Laser GNSS receiver: measuring points without a pole

A classic GNSS receiver measures the point where the pole is placed. But there are points where a pole cannot be placed: a building corner, a fence, a dangerous edge, a blocked or flooded area. A laser GNSS receiver solves this problem. It has a built-in laser rangefinder, and the rover measures the position of a point from a distance.

How it works

The receiver determines its own position by RTK. The laser measures the distance to the target point, and the orientation sensors (IMU) give the direction and tilt. From these data the software calculates the coordinates of the target point. So you do not need to approach the point itself.

What it gives you in practice

• Measuring building corners and facades without touching them
• Surveying fences, road edges and hard-to-reach outlines
• Safety: you can measure from outside a dangerous zone, for example next to a busy road or a trench
• Speed: you do not walk around obstacles to place the pole on the point

Models in the catalog

The receivers with laser are:

• M20L: green laser, horizontal accuracy ±(8 mm + 3 mm/m) and vertical ±(15 mm + 3 mm/m), 120° IMU without calibration, 4G, Bluetooth, WiFi
• M25: laser with a 120 m range and an AR camera
• ML2: a compact laser version
• Warrior: a rover with laser and camera

For those who also need photogrammetry there is the laser and photogrammetry category:

• M20LV: 5th-generation laser module, range over 200 m, frequency up to 10 Hz, photogrammetry with 5–10 cm accuracy at 10 m
• M27LV: laser with a camera, laser-visual fusion and photogrammetry

The values come from the manufacturer's data; full specifications and configuration are confirmed when you request a quote.

A typical scenario

You survey buildings along a street for a site plan. Instead of stepping into traffic for every corner, you stay on the pavement, get a fixed RTK solution, aim the laser at the corner and save the point. The same applies to a fence behind a ditch or an object on a waterside. This way surveying is faster and safer for the operator.

Accuracy decreases with distance

The formula ±(8 mm + 3 mm/m), stated for the M20L, shows something important: the laser error grows with distance. The farther the point, the larger the error. In addition, the point coordinates also depend on the receiver position: without a fixed RTK solution, a laser-measured point will not be better than the receiver position. For important points choose short distances.

Limits of the method

• The laser needs a direct line of sight to the point
• Lighting and the target surface can affect the measurement; see the manufacturer's instructions
• The receiver must have a good GNSS signal: under dense tree canopy or next to tall buildings the method does not help
• Follow the safety instructions for laser devices in the manufacturer's documentation

Laser, cameras or both

The laser and the cameras solve related problems in different ways. The laser gives the coordinates of a specific point. Cameras (visual receivers M20 and M30) let you measure points from images and stake out in augmented reality. Photogrammetry in the M20LV and M27LV helps with hard-to-reach points or points hidden by obstacles. Choose according to the work you do most often.

When it is worth it

A laser receiver is worth it if you often survey details next to buildings, fences and obstacles or work where access is dangerous. If you work mostly on open terrain and put the pole on every point, a universal rover is enough and lighter.

Not sure which model fits? Describe your work, add models to the quote cart or write to us on the Contacts page. See also the article on how to choose a GNSS receiver.