Nonlinear Interferometric Imaging Sensor for High-Velocity Debris Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional radars are inadequate for simultaneously detecting, tracking, and discriminating a large number of small moving targets within a short period and small three-dimensional volume due to range and velocity aliasing, insufficient integrated energy, and the inability to steer beams quickly enough to capture data during high-speed events, especially in the blinding flash of a fireball.
Innovation Solution
The use of Continuous Wave (CW) or high-duty pulsed waveforms with wide-field-of-view antennas that employ digital beam forming and a novel Doppler Filter for trajectory-dependent correlation, enabling high-resolution Doppler measurements and mass estimation of ballistic targets by combining Radar Cross Section (RCS) and drag-induced velocity slowdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional radars use traditional pulsed waveforms with beam steering, then they can detect targets, but they cannot simultaneously detect and track a large multitude of small moving targets in a short period due to insufficient integrated energy and slow beam steering
Solution Approach 1:
The patent employs Continuous Wave (CW) radar waveforms instead of traditional pulsed waveforms, enabling continuous transmission of radar energy throughout the observation period. This continuous energy transmission maximizes the integrated energy on target, allowing detection of small debris fragments even during the brief fireball expansion phase, thereby resolving the contradiction between detection capability and observation time
Solution Approach 2:
The patent uses an array of receive antennas that view all targets simultaneously in parallel, rather than sequentially steering a single beam. Each antenna element captures signals from multiple targets at once, enabling the system to detect and track a large multitude of targets concurrently, thus resolving the productivity-time contradiction
2Measurement precision
If conventional radars use narrow beam widths for velocity resolution, then they achieve good velocity measurement, but they cannot cover a wide field of view to detect all targets simultaneously
Solution Approach 1:
The patent transitions from a single-beam radar system to a two-dimensional array of receive antennas. This spatial arrangement allows the system to achieve wide field of view coverage in one dimension while maintaining high velocity resolution through Doppler processing in another dimension, effectively resolving the contradiction between coverage area and measurement precision
Solution Approach 2:
The patent replaces mechanical beam steering with digital beam forming algorithms. Instead of physically moving narrow beams to scan the field of view, the system uses computational methods to synthesize beam patterns across the antenna array, enabling simultaneous wide-area coverage and high-precision velocity measurements through post-processing of signals from all antenna elements
3Measurement precision
If conventional radars use long scan times to achieve high spatial and velocity resolution, then they get detailed target data, but they cannot capture high-speed events that occur in short duration
Solution Approach 1:
The patent positions multiple receive antennas in advance at known geometric locations surrounding the imaging volume before the event occurs. This pre-deployment of the sensor array allows the system to capture high-resolution spatial and velocity data of high-speed debris during the brief fireball expansion, as all sensors are already in place to record the event without requiring time-consuming scanning or repositioning
4Reliability
If conventional radars use beam steering to track individual targets, then they can follow target trajectories, but they cannot detect and verify a large number of targets quickly enough
Solution Approach 1:
The patent segments the target detection and tracking process into parallel operations performed by multiple receive antennas. Each antenna independently captures signals from multiple targets simultaneously, and digital beam forming algorithms process these parallel signals to extract trajectories of individual debris fragments. This parallel processing approach maintains reliable tracking accuracy while dramatically increasing the throughput of target detection and verification
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
Enables the detection, tracking, and discrimination of high-velocity debris through a fireball, providing accurate trajectory data and mass measurements of fragments with inexpensive RF sensing hardware, overcoming the limitations of traditional radar and optical/IR techniques.
Implementation Method 1
employing a Nonlinear Pulse Compression (PC) Doppler Filter for each trajectory to unwrap the nonlinear Doppler frequency
Implementation Method 2
Knowing the strength of the received signal of the target over the path of the trajectory relative to the given receiver antenna also gives an indication of the fragments radar cross-section (RCS)
Implementation Method 3
combining the measured Radar Cross Section (RCS) of the target(s) and the rate of velocity slow down due to drag (Beta)
Data Source
AI summary
A new radar is disclosed possessing desirable attributes for close range, short event time, high data rate sensing and data collection applications. A Continuous Wave (CW) or very high Pulse Repetition Frequency (PRF) Pulse based waveform, nominally with very high duty cycle (i.e. highly range aliased), is amplified and transmitted from one antenna, and after reflection from targets of interest, is received by one or a plurality of receive antennas. Both transmit and receive are optimally synchronous and phase coherent. The received signals are down converted to baseband leaving only the Doppler frequency from the targets of interest. These Doppler frequencies change over Fast Time as a function of the specific target trajectory and speed. A bank of time dependent correlation filters, each tuned to a different trajectory hypothesis, are used to integrate up the Doppler Signal for targets traveling the hypothesized trajectory, and decorrelated those that are not.