How to Choose a Long-Range LiDAR Scanner: 5 Comparison Points to Avoid Mistakes

LiDAR scanning (3D laser scanning), which can measure environments and structures over long distances, is increasingly being used across a wide range of fields such as construction, surveying, and infrastructure inspection. When acquiring 3D data of vast sites or high-rise buildings, choosing inappropriate LiDAR equipment or methods can result in failures like “the range didn’t reach as expected and areas were left unmeasured” or “the accuracy was insufficient and the data became unusable.” To successfully perform long-range LiDAR scans, there are comparison and evaluation points you should confirm in advance.

In this article, we explain five comparison points to help practitioners evaluating long-range laser scanning avoid mistakes. We support you by helping you understand in advance important matters such as measurement range, accuracy, and operating environment, so you can select the optimal LiDAR scan for your objectives. Now, let's go through them in order.

Table of Contents

• Measurement distance and coverage area

• Accuracy and resolution

• Acquisition speed and work efficiency

• Field environment and operability

• Data processing and accuracy management

• Summary

1. Measurement Distance and Coverage Area

First and foremost, you should prioritize the LiDAR's maximum measurement range and coverage. When choosing a long-range LiDAR scanner, the fundamental question is whether the laser can reach the target. Measurable distances vary greatly by model, ranging from those that reach on the order of tens of meters (tens of ft) to high-powered models that can measure hundreds of meters (hundreds of ft) ahead. For example, if you want to survey an entire expansive development site at once, or capture data up to the tops of chimneys or bridges that reach heights of tens of meters (tens of ft), you need a LiDAR with a measurement range sufficient to capture the farthest parts of the target. If the selected scanner's effective range is insufficient, distant parts may not be acquired as point clouds, creating blind spots, and you may have to repeatedly relocate and set up the equipment to cover the area, greatly reducing efficiency.

Also, the coverage depends on the scanner’s horizontal and vertical scan angles (field of view). Many terrestrial 3D laser scanners (TLS) are equipped with a rotation mechanism that can turn 360° horizontally, but the vertical range varies by model—from several tens of degrees to 180° or more. For example, if you cannot directly measure straight up or straight down, you need to take multiple scans and merge the point clouds. Therefore, check whether the field of view can cover the entire site in a single pass. In particular, long-range types of LiDAR can measure far with a telescopic laser, but they may cover a narrow area at one time. It is important to visualize, relative to the extent of the area you want to measure, how many setup locations will be required and how much you will need to adjust the device’s orientation.

Furthermore, the practical maximum measurable distance also varies depending on the target's reflectivity and environmental conditions. The "effective range ○○ m (○○ ft)" listed in manufacturers' specifications is often based on ideal conditions targeting a highly reflective white panel, and in real-world situations measuring dark asphalt, vegetation, or water surfaces the reachable distance can be shorter. In long-distance measurements, the laser beam attenuates and scatters more the farther it travels through the atmosphere, so you must also pay attention to weather and lighting conditions. Because strong sunlight, fog, or rain can reduce the effective range, it is advisable, when possible, to choose days with good weather or times such as early morning or evening when lighting conditions are more stable. As above, first consider the distance relationship to the measurement target and the extent of the area, and compare and evaluate LiDAR devices from the perspectives of "can it even reach?" and "how much can it cover at once?"

2. Accuracy and Resolution

Next, an essential consideration is comparing the accuracy of the acquired data and the resolution (point cloud density). For long-range LiDAR measurements, equipment that "can reach far but is coarse in accuracy" cannot be used effectively in practice. Confirm whether the device can ensure accuracy appropriate for the intended application. The accuracy of a LiDAR scanner is generally determined by distance accuracy (the error range of the laser's distance measurements) and angular resolution (the fineness of the scan, resolution).

First, regarding distance accuracy, the higher-performance models have smaller errors: at short range they can achieve errors on the order of millimeters (mm, in), and at long range they can maintain accuracy of a few centimeters or less (cm, in). On the other hand, simple LiDAR units can exhibit errors on the order of around ten centimeters (10 cm (3.9 in)), making them unsuitable for precise dimensional measurements. Especially for measurements that include high elevations, small errors can accumulate in the vertical direction and become problematic, so check whether the device can meet the required accuracy level (for example, within a few centimeters (cm, in) or whether millimeter-level precision (mm, in) is necessary). For projects that demand high precision—such as displacement measurements of important structures or construction management—you should choose a higher-end model without hesitation; conversely, if you only need a rough understanding of terrain, moderate accuracy may be acceptable.

