In an era of missing or jammed GPS, a new generation of accelerometers can help. Safran Navigation’s Irish D. Torres explains
Looking at today’s aviation scene, we can see a great dependence on precise, reliable sensors that are capable of operating in the most demanding environments. Accelerometers sit at the heart of this requirement. They help determine aircraft motion, stabilise flight control systems, and feed critical data to avionics that pilots use every single day.
But here’s the problem. Aviation has an increasing reliance on autonomous systems in GPS-constrained environments. More frequently, aircraft will be traveling safely within areas of weak, jammed, or completely absent GPS signals. Because modern aircraft lack high-precision inertial sensors, small errors compound quickly, affecting navigation and autopilot capabilities and endangering flight safety.
This is where aerospace-grade MEMS accelerometers showcase their value. In a 2021 study, researchers described a navigation-grade MEMS inertial measurement unit flown aboard the Lobster Eye X-ray Satellite in 2020 that demonstrated in-orbit gyroscope performance better than 0.02 degrees per hour, with bias instability near 0.006 degrees per hour and angular random walk close to 0.003 degrees per square root hour. According to the authors, this represented the highest precision MEMS IMU publicly reported for commercial aerospace use.
This example shows that when engineered, calibrated, and deployed with care, MEMS-based inertial sensors can meet the stringent demands required for space-grade navigation and stability systems. By extension, MEMS accelerometers can also achieve comparable reliability in advanced aviation applications.
An aircraft operates over a wide variety of conditions, including temperature, pressure, and a vibrating environment, making it an essential sensor in aerospace applications. Accuracy is of the utmost importance, but so too is reliability. Accelerometers cannot drift, degrade, or lose calibration while a flight is underway, particularly during the mission-critical phases of flights.
Aircraft function in varied temperatures, pressures, and levels of vibration; hence, the aerospace-grade MEMS devices are meant to maintain their stability under all forms of acceleration (extreme and otherwise) and extreme mechanical shocks and environmental fluctuations.
Making a MEMS
To meet aerospace standards, a MEMS accelerometer must go through the same stringent qualification programs required for any other industrial or automotive applications. However, they are required to endure more extreme use environments, such as extreme thermal cycling, sustained vibration, rapid pressure fluctuations, and a variety of mechanical shock events during flight operations.
In addition to its capacity to withstand these conditions, aerospace MEMS accelerometers must also provide long-term repeatability of biases with little or no change over the life of a mission, as well as consistent response throughout their entire range of operating temperatures.
Since aerospace applications use components that have been subjected to continuous usage throughout many years of operation, aerospace MEMS accelerometers must undergo rigorous durability testing, environmental qualification, and performance testing to demonstrate they will continue to provide the same level of precision under a wide range of environmental variables.
The cumulative effect of following established engineering disciplines, combined with ongoing extensive validation of MEMS accelerometer performance, establishes aerospace-grade status.
Industry Trends
As modern aircraft increasingly incorporate autonomous systems and capabilities, the performance of accelerometers is becoming more vital than ever. This trend is particularly apparent in defence aviation applications, where there is a need for continued reliable navigation when accessing areas where GPS signals may be compromised or unavailable.
Many companies are now focusing on improving the performance expectancy of acceleration sensors. Companies like Safran, which manufacture MEMS accelerometers and inertial sensors, clearly demonstrate this trend in the industry to improve stability, reduce noise, and improve long-term reliability, which is now influencing the performance standards required from inertial sensors by both customers and regulatory authorities.
Growing Role in Future Navigation
As next-generation aircraft become reliant upon onboard navigation systems, so will MEMS accelerometers continue to gain importance. The size of these devices accommodates placement within systems that require the weight of each component to be kept as low as possible, whilst their trending performance provides evidence that MEMS accelerometers can also satisfy aerospace requirements.
With a shift toward more resilient navigation systems, particularly in areas that limit the use of GPS, robust inertial sensing will become increasingly valuable. Aerospace-grade MEMS accelerometers are providing the foundation for the advancement of aircraft control, stability, and situational awareness regardless of external environmental conditions.
Why Accelerometers Matter in Aviation
An accelerometer measures an object’s linear acceleration or deceleration. In aviation, accelerometers provide information on the following:
Inertial Navigation Systems
Autopilot and Flight Control Systems
Attitude and Heading Reference Systems
Vibration Monitoring
Flight Test Instrumentation
Structural Health Monitoring and Analysis