RF Cable Layout for Multi-Pack Launchers to Prevent Interference
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Solution Overview
Problem
Existing systems face challenges in effectively managing RF signals and preventing unintentional missile launches due to interference and mechanical misalignment issues in multi-launch systems, particularly when cables are damaged or obstructed.
Innovation Solution
A cable system comprising an outer jacket, shielded braid, and inner wires acting as antennas, along with a control PCB and RF filter, ensures RF signal transmission to missiles while preventing interference. A current sense circuit detects obstructions, and a built-in fuse safeguards against cable damage, and a box interface isolates RF signals from the metal case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the cable uses shielded wires to prevent RF interference, then electromagnetic compatibility is improved, but the cable structure becomes more complex and harder to manufacture
Solution Approach 1:
The cable is divided into distinct functional segments: an inner pair of shielded wires for signal transmission and an outer pair of unshielded wires for RF transmission. Each segment serves a specific purpose, allowing the cable to handle both shielded and unshielded functions simultaneously without requiring complete shielding of all conductors.
Solution Approach 2:
Different parts of the cable have different shielding characteristics. The inner wires have shielding for low-frequency signal protection, while the outer wires remain unshielded for high-frequency RF transmission. This local differentiation of shielding quality optimizes performance for each function while reducing overall complexity.
2Reliability
If the cable is made more robust to prevent damage, then reliability is improved, but the ease of installation and routing deteriorates
Solution Approach 1:
The cable incorporates a built-in fuse that can blow under damage conditions, providing a dynamic safety mechanism. This allows the cable to remain flexible and easy to install under normal conditions while automatically protecting the system from damage through the fuse mechanism when excessive force or damage occurs.
3Reliability
If RF signals are transmitted through the cable to missiles, then launch control reliability is improved, but the risk of unintentional launches due to interference increases
Solution Approach 1:
The cable separates RF signal transmission from missile control signaling into different wire pairs. The inner shielded wires carry control signals while the outer unshielded wires carry RF signals to the missile antennas. This segmentation prevents RF interference from corrupting control signals while maintaining reliable launch control.
Solution Approach 2:
The cable structure acts as an intermediary that selectively transmits different signal types through different pathways. The shielded inner pair mediates control signals with protection from RF interference, while the unshielded outer pair mediates RF transmission to antennas, preventing direct interference between the two functions.
4Adaptability or versatility
If the cable includes multiple wires for different functions, then functionality is improved, but the difficulty of detecting and measuring cable integrity increases
Solution Approach 1:
The built-in fuse provides a clear feedback mechanism for cable integrity. When the cable is damaged or subjected to excessive force, the fuse blows and provides a distinct electrical discontinuity that is easy to detect. This simplifies integrity checking despite the multi-functional complexity of the cable.
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 ensures reliable RF signal transmission to missiles, prevents unintentional launches, and maintains mechanical integrity by detecting and addressing obstructions and cable damage, enhancing safety and functionality.
Implementation Method 1
the third wire and the fourth wire act as an antenna
Implementation Method 2
The wire may be shielded and filtered at the box interface so that any radio frequency (RF) signals picked up by the wire do not find their way into the box
Implementation Method 3
the RF signals produced by the cable may be filtered with an RF filter disposed on the PCB
Data Source
AI summary
Systems, devices, and methods including a launch control box; a multi-pack launcher (MPL) box; and a cable connecting the launch control box and the MPL box, where the cable comprises: an outer jacket, a shielded braid, a first wire, a second wire, a third wire, and a fourth wire, where the first wire and the second wire are shielded by the shielded braid, where the third wire and the fourth wire are outside of the shielded braid, and where the third wire and the fourth wire act as an antenna.