RFGeolocation

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Testbed for RF Geolocation by Nathan Catt and Andrew Belk

RHLogo.jpg

The goal of this project, Testbed Development for Geolocation of RF Emitters, was to improve upon the testbed used in conjunction with the Air Force Research Laboratory (AFRL) geolocation algorithm. The military has many applications where locating radio signals are important. Locating downed pilots or pinpointing communication signals of the enemy are just a couple of examples. Rose-Hulman Institute of Technology is currently working on compressive sensing algorithms to help locate the source of radio frequency (RF) signals. These algorithms will be implemented on a ground based mobile platform as part of this project development. The mobile platform will be controlled by a user. A system must first be designed that includes reconfigurable sensors with at least one transmitter and two receivers. The mobile testbeds will need to demonstrate the ability to receive signals and locate the transmitter. A final demonstration will be completed at the AFRL. This testbed could be made autonomous or implemented on an aerial platform in future development. The main goal of this project was to create a system that had individual sensors that can navigate through a predefined grid and use the received signal strength taken at different points and angles to locate the emitting signal. Our team used a mobile platform that has a programmable motor controller, a Software Defined Radio (SDR), a microprocessor, and various sensors. Our team was able to implement an Xbox 360 remote as a user control for movement and access to sensor data. The initial plan was to have an autonomously controlled system, but the accuracy of the off-the-shelf GPS was not sufficient. Our team suggests using a more accurate GPS sensor in order to implement a waypoint navigation algorithm.

Transmitting Sensor

Project Overview

For this project, our team has been working for the United States Air Force Research Lab (AFRL). The United States Air Force (USAF) has the desire to be able to locate emitters at different frequencies for a number of different reasons, including locating enemy communication signals. The goal of our team’s project was to create a testbed that would collect the required data to run a compressive sensing algorithm that is currently being developed by the Rose-Hulman Institute of Technology Department of Mathematics. Our project was intended to be a fundamental stepping block for much more complicated data collection, but more importantly, to collect data to test the effectiveness of the geolocation algorithms. The main deliverables for this project include the testing hardware developed by our team and a detailed testing plan. Our team was able to achieve creating reconfigurable sensors that are mobile and able to collect data when requested by the user.

Logical Architecture

Logical Architecture

Domain Model

Domain Model

Hardware

Microprocessor

We chose to use the BeagleBone Black for our microprocessor. This enabled us to have plenty of room for additional sensor expansion. A BeagleBone Proto Cape was used to get rid of wire clutter.

GPS

Compass

Software Defined Radio

Daughterboard

Antennas

Payload Housing

Mobile Platform

Wild Thumper

T'Rex Motor Controller

Power System

User Control

Software

Our code can be cloned from GitHub.

Software Flow Diagram
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Control Flow Diagram

Client

The Client code is ran on the BeagleBone. This code integrates all of the sensors and communicates information back to the host computer.

Server

Software Defined Radio

MATLAB

Testing

Subsystem Testing

Full System Testing

For correct operation, the following boot sequence must be followed:

  1. Power on the Wi-Fi router
  2. Connect