RF Ranging in RF-Opaque Environments Using Transponders
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Solution Overview
Problem
In environments with dense foliage, such as jungles, GPS and laser-based surveying methods are ineffective due to RF opacity and line-of-sight issues, making it challenging to accurately and efficiently determine property boundaries.
Innovation Solution
Implementing an RF ranging system that uses transponders on the property line, transmitting and receiving RF signals at different frequencies to calculate a perpendicular distance from a ranging device to the property line, utilizing VHF frequencies that can penetrate dense foliage and mitigate issues with pulse and continuous-wave RADAR systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If GPS receivers are used for surveying, then surveying is made easier in most environments, but GPS does not perform well in RF-opaque environments like jungles with dense foliage
Solution Approach 1:
The patent changes the RF frequency parameter from GPS frequencies (1575.42 MHz and 1227.60 MHz) to VHF frequencies (30-300 MHz), specifically using 151.5 MHz for transmission and 75.75 MHz for reception. This parameter change allows the RF signals to penetrate dense foliage effectively, resolving the reliability issue in RF-opaque environments while maintaining ease of operation
2Measurement precision
If laser-based ranging is used, then ranging capabilities are provided, but laser-based ranging is precluded by line-of-sight issues in jungle environments
Solution Approach 1:
The patent replaces optical laser-based ranging with RF-based ranging using VHF frequencies. The RF signals can diffract around obstacles and penetrate foliage where laser beams cannot pass, providing the same measurement precision capability while adapting to RF-opaque environments through the use of transponders and frequency conversion
3Measurement precision
If pulse and continuous-wave RADAR systems are used, then ranging is provided, but these systems suffer from interference and accuracy issues in dense foliage environments
Solution Approach 1:
The patent segments the RADAR system into separate transmission and reception frequency bands. By transmitting at 151.5 MHz and receiving at 75.75 MHz (half the transmit frequency), the system eliminates self-interference between transmit and receive signals. This frequency segmentation allows accurate ranging in dense foliage without the interference problems that plague conventional pulse and continuous-wave RADAR systems
Solution Approach 2:
The patent introduces transponders as intermediary devices placed on the property line. These transponders receive the transmitted RF signals, convert them to the appropriate frequency, and retransmit them back to the ranging device. This intermediary approach enables accurate distance measurement by providing clean, separated receive signals that are not contaminated by direct transmit signal leakage
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 and efficient surveying in RF-opaque environments by isolating transmit and receive signals, improving accuracy and reducing interference, allowing for precise determination of property boundaries.
Implementation Method 1
A transmit antenna transmits RF signals at a first carrier frequency (f1)
Implementation Method 2
A receive antenna receives RF signals at a second carrier frequency (f2)
Implementation Method 3
calculates a first distance from the apparatus to the first transponder based on the first RF signal and the first RF rebroadcast
Data Source
AI summary
The embodiments described herein provide ranging capabilities in RF-opaque environments, such as a jungle, utilizing transponders located on a property line. In particular, the embodiments described herein provide for determining a perpendicular distance to a property line from a ranging device. The transponders are located on the property line and a separated from each other by a known distance. The ranging device transmits RF signals to the transponders, which are received by the transponders and re-broadcasted back to the ranging device on a different frequency. The ranging device uses information about the transmitted and received RF signals and the known distance to calculate a perpendicular distance from the ranging device to the property line.