Labor reduction by leveraging position correction information: Smartphone- and small-device-compatible LRTK enables reduced wiring and offline positioning

Table of Contents

• Introduction

• What is position correction information

• Labor savings and efficiency improvements brought by position correction information

• Challenges and evolution of high-precision positioning technology

• What is LRTK? A new positioning solution compatible with smartphones and small devices

• Reduced cabling and offline positioning enabled by LRTK

• Benefits and use cases of implementing LRTK

• Summary

• FAQ

Introduction

In recent years, high-precision positioning technologies that utilize "position correction information" have attracted attention across various fields such as construction and civil engineering, agriculture, logistics, and autonomous driving. As needs to address labor shortages and improve operational efficiency grow, there are increasing situations where centimeter-level accurate position information is required as a means to realize on-site labor-saving (reduction and automation of manpower). Conventional satellite positioning such as GPS produces errors of several meters, but by using position correction information, errors can be reduced to within a few centimeters. The use of this high-precision positioning information enables autonomous operation of drones and construction machinery, autonomous driving of agricultural machinery, and digitization of on-site work, resulting in substantial reductions in staffing and labor effort.

On the other hand, there has been the issue that using high-precision positioning in the field requires specialized equipment and expertise. However, recently solutions have begun to emerge that enable centimeter-level positioning easily on smartphones and small devices. In this article, we explain what "position correction information" is and how its use contributes to labor savings. Furthermore, we focus on the latest high-precision positioning device for smartphones and small devices, LRTK, and introduce the mechanism and benefits of "reduced-wiring, offline positioning," which cuts down on complex wiring and can be used even outside Internet coverage.

What is position correction information?

First, "position correction information" refers to data used to correct errors in satellite positioning. GNSS (Global Navigation Satellite Systems), such as the GPS used in car navigation systems and smartphone maps, can experience positioning errors due to weather, slight satellite clock deviations, atmospheric effects, and so on. Typical smartphone GPS can be off by about 5 to 10 meters. To reduce these errors to the centimeter level, it is necessary to use correction data in addition to standalone GNSS positioning.

A typical example of position correction information is correction data sent from a reference station (a fixed receiver) with a known precise position. Because the reference station knows its own position, it can calculate in real time how much error is currently occurring by taking the difference between the position computed from the received satellite signals and its known position. By transmitting that error amount (the correction information) to a moving receiver (the rover), the rover can apply the correction to its own positioning result and cancel out the error. This is the basic principle of the high-precision positioning technique called RTK（Real Time Kinematic）. In short, it is a mechanism that cancels out errors by measuring together with a point whose position is known.

Traditionally, this correction information has been transmitted and received via wireless communications and the Internet. For example, one method is obtaining reference station data via base station radio signals or mobile communication networks. In recent years, reference station networks maintained by governments and telecommunications carriers have been established, and services that provide correction information nationwide have emerged. In Japan, the Quasi-Zenith Satellite System "Michibiki" has launched the centimeter-level augmentation service (CLAS), making it possible to receive correction signals directly from satellites overhead. By leveraging these position correction data, errors caused by weather and terrain can be greatly reduced, dramatically improving GNSS positioning accuracy.

Labor-saving and Efficiency Improvements Brought by Positioning Correction Information

When high-precision positioning information becomes available, effects such as labor savings and improved operational efficiency appear across various worksites. To illustrate which specific fields benefit, let's look at a few examples.

• Construction & Civil Engineering: High-precision positioning is useful at construction sites for operating heavy equipment and measuring as-built conditions. In GPS-equipped construction machines known as ICT construction machinery, it is possible to compare design data with the machine's real-time position and automatically control the blade. This enables accurate grading and excavation without relying on operator skill, reducing the number of personnel required for the work. Also, if site supervisors can check as-built conditions themselves using high-precision GNSS equipment, there is no need to call a surveyor each time, leading to labor savings in construction management.

• Agriculture: The use of high-precision positioning is advancing in the agricultural field as well, such as in self-driving tractors and rice transplanters. Automatic steering based on position correction information enables straight, uniform tilling and planting without human intervention. Because GPS guidance allows accurate work even at night, it contributes to alleviating labor shortages and shortening working hours.

• Logistics & Transport: At outdoor logistics centers and ports, autonomously moving transport vehicles and drones have been demonstrated. With high-precision positioning, forklifts inside warehouses and transport vehicles in container yards can be automated, enabling 24-hour operation while reducing human errors.

• Infrastructure inspection and disaster prevention: When autonomously flying drones for infrastructure inspections such as bridges and dams, high-precision positioning information contributes to stable flight and precise data acquisition. Also, when operating unmanned aircraft or robots in disaster-affected areas, having position correction information more accurate than GPS alone makes it easier to entrust work in hazardous areas that people cannot enter to machines.

