, leading to differences between drawings and the site.

• Insufficient current-condition information: If on-site surveys at the design stage fail to capture subtle slopes, elevation differences with neighboring land, or the exact locations of existing structures, design changes or on-the-spot adjustments may occur during construction, causing the finished result to differ from the original drawings. For example, adjusting heights during construction to ensure drainage slope may lead to a finished state that differs from the drawing.

• Lack of information sharing and coordination: If surveying data and design intent are not adequately shared between building and exterior personnel, misreading drawings or misunderstandings can cause construction errors. It is especially important to share accurate coordinate information among stakeholders for critical areas such as structures near boundary lines.

These factors combine to cause situations where, even if construction appears to have followed the drawings, discrepancies arise in reality. So how can we bridge this gap between on-site measurement and design?

How LRTK Changes On-site Measurement and the Design Process

A new solution that can address these challenges is LRTK. LRTK is an ultra-compact high-precision GNSS positioning device that attaches to a smartphone and, when used with an iPhone or iPad, enables centimeter-level positioning (half-inch-level). This allows surveying work that previously required skilled personnel and specialized equipment to be performed quickly and with high accuracy by a single person. In other words, it is on-site DX using “iPhone surveying.”

On-site measurement using LRTK links a smartphone’s camera and LiDAR sensor with high-precision GPS to scan the surroundings while walking and acquire detailed point cloud data. Because all points in the obtained point cloud are assigned absolute coordinates in a global geodetic system, it is easy to later compare them with design drawings or BIM models or to calculate earthwork volumes. Even in complex gardens or sites with large elevation differences, details that are easily overlooked can be digitally recorded, enabling accurate understanding of on-site conditions from the design stage. Tasks that used to require expensive 3D laser scanners and multiple personnel can be completed by one person in a short time with LRTK.

This also brings major changes to the design process. Designers can use the high-precision as-built data obtained with LRTK to prevent discrepancies between drawings and the site in advance. Importing point clouds and measured coordinates into CAD software enables planning based on actual measurements, from terrain undulations to dimensions around the building. This reduces situations where vertical planning does not match the actual site slope and requires adjustments during construction. LRTK also allows design verification via AR display on the smartphone. By overlaying design drawings or 3D models of the completed state at full scale while standing on site, potential issues—such as whether a gate can open and close without obstruction when placed according to the drawings—can be examined before construction. The AR always maintains accurate position and scale thanks to LRTK’s high-precision GNSS position corrections. Moreover, since LRTK can instantly sync all acquired data to the cloud, measured information can be shared on the spot with office colleagues and clients. With the boundary between site and design removed and the entire team referencing the latest accurate data, measurement and design processes in exterior work are dramatically streamlined.

Main Features of LRTK and On-site Utilization Workflow

Let’s look at the main features LRTK provides along the flow of an exterior project.

• Pre-site survey (high-precision positioning and point cloud scanning) Attach the LRTK device to a smartphone on site, launch the app, and start surveying. Simply walk around the site with the smartphone in hand; the built-in LiDAR and camera automatically scan the surroundings and acquire high-density 3D point cloud data. At the same time, LRTK positions and records the coordinates of each point with centimeter accuracy (half-inch accuracy), allowing you to capture the entire site’s terrain and existing object locations as a digital model with absolute coordinates. Use the photo-positioning feature to capture photos of areas of interest with the smartphone; this records the object’s coordinates and orientation so no detail is missed.

• Using data in design (cloud sync and drawing verification) Acquired point cloud data and coordinate information can be uploaded to the LRTK cloud from the site with a single tap. Office designers can immediately view the site’s point cloud model and survey point data on the cloud to verify the current conditions against design drawings and calculate required dimensions. For example, you can accurately understand site elevation differences or distances to neighboring boundaries at the desk, reducing the need for additional on-site verification. Point cloud data can be imported into CAD software as base data for design, dramatically improving planning accuracy and speed. Because the whole team can share the same up-to-date data in the cloud, gaps between drawings and site information can be resolved early.

• Use during construction (AR-based design verification and coordinate guidance) Even after construction begins, LRTK helps ensure construction accuracy. Using the AR function in the LRTK app, you can overlay design drawings or 3D models uploaded to the cloud on the real site view to check for any placement discrepancies at full scale. For example, you can display a planned fence alignment on the ground in AR to confirm that the required setback from the neighboring boundary is maintained as per the drawings. The coordinate guidance (AR navigation) feature shows direction and distance to a set target point in real time on the smartphone screen. With this, you can find points without markers—such as stake positions or buried boundary markers—without confusion. Even inexperienced staff can accurately perform layout, substantially reducing errors and labor compared with traditional chalk-line layout.

• Verification and record-keeping after completion (as-built measurement and reporting) At project completion, use LRTK to measure and record the as-built condition. Re-scanning the site with a point cloud captures the shapes of finished structures and the ground as 3D data, enabling verification of discrepancies by comparing this with design drawings and pre-construction data. For example, you can calculate actual excavation or fill volumes from the point cloud and check for differences from the quantities estimated during bidding—simple quality checks become possible. The acquired as-built data and positioning photos are saved to the cloud and serve as useful materials for client reports or future renovation planning. Accurate digital records convey information that paper drawings or photos cannot, which is a major advantage.

