Weather Radar Null Response Terrain Elevation
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Solution Overview
Problem
Conventional terrain awareness systems face challenges in accurately sensing terrain elevation, particularly during precipitation, due to beam shape effects and contamination from weather returns, necessitating a more accurate and cost-effective radar-based terrain sensor that is less susceptible to noise and beam shape issues.
Innovation Solution
The method involves separating and summing portions of radar return data to generate a null response, which is used to determine terrain elevation, utilizing a weather radar system with a processor to analyze and adjust radar return data, thereby enhancing the distinction between terrain and weather responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radar-based terrain awareness systems are used, then terrain elevation can be sensed, but the measurement precision deteriorates due to beam shape effects and contamination from weather returns
Solution Approach 1:
The radar return data is segmented into multiple portions based on range gates, with weather returns separated from terrain returns using different gate configurations. By processing different portions of the radar scan separately and combining them, the system isolates terrain elevation information from weather contamination.
Solution Approach 2:
The system extracts terrain elevation information by removing weather return contamination through null response processing. The harmful weather returns are identified and extracted from the total radar return, leaving only the terrain elevation signal for measurement.
2Measurement precision
If additional hardware is added to improve terrain sensing accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The existing weather radar system is made multi-functional by enabling it to perform both weather detection and terrain elevation measurement using the same hardware. The processor is programmed to execute different processing algorithms (null response processing) to extract terrain information from the weather radar returns without requiring dedicated terrain sensing hardware.
Solution Approach 2:
The weather radar system serves itself by using its own returns to determine terrain elevation. The same antenna and transmitter that detect weather also provide the signals used for terrain sensing, eliminating the need for separate terrain sensing hardware.
3Ease of manufacture
If conventional radar processing is used, then the system operates simply, but the measurement precision deteriorates during precipitation due to weather return contamination
Solution Approach 1:
The system dynamically adjusts its processing mode based on weather conditions. During precipitation, the null response processing algorithm is activated to filter weather returns, while in clear conditions conventional processing suffices. The processor dynamically selects and applies different processing strategies to maintain precision across varying environmental conditions.
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 approach provides a more accurate and reliable terrain elevation estimation with improved resolution, allowing for better differentiation between terrain and weather conditions, even in adverse weather, without requiring additional hardware, and achieves a sharpening ratio greater than 5:1, effectively addressing the limitations of existing systems.
Implementation Method 1
The present disclosure relates more specifically to the field of terrain elevation estimation in an aircraft. Conventionally, pilots use terrain warning systems such as terrain awareness and warning systems (TAWS), ground proximity warning systems (GPWS), and enhanced GPWS (EGPWS). Terrain warning systems have been designed to provide critical information to pilots and flight crews to reduce aviation accidents related to controlled flight into terrain. Certain conventional terrain awareness systems and methods sense terrain height using a radar
Data Source
AI summary
A weather radar system coupled to a weather radar antenna, including a receive circuit for receiving radar returns received by the antenna and a processor for summing portions of the radar return data to obtain a null response. The null response is utilized to determine presence of terrain.