RTK Stake Marking with Your Smartphone: A Simple Guide for Beginners

Table of Contents

• What is RTK stake marking?

• Advantages of smartphone RTK stake marking

• What you need for RTK stake marking

• Procedure for RTK stake marking

• Tips and precautions for RTK stake marking

• Summary

• FAQ

What is RTK stake marking?

RTK stake marking is the process of driving stakes (marking positions) on site using high-precision GNSS positioning based on the RTK (Real-Time Kinematic) method. Traditionally, staking out positions on construction and civil engineering sites required dedicated equipment such as total stations and careful measurements by multiple personnel. However, with the advent of RTK-GNSS, it has become possible to determine your position from satellite positioning with an accuracy of a few centimeters (a few inches) and place stakes according to specified coordinates. (Here, "stake marking" refers not to driving foundation piles in building construction but to placing marker stakes or pins at points as a surveying task.)

RTK is a technique that uses correction information from a base station to correct positioning errors in GPS and other satellite systems in real time, obtaining highly accurate position coordinates. Using this technology, you can compare your on-site position with predetermined design coordinates (for example, boundary lines or positions for structures) and place stakes accordingly. The system performs the complex calculations automatically, so even non-specialist personnel can increasingly perform the task of installing stakes in the correct positions. RTK stake marking is a new construction style that enables site workers to establish reference points themselves and drive stakes indicating points on design drawings.

Advantages of smartphone RTK stake marking

• Easy to operate without specialized knowledge: Surveying apps on a smartphone guide you on the screen, making them easy to use even for beginners without surveying skills. Complex coordinate calculations and corrections are handled automatically by the system, so operation is often as simple as tapping buttons.

• Quick staking by one person: Tasks that used to take a whole day with several people including surveyors can be completed quickly by one person with an RTK-capable GNSS and a smartphone. This eliminates the need to secure personnel or coordinate schedules, dramatically improving site productivity.

• Centimeter-level accuracy (half-inch accuracy): RTK positioning has high precision with errors within several centimeters (within several inches), keeping stake placement deviations very small. This enables accurate positioning according to design drawings and reduces rework and mistakes.

• Excellent mobility and portability: With just a smartphone and a small GNSS receiver, you don’t need to carry large tripods or heavy equipment. You can easily move and position yourself in tight spaces or at height, and take out the devices for immediate measurement and staking when needed.

• Intuitive guidance: Survey apps show the direction and distance to the target on the smartphone, and alert you with sounds or alarms as you approach, so you can find the target point without getting lost. Some apps can overlay virtual stakes or design data in the camera view with AR, allowing intuitive understanding of positions on site.

• Digital recording and sharing: The positions of stakes and survey results can be saved as digital data on the smartphone. There is no need to take paper notes, and cloud integration makes it easy to instantly share coordinates obtained on site with the office. Data can be exported in common formats such as CSV and later imported into CAD drawings.

• Wide range of use cases: Smartphone RTK surveying can handle tasks that previously required professional surveyors, such as staking out boundaries on site, locating buried objects, and checking as-built conditions. It can be flexibly used for everything from marking small structures to rapid condition surveys after disasters.

What you need for RTK stake marking

• Smartphone or tablet: You need a smartphone that can install a surveying app that supports RTK positioning. Modern iPhones and Android devices are generally sufficient in terms of performance. Because high-precision positioning requires connection with external equipment, prepare a device that can connect to equipment via Bluetooth or USB.

• RTK-capable GNSS receiver: To achieve centimeter-level accuracy, you need an RTK GNSS receiver rather than the phone’s built-in GPS. Recently, small receivers that attach to smartphones or GNSS devices that connect via Bluetooth to phones are commercially available. These receivers obtain high-precision positioning from satellite signals and provide position information to the smartphone.

• Correction information from a base station: RTK positioning requires correction data sent from a reference base station. In many cases, the smartphone connects to an RTK correction service (Ntrip, etc.) delivered over the internet to obtain correction information from a regional network of reference stations. Japan has a nationwide network of Continuously Operating Reference Stations managed by the Geospatial Information Authority, and you can also use paid VRS services or real-time correction services provided by local governments. For sites without internet access, you can set up your own base and rover and receive correction data via radio.

