inertial integrated navigation system manufacture

In the design of navigation and control systems, AHRS (Attitude and Heading Reference System) and INS (Inertial Navigation System) are two key technical modules. Although they are both based on inertial measurement units (IMUs), their processing methods, output results, and application scopes are essentially different. This article will compare AHRS and INS in depth from the dimensions of system composition, sensor fusion algorithm, mathematical model, error source analysis, and typical applications, to provide theoretical and application support for engineering practice and research. 1. System Structure Overview AHRS System Structure AHRS systems are usually composed of three types of sensors:Three-axis gyroscopes (Angular Rate Sensors)；Three-axis accelerometers (Linear Acceleration Sensors)；Three-axis magnetometers (Earth Magnetic Field Sensors) These data are fused through a filtering algorithm to estimate the current three-dimensional posture (expressed in Euler angles or quaternions). INS system structure INS systems are usually composed of IMU (gyroscope + accelerometer), and realize navigation functions through integral calculation: Integrate acceleration to get velocity, and then integrate to get position; Integrate angular velocity to calculate attitude changes. INS can be integrated into an "autonomous navigation system" to achieve continuous positioning for a certain period of time even in an environment where GPS is not available. 2. Core Mathematical Formulas and Calculation Process 1. Attitude estimation (AHRS) Assume that the three-axis angular velocity isUsing quaternionRepresents the posture, then the posture update formula is as follows: Combined with the magnetometer and accelerometer, attitude error correction is achieved through complementary filtering or extended Kalman filtering (EKF). Schematic diagram of attitude error correction formula (complementary filtering):             2. Inertial Navigation (INS) The core of INS is to integrate acceleration twice: Speed ​​calculation: Position calculation: Since the IMU data contains noise and bias, the integration process will lead to the accumulation of errors (drift): To this end, INS is often fused with GPS, vision, or UWB to constrain error drift. 3. Error model analysis Error Source AHRS INS Gyroscope Bias Causes slow attitude drift, correctable via magnetometer Accumulates into significant drift in attitude, velocity, and position Accelerometer Error Affects gravity direction estimation Severely impacts position estimation; long-term errors grow quadratically Magnetometer Interference Impacts yaw (heading) estimation Generally unaffected (no magnetometer used) Numerical Integration Error First-order integration with manageable errors Second-order integration leads to significant errors Algorithm Robustness High (mature attitude decoupling algorithms) Moderate; requires robust filtering and error modeling support 4. Comparison of Sensor Fusion Algorithms Algorithm Type Typical Usage in AHRS Typical Usage in INS Complementary Filtering Fast attitude fusion for low-computational-power devices Rarely used (insufficient precision) Kalman Filter (EKF) Fuses gyro, accelerometer, and magnetometer to correct errors Fuses gyro, accelerometer, and external references (e.g., GPS) Zero-Velocity Update (ZUPT) Not used Commonly applied in pedestrian navigation to reduce drift SLAM/Visual-Inertial Navigation Not applicable Combined with visual sensors to enhance navigation accuracy   5. Comparison of Typical Application Scenarios Application AHRS INS Small UAVs ✅ For attitude control & heading estimation ✅ Used for path planning or in GPS-denied environments VR/AR Headsets ✅ Provides head orientation tracking ❌ Not required (position accuracy unnecessary) Autonomous Vehicles ❌ Attitude alone insufficient for navigation ✅ Critical for high-precision map matching and dead reckoning in GPS-denied zones Rocket Guidance ❌ Insufficient precision for standalone use ✅ High-precision INS required in high-dynamic environments Underground/Underwater ❌ Magnetometer failure in such environments ✅ Combines with sonar/UWB for precise navigation 6. Summary: A5000 vs I3700: Practical application of high-precision sensors in AHRS and INS A5000 – High-precision MEMS AHRS attitude sensor A5000 is a highly integrated digital output high-precision AHRS (attitude and heading reference system). Its core features include: Built-in three-axis high-precision accelerometer, gyroscope and magnetometer Use 6-state Kalman filter for sensor fusion to enhance the robustness of attitude estimation Output includes heading angle (Yaw), pitch angle (Pitch), roll angle (Roll) and angular velocity, acceleration information Suitable for attitude perception scenarios such as drones, robots, mining vehicles, AGVs, agricultural automation equipment, etc. Miniature design, suitable for space-constrained applications   I3700 – Full-featured Inertial Navigation System (INS) In contrast, the I3700 is an inertial navigation system for high-dynamic autonomous navigation applications, integrating a high-performance IMU module and supporting fusion with external signals (such as GPS). Its key features include: Output attitude angle + velocity + 3D position, supporting long-term navigation Suitable for scenarios that require full autonomous navigation capabilities, such as underground mines, GPS-free environments, precision agriculture or marine unmanned systems Supports multiple data interfaces, compatible with SLAM, GPS, and UWB fusion systems   With a powerful digital signal processing unit, it has excellent stability and long-term drift control capabilities A5000 Heading 9 Axis Navigation System Navigational Guided System Low Price High Accuracy   I3700 High Accuracy Agricultural Gps Tracker Module Consumption Inertial Navigation System Mtk Rtk Gnss Rtk Antenna Rtk Algorithm