Through-Wall Radar Using Pulsed MTI and Digital Beamforming
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing through-wall radar systems face challenges in accurately detecting and differentiating between moving and stationary targets behind obstacles, particularly in environments with high RF interference and severe multipath conditions, such as urban combat scenarios.
Innovation Solution
A Moving Target Indicator (MTI) radar sensor system that transmits series of radar pulses at frequencies less than 5 GHz, processes radar return signals using a digital beamformer to form multiple beams, and employs advanced signal processing techniques like 2D FFT, fixed threshold detection, and Kalman tracking to differentiate between moving and stationary targets, while also determining and mitigating the effects of RF interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous wave transmitter and antenna array are used for through-wall radar imaging, then imaging capability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent employs pulsed radar operation instead of continuous wave transmission, where the transmitter operates in periodic pulses with duty cycles typically 1-10%. This allows the system to achieve imaging capability through coherent integration of multiple pulses while reducing average power consumption and enabling portable deployment. The pulsed operation with phase coherence across pulses maintains the ability to form images through signal processing.
Solution Approach 2:
The patent divides the radar system into separate transmit and receive antenna arrays, allowing independent optimization of each subsystem. The receive array processes signals from multiple elements through beamforming and imaging algorithms, enabling complex imaging functionality while keeping the transmit subsystem relatively simple. This segmentation also enables the use of lower power transmit amplifiers.
2Reliability
If radar operates in high RF interference environments, then situational awareness capability is maintained, but measurement precision deteriorates due to interference
Solution Approach 1:
The patent employs moving target indication (MTI) processing that exploits the Doppler effect to distinguish moving targets from stationary clutter and RF interference sources. By analyzing frequency shifts in returned signals, the system can suppress stationary interferers and enhance moving target detection, effectively converting the challenge of RF interference into a means for improved target discrimination in complex electromagnetic environments.
Solution Approach 2:
The patent implements adaptive clutter suppression and interference rejection algorithms that use feedback from the received signal environment to dynamically adjust processing parameters. The system analyzes the statistical characteristics of received signals and adapts beamforming weights, detection thresholds, and filtering parameters to optimize performance in varying interference conditions, maintaining detection accuracy despite changing RF environments.
3Productivity
If pulse group repetition rate is increased for better target detection, then detection speed is improved, but power consumption increases
Solution Approach 1:
The patent uses pulsed radar operation with controlled duty cycles, where the transmitter operates in periodic pulses rather than continuously. By optimizing the pulse repetition frequency and duty cycle, the system achieves adequate detection speed for tactical applications while maintaining average power consumption at levels suitable for portable and vehicle-mounted platforms. The coherent integration of multiple pulses compensates for the reduced transmission time.
4Adaptability or versatility
If digital beamforming and multiple processing paths are used to detect both moving and stationary targets, then target detection capability is improved, but device complexity increases
Solution Approach 1:
The patent implements a unified radar system that performs both moving target indication and stationary target detection through integrated signal processing. The same transmit and receive arrays, along with the digital beamforming processor, handle both detection modes by adjusting processing parameters and algorithms rather than requiring separate dedicated subsystems. This multi-functional approach achieves versatile target detection capability while controlling overall device complexity through shared hardware resources.
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 accurate detection and tracking of both moving and stationary targets through walls or obstructions with reduced power consumption and interference mitigation, suitable for handheld or vehicle-mounted applications, providing enhanced situational awareness in complex environments.
Implementation Method 1
Through wall radar sensors provide users with a stand-off capability to detect, locate, and 'see' personnel who are hidden behind walls, doors and other obstructions
Implementation Method 2
a receiver for receiving reflected portions of said transmitted signals from said object
Data Source
Figure 1~2
Figure 3
Figure 4A
AI summary
A method and apparatus for sensing a target through a wall or obstruction by a Moving Target Indicator (MTI) radar sensor. In an exemplary embodiment, a series of radar pulses are transmitted at frequencies less than about 5 GHz. Radar return signals are received at a plurality of receive antenna array subapertures. The radar return signals are processed by a digital beamformer to form multiple beams. Target detection processing detects moving and stationary targets through a plurality of parallel target detection signal processing paths.