3D Capture & Reality Modeling

Types of LiDAR

There is no single kind of LiDAR. Systems are grouped three different ways at once — by the platform that carries them, by what they measure, and by how they steer the beam. Knowing which axis matters for your job is the fastest way to pick the right sensor. If you are new to the technology, start with What is LiDAR? first.

By platform
Airborne, mobile/UAV, terrestrial (tripod), and handheld/SLAM.
By target
Topographic (land, infrared) vs bathymetric (underwater, green laser).
By beam steering
Mechanical (spinning/mirror) vs solid-state (MEMS, flash, OPA).
By detection
Single-return, multi-return, and photon-counting (single-photon / Geiger).

By Platform: Where the Sensor Rides

The same ranging physics behaves very differently depending on what carries the scanner and how far it sits from the target.

Airborne LiDAR (ALS)

Mounted in a crewed aircraft or large UAV and flown over the landscape. Airborne systems cover enormous areas in a single mission and, thanks to multiple returns, are the workhorse for terrain and forestry mapping. Accuracy depends heavily on the integrated GNSS and IMU that georeference every pulse from a fast-moving platform.

Airborne LiDAR point cloud of New York City's Central Park, shaded with orthophoto color
Airborne LiDAR over Central Park, New York City — terrain, trees, and buildings captured in one pass and shaded with orthophoto color. Image: U.S. Geological Survey (public domain).

Mobile & UAV LiDAR (MLS)

A scanner bolted to a car, truck, train, or drone, mapping continuously as the platform moves. Mobile mapping is ideal for roads, rail corridors, and utility lines — capturing a road and everything along it at driving speed. Drone LiDAR brings airborne-style coverage to small sites at far lower cost.

Terrestrial LiDAR (TLS)

A high-precision scanner on a survey tripod, capturing a dense 360° scan from a fixed station. Multiple stations are then registered together into one cloud. TLS delivers the highest point density and accuracy of any platform and is the standard for as-built surveys, building documentation, and forensic capture.

Close-up of a terrestrial LiDAR laser scanner head with rotating mirror
A terrestrial laser scanner — the rotating head and mirror sweep the beam across a full 360° from a fixed tripod station. Image: David Monniaux, CC BY-SA 3.0, via Wikimedia Commons.

Handheld & SLAM LiDAR

Walk-and-scan systems that build a cloud while you move through a space, using SLAM (Simultaneous Localization and Mapping) to track their own position without GNSS. They trade some accuracy for speed and access — perfect for indoor spaces, tunnels, and cluttered sites where setting up a tripod for every scan is impractical.

Topographic vs Bathymetric

The biggest split by what a LiDAR measures comes down to wavelength.

Topographic

  • Near-infrared laser (~905 / 1550 nm)
  • Maps land, vegetation, structures
  • Water reads as a void
  • The vast majority of LiDAR

Bathymetric

  • Green laser (~532 nm)
  • Penetrates clear water
  • Maps riverbeds, coasts, shallows
  • Limited by water clarity

Topobathymetric

  • Both lasers in one system
  • Seamless land-to-seabed model
  • Coastal & flood mapping
  • Single continuous surface
Topobathymetric elevation model of Barnegat Bay combining land elevation and underwater depth
A topobathymetric model of Barnegat Bay, New Jersey — green-laser bathymetric LiDAR fills in the underwater depths that infrared cannot reach, joined seamlessly to the land surface. Image: U.S. Geological Survey (public domain).

Mechanical vs Solid-State

How the beam is swept across the scene defines a sensor’s reliability, field of view, and cost — the axis that matters most for autonomy and high-volume manufacturing.

  • Mechanical (spinning) — a rotating assembly or oscillating mirror physically aims the laser, giving a wide field of view and a mature, well-understood scan pattern. The moving parts add cost and a wear point.
  • MEMS — a tiny micro-electromechanical mirror steers the beam with no large moving assembly: smaller, cheaper, more rugged, but usually a narrower field of view.
  • Flash — illuminates the whole scene with one wide pulse and reads it on a detector array, like a 3D camera. No scanning at all, so it freezes a frame instantly — at the cost of range.
  • Optical phased array (OPA) — steers the beam purely electronically with no moving parts at all. The most solid-state of all, and an active area of development.

Single-Return, Multi-Return & Photon-Counting

Sensors also differ in how they interpret the echo:

  • Single-return records one distance per pulse — common in simple or automotive sensors.
  • Multi-return records several echoes per pulse (first through last). This is what lets airborne LiDAR see both canopy and bare earth.
  • Full-waveform digitizes the entire returning signal, preserving the most information for advanced analysis.
  • Single-photon & Geiger-mode are sensitive enough to register individual photons, enabling very high altitude or long-range collection at high point rates.
LiDAR cross-section comparing old-growth forest canopy structure with a young plantation
Multi-return airborne LiDAR resolves the vertical structure of a forest — old-growth canopy (right) versus a young plantation (left) — something only repeated returns per pulse can reveal. Image: Sarah Frey, Oregon State University, CC BY-SA 2.0, via Wikimedia Commons.
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These categories stack

A real sensor sits on every axis at once — e.g. a drone-mounted, topographic, MEMS, multi-return LiDAR. When comparing systems, decide which axis your project actually constrains (range? water? cost? moving parts?) and let that drive the choice.

Choosing the Right One

Work down from the job to the sensor: What is the range to the target? Do you need to map underwater? Is the platform moving, and do you have GNSS? How much detail (point density) does the deliverable require, and what is the budget? Those four answers usually narrow the field to a handful of sensors.

For specific hardware across these categories — from budget depth cameras to survey-grade and underground scanners — see our guide to choosing a LiDAR system. If you are still weighing LiDAR against camera-based capture, read LiDAR vs Photogrammetry.