Helicopter Radar Beam Synthesis for Brownout Landing
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Solution Overview
Problem
Vertical takeoff vehicles face challenges during landing operations in low visual acuity environments due to terrain irregularities and 'brownout' conditions, which can lead to accidents, as existing radar altimeters fail to provide sufficient information on landing surface topography and obstacle avoidance.
Innovation Solution
A radar ranging system utilizing multiple transmitter and receiver arrays to form a large number of pencil beams, processing time delays to create a topographic profile, and displaying this information to pilots to assist in safe landing decisions, including hazard detection and suitable landing area identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wide-beam radar altimeter is used to monitor aircraft height, then the aircraft height can be tracked even when in a bank or flying near steep slopes, but the system cannot provide useful information regarding the topography of the desired landing surface
Solution Approach 1:
The patent segments the radar beam into multiple narrow pencil beams arranged in a grid pattern across the landing zone, rather than using a single wide beam. This segmentation allows each pencil beam to independently measure range to specific ground points, collectively building a detailed topographic map of the landing surface while maintaining reliable height monitoring.
Solution Approach 2:
The patent transitions from one-dimensional height measurement (single wide beam) to two-dimensional topographic mapping (grid of pencil beams). By arranging beams in multiple azimuth and elevation angles, the system captures range information across the entire landing zone, adding spatial dimensionality to the measurement capability.
2Ease of operation
If existing radar altimeters are used in brownout conditions, then basic height information can be obtained, but sufficient information on landing surface topography and obstacle avoidance is not provided
Solution Approach 1:
The patent creates a multi-functional radar system that simultaneously performs basic height monitoring and detailed topographic mapping. The grid of pencil beams serves dual purposes: maintaining aircraft altitude awareness while also generating comprehensive landing zone imagery for obstacle detection and safety assessment.
Solution Approach 2:
The patent introduces an intermediary processing system that receives raw range data from multiple pencil beams and synthesizes it into a coherent topographic representation. This intermediary layer processes the multi-dimensional data to create actionable information about landing surface safety, bridging the gap between raw measurements and pilot decision-making.
3Measurement precision
If multiple transmitter and receiver arrays are used to form pencil beams for topographic mapping, then accurate landing surface information is provided, but the device complexity increases
Solution Approach 1:
The patent merges multiple transmitter and receiver arrays into a coordinated phased array system. By combining the arrays and applying phase shifting techniques, the system generates multiple pencil beams through electronic steering rather than requiring physically separate beam-forming hardware for each beam, thereby reducing overall system complexity.
Solution Approach 2:
The patent utilizes parameter changes in the phased array system, specifically adjusting phase and amplitude parameters across the array elements to electronically steer and focus multiple pencil beams. This parametric control allows dynamic beam formation without mechanical movement or complex physical reconfiguration.
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 provides accurate topographic information and obstacle detection, enhancing pilot safety by enabling informed landing decisions even in degraded visual conditions, reducing the risk of accidents and operational costs associated with 'brownout' incidents.
Implementation Method 1
The basic radar altimeter utilizes a radar ranging system which measures the time delay of the signal reflected from the nearest object
Implementation Method 2
measures the time delay of the signal reflected from the nearest object
Implementation Method 3
at least one linear arrays of, for instance, 32 transmitter elements that transmit transmitter beams comprising a sequence of ranging signals phased to form a beam pattern
Implementation Method 4
the at least one processor forms a multiplicity of receiver beams complementary to the transmitter beams such that the combination of the transmitter beams and the receiver beams form pencil beams
Data Source
AI summary
According to one aspect of the present invention, a radar system is provided which accurately measures the surface profile in a wide sector beneath and forward of a helicopter, to aid low level transit and landing in poor visibility. This uses an electronic beam synthesis technique to form multiple beams directed at the area of interest, each measuring the distance to the first reflected signal received by each beam. These distances represent the profile of the ground and any objects on the ground. A processor then compares the measured profile with the ideal ground profile for safe landing. If the deviations from straight and level exceed the specified requirement for safe landing, or if sufficient rotor clearance is not detected, then a warning is given to the operator. A display will show the measured ground profile highlighting the unsafe regions, allowing the operator to seek a safe region to land. The novelty lies in the way the beams are formed to measure and display the ground profile and provide a warning system. This beam-forming technique is simpler and more cost effective than with a conventional phased array radar.