Elevation Null Command Generator for Monopulse Radar
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing terrain following-terrain avoidance radars face accuracy issues due to bias effects from strong targets off the monopulse null, which are exacerbated by the need to maintain signal-to-noise ratio, limiting the system's ability to accurately direct the elevation monopulse null plane.
Innovation Solution
The elevation null command generator processes sum and difference channel outputs through multiple pairs of range gates spaced above and below a central range gate, cross-multiplying signals to isolate the elevation monopulse null direction independently of terrain backscatter, thereby improving pointing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single range gate generator is used to stabilize the elevation monopulse null, then the system can maintain operation, but the accuracy is reduced due to bias effects from strong targets off the monopulse null
Solution Approach 1:
The single range gate is divided into multiple range gates (first range gate, second range gate, third range gate, etc.) spaced at different time delays. Each range gate processes signals from different spatial regions, allowing the system to segment the terrain backscatter analysis and eliminate bias effects from strong off-null targets through comparative processing.
Solution Approach 2:
The patent introduces an intermediary processing system that receives signals from multiple range gates and performs comparative analysis. This intermediary processing eliminates the direct harmful influence of strong off-null targets by using the multiple gated signals to compute a stabilized elevation monopulse null reference that is immune to such bias effects.
2Object-affected harmful factors
If the time width of the range gate is narrowed to reduce bias effects, then the bias from off-null targets decreases, but the signal to noise ratio decreases, again impairing accuracy
Solution Approach 1:
The patent merges the outputs of multiple range gates through a processing system that combines the signals from the first, second, third and subsequent range gates. This merging process maintains a high effective signal-to-noise ratio by aggregating energy from multiple gates while simultaneously eliminating bias effects through the comparative processing architecture.
3Measurement precision
If multiple pairs of range gates are used with cross-multiplication processing, then the elevation monopulse null direction can be isolated independently of terrain backscatter, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical or hardware-based terrain compensation mechanisms with an electronic signal processing approach. By using multiple range gates and electronic cross-multiplication processing, the system achieves independent isolation of the elevation monopulse null direction from terrain backscatter effects without requiring additional mechanical components or complex physical systems.
Data Source
AI summary
There is disclosed an elevation null command generator (ENCG) for use in airborne monopulse radar, and a novel missile guidance system made possible by use of the ENGC. The ENCG provides an accurate means of directing the elevation monopulse plane of a radar antenna at a patch of ground defined by a range signal generated within the radar or its associated equipment. It is shown that within the system range can define the elevation angle of concern. The ENCG includes a central range gate centered at the command range and a plurality of pairs of range gates, the two gates of each pair being time spaced before and after the central range gate, and has circuit means for normalizing the output of the range gates to eliminate the bias effects of strong targets adjacent to the monopulse null plane and ground surface intersection.