RTK Inspection Implementation Guide: 5 Steps to Smooth Field Adoption

Contents

• Introduction

• Step 1: Clarify the Purpose and Benefits of RTK Inspections

• Step 2: Prepare Required Equipment and Environment

• Step 3: Develop an Operation Plan and Conduct Training

• Step 4: Pilot on Site and Start Smooth Operations

• Step 5: Utilize Inspection Data and Pursue Continuous Improvement

• Simple Surveying with LRTK

• FAQ

Introduction

For routine inspections and maintenance of infrastructure facilities, it is essential to record field conditions in detail so they can be accurately understood later. Among these, the accuracy of “when, where, and what happened” — i.e., the location information — greatly affects the credibility of reports and the efficiency of subsequent responses. However, conventional inspections have had several issues with on-site location recording. For example, inspectors often relied on methods that were not necessarily precise or convenient, such as marking inspection points by hand on paper drawings or recording approximate coordinates in photos with GPS-enabled cameras. As a result, problems frequently occurred, such as “the location described in the report did not match the actual site, causing time-consuming rechecks” or “it was difficult to identify exactly which part of the site a damaged area shown in a photo corresponded to.”

A trump card for solving these issues and making inspection records more accurate and efficient is RTK (Real Time Kinematic) positioning technology. RTK refers to a high-precision positioning method using GNSS (satellite positioning such as GPS) that can determine positions with errors down to a few centimeters (a few in). While regular GPS can have errors of several meters (several ft) due to satellite signal errors, RTK uses two receivers — a base station (receiver placed at a reference point) and a rover (the device being positioned) — and applies the error information obtained at the base station to the rover in real time, achieving centimeter-level accuracy. This enables direct linking of accurate field coordinates to photos and record data at inspection sites, making high-precision location recording and sharing, which was difficult with conventional methods, dramatically easier.

This article explains five key steps to keep in mind when introducing RTK into inspection work. From planning for smooth field adoption to equipment preparation and post-deployment utilization, we will go through concrete steps in order.

Step 1: Clarify the Purpose and Benefits of RTK Inspections

The first step is to clarify what you want to achieve by introducing RTK and the expected benefits. Organize what issues you currently face in inspection operations and how you want to address or improve them by introducing RTK. For example:

• There are errors in location recording of inspection points, causing doubts about the credibility of reports → Obtain precise coordinates with RTK to improve the accuracy of report contents

• Creating and managing inspection records is time-consuming → Streamline record-keeping with RTK’s automatic position logging and reduce office processing time

• It is difficult to track long-term changes → Enable high-precision comparisons of measurements at the same points to improve traceability of deterioration progress

Listing the concrete benefits that RTK implementation will bring makes it easier to gain internal understanding and cooperation. Benefits from precise location information include improved report credibility, more efficient re-inspections and repair planning, and enhanced information sharing via integration with digital ledgers (infrastructure management systems). Share the purpose and expected effects of introducing RTK with the team so everyone aims for the same goal.

Step 2: Prepare Required Equipment and Environment

Once the purpose is set, next prepare the equipment and environment needed for RTK operations. High-precision positioning requires specialized preparations such as GNSS receivers and communication environments. The main options are the following two approaches.

1. Setting up your own base station: Prepare a GNSS receiver for the base station that serves as the positioning reference and radio equipment to send correction information to the field. Because the base station needs known accurate coordinates, perform positioning at a control point or secure known points in advance. For wireless transmission of correction information, license-free frequencies such as low-power specific radio (920 MHz band) can be used, but if more stable communication or long-distance transmission is required, you may use UHF-band radios that require license applications. The advantage of the self-hosted approach is that, once equipment is purchased, there are no recurring service fees and it can operate in mountainous areas without Internet access. However, there are constraints such as initial costs and setup effort for the base station equipment, and accuracy tends to degrade if the distance between base and rover is too large — generally ideally within several kilometers (several mi).

2. Network RTK (using a correction service): Obtain correction information via the Internet. Representative methods include the VRS method (Ntrip protocol), which uses multiple existing base stations such as the Geospatial Information Authority of Japan’s continuously operating reference station network to set a virtual reference point near the user and distribute correction data. In this case, all you need on site is an RTK-capable GNSS receiver (rover) and a smartphone or mobile router for communications. There is no need to set up your own base station on site, reducing local burden. On the other hand, there are running costs such as fees for correction service providers and mobile communications charges, and the method may be unusable where mobile communications are out of range, such as in deep mountain areas. Also, accuracy can decline in regions too far from reference stations, so choose the appropriate method according to radio conditions and the area of use.

