Enhanced Codeset Passive Wireless SAW Sensor-Tags and System

The proposed project will develop a set of at least 100 passive wireless surface acoustic wave (SAW) RFID sensor-tags for near-simultaneous remote monitoring of groups of conventional sensors. Coded SAW sensor-tags have been demonstrated by ASR&D under NNX09CE49P to be capable of providing a passive wireless interface to external sensors, including switches, thermistors, and strain gages, as well as external sensors that generate voltages. These sensor-tags consist of a SAW device with an antenna attached to one port and sensor(s) and reference impedance(s) connected to the other ports. RF signals of the correct frequency range are reflected off of the surface wave device, and their reflection characteristics are modified by changes in the impedance/voltage of the attached sensor(s). Under NNX10RA68P a set of 32 individually identifiable coded SAW temperature sensor devices that avoids the serious problems with code collision seen in conventional SAW RFID systems was developed using CDMA and TDMA. Wireless measurement confirmed the ability to selectively detect any single sensor out of the combined response of multiple sensors. The proposed effort will incorporate direct sequence spread spectrum (DSSS) codes into SAW tag devices also using time diversity, to produce sets of more than 100 individually identifiable coded sensor-tags. DSSS coding has been demonstrated by researchers at the University of Maine to produce sets codes with good auto- and cross-correlation properties. These sensor-tags will be tested to verify that they can be used as an interface to external pressure sensors and strain gages. This project will also evaluate the wireless reader system architectures commercially available and currently being developed at ASR&D and at other research institutions to determine what system architecture is most beneficial for operation with the codesets developed. This will form the basis of recommendations for future system development work.

The proposed sensor-tag interface devices will also find wide usage for distributed wireless monitoring of sensors in aerospace and other commercial applications. Monitoring of commercial airframes for aging and deterioration is a high priority for aerospace firms and for military and civilian aircraft operators. Civil infrastructure monitoring could enhance our understanding of the condition of bridges, tunnels, and pavements, with real-time detection of cracks, delamination, and other growing failure mechanisms in concrete, metal, composites, and other materials. This would provide actionable intelligence and allow effective prioritization of limited maintenance and repair resources. Other commercial applications will likely include inventorying and tracking high value industrial assets, and distributed sensing systems for environmental applications such as landfills.

Sets of the coded passive wireless sensor-tags proposed and appropriate wireless readers would enable remote monitoring of external sensors throughout NASA programs and facilities, reducing the wiring infrastructure for DFI and for vehicle/structure monitoring systems. While the proposed work will develop interface devices for use with strain gages and pressure sensors, prior work makes it clear that the results of the proposed work can be extended for use with other sensor types provided the sensor produces a change in impedance or a voltage in response to an external stimulus (or change in a measurand). Thus, sensor-tag interface devices could be used to provide wireless interfaces to numerous existing sensors. This would allow NASA to re-use existing flight qualified sensors in a wireless mode, by qualifying a wireless link device suitable for use with each class of sensors, avoiding the need to qualify new sensors for every application.

This is early/mid-stage (TRL 3) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.