Attention Construction Companies!
Obtain High-Speed FIX and Location-Tagged Photos with LRTK-equipped GPS

The Increasing Importance of RTK Surveying on Construction Sites

The importance of RTK (Real-Time Kinematic) surveying, which measures positions with millimeter-level accuracy, is growing rapidly on construction sites. Traditional surveying methods, such as total station measurements or standalone GPS positioning, were time-consuming, labor-intensive, and required multiple workers. For instance, setting up reference points and conducting positioning tasks with multiple personnel was a significant burden for general contractors (GCs). However, in recent years, advancements in RTK technology have led to a major transformation in the way field surveys are conducted. The widespread adoption of domestic satellite systems and network-based RTK services has made it possible to perform RTK measurements without a fixed base station, reducing the setup time and costs significantly.

Against this backdrop, the latest RTK surveying GPS devices featuring LRTK technology have emerged. This article will explain the features and advantages of this new surveying device, comparing it to traditional methods.

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What is the RTK Surveying GPS Device with LRTK Technology?

First, let’s briefly explain the term "FIX (Fixed Solution)" in RTK surveying. RTK (Real-Time Kinematic) surveying uses two GNSS receivers: a base station placed at a known point and a rover that moves while performing measurements. The base station sends error correction data to the rover, enabling high-precision, real-time positioning. Unlike standalone GPS, which typically has an error of tens of meters, or differential GPS, which still has errors around a few meters, RTK can achieve accuracy within a few centimeters. The key to achieving this ultra-high precision is the "FIX" solution, which refers to resolving the ambiguity in satellite signal phases (integer ambiguity). When a FIX solution is obtained, RTK is able to provide centimeter-level positioning.

Now, what is the RTK Surveying GPS device with LRTK technology? LRTK is a new technology that further enhances RTK surveying by improving accuracy, positioning speed, and ease of use. Specifically, it uses a high-performance multi-GNSS receiver and proprietary algorithms to obtain a FIX solution more quickly and stably than traditional methods. A major feature of this device is its integration with smartphones, making it a compact, easy-to-use system. By simply attaching a small receiver device to a smartphone, anyone can easily perform RTK surveying.

For example, the LRTK device “LRTK Phone” from Lefixea is an ultra-compact device that weighs only 125g and is about 13mm thick. By attaching this device to an iPhone, you can achieve centimeter-level positioning that traditionally required stationary equipment. This compactness and simplicity differentiate it from traditional surveying equipment.

The performance of LRTK technology is also impressive. The LRTK device is equipped with the latest GNSS technology and can achieve high-precision positioning comparable to traditional equipment, with horizontal error within ±2 cm and vertical error within ±3 cm. Additionally, it requires a shorter amount of time to acquire a FIX solution, significantly reducing waiting time on-site. This represents a significant improvement over conventional RTK devices or optical distance meters. Moreover, the LRTK device operates via a smartphone app, automating the recording and processing of positioning data. Its ease of use, without the need for complex operations or specialized knowledge, is another key attraction of the LRTK-enabled device.

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Benefits of High-Speed FIX and Location-Tagged Photos

With the realization of high-speed FIX, the efficiency of surveying operations has dramatically improved. Traditionally, RTK surveying took time to capture satellites and obtain a FIX solution, often requiring a wait of several minutes. However, with the LRTK device, thanks to its multi-frequency support and high-performance correction technology, the time to achieve FIX has been shortened to the point where positioning can start immediately upon arrival on-site. This allows for a significant reduction in surveying work time.

For example, during construction, marking the location and height of structures based on coordinates from a drawing is critical. This task, which requires precision, can now be done by one person accurately with LRTK.

Previously, two people were required to use a total station, dividing the tasks of indicating positions and operating the equipment. With LRTK, one person can now establish the points independently. Moreover, since the error is smaller, the need for re-measuring or adjustments is reduced, improving the reliability of the construction management process. By obtaining FIX quickly, the process from starting the survey in the morning to obtaining results runs smoothly, contributing to an overall increase in site productivity.