Angular resolution (resolution) is another point you must not overlook. LiDAR scans surfaces by finely sweeping laser beams, but if that angular step is coarse the spacing between points becomes large at long distances. For example, if a scanner emits a laser every 0.1 degree, at 100 m (328.1 ft) away the points would be plotted at approximately 17 cm (6.7 in) intervals. That is not sufficient to capture fine structures and will result in a point cloud full of gaps. To compensate, you need to choose higher-resolution equipment (for example, one capable of scanning in 0.01-degree increments) or measure closer to the target. The latter runs counter to the purpose of long-range scanning, so ideally you should select a LiDAR that can ensure a certain point cloud density even at long range.

There is also a large variation between models in the number of acquired points (the laser pulse emission rate or the number of measured points per second). Higher-performance units can acquire enormous point clouds of hundreds of thousands to a million points per second, resulting in high-density, detailed 3D data. With higher resolution and point rate, it becomes more likely that small cracks or the positions of pipes can be identified from long distances. However, because the data volume also increases, consider the balance with the processing aspects described below. Overall, accuracy and resolution are about judging whether you can secure the level of quality that is necessary and sufficient. Point clouds with errors that are too large or that are too coarse cannot be used in practice and, in the worst case, may require re-measurement, creating duplicated work. In light of your intended use, compare and evaluate the nominal accuracy specifications and past performance values of each LiDAR system, and choose one that provides reliable accuracy.

3. Acquisition Speed and Work Efficiency

The third point of comparison is the speed of data acquisition and on-site work efficiency.

In long-range LiDAR scanning operations, covering a wide area tends to make the time required for acquisition substantial. The amount of effort and the time needed for field measurements can vary greatly depending on the system chosen. Therefore, let’s look at how quickly data can be collected and whether operational efficiency is good.

Representative terrestrial laser scanners (tripod-mounted types) typically take several to a dozen or so minutes to perform a detailed 360° scan at a single location. High-resolution settings for long-distance use can require more time for a single scan. This type yields high-precision point clouds in one scan, but covering a wide area alone requires relocating to multiple positions and taking measurements at each, so the total on-site work can take from several hours to days. On the other hand, mobile-mapping LiDAR (vehicle-mounted or backpack-carried mobile surveying types) can acquire point clouds in real time while moving, allowing collection of data over a wide area with a single pass. Measuring the same area this way takes far less time than with stationary systems. However, because measurements taken while moving can have slightly reduced accuracy, it is necessary to consider the trade-off between accuracy and efficiency.

Drone-mounted LiDAR that measures from the air is also a powerful means of acquiring wide-area data in a short time. By performing laser scans from a drone, you can capture ground topography and entire structures quickly on open sites with few obstacles. Its efficiency is especially high in terrain that is difficult for people to survey on foot, such as forests and riverbeds. However, because drones have flight time (battery) limits, bear in mind that surveying very large areas at high density may require multiple flight plans, and that obtaining permissions and implementing safety measures under aviation law and related regulations will also take time and procedural steps. Whichever method you use, it is important that it matches the time and personnel resources available on site. For example, if work can only be done at night you should choose an approach that can be completed in a short time, and if personnel are limited a system that is easy for one person to operate is desirable.

Furthermore, the time and effort required for initial setup and teardown also affect efficiency. Large, fixed-installation LiDAR systems can take time for equipment transport, tripod setup, and leveling, whereas compact LiDAR devices may allow you to start measurements immediately after powering on. Recently, LiDAR systems controllable via tablets or smartphones have appeared, and measures have been implemented to reduce complicated cable connections and on-site calibration tasks. You should also check for these time-saving operational features. Ultimately, succeeding in long-range LiDAR scanning hinges on being able to collect data efficiently within limited time while meeting accuracy requirements. If multiple methods or pieces of equipment are being considered, simulate the on-site workflow for each and choose the option that can be operated most smoothly.

