A 24 GHz SIMO radar tachymeter for precise transponder localization

A tachymeter is a device that measures angle and distance to a cooperative target. Optical tachymeters are well established but they have shortcomings under harsh environmental conditions such as dense smoke, fog, dust, rain or snow. As a robust alternative, we developed an innovative radar tachymeter for precise and highly reliable operation. This device is a 24 GHz single-input and multiple-output radar system with a frequency-modulated continuous-wave secondary radar base station that measures the distance to a cooperative responder unit. The synthesizer is optimized for low phase noise and features highly linear frequency modulation for high-precision ranging. The radar system incorporates a sparse antenna array with 1 transmit and 8 receive channels. Angle and range are precisely estimated with a spatial optimal filter algorithm and a dedicated synchronization concept implemented on a compact embedded platform. The developed radar tachymeter has been tested in indoor scenarios as well as on a truck-mounted crane. The measurement campaigns showed that the root-mean square errors are as low as 0.1° and 1 cm, for angle and range respectively.