The VTX-1 altimeter

The innovative airborne remote sensor
coming from the spatial industry, dedicated to the spatial industry

A unique and complementary instrument to the VorteX-io micro-station, the VTX-1 light altimeter is a laser rangefinder  dedicated to measuring the water level of continental hydrological surfaces and coastal areas. 

The VTX-1 can perform different types of missions:

Hydrological Linear

Rivers, estuaries, lakes


Ocean and coastline

Freeboard thickness

Sea ice (pack ice)


Surface masks

The VTX-1 instrument

The VTX-1 in a few points:

  • a class 1 laser emitting in the near infrared (NIR),
  • an IMU inertial unit,
  • a GNSS RTK system,
  • a nadir camera,
  • a 3G/4G chipset

© Photo/video credits and thanks: i-Techdrone

Embeddable on any type of drone

Weighing only 780g, the VTX-1 airborne sensor is compatible with all types of professional UAV. It can be embedded on any type of device equipped with a payload of 1 Kg or more and a gyro-stabilized gimbal.
Examples of compatible drones: DJI (Matrice 300 RTK, Matrice 200 RTK), MicroKopter, Altigator, etc.

Multi-beam transmission

The class 1 NIR laser sensor emits 8 beams spread over 16°, along the flight direction of the UAV. While measuring at different angles of incidence, the surface height of the water can be recovered directly or through the combination of different beams.

3G/4G mobile network

The VTX-1 is equipped with a 3G/4G internet connection dedicated to the monitoring of the instrument during the flight and to the real time display of the data acquisition thanks to an authenticated data viewer. A first estimate of the range is visible at a glance in near real-time.

Great autonomy

The LiDAR laser technology used by the VTX-1 induces low power consumption. Each removable battery provides up to 3 hours of autonomy. No output connection is required from the drone.

Use cases

The VTX-1 is used in projects with several players in the space field. It is notably used to establish reference measurements to validate satellite calibration, to carry out the topography of rivers, estuaries and streams, as well as to measure the thickness of the ice pack.
It can also be used for operational response in the field in case of extreme hydrological events



Sentinel-3 is a series of Earth observation satellites developed within the European Commission’s Copernicus program.

Definition of the hydrological CalVal of the Sentinel-3 mission

  • Linear and hydrological transect measurements 
    Rhine, Garonne, Seine (France), Po, Tiber (Italy)
  • Ice pack thickness measurements
  • Orthophotography



The SWOT (Surface Water and Ocean Topography) mission aims to measure the height of hydrological surfaces and to map ocean currents.

Participation in the Cal/Val hydrological design of the innovative SWOT satellite

  • Hydrological linear measurements on rivers
    Willamette River (USA), Garonne (France)



Provision of validation data for innovative satellite data processing algorithms.

Sentinel-3 FFSAR study on estuaries

  • Hydrological linear measurements on estuaries Rhône (France), Severn (United Kingdom)

Drone Ocean


Sino-French mission dedicated to the observation of wind and waves in the open ocean.

New CFOSAT in situ calibration facilities

  • Swell spectra measurements
    Saint-Jean-de-Luz, Étretat (France)



Participation in the validation of the technical choices of the future Sentinel-3 Next Generation mission on hydrological zones.

Inter-mission comparison: SWOT / Sentinel-3 / Sentinel-6

  • Hydrological linear measurements on rivers Danube (Germany), Po (Italy)

Future developments

The autonomous drone

To overcome the current constraints of drone altimetric measurement campaigns, our R&D team is developing an ambitious project for a fully autonomous drone,supported by CNES.

As its name suggests, the drone will perform water height measurements without human action in collaboration with our partner I-TechDrone.

This crucial data at the heart of the Cal/Val satellite missions will be perfectly colocated in time and position with satellites such as Sentinel-3.
This will greatly facilitate the collection and processing of data to produce baseline measurements.

This major innovation will allow the measurement of river lines to enter a new era.

The digital twins

The combination of the measurements made by the drones on the one hand and those made by our micro-stations on the other will eventually provide an accurate estimate of the water height over the entire stretch of river measured by the altimeter.

This method will allow us to develop digital twins of the rivers.
The development of autonomous drones and the large-scale deployment of our constellation of micro-stations will make it possible to monitor hydrological networks along their entire length.

This development work is carried out in the continuity of projects carried out in collaboration with space agencies.

They trust us

Want to learn more?

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The vorteX-io solutions

The VTX-1 lightweight altimeter complements the vorteX-io micro-station constellation and the Maelstrom® software platform.

micro-station vorteX-io capteur hydrologique innovant

The vorteX-io micro-station



The Maelstrom® SaaS platform

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