Role-specific Benefits of Adopting LRTK

The benefits of adopting LRTK vary by role. Here are the main advantages from the perspectives of site managers, designers, and business owners.

• Site managers: Because surveying can be completed quickly by one person, staffing and work-hour burdens are greatly reduced, enabling focus on other site management tasks. High-precision surveying reduces construction errors and rework, leading to shorter schedules and smoother process management. Immediate sharing of measurement data and site photos via the cloud speeds up reporting and communication with the office and clients, improving reliability and efficiency in site management. Additionally, AR functionality allows checking design drawings on site, enabling precise construction instructions and inspections.

• Designers: Using current point clouds and precise coordinate data, designers can reproduce the site accurately at the desk and prevent design errors caused by insufficient site surveys. The ability to measure required dimensions and elevation differences in the data reduces the need for additional on-site measurements or rework, greatly improving design efficiency. Presenting the completed image in AR to clients helps convey design intent more clearly and facilitates smoother consensus building. Verifying constructability from the design stage reduces discrepancies between drawings and the site to the minimum.

• Business owners: Improved efficiency in surveying and construction reduces unnecessary labor costs and rework expenses, increasing overall project profitability. Shorter project durations due to labor savings free up resources to take on additional projects and expand sales opportunities. Delivering high-precision, high-quality construction through the adoption of advanced technology raises customer satisfaction and can lead to more repeat and referral business. Furthermore, being a company that adopts cutting-edge approaches enhances external credibility and helps in recruiting talented personnel and strengthening relationships with partner companies.

Points for Introducing and Utilizing LRTK

Finally, check these points to maximize the effectiveness of introducing LRTK on site.

• Check the positioning environment: Confirm in advance whether stable GNSS positioning is possible at the actual site. In mountainous areas or regions without mobile phone coverage, LRTK’s support for the quasi-zenith satellite system (e.g., Michibiki) reinforcement signals should be considered; in urban areas take care regarding satellite occlusion by high-rise buildings and signal reflection (multipath). Inspect the site’s sky visibility and surrounding environment beforehand, and prepare by selecting positioning points as necessary.

• Prepare equipment and smartphones: Ensure the LRTK device itself, a high-precision GNSS receiver, and the smartphone used for connection (recommended: iPhone/iPad) are fully prepared. Verify whether the device you plan to purchase has the latest firmware, supports the needed positioning signals, and has sufficient continuous operation time. Install the dedicated LRTK app on the smartphone and pair or confirm operation in advance for Bluetooth or direct Lightning connections. Fully charge batteries before surveying and carry a mobile battery to prepare for long work sessions.

• Cloud usage and data management: To make survey and point cloud data usable by the team, leveraging the LRTK cloud service is key. Complete account registration and establish internal data management rules, such as creating project-based folders. On first use, try uploading point clouds and photos experimentally to confirm they can be viewed in a browser. When data is organized in the cloud, handling multiple projects concurrently and sharing information becomes smooth.

• Safety measures: When conducting surveys alone on site, never neglect safety. Pay close attention to surrounding conditions such as heavy machinery and vehicle traffic. As basic measures, wear a helmet and reflective vest and set out cones indicating surveying work. Share the work date and location within the company in advance and set regular check-in times and emergency contact methods. Operating with safety as the top priority ensures sustainable effectiveness.

• Operational training: Become proficient in LRTK operation before going to live sites. Practice all procedures—from using the app’s positioning button to recording coordinates by photographing and performing point cloud scans. For example, perform a few positionings on a familiar site and verify that correct coordinates are obtained for known reference points. If possible, also test the coordinate guidance feature to navigate to specified coordinates and upload acquired data to the cloud for office-side viewing. Pre-training enables calm and proper equipment handling in real operations.

• Gradual introduction: If you are introducing LRTK for the first time, it is advisable to start with pilot use on small projects rather than deploying it immediately on large-scale jobs. Initially run LRTK in parallel with conventional surveying methods to compare results, and verify data accuracy and operational workflows internally. Field staff may feel uncertain about new equipment at first, but gradually expanding the application scope helps the system to be accepted without resistance.

Conclusion

LRTK offers a wealth of easy-survey functions that anyone can master without specialized skills. Examples include photo-positioning that records exact coordinates of objects simply by taking a smartphone photo; AR display that overlays design drawings and 3D models on the actual site; cloud sync that shares data with the whole team immediately; monopod measurement using a dedicated lightweight pole that lets one person easily measure height and position; and coordinate recording that saves measured coordinate data with a single tap. With these intuitive functions, staff without surveying expertise can easily acquire and utilize accurate on-site data. The way on-site measurement and design are conducted in exterior work is already starting to change with LRTK adoption. Beyond efficiency gains, you can expect major benefits such as improved accuracy and enhanced quality through better communication. If you are involved in exterior construction, consider trying LRTK and experiencing the next-generation on-site surveying style.