# Ainstein US-D1 Standard Radar Altimeter
Tip This supersedes the Aerotenna uLanding Radar (discontinued) but uses the same driver/setup.
The Ainstein US-D1 Standard Radar Altimeter (opens new window) is a compact microwave rangefinder that has been optimised for use on UAVs. With a sensing range of about 40 metres, it is useful for applications including terrain following, precision hovering (e.g. for photography), anti-collision sensing etc. Particular advantages of this product are that it can operate effectively in all weather conditions and over all terrain types (including water).
The rangefinder is not automatically included in most firmware, and hence cannot be used just by setting a parameter through QGroundControl (as is possible with some other rangefinders). To use it you will need to add the driver to firmware and update a configuration file to start the driver on boot. The sections below explain how.
# Hardware Setup
The rangefinder is supported by any hardware which runs a NuttX or Posix OS and which can offer a serial port for the interface. Minimally this will include most, if not all, Pixhawk Series controllers.
US-D1 can be connected to any unused serial port (UART), e.g.: TELEM2, TELEM3, GPS2 etc.
# Parameter Setup
Note If the configuration parameter is not available in QGroundControl then you may need to add the driver to the firmware: