Municipalities Take Note! Improving Public Survey Efficiency with Smartphone Surveying

Surveying work is indispensable for infrastructure inspections and disaster response. Improving its efficiency is an urgent issue for many municipalities. In recent years, “smartphone surveying,” which leverages smartphones, has attracted attention as a new solution. This article explains in detail the current challenges of municipal surveying work, the benefits of smartphone surveying, concrete use cases, and the effectiveness of LRTK for enabling high-precision positioning.

Challenges in Municipal Surveying Work

Local governments conduct many surveying tasks daily for infrastructure management such as roads, bridges, and water and sewage systems. However, conventional public surveying has faced various challenges. The main issues are as follows:

• Labor shortages and an aging workforce: The number of staff responsible for surveying is decreasing, requiring a limited workforce to cover large areas

• Time- and labor-intensive work: Although traditional instruments like transits and levels provide high accuracy, measuring each point requires considerable time and multiple personnel

• Inefficient data sharing: Summarizing survey results on paper drawings and organizing data is time-consuming, delaying sharing and handover to stakeholders

• Cost burdens: When surveying is outsourced to private survey companies, the costs become a burden on municipal budgets

Increasing natural disasters such as heavy rains and earthquakes have also posed new challenges for municipal surveying. Immediately after a disaster, 빠く状況を把握する必要がありますが, traditional methods (on-foot inspections or plane-table surveying) involve risks and may be unable to keep up when there are many damaged sites. In disaster areas where aftershocks and secondary disasters are possible, having staff repeatedly visit sites also raises safety concerns. Thus, a surveying method that simultaneously achieves labor reduction, faster response, and improved safety was needed.

Reduced Workload and Faster Operations with Smartphone Surveying

As a solution to these challenges, municipalities have recently been focusing on smartphone surveying. Smartphone surveying, as the name implies, uses smartphones equipped with satellite positioning functions such as GPS/GNSS, cameras, and sensors to obtain location and terrain data. Modern smartphones have become highly capable, providing many functions useful for positioning and measurement despite their small size. Introducing smartphone surveying can be expected to deliver substantial efficiency gains and reduced on-site burden compared to traditional surveying.

One of the biggest advantages of smartphone surveying is its ease of use and mobility. There’s no need to carry heavy tripods or stationary equipment; staff can move around sites with just a smartphone. For example, recording a survey point’s coordinates can be completed simply by tapping the smartphone screen, eliminating the need for auxiliary personnel. This enables solo surveying, allowing efficient response even where staffing is limited. Also, since smartphones are typically connected to networks, it is easy to share data to the cloud in real time from the field. The time-consuming steps of returning to the office to create drawings or copying data via USB are eliminated, dramatically speeding up information sharing among stakeholders.

Some may be concerned about accuracy, but smartphone positioning accuracy has improved recently, and when combined with RTK (real-time kinematic) technology devices described later, centimeter-level high-precision positioning is possible. Thanks to these technological advances, smartphone surveying is achieving both “ease of use” and “improved accuracy,” strongly supporting municipalities’ surveying DX (digital transformation). In fact, the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative promotes the use of ICT in surveying and construction, and new methods like smartphone surveying are spreading in municipal operations as part of that effort.

Smartphone Surveying Applications in Road Operations

Smartphone surveying is also being adopted in the road sector managed by municipalities. By incorporating smartphone surveying into tasks such as updating road ledgers, preliminary investigations for roadworks, and checking surface or slope deterioration—work that previously required specialized surveying teams and long time—efficiency can be improved. A major advantage is that a staff member can walk along a road with a smartphone and sequentially record the locations of required points, allowing field surveys and surveying to proceed concurrently.

For example, in road maintenance, when a road depression or damaged guardrail is discovered, the location can be measured and photographed on the spot with a smartphone. The resulting photos with accurate coordinates are uploaded immediately to a cloud-based sharing system, so supervisors and related departments can review the information by the time the staff returns to the office. Previously, reports often relied on vague descriptions like “about 50 m (164.0 ft) east of XX intersection,” but smartphone surveying can specify latitude and longitude pinpoint locations, making later site identification and arranging responses much smoother.

Smartphone surveying also helps in route selection and design stages for new roads. Large-scale topographic surveys that once required surveyors to measure points one by one across forests and fields can be made more efficient by combining drone aerial photography and smartphone surveying. By obtaining high-precision geotagged photos with a smartphone’s GPS receiver or an external device and later converting them into point cloud data with analysis software, detailed 3D terrain models can be produced in a short time. This significantly shortens the lead time for creating as-built maps needed for road planning. Processes that used to take days to weeks from field surveying to drawing production can be compressed, providing greater leeway in the overall road construction schedule.

Smartphone Surveying for Disaster Response

Smartphone surveying also proves highly effective at disaster sites where natural disasters occur frequently. Rapidly grasping damage immediately after a disaster is a race against time, and smartphone surveying allows staff to conduct surveys quickly from safe locations to rapidly understand the overall damage.

Consider a large-scale landslide caused by heavy rain. Traditionally, surveyors would risk approaching the damaged site, set up surveying instruments, and measure the extent of the debris. With smartphone surveying, it is possible to measure the edges of the collapsed area from a safe distance using a smartphone’s GPS and camera and plot the extent on a digital map. Moreover, if the acquired data is used to automatically calculate the volume of collapsed soil, the number of machines needed and the amount of soil to be transported by dump trucks can be estimated immediately. Such information directly supports early restoration planning.

Recording data quickly at disaster sites is also critical. High-precision damage maps and 3D models created by smartphone surveying serve as design materials for restoration work and as damage reports. In one municipality, a smartphone surveying system combining an iPhone with a high-precision GNSS receiver was used to record locations of heavy-rain disaster damage. As a result, they were able to collect restoration-critical data more quickly than before and reduced outsourcing costs for surveying. Visualizing damage with high-precision surveying data enhances municipal disaster response capabilities and directly contributes to residents’ safety and security.

