LV2 IMU (analog section) Design Paper
Abstract and Scope of Work
This paper describes the design of the analog section of a strapdown microelectromechanical (MEMs) six degree-of-freedom (DOF) inertial measurement unit (IMU) that is meant to be used as part of an avionics system for an amateur rocket. The design attempts to minimize sensor noise (which maximizes the IMU's performance) while being harshly constrained by cost, size, weight, and power consumption. Included in the design is the proposed hardware and software interface to a local microcontroller for use in a "flight computer with intelligent sensor nodes" avionics system.
Introduction
- IMU basics
- IMU theory of operation: sensors, types of systems, relation to GPS
- IMU in context of an avionics system (block diagram!)
- IMU node discussion (block diagram!)
- IMU software discussion (microcontroller software, flight computer software, calibration, etc)
Requirements
- Tradeoffs and constraints: Reduce noise, be cheap (< $500), reduce power, simple, 2 layer board, COTS sensors, etc.
- Performance specifications
- Environmental specifications
- Hardware and software interface requirements (node to IMU, not IMU to node)
Design & Component Specifications
Schematics
Board Layout
Sensor selection
- Accelerometers:types, costs, choice
- Gyroscopes: types, costs, choice
Sensor placement
- How to maximize performance based on axis orientation and grouping
ADC selection
- ADCs: types, bits, costs, choice
SCF selection
- antialiasing filters: types, costs, choice
Power supply
Operational Interface
Construction and Test Plan
- discussion of testing
- Create tests for an IMU (your design or another)