• Surveying app: You need a dedicated app that displays the high-precision position information from the GNSS receiver and navigates you to the target stake coordinates. Install an app that supports your GNSS receiver or a general-purpose surveying app. The app allows you to input or import target point coordinates and display real-time distance and direction from your current location. Choosing an app that supports Japanese coordinate systems such as plane rectangular coordinates makes it convenient to use design drawing coordinates directly.

• Other useful tools: Prepare stakes themselves (wooden or plastic stakes), a hammer, chalk or spray paint for marking, and other on-site marking tools. A pole or monopod to stably hold the GNSS receiver is also handy. Using a pole helps keep the receiver height constant, enabling more accurate positioning and stable work.

Procedure for RTK stake marking

• Prepare target coordinates in advance: Prepare coordinate data for the points to be staked in advance. List the target point coordinates (latitude/longitude or plane rectangular coordinates) obtained from design drawings or survey maps. If possible, create coordinate files in formats supported by your surveying app (CSV, SIMA, etc.) so you can import them into the app later.

• Set up the RTK positioning environment: On site, connect the smartphone and GNSS receiver and get ready for RTK positioning. Turn on the GNSS receiver and connect it to the phone via Bluetooth, or attach it to the phone if it is an attachable model. Then connect to the correction service within the surveying app and confirm that an RTK "Fix" has been obtained. If satellite reception is good and accuracy on the order of a few centimeters (a few inches) is achieved, you are ready.

• Set the target points: Enter or import the target coordinates you want to stake into the surveying app. You can enter them one by one, but importing a prepared coordinate file lets you register multiple points at once conveniently. Target points will be displayed on the app as a map or list and be selectable.

• Navigate to the target location: Start the staking work on site. When you select a target point in the app, the screen will show the direction and distance from your current position to that point. Walk while holding the smartphone and follow the on-screen arrow or map toward the target. Some apps have a close-range mode that provides more detailed display as you approach the target and allows fine adjustment down to a distance of a few centimeters (a few inches). Use voice guidance or alarms if available to help locate the exact position.

• Place the stake (marking): When the app indicates that your current location nearly coincides with the target point and the distance error is within a few centimeters (preferably about 1-2 cm (0.4-0.8 in)), drive the stake at that location. Use the wooden or plastic stakes you brought and hammer them into the ground, leaving the head as a marker. If the ground is too hard to drive a stake, mark the pavement with spray paint or chalk, or place a marker pin. Mark stakes or marks with numbers or labels to make later verification easier.

• Post-installation check and recording: After installing the stake, measure the stake’s coordinates on the smartphone to verify there is no deviation from the target. If the error is within the acceptable range, the placement is successful. Some apps let you save the point coordinates to the cloud or take photos for records. Repeat the same procedure for all target points and organize the recorded data after completing the work.

Tips and precautions for RTK stake marking

• Ensure good satellite reception environment: Accurate RTK positioning is best achieved with a clear view of the sky. Tall buildings or dense trees nearby can block or reflect satellite signals and cause errors. When staking, work in locations with good visibility as much as possible and, if necessary, temporarily avoid surrounding obstructions.

• Maintain RTK fixed solution: During work, always pay attention to whether the RTK solution remains in the "Fix" state. Moving into a tunnel or under tall trees can temporarily degrade accuracy and revert to a "Float" solution. If positioning accuracy decreases, stop and wait calmly until a fixed solution is regained before resuming staking.

• Battery management: Monitor battery levels for both the smartphone and GNSS receiver. RTK positioning and screen use consume significant battery, so carry spare batteries or a power bank for long tasks. Be especially mindful that batteries drain faster in cold environments such as mountainous areas.

• Check coordinate systems and datums: Confirm that the target coordinate system is set correctly beforehand. GNSS measurements are typically in the WGS84 datum, while design drawings may use plane rectangular coordinates or a local coordinate system. If your surveying app supports coordinate transformation (localization), apply it to match local reference points and avoid placement discrepancies.

• Keep the device stable: When holding the GNSS receiver by hand, try to keep it as vertical as possible. Position the antenna directly above the target point and maintain a consistent height to minimize horizontal position error. Even if your pole or monopod has tilt compensation, avoid steep angles.

• Post-work verification: After staking, consider verifying positions using another method when possible. For important reference points, you might verify differences by measuring with a conventional total station, for example. Double-checking important points provides greater assurance. While you can trust RTK coordinates, performing backup checks on critical locations helps prevent problems.