As described above, centimeter-level positioning that leverages position correction information is important not only because it simply "makes positions more accurate" but as a foundational technology that supports automation and real-time processing. Because machines and systems can accurately perform tasks that humans used to do manually, it can reduce the required workforce while improving work speed.

Challenges and Evolution of High-Precision Positioning Technology

However, when attempting to utilize high-precision position measurement in the field, there used to be various hurdles. Centimeter-level positioning using the RTK method offers extremely high accuracy, but its operation requires specialized knowledge and equipment, and it was not a technology that anyone could easily handle. Below, we outline the main challenges associated with using conventional high-precision GNSS devices.

• Large-scale equipment and wiring: In conventional RTK positioning, in addition to high-performance GNSS receivers and antennas, it was necessary to bring many devices to the site for the base station—tripods, external batteries, radios, and communication modems. The rover receiver and controller were connected by cable, and communication equipment to receive data from the base station also had to be wired, so setup and takedown were time-consuming. These cumbersome wiring tasks imposed a significant burden when handling equipment on site.

• Securing reference stations and dependence on communications: To obtain highly accurate correction information, connection to nearby electronic reference points or reference station services is indispensable. If installing your own reference station, you must mount the antenna on a known point with no error, and securing the installation site and arranging rights are also challenges. It is possible to use public or private reference station networks (e.g., the Geospatial Information Authority of Japan’s electronic reference point network or carriers’ VRS services), but in that case stable Internet connectivity at the site is a prerequisite. In mountainous or out-of-coverage areas, correction information via the network cannot be obtained, and high-precision positioning could not be performed.

• Cost and expertise: High-precision GNSS receivers and RTK systems were expensive and required a substantial investment to introduce. In addition, equipment setup and management of positioning modes required specialized knowledge, so they were not something field staff could easily use. As a result, surveys were often commissioned to specialist contractors or surveyors each time, increasing labor costs and the number of days required.

To address these challenges, the latest high-precision positioning solution, LRTK, has been introduced. In the next chapter, we will look at the all-in-one RTK device LRTK, which can be handled by smartphones and small devices, its features, and the mechanism behind "reduced wiring and offline positioning."

What is LRTK? A new positioning solution for smartphones and small devices

LRTK (Lightweight RTK) is a next-generation GNSS receiver that integrates into a compact device the full set of RTK positioning equipment that were previously separate. Developed by Reflexia Inc., it is attracting attention as an innovative solution that eliminates the complexity of conventional high-precision positioning systems. It houses all components required for RTK—antenna, receiver, battery, communication module, and so on—and is characterized by being condensed into a palm-sized form.

In particular, the smartphone-compatible model called "LRTK Phone" turns your existing smartphone into a surveying instrument with centimeter-level accuracy simply by attaching a slim receiver weighing only about 150 g to the phone. It operates in conjunction with a dedicated app, allowing intuitive start/stop of positioning and data saving from the smartphone screen. It communicates with the smartphone via Bluetooth or Wi‑Fi, so there is no need for cables and handling is simple. With the ease of "all you need is your smartphone," you can minimize the equipment you bring to the job site.

There is no longer any need to separately prepare base station equipment or a dedicated controller terminal as before. With an LRTK device and a smartphone, RTK positioning is completed with that combination alone. You are freed from cumbersome wiring and power cables, and the initial positioning setup is finished with a single touch. This allows quick, high-precision positioning on site even without specialist technicians.

LRTK-Enabled Reduced Wiring and Offline Positioning

One of LRTK's major advantages is "reduced wiring". As noted above, because LRTK integrates the antenna and power supply and can wirelessly connect with a smartphone, cable connections across the entire positioning system are largely unnecessary. For example, whereas conventional setups required a cable to connect the GNSS receiver to the controller and a power cable to an external battery, LRTK eliminates those wiring needs. This dramatically simplifies on-site setup and removes the stress of cables getting tangled when handling equipment. Even at heights or in areas with poor footing, a cordless, compact positioning device allows work to be performed safely and smoothly.

Another key point is support for "offline positioning". LRTK is a multi-band (multi-frequency) GNSS receiver and is equipped with the capability to directly receive CLAS (centimeter-level augmentation information) provided by Japan's Quasi-Zenith Satellite Michibiki. This enables it to obtain position correction information from satellites overhead and maintain high-precision positioning even in environments such as mountainous areas or remote islands where cellular signals do not reach. Previously, real-time corrections were difficult without a network connection, but with LRTK, which can obtain correction signals directly from satellites, centimeter-level positioning is possible even completely offline.

Furthermore, because Michibiki (QZSS) follows an orbit that always has one satellite present over Japan, it has the advantage of being relatively better at receiving satellite signals even in areas prone to blockage, such as mountainous regions or in the shadow of high-rise buildings. There have also been reports that, in situations where other GPS devices show errors of several meters, LRTK was able to perform positioning by utilizing satellite augmentation information.

As described above, LRTK is excellent as a precision positioning tool for field use, eliminating the need for wiring while maintaining high accuracy even in offline environments.

