Radar altimeter series altitude or distance sensor

The Ainstein Radar altimeter series is a family of radar altimeters for unmanned aircraft, built by Ainstein, that measure height above ground or water with a radar sensor. The long-range LR-D1 model is the one described here, and it is aimed at large, fast industrial UAVs.

Barometric altitude loses accuracy close to the ground, laser rangefinders do not work in every environment, and GNSS height depends on signal strength. A radar altimeter does not depend on any of these. Ainstein states that the LR-D1 operates in all weather and relies on its own measurement, which suits take-off and landing phases and low-level flight where a flight controller needs a trustworthy height above ground.

The LR-D1 operates in the 24 GHz band with 250 MHz of bandwidth. It measures from 0.7 m to 500 m, with a stated precision of 0.365 m and an update rate of 40 Hz. Readings below 0.7 m fall in a blind zone and are unreliable. The field of view is 43 degrees in azimuth and 30 degrees in elevation, so the sensor should face the ground or water with a clear view and few other objects in the beam. Every altitude value is paired with a signal-to-noise ratio, and values under about 13 dB are treated as low-confidence. The unit also reports an error code, for example for saturation at low altitude, which lets the autopilot decide when to trust a reading.

For integration, the LR-D1 offers RS-232 and RS-422 serial interfaces and runs from 10 to 30 V. It measures 112 mm x 102.5 mm x 29 mm, weighs 300 g and has an IP67 rating, with an operating temperature range of -40 to +60 degrees C. A data sheet, technical user manual, CAD file and firmware update tool are published by the maker. Ainstein components are ITAR free and ship from the US under ECCN EAR99, and a first purchase includes 6 hours of integration assistance from the engineering team.

The maker lists industrial UAVs of 85 kg and above, assisted take-off and landing, tactical and ruggedized platforms, reconnaissance and surveillance, aerial targets, geophysical surveying and terrain mapping, defense drones, and ultra-heavy-lift drones carrying water or cargo as typical uses. In each case the altimeter provides a height-above-ground input to the flight control system.