Summary

RTK stake marking with a smartphone is changing surveying and positioning tasks that once required specialists. With a small GNSS device and a smartphone app, beginners can accurately place stakes in a short time, contributing to improved site productivity and relief from labor shortages. It’s also attractive because it does not require the expensive and complex equipment of the past and is easy to get started with. Try experiencing centimeter-level positioning—its ease and accuracy will likely surprise you.

These simple high-precision surveying tools also align with site DX (digital transformation) initiatives promoted by the Ministry of Land, Infrastructure, Transport and Tourism, such as i-Construction, and are expected to become more widespread.

If you want to introduce RTK surveying more easily, consider [Simple surveying with LRTK](https://www.lefixea.com). LRTK, which consists of an ultra-compact RTK-GNSS receiver that attaches to a smartphone and a dedicated app, provides end-to-end guidance from centimeter-precision positioning to stake placement without requiring complicated setup. It also includes features for saving and sharing survey data and AR-based intuitive position confirmation, significantly lowering the barrier to on-site surveying. It is designed to be easy for beginners to use, so if you want to try high-precision stake marking with your own smartphone, check out the LRTK solution.

FAQ

Q: Can I use my own smartphone for RTK stake marking? A: Yes. In general, you can use your current smartphone (iPhone or Android) as long as a compatible surveying app can be installed. Any device capable of installing the dedicated app and connecting to a GNSS receiver can be used. Newer, high-performance models have advantages in processing speed and battery life, but unless the phone is extremely old, it should work for RTK stake marking.

Q: Why is an external GNSS receiver necessary instead of the phone’s built-in GPS? A: Built-in smartphone GPS (GNSS) typically has position errors on the order of meters and is not suitable for precise tasks like staking. Using an external RTK-capable GNSS receiver allows centimeter-level positioning by incorporating correction information. External receivers are designed for surveying and have higher satellite reception sensitivity, providing stable high-precision positions.

Q: How do I use RTK correction services? A: Generally, you connect the surveying app to an RTK correction service provided over the internet. You can subscribe to private VRS services or use base station data provided by local governments. By entering base station information (Ntrip server details and login credentials) in the app, the app will automatically receive correction data and apply it for real-time positioning. In Japan, some receivers can use the Quasi-Zenith Satellite System "Michibiki" CLAS service to achieve high-precision positioning without an internet connection.

Q: Initial costs seem high. Are there cheaper ways to start? A: Compared to traditional surveying equipment, RTK systems using a smartphone and a small GNSS receiver are much more affordable. High-precision GNSS receivers are not cheap, but costs have decreased and more affordable models are available. There are also rental and subscription options, so you can start according to your budget. Once introduced, you can reduce external surveying costs, so there are significant long-term cost benefits.

Q: Can beginners with no surveying experience really stake accurately? A: Yes. If you follow the correct procedures, beginners can stake accurately. As described in this article, the app provides visual guidance and the system ensures positioning accuracy automatically. It’s good to start by testing in a wide open area and staking at known reference points to confirm accuracy. It may take longer at first, but with practice anyone can achieve position accuracy of several centimeters (several inches). In actual device verifications such as with LRTK, results have been reported showing only a few millimeters (a few hundredths of an inch) of error compared to professional high-precision surveying equipment. If you are unsure, have professionals check only critical points for added assurance.

Q: Is RTK stake marking possible in mountainous areas or remote islands with no cell reception? A: RTK stake marking is possible without internet connection, but you need to prepare a mobile base station yourself and transmit correction information wirelessly to the rover receiver. This requires more advanced setup, but once configured, high-precision positioning can continue offline. Also, receivers that directly support Michibiki (CLAS), such as some LRTK devices, can achieve centimeter-level positioning nationwide in Japan without setting up a base station, making them effective for mountainous surveys.

Q: Can it be used indoors or in tunnels where satellites are not visible? A: Unfortunately, GNSS positioning cannot be used indoors or underground where satellite signals are blocked. Surveys in such locations require other methods, such as total stations. However, you can sometimes combine methods—for example, perform GNSS positioning near the entrance and then use a laser distance meter indoors. Currently, RTK stake marking is most effective outdoors.