Each month, NTB highlights tech briefs related to a particular area of technology in a special section called Technology Focus. Here are some of the technologies featured in the October issue focus on Sensors.

Wirelessly Interrogated Position or Displacement Sensors

Researchers at NASA's Langley Research Center have developed two simple position or displacement sensors based on inductance-capacitance resonant circuits. The sensors are both powered and interrogated wirelessly, and without making contact with other objects. Their mode of operation doesn't depend on maintenance of environmental conditions, so they can be used in harsh conditions such as cryogenic temperatures and radioactivity. (Page 20)

Ka-Band Radar Terminal Descent Sensor

NASA's Jet Propulsion Lab has developed the terminal descent sensor (TDS), a radar altimeter/velocimeter that improves the accuracy of velocity sensing by more than an order of magnitude over existing sensors. The TDS uses a millimeter-wave center frequency to eliminate angle-of-arrival errors that can result in large velocity errors. It can be used in helicopters and fixed-wing aircraft. (Page 24)

Inductive Linear-Position Sensor/Limit-Sensor Units

A new sensor developed at NASA's Marshall Space Flight Center provides an absolute position measurement. A motorized linear-translation stage contains an electronic unit that functions as both a non-contact sensor to measure absolute position of the stage, and the equivalent of a limit switch that is tripped when the stage reaches the nominal limit position. The sensor can be scaled up or down, and can be used in a MEMS device. (Page 28)

Read previously published tech briefs on Sensors here .