4. On-site Environment and Operability

The fourth point is adaptability to the field environment where measurements are performed and the operational usability of equipment. Long-range laser scanning is often used outdoors to cover large areas, but the optimal method varies depending on site conditions. First, the technologies available differ between outdoor and indoor environments. In open outdoor areas, measurements using GNSS or drone LiDAR are promising, but in indoor spaces or inside tunnels where GNSS cannot be used and drone flight is difficult, a method in which a person carries and scans with portable ground-based LiDAR (such as handheld LiDAR equipped with SLAM functionality) is more suitable. In this way, assess and select equipment that can be used according to the site's environmental conditions.

Terrain and footing conditions also affect equipment selection. In mountainous or sloped areas where setting up a tripod is difficult, using a small, lightweight LiDAR system or a drone is a practical option. Conversely, on paved ground where a robust stationary setup is possible, it can be preferable to install a high-precision large scanner and take measurements carefully. Furthermore, at civil engineering sites with blowing dust or when working in the rain, whether the equipment has high dustproof and waterproof performance becomes important. Many outdoor LiDAR units comply with dust and waterproofing standards, but the higher the rating (IP standard), the more confidently they can be used in rainy conditions. Long-range LiDAR tends to be larger and more delicate because it is equipped with high-output lasers. Also confirm reliability aspects such as whether the device can operate stably in harsh climates like high heat and humidity or extreme cold, and whether it is designed to withstand long periods of continuous operation. For use under direct midsummer sunlight or in subfreezing midwinter conditions, there are models equipped with fans or heaters to prevent internal overheating or condensation. It is important to anticipate the site’s temperature and weather and verify in advance that the specifications can accommodate them.

Operational usability (ease of use): in this respect, let's compare on-site equipment handling and operability. Stationary laser scanners that can weigh several dozen kilograms require transportation by vehicle and installation by multiple people, whereas a compact LiDAR unit can be carried by one person and easily installed at height. For example, for measurements in hard-to-reach places such as narrow scaffolding or on bridge girders, choosing a small, lightweight LiDAR is safer and more efficient. The user interface is also important. Models that support Japanese display and intuitive touch-panel operation are easier for all field personnel to use. There are various options, from simple devices that can start a scan with the push of a button without specialist knowledge to advanced units that allow detailed scan settings to be configured on a PC. Selecting equipment that matches the team’s skill level can reduce operational stress on site.

Safety aspects cannot be overlooked. Laser scanners are basically designed with wavelengths and output levels that are not harmful to the human eye, but some long-range, high-power lasers are products in a class that require caution to avoid direct viewing at very close range. If you are considering safety measures for workers and people nearby (access restrictions and warning notices), it is prudent to choose equipment that complies with laser standards of as high a safety class as possible (eye-friendly). Finally, power and battery issues also become realistic constraints on site. If long continuous operation is required but the device has a short battery runtime, you will be delayed by charging and battery swaps. If generators cannot be used on site, you need to prepare spare batteries or choose a LiDAR designed for low power consumption. By carefully matching the site’s constraints with the suitability of the equipment in this way, you can avoid the failure of “it didn’t fit the site and couldn’t be used” when the time comes.

5. Data Processing and Accuracy Management

As a final point of comparison, also consider the post-acquisition data processing workflow and methods for quality control. The point cloud data acquired by LiDAR is not finished just by scanning; you need to plan for its subsequent processing and use. The longer and larger the survey, the more massive the resulting point cloud becomes, making processing on high-performance PCs and dedicated software indispensable. Because each LiDAR system differs in data processing steps, difficulty, and supported formats, compare how easy each is to operate including downstream workflows.

First, the method for merging and aligning (registering) point cloud data. When using fixed laser scanners to survey from multiple positions, it is necessary to integrate the individual point clouds into a single coordinate system. One approach is to install target markers on site in advance and use them as common reference points for each scan. Whether targets are used and whether the equipment or software has automatic alignment functions are important to check. Some high-end laser scanners are equipped with built-in compasses, tilt sensors, and even GNSS receivers, which automatically determine each scan position and simplify post-processing. On the other hand, mobile mapping LiDAR and drone LiDAR record the sensor platform’s position during acquisition using an IMU (inertial measurement unit) and high-precision GNSS, directly assigning geographic coordinates to the point cloud. This allows the acquired point cloud to be overlaid directly on map coordinates, which is advantageous for wide-area surveys. However, this requires an environment where GNSS reception is stable, and it is also necessary to perform trajectory computations afterward (SLAM or integrated GNSS-IMU processing). When selecting a system, consider whether your organization can handle these data processing workflows in-house or whether you will rely on external services.