Whichever method you choose, common required equipment includes an RTK-capable GNSS receiver (such as an integrated antenna positioning terminal) and a communication means for the rover to receive correction data (radio module or Internet-connected device). Also consider installing dedicated apps or software so you can view and record position information on smartphones or tablets. Recently, products that combine small GNSS receivers that attach to smartphones and apps to achieve RTK positioning have emerged, making introduction easier compared to traditional equipment. Choose a configuration that fits your company size and operating conditions, and prepare an environment that enables stable centimeter-level positioning (centimeter-level positioning (inch-level positioning)) in the field.

Step 3: Develop an Operation Plan and Conduct Training

In parallel with equipment preparation, plan the new operating procedures using RTK and provide education and training for field staff. First, design a specific workflow for how RTK positioning will be integrated into the inspection process. For example, specify steps such as “when an inspection point is found, measure the current position with the GNSS device and record coordinates simultaneously with photographing” or “at the end of the day, upload data from devices to the cloud.” Clearly document when, who, and how RTK measurements will be performed. If there are existing report formats or management ledgers, review them and add fields for high-precision position information as needed.

Once the operation procedures are set, provide operational training for the personnel who will handle the equipment and inspectors. In addition to basic operation of GNSS receivers and apps, explain factors that affect positioning accuracy (satellite reception conditions, surrounding obstructions, radio interference, etc.) and share tips for achieving stable positioning in the field. It is also important to test the equipment outdoors at first to check for unexpected issues. For example, learning through hands-on experience that “positioning is unstable under overpasses because satellites are hard to capture” or “be careful of multipath from nearby buildings or structures” will help allay concerns before real operations.

In training, also re-emphasize the purpose and benefits of introducing RTK. It is essential for field workers themselves to understand why the technology is necessary and how it helps for smooth adoption. Compile FAQs and manuals for common questions and make them readily accessible to reduce confusion on site.

Step 4: Pilot on Site and Start Smooth Operations

After training is complete, begin pilot implementation of RTK positioning at actual inspection sites. Start with a trial operation on a small scale or for a limited period, and verify the collected data and operational issues. During the trial, pay attention to the following points.

• Initialization and positioning accuracy checks: Upon arrival at the site, start the rover GNSS receiver and obtain correction information to initialize RTK (achieve an integer fixed solution). It may take several tens of seconds to several minutes for positioning to stabilize, so first confirm that a sufficient number of satellites have been acquired. For the base-station approach, ensure base station setup and configuration are correct and verify that errors relative to known points are within expected limits.

• Dealing with inability to position: In environments where satellite signals are hard to receive, such as urban canyons or mountainous areas, RTK positioning may fail. If real-time positioning cannot be achieved, consider alternatives such as leaving a location note to position later, or correcting positions by synchronizing photos with PPK (Post-Processing Kinematic) post-processing.

• Concurrent use with existing procedures: During trials, continue to use conventional location recording methods (e.g., handwritten notes or standard GPS logs) as a precaution and check consistency with RTK data. This allows you to understand differences between old and new methods and objectively evaluate the effectiveness and reliability of RTK introduction.

Use feedback obtained during trial operations to improve procedure documents and manuals, and prepare for full-scale introduction. Once sufficiently validated, begin full operation of RTK inspections. When RTK positioning is embedded in routine site work, inspectors will routinely handle precise location information. At first it may take a little longer or feel awkward, but with experience positioning and recording will be completed in a very short time. Listen to field input and fine-tune operations to support gradual, sustainable adoption of RTK inspections.

Step 5: Utilize Inspection Data and Pursue Continuous Improvement

The high-precision inspection data obtained by RTK realize their full value only when shared and effectively used among the office and stakeholders, not just recorded on site. After introduction, consider the following utilization strategies.

• Integration into a digital ledger: Coordinates and photo data for inspection points obtained via RTK should be imported into internal infrastructure management systems or GIS (geographic information systems) for centralized management. This enables intuitive visualization of inspection histories on maps from past to present and supports anomaly trend analysis and repair planning.

• Streamlining report preparation: With automatic recording of location information, the manual work of looking up and entering coordinates during report preparation is eliminated. If photos are tagged with accurate position data, it becomes immediately clear which photo corresponds to which location. This streamlines consolidation of inspection results and reduces the workload for staff.

• Remote information sharing: If inspection data are shared in real time via the cloud, headquarters and related departments can grasp conditions without visiting the field. For example, data captured and recorded on site can be uploaded immediately so office managers can check progress or anomalous points on a map. Smooth remote information sharing enables quicker decision-making and support.

Even after RTK inspections are operating smoothly, it is important to collect regular feedback from the field and pursue continuous improvement. Unexpected issues that were not anticipated at the time of introduction may appear. For example, “tablets are hard to operate in rain, so provide waterproof cases” or “data communication volume is high, so review the plan” — accumulate such small improvements to refine systems for practical on-site use. Positioning technologies and related software evolve rapidly; regularly gather update information and new product news, and consider upgrading the deployment environment as needed. A mindset of continually adopting the latest best practices leads to long-term improvements in field efficiency and maintenance of accuracy.

