Asynchronous UWB Tracking System for Noisy Multipath Environments
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Solution Overview
Problem
Existing tracking systems, such as GPS and radar, are unsuitable for long-range line of sight tracking in environments like lunar or Mars missions due to low resolution, synchronization errors, and interference issues, especially in electrically noisy multipath environments.
Innovation Solution
A two-cluster angle of arrival (AOA) tracking system using asynchronous ultrawideband (UWB) receivers that estimates time difference of arrival (TDOA) through cross-correlation peak detection (CCPD) method, eliminating the need for synchronization and providing high accuracy in noisy conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS or radar tracking systems are used, then long-range tracking capability is achieved, but synchronization errors and interference issues arise in electrically noisy multipath environments
Solution Approach 1:
The patent extracts and eliminates the synchronization requirement from the tracking system. By using asynchronous UWB receivers that do not require synchronization with the transmitter, the system removes the source of synchronization errors while maintaining tracking capability in challenging environments
Solution Approach 2:
The patent changes the operational parameters by using ultrawideband signals with extremely low power spectral density. This parameter change allows the system to operate in electrically noisy multipath environments without causing or suffering from interference, achieving reliable tracking where traditional systems fail
2Measurement precision
If prior art AOA tracking systems are used, then angle information is extracted from continuous sinusoidal signals, but resolution is relatively low resulting in large tracking errors
Solution Approach 1:
The patent replaces the traditional continuous sinusoidal signal processing with ultrawideband impulse signal processing. This substitution enables the use of TDOA measurements with picosecond precision, dramatically improving tracking resolution from the meter level to the centimeter or millimeter level
Solution Approach 2:
The patent uses periodic UWB pulse transmission from the transmitter followed by correlation processing at the receivers. This periodic impulse action allows for precise time delay measurement through cross-correlation, achieving high resolution tracking without the limitations of continuous wave systems
3Measurement precision
If synchronization between transmitter and receivers is required, then phase information can be extracted, but synchronization error translates linearly into large ranging error
Solution Approach 1:
The patent inverts the traditional approach by making the receivers asynchronous rather than synchronized. Instead of requiring the receivers to synchronize with the transmitter, the system allows each receiver to operate independently and uses post-processing correlation to determine time differences, eliminating the linear translation of synchronization error into ranging error
4Area of stationary object
If traditional tracking systems operate in electrically noisy multipath environment, then coverage is maintained, but interference with other electronic equipment and affected by interference occurs
Solution Approach 1:
The patent changes the power spectral density parameter to extremely low levels while using ultrawideband signals. This allows the system to maintain tracking coverage in multipath environments without generating harmful interference to other electronic equipment or suffering from such interference, as the low PSD UWB signals coexist peacefully with other communications
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
The system achieves accurate tracking with less than 1% error up to 3500 feet, coexists with other communication systems without interference, and maintains high resolution in multipath environments, demonstrating improved tracking capabilities compared to GPS.
Implementation Method 1
estimates time difference of arrival (TDOA) of UWB pulses utilizing a cross-correlation peak detection (CCPD) method
Implementation Method 2
utilizing a cross-correlation peak detection (CCPD) method for time difference of arrival (TDOA) estimates
Data Source
AI summary
A passive tracking system is provided with a plurality of ultrawideband (UWB) receivers that is asynchronous with respect to a UWB transmitter. A geometry of the tracking system may utilize a plurality of clusters with each cluster comprising a plurality of antennas. Time Difference of Arrival (TDOA) may be determined for the antennas in each cluster and utilized to determine Angle of Arrival (AOA) based on a far field assumption regarding the geometry. Parallel software communication sockets may be established with each of the plurality of UWB receivers. Transfer of waveform data may be processed by alternately receiving packets of waveform data from each UWB receiver. Cross Correlation Peak Detection (CCPD) is utilized to estimate TDOA information to reduce errors in a noisy, multipath environment.