Compatibility with point cloud processing software is also important. Each LiDAR manufacturer provides proprietary data formats and analysis software, but looking ahead it is preferable to have equipment that can export common point cloud formats (such as LAS or E57). It is also reassuring to check whether the data format can be easily imported into the CAD or GIS software you regularly use in-house and whether any unnecessary intermediate conversions will be required. In the construction sector in particular, creating drawings or BIM models from point clouds is common, so data compatibility and ease of editing directly affect productivity.

The last thing to address is methods for accuracy control (quality control). In long-range LiDAR scanning, it is important to verify how much accuracy is actually achieved under real field conditions, even with instruments that claim high precision. For example, by preparing several known-coordinate reference points on site and comparing them with the acquired point cloud to check for errors, you can confirm the reliability of the data. It is common to use a total station or a GNSS surveying instrument in combination to measure such reference points (control points). Recently, methods that use RTK-GNSS to easily obtain high-precision coordinates and apply them to point-cloud alignment and verification have become widespread. For example, by using an RTK system consisting of a base station and a rover, or a network RTK service, you can obtain coordinates of arbitrary points with centimeter-level positional accuracy (half-inch accuracy). Based on these acquired reference data, performing accuracy adjustments and error corrections on the point cloud data can ensure high accuracy across the entire measurement area even for long-range scans.

When you consider the workflow through data processing and accuracy management, you need to look not only at the performance of the LiDAR unit itself but also at combinations with other technologies. If you cannot spend much time processing point clouds after acquisition, you should select a solution with well-developed automatic processing features, or decide to adjust the resolution to reduce data volume. There are also cases where GNSS and photogrammetry are used together to complement accuracy and interpolate missing areas. In this way, envisioning the entire flow from measurement to data utilization and comparing the optimal system configurations is the key to avoiding failure when introducing long-range LiDAR scanning.

Summary

It is no exaggeration to say that the success or failure of long-range LiDAR scans covering wide areas is determined by the prior selection of equipment and planning. In this article, we explain comparison points from five perspectives: 「measurement distance and coverage」「accuracy and resolution」「acquisition speed and work efficiency」「on-site environment and operability」「data processing and accuracy management」. Each of these is an indispensable element, and overlooking even one can cause you to get stuck in an unexpected place. Conversely, if you firmly grasp these five points, you can greatly reduce the risk of choosing equipment unsuited to your application and 「failing」.

Finally, in recent years methods that use smartphones as a new option for LiDAR surveying have also emerged. Although the simple LiDAR built into smartphones has an effective range of only a few meters, attention has focused on the fact that, when combined with high-precision GNSS, it allows easy 3D surveying. For example, by using an iPhone-mounted high-precision GNSS receiver called LRTK, centimeter-level (cm level accuracy (half-inch accuracy)) positioning information can be appended in real time to point clouds obtained with a smartphone. Tasks that previously required expensive specialized equipment and multiple personnel can be performed efficiently by a single person using only a smartphone and a receiver like LRTK. While professional-grade LiDAR remains indispensable for long-range, large-scale surveys, these low-cost, highly mobile measurement solutions can be a strong ally for supplementary measurements in confined areas and routine field documentation. In practice, use cases are already appearing where inspectors attach an LRTK to a handheld iPhone to generate point clouds of bridge piers in bridge inspections. With the advancement of new technologies, we can expect an era in which measurement methods can be chosen with increasing flexibility.

Choosing a long-range LiDAR scan is not straightforward, but if you focus on the key points you will naturally narrow down the options. Please use the comparison perspectives introduced in this article as a reference to determine the 3D measurement methods and equipment that best meet your site needs. Depending on the situation, it is recommended to combine not only traditional laser scanners but also methods such as photogrammetry or smartphone + GNSS and use them wisely. By selecting and implementing the right solution, understanding vast sites and precise structure management can be achieved more efficiently and more safely than before. I hope that leveraging long-range LiDAR scanning suited to your site will greatly contribute to improved productivity and quality assurance in your operations.