Pulse Beacon Attitude Sensing With Low-Cost IMU Calibration
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Solution Overview
Problem
Current projectile navigation systems rely on expensive inertial measurement units (IMUs) to determine attitude, which increases cost, weight, and power consumption, limiting their performance and ability to produce a low-cost, small, and effective projectile.
Innovation Solution
A system using a pulse beacon, a rearward-facing sensor, a precision clock, a low-cost IMU with tactical grade accuracy, a barometer, and a processor to integrate data and determine attitude, range, and velocity, reducing the need for expensive IMUs by using a pulse beacon to deliver timed pulses and a sensor to detect these pulses, thereby improving accuracy and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive inertial measurement units (IMUs) are used to determine attitude, then measurement precision is improved, but cost, weight, and power consumption increase
Solution Approach 1:
The patent introduces a pulse beacon as an intermediary external reference source that transmits timed pulses to the projectile. This external beacon serves as a mediator between the ground control system and the projectile, enabling attitude determination without requiring expensive onboard inertial sensors. The beacon provides reference signals that the projectile uses to calculate its orientation relative to the ground.
Solution Approach 2:
The patent replaces the mechanical inertial measurement system with an electromagnetic signal-based system. Instead of using physical gyroscopes and accelerometers to measure attitude, the system uses RF or optical pulse signals transmitted from the beacon and received by the projectile to determine orientation through timing and direction of arrival measurements.
2Measurement precision
If expensive inertial measurement units (IMUs) are used to determine attitude, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the complex attitude determination function from the projectile itself and relocates it to an external ground-based beacon. The computationally intensive tasks of providing reference signals and enabling attitude calculation are performed externally, leaving the projectile with only simple pulse reception and basic calculation capabilities.
Solution Approach 2:
The pulse beacon serves multiple functions simultaneously: it provides timing references for velocity measurement, directional references for attitude determination, and range measurement capabilities. This multi-functionality eliminates the need for separate systems for each measurement type, reducing overall system complexity.
3Measurement precision
If expensive inertial measurement units (IMUs) are used to determine attitude, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The ground-based beacon provides the reference signals needed for attitude determination, eliminating the need for the projectile to generate its own complex reference frame. The projectile essentially uses the beacon's signals to determine its own attitude, reducing its own power requirements for this function.
Solution Approach 2:
The patent replaces power-consuming mechanical inertial sensors with passive electromagnetic signal reception. The projectile's receiver consumes significantly less power than active inertial measurement units, as it only needs to detect and process external pulse signals rather than maintain and read complex sensor arrays.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the accuracy of attitude determination and reduces downrange dispersion from 2-3 Km to 10-100 meters, allowing for more precise targeting and reducing the overall system cost by leveraging a low-cost IMU and pulse beacon technology.
Implementation Method 1
a rearward facing sensor located on an airborne object, the sensor being configured to detect the sequence of timed pulses
Data Source
AI summary
The system and method of attitude determination by pulse beacon and extremely low cost inertial measuring unit. A pulse beacon is used to generate a plurality of pulses detected by a detector or receiver located on the rear of a projectile such that direction of arrival can be determined. A synchronized clock proved for velocity and range information. Altitude can also be determined and may use an altimeter or the like. The use of a low cost IMU is possible with internal calibration by the system. Real-time attitude information provides for correction for crosswind and other drift enabling the system to have less down range dispersion.