Smartphone Surveying for Infrastructure Maintenance Management

Smartphone surveying is useful for maintenance management of municipal infrastructure assets such as roads, bridges, water and sewage facilities, and park equipment. When an abnormality is found during routine inspections, accurately recording that location is essential for improving repair planning and the accuracy of management ledgers. By introducing smartphone surveying, inspectors can simply take a photo and have the precise location coordinates automatically recorded, eliminating later confusion about “which location it was.”

For example, when a streetlight bulb is found to be out or damaged during patrol inspections, the traditional procedure involved marking the location on a map or memo and taking it back to the office to identify the location on the map. With smartphone surveying, the inspector can measure the position on the spot by pointing a smartphone and upload the photo to the cloud along with the coordinates. Once the office checks the photo with coordinates on a PC screen, the exact location on the map is immediately apparent, and repair staff can head to the site without delay. This reduces unnecessary site searches and shortens response time.

Furthermore, the high-precision location data accumulated through smartphone surveying is powerful for long-term monitoring of infrastructure equipment. If the same bridge component or road depression is periodically measured with RTK and coordinates are recorded, even a settlement or displacement of a few centimeters (a few inches) can be detected in the data. This shifts anomaly detection from reliance on the experience and intuition of veteran staff to objective, data-driven judgment. Such data can also be easily incorporated into asset ledgers managed by GIS (geographic information systems), facilitating organization-wide sharing of field information. Smartphone surveying is a key to evolving infrastructure maintenance into smart and efficient operations.

Centimeter-Class Positioning Achieved with LRTK

When discussing smartphone surveying, the use of high-precision positioning technology called RTK is indispensable. Typical smartphone GPS positioning has errors on the order of several meters, but by using the RTK (real-time kinematic) method, those errors can be reduced to a few centimeters. RTK receives satellite signals at both a base station installed at a known position and a rover (the mobile unit), and uses correction information broadcast from the base station to improve positioning accuracy in real time. This enables a level of accuracy that previously required dedicated surveying equipment to be achieved with compact devices.

A representative tool for this is LRTK. LRTK is a small, high-precision GNSS receiver that attaches to a smartphone and, when combined with an iPhone or iPad, enables centimeter-class positioning easily. By utilizing LRTK, anyone can perform high-precision smartphone surveying without specialized knowledge. Some main features of LRTK include:

• Palm-sized and easy to carry: With a weight of only about 160 g and an ultra-compact design with a thickness of about 1 cm (0.4 in), it fits in a pocket and is a convenient surveying device. It doesn’t get in the way on site and can be taken out and used whenever needed.

• Centimeter-class positioning accuracy: Supports the RTK method and achieves high positioning accuracy of approximately horizontal ±2 cm (±0.8 in) and vertical ±4 cm (±1.6 in). The obtained coordinate data includes not only latitude and longitude but also elevation, allowing height information required in public surveying to be acquired simultaneously.

• Built-in long-lasting battery: The internal battery supports about 6 hours of continuous positioning, and with a mobile battery, it can withstand a full day’s work. Charging is via USB Type-C, so it can be conveniently powered on site.

• Correction even without cellular coverage: Supports correction signals (CLAS) provided by Japan’s Quasi-Zenith Satellite System “Michibiki,” allowing reception of correction information directly from satellites in mountainous or radio-challenged areas. This maintains accuracy even at sites without cellular coverage, enabling stable positioning.

• Various smartphone connectivity features: Using a dedicated app, you can utilize advanced functions such as 3D scan surveying linked with the smartphone camera and sensors, AR-based on-site projection, and navigation to stake-out positions, in addition to coordinate recording. Positioning data and captured photos sync automatically to the cloud, so the information obtained on site can be shared and used immediately.

With LRTK, a smartphone can quickly become an all-in-one high-precision surveying device. It is revolutionary that public-survey-level accuracy can be achieved with a handheld smartphone and a compact receiver without investing in expensive dedicated GNSS equipment. Moreover, the cost of introducing tools like LRTK is significantly lower than that of conventional high-precision surveying equipment, making it an economically attractive solution. Since on-site data is immediately saved to the cloud, cumbersome data organization after returning to the office is unnecessary. As a truly “easy-to-use” smartphone surveying tool, LRTK is drawing attention from many municipal stakeholders.

Effects and Future Prospects of Introducing Smartphone Surveying

By introducing smartphone surveying and LRTK, municipal surveying work has stepped into a new stage of balancing efficiency and high precision. In addition to shortening fieldwork time and reducing personnel burden, there are many benefits such as rapid decision-making enabled by immediate sharing of accurate data, reduced outsourcing costs, and improved safety. Municipalities that have adopted smartphone surveying report outcomes like “surveying time has been reduced to less than half” and “data collection at disaster sites has become much faster, accelerating recovery decisions.”

The national push for i-Construction and DX also supports this trend, and smartphone surveying is expected to spread to even more municipal tasks. Even for first-time adopters, simplified high-precision positioning tools like LRTK can be used on site without special technical training, facilitating smooth acceptance within departments. Going forward, public surveying sites are expected to transform from work reliant on the experience of skilled personnel to smart operations using digital devices and data utilization.

Summary: Smartphone surveying is a powerful ally for municipal civil engineering and infrastructure management departments. By leveraging this new method that combines labor savings, speed, and reliable accuracy, municipalities can achieve high-quality public surveying with limited personnel. Simplified high-precision surveying with LRTK is already delivering results in many places as a solution that combines ease of use and reliability. Consider adopting smartphone surveying in your organization’s operations to experience improvements in efficiency and service.