Benefits and Use Cases of Introducing LRTK

What concrete benefits can be obtained by introducing LRTK on-site? Finally, we summarize the effects LRTK brings and the anticipated use cases.

• High-precision positioning usable even by beginners: LRTK is a device designed to allow "anyone, anywhere, easily" to handle centimeter-level positioning. Even without a professional surveyor, on-site workers and technicians can use it with the ease of a smartphone. The dedicated app's clear UI and one-touch positioning start keep training costs to a minimum. For example, if a young field staff member can immediately perform an urgently needed survey by themselves, it reduces waiting time and leads to improved on-site productivity.

• Equipment reduction and improved mobility: Previously, transporting tripods and large batteries was a major hassle, but with LRTK you only need a single pocket-sized receiver. The drastic reduction in equipment is particularly effective in confined sites and high-altitude work. Because you no longer need to lift heavy equipment or allocate people for wiring during surveys at height, safety is also enhanced. Increased mobility makes it easier to acquire data in locations that were previously difficult to measure and to perform flexible additional measurements of inspection points.

• Real-time sharing and DX promotion: LRTK integrates with smartphones, making it easy to send acquired coordinate data and point cloud data to the cloud or share them on the spot. Because positioning data can be used to immediately update drawings and share results with stakeholders, tasks that were traditionally taken back to the office for processing become real-time. This is also an important step in advancing on-site DX (digital transformation).

• Cost reduction：By bringing high-precision positioning in-house, you can reduce the frequency of relying on external surveying contractors. Once LRTK is implemented, it can be used repeatedly across multiple sites, leading to long-term reductions in surveying costs. In addition, improved efficiency can be expected to reduce labor costs and shorten project timelines.

Thus, LRTK is not merely a miniaturization of positioning equipment, but a solution that can transform on-site workflows and the allocation of roles. At actual deployment sites, there have been reports such as "tasks that used to require waiting for a surveyor can now be completed on the spot by the site supervisor themselves," and it is being regarded as a tool that overturns conventional wisdom.

Summary

High-precision positioning that leverages position correction information is a key enabler of labor reduction and efficiency improvements across various industries. With centimeter-level accurate location information, a wide range of applications becomes possible, from automated machine control to simplification of on-site work. Positioning technologies that were once the domain of specialists are becoming more accessible thanks to smartphone- and small-device-compatible solutions like LRTK.

Using LRTK, anyone can perform high-precision positioning immediately on-site without being bothered by complex wiring or bulky equipment. Because it can receive correction information directly from satellites and perform positioning even in locations without an Internet connection, it will demonstrate its capabilities in situations that were previously difficult, such as surveying in mountainous areas and investigations during disasters.

By harnessing highly accurate location information, on-site DX and labor-saving will accelerate even further. If you feel there are hurdles to introducing high-precision positioning, why not start with simple surveying using LRTK, which can be easily used on a smartphone? You'll likely be surprised by how easy and useful it is.

FAQ

Q: What is position correction information? A: Position correction information refers to data used to correct errors that occur in satellite positioning such as GPS. It denotes error amounts calculated by reference stations (receivers with accurately known positions) and augmentation signals distributed from quasi-zenith satellites (such as CLAS). By using this information, the accuracy of satellite positioning can be improved from several meters to several centimeters.

Q: Do you need any special qualifications or knowledge to use LRTK? A: No. LRTK is designed to be used even by non-professional surveyors. If you follow the guidance in the dedicated app, you can achieve centimeter-level positioning without advanced GNSS knowledge. However, depending on the intended use, official use of survey results may require supervision by a licensed surveyor, so appropriate consideration is necessary.

Q: In what environments can LRTK be used? A: LRTK features a dustproof and waterproof design, allowing it to withstand harsh outdoor environments. Even in mountainous or remote areas without internet connectivity, it can directly receive Michibiki (QZSS) CLAS signals to perform high-precision positioning, making it usable where cellular signals do not reach. However, in countries or regions that do not support CLAS, it may be necessary to use it in conjunction with conventional network RTK services.

Q: Which smartphone models are supported? A: LRTK's smartphone-compatible models (LRTK Phone) include types that can be attached to iOS devices such as iPhone and iPad, as well as types compatible with Android devices. The specific supported models depend on the product specifications, but most modern smartphones can connect via Bluetooth or Wi‑Fi. By installing a dedicated app on the smartphone, you can display, save, and share positioning data.

Q: What specific effects can be expected when introducing LRTK? A: Introducing LRTK dramatically improves the efficiency of on-site surveying work. For example, site supervisors can measure as-built conditions themselves and verify them instantly, eliminating the need to wait for an external surveying team. This can shorten construction schedules and reduce labor costs, and allows flexible response to sudden measurement needs. In addition, because data can be shared digitally and immediately, the effort required to prepare reports is reduced, contributing to the promotion of DX across the entire project.