Northrop Grumman of the United States announced the progress of its "Advanced Hypersonic Technology Inertial Measurement Unit" (AHT IMU), which provides anti-jamming and autonomous navigation capabilities for autonomous aircraft operating at high speeds above Mach 5. It has completed flight verification on the Stratolaunch Talon-A reusable hypersonic aircraft, and has acquired several hours of ground and flight telemetry data, with the performance meeting expectations.
Hypersonic flight brings extreme thermal, vibration and acceleration challenges: the temperature of the airframe's leading edge can exceed 1,650 degrees Celsius, internal sensors and electronic equipment are subjected to severe thermal stress, and loads of up to 60g and strong vibrations may occur during flight; at the same time, the ablation of heat-proof materials will change the mass and aerodynamic characteristics, further increasing the complexity of navigation. In military scenarios, GPS is susceptible to interference and spoofing, and the ionospheric plasma "sheath" formed by hypersonic flight may also block external signals. Therefore, it is necessary to rely on autonomous, encapsulated, and radiation-resistant inertial navigation to achieve precise positioning and maneuvering in a "GPS-denied" environment.
AHT IMU uses "dead reckoning" as the principle framework, continuously measures motion status through high-precision gyroscopes and accelerometers, independently completes position and trajectory calculations, and is compatible with AI autonomous flight systems. Its core sensor is a micro hemispheric resonant gyroscope (mHRG), which uses an integrated quartz hemispheric resonant structure and is a solid-state design without easy-to-wear parts such as bearings and mirrors. Officials say that this solution has ultra-long-term reliability, inherent radiation resistance, and is superior to traditional large-size laser gyro systems in terms of accuracy and volume trade-off. The matching silicon accelerometer (SiAc) and customized ASIC are used for signal processing, which can distinguish acceleration changes down to micro-g level to meet the measurement needs under hypersonic maneuvers.
The whole machine adopts a ruggedized, independent packaging design and is oriented to thermomechanical loads in hypersonic and aerospace environments. The goal is to maintain the continuity and accuracy of track and attitude calculations without relying on satellite navigation. In the completed flight, the AHT IMU performed the mission with Talon‑A and ran stably, providing data support for subsequent engineering finalization and mission system integration.