Simple Surveying with LRTK

When introducing RTK inspections, some may feel that preparing dedicated equipment or purchasing expensive receivers will be a hurdle. In such cases, a convenient RTK solution using smartphones, called LRTK, can be a reliable option. LRTK is a product line consisting of a small high-precision GNSS receiver that attaches to a smartphone and a dedicated app, designed to enable simple surveying even by non-specialist surveying personnel.

For example, using a device called LRTK Phone, users can attach it to their usual smartphone and start the app to obtain centimeter-level current location information in real time. The interface is intuitive, and at inspection sites you can record position-tagged data as easily as taking photos with your phone. Surveying tasks that previously required specialized equipment and advanced skills can be performed by on-site inspection staff in a short time using LRTK. For instance, you can photograph bridge cracks while recording their precise coordinates, or measure structural displacement before and after repairs on your own.

The LRTK series includes variations to meet field needs, such as rugged stationary models with dust- and water-resistant specifications and unique helmet-integrated models that allow positioning simply by walking. Subscription (monthly) plans also provide flexibility to reduce initial costs, making it easier for small businesses or first-time RTK adopters to try the technology. Using such modern tools significantly lowers the barriers to adopting RTK inspections. If interested, check official LRTK information. Start simple surveying with RTK to dramatically improve the accuracy and efficiency of infrastructure inspections.

FAQ

Q1. What is RTK? How is it different from regular GPS? A1. RTK (Real Time Kinematic) is a technology that uses two GNSS receivers — a base station and a rover — to apply real-time position corrections and achieve centimeter-level positioning accuracy. Regular GPS positioning typically has errors of several meters (several ft), but RTK applies error information calculated by the base station to cancel out error factors and improve accuracy to the scale of a few centimeters (a few in). In short, it is easy to think of RTK as “very accurate GPS.”

Q2. What benefits does introducing RTK into inspection work bring? A2. The primary benefit is that the accuracy of location information in inspection records improves dramatically. You can attach precise coordinates to photos and notes, increasing report credibility and reducing the need for later on-site rechecks. Also, it becomes easier to integrate inspection data with digital ledgers and mapping systems, allowing accumulated information to be used for long-term maintenance and deterioration trend analysis. Furthermore, automating location recording improves work efficiency, eliminating tasks like handwriting on paper drawings or transcribing coordinates and reducing the burden on staff.

Q3. What equipment and costs are required to introduce RTK? A3. Basically you need an RTK-capable GNSS receiver (rover) and either a base station to provide correction information or a network RTK service. If you set up your own base station, you need base station GNSS equipment and radio communication equipment; initial costs are higher, but operational costs can be kept low. If you use network RTK, there are running costs such as service fees and communication charges, but initial introduction hurdles are lower. Recently, affordable smartphone-attached RTK devices (e.g., LRTK) have appeared, and subscription-based monthly usage can allow you to start without purchasing an entire set of expensive surveying equipment. Consider the best option based on your budget and usage frequency.

Q4. Are special qualifications or licenses required to use RTK? A4. No qualifications are required simply to use RTK positioning itself, but depending on the operation mode, radio-related licenses may be necessary. For example, if you transmit correction data from a base station to a rover via UHF-band radio, opening a radio station and licensing of technical personnel may be required in Japan. On the other hand, network RTK using smartphone communications or low-power specific radio in the 920 MHz band can be operated without a license. When implementing, check the requirements for the frequency band and communication methods you plan to use and carry out required procedures as necessary.

Q5. Is RTK positioning possible inside buildings or in mountainous areas? A5. RTK relies on signals from GNSS satellites, so it generally requires an open sky to achieve accuracy. Inside buildings, in tunnels, or under dense tree cover, satellite signals may be blocked or reflected, making RTK positioning unstable or impossible. In such environments, consider measures such as performing positioning outdoors first and then measuring relative positions indoors, re-positioning later under satellite-visible conditions, using satellite augmentation services (e.g., QZSS CLAS), or supplementing with conventional terrestrial surveying. Also, in mountainous areas where mobile communications are out of range, network RTK cannot be used, so you will need to prepare your own base station or handle positions via post-processing.

Q6. Can a small company introduce RTK? I’m worried about cost-effectiveness. A6. Yes, small businesses can introduce RTK with some creativity. While expensive equipment used to be required, low-cost RTK services such as LRTK have appeared. Subscription plans rather than purchases can reduce initial cost burdens and allow flexible use for only the required period. If the benefits of RTK introduction (work efficiency, reduced mistakes, improved credibility) are substantial, you can expect returns that justify the investment in the medium to long term. It is a good idea to start with rentals or trials to experience compatibility and effectiveness with your operations before committing to full-scale introduction.