 

The location-tagged photo feature seamlessly integrates the photo data obtained on-site with the positioning information. During field surveys or infrastructure inspections, simply taking a photo automatically records its precise location, eliminating the need to later confirm "where the photo was taken." In traditional field surveys, it was necessary to take photos with a digital camera and manually write the location and direction on paper maps, a cumbersome process. However, with LRTK, the location and orientation are automatically measured on-site and saved along with the timestamp and notes.

Traditionally, managing photos required a significant amount of time, and mistakes were often made regarding the location where the photos were taken. In contrast, with LRTK's location-tagged photo feature, photos taken on-site are synchronized to the cloud with just one tap, and are automatically plotted on a map. The direction in which the photo was taken is also recorded, eliminating the need to write notes for each photo on-site or create a ledger in the office. This functionality dramatically improves the efficiency of field surveys and maintenance record-keeping while also preventing human errors. With quick positioning via high-speed FIX and the smart management of data through location-tagged photos, significant benefits are gained in both surveying tasks and on-site record management.

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Introduction to LRTK Products

The products that have turned the technology introduced so far into a concrete solution are the RTK surveying GPS devices equipped with LRTK technology. Among them, the LRTK Phone, as mentioned earlier, is an innovative device that transforms an existing smartphone into a powerful surveying tool. The key features of the LRTK terminal are summarized as follows:

• Centimeter-level High-Precision Positioning: By utilizing correction data from the reference station and satellite signal carrier phase, positioning accuracy of ±2 cm horizontally and ±3 cm vertically is achieved. This level of precision, which was not possible with conventional GPS or simple positioning, enables accurate location marking and shape management based on design coordinates.

• Fast FIX Acquisition: With the latest GNSS chips and multi-frequency support, the time required to obtain a FIX solution is significantly reduced. Under optimal satellite capture conditions, positioning can start immediately after powering on. This reduces the waiting time for surveying and improves the responsiveness on-site.

• Ease of Use and Portability: Despite being a specialized device, the LRTK is compact and can be used by simply attaching it to a handheld smartphone. No complex setup is needed, and anyone can perform positioning through an intuitive app interface. The "one device per person" concept allows workers to easily take it to the field and quickly begin measurements when needed.

• Location-Tagged Photos & Memo Function: When a photo is taken and saved simultaneously with the positioning, it is automatically tagged with high-precision location coordinates, orientation, and time information. This allows you to later verify the location relationship of each photo on the map and share the captured data via the cloud, enabling the digital transformation (DX) of field records.

• 3D Point Cloud Measurement and AR Utilization: LRTK goes beyond simple point surveying, allowing for the acquisition of 3D point cloud data using the smartphone's camera and sensors. The collected point cloud and photo data can be managed centrally via a web cloud, enabling instant data sharing with the office from the field. Additionally, the AR functionality enables the application of overlaying design models or previous measurement results onto the real-world site, making this a reality.

 

Traditionally, when specialized surveying equipment and GPS cameras were used separately, the LRTK's major strength is that it can complete tasks with just a single smartphone.

Compared to other surveying equipment, LRTK products stand out due to their ease of use and all-in-one functionality.

For example, a typical RTK surveying set requires two receivers and communication devices, one for the base station and one for the rover station. On the other hand, the LRTK terminal utilizes Japan's nationwide electronic reference point network and satellite augmentation signals, allowing positioning without the need for additional base stations. This provides a significant advantage for small-scale civil engineering companies or surveying technicians who are new to RTK surveying, as it lowers the entry barrier. Additionally, the collected positioning data can be instantly shared via the cloud, eliminating any time lag from bringing the information back to the office for processing. It is truly a solution that revitalizes the surveying workflow, enabling real-time assessment of site conditions and decision-making.