Creare develops technology for a wide range of sensors, instrumentation, and control applications. We combine a sound understanding of the fundamentals of physics with experience and skills in state-of-the-art control algorithms, data acquisition, real-time signal processing, computer and digital signal processing, analog and digital circuits, and electromechanical systems.
The following examples illustrate our depth and diversity:
- Low cost, wireless physical activity monitor for human movement
- Wireless sensor networks based on both IEEE 802.11 and 802.15 standards
- Micromachined bone conduction transducers
- Control algorithms and software for immersive environments
- Feedforward active noise reduction for communication and hearing assessment headsets
MEMS-based sensors have a number of advantages, including their small size and weight, very low power consumption, high resistance to vibration and shock, and low cost. Creare has exploited these attributes to develop orientation and location sensor systems for integration into aircraft guidance systems, to provide heading information for towed sonar array cables, to determine azimuth and elevation of mortar gun barrels, and for use on pico-satellites. We use our expertise in hardware development and advanced signal and image processing algorithms to extract signals from relatively low cost, MEMS sensor devices to provide capabilities previously unattainable or only achievable with high-value custom-designed sensor equipment.
Some recent projects in this area include:
- Development of a high performance, MEMS gyrocompass that provides measurement of azimuth, roll, and pitch with high accuracy in a ruggedized package.
- Pointing system that determines azimuth and elevation using novel MEMS rate gyros and inclinometers.
- Creare and the NASA Jet Propulsion Laboratory (JPL) teamed to develop an advanced wafer-level packaging approach that offers the extremely low, sustained vacuum levels required for long-term, high-Q operation of navigation grade MEMS inertial sensors
- Creare designed, built, and tested a micromachined nano-g accelerometer mounted on a rotating platform to obtain measurement of orbital drag in LEO.
- MEMS-based sensor system that provides improved control of small aerial vehicles and enables their use for military recognizance and search-and-rescue operations.
Adaptive noise cancellation can be used to reject structured noise created by vehicles and machinery, for example, and to enable accurate detection and measurement in busy environments. Creare has developed adaptive noise cancellation systems for auditory screening, acoustic signal identification, and audio headsets. Our expertise includes system engineering, real-time, embedded microcontroller development, fabrication and testing.
A sampling of recent projects includes:
- Novel seismic monitoring system that exceeds the detection range of existing systems and is able to detect intruders in the presence of ground noise typical of an urban environment.
- Low-cost mobile otoacoustic emissions probe for hearing tests. Adaptive noise rejection and noise reduction algorithms improve the signal-to-noise ratio by at least 10 dB even in noisy conditions.
- Innovative communication headset that employs active noise reduction to reduce the harmful effects of high noise levels on personnel, while simultaneously enhancing the speech intelligibility of electronic messages.
Acoustic sensors, such as Sonic Detection and Ranging (SODAR) devices, can provide accurate and reliable height and velocity measurements. For precision airdrop systems, GPS-based control is sufficient for lateral guidance, but the uncertainty of GPS height information is unacceptable. Creare developed a robust and accurate SODAR height sensor (SHS) that allows final deceleration maneuvers to be precisely timed. The SHS determines its height above ground by emitting acoustic pulses and analyzing the return signals. It incorporates a speaker, microphone, barometer, and temperature sensor. Advanced estimation algorithms running on a digital signal processor produce continuous estimates of the sensor height above ground.
With funding from NASA, NSBRI, and the Navy, Creare engineers have developed an approach to monitor and measure noninvasively the formation of nitrogen bubbles both in the bloodstream and in tissue, for the purpose of generating data to better characterize and understand the physical etiology of decompression sickness (DCS) in underwater divers. The instrument is able to detect and size intravascular gas bubbles in the range of 30 to 200 microns, and extravascular bubbles on the order of 1 micron in diameter. These extravascular bubbles and their precursors are thought to play an important role in DCS, but there previously has been no way to detect them. The device uses ultrasonic energy at two frequencies to resonate the bubbles, and the reflected signal is processed to detect and size the bubbles.
Creare has recently carried out several other projects to develop ultrasonic sensors, including:
- Development of multi-layer ultrasonic transducer arrays for high frequency (10-100 MHz) ultrasound imaging.
- Autonomous imaging ultrasound system for underwater inspection of ship hulls.
- High-resolution, high-precision, imaging ultrasound system to detect and characterize recrystallization in single-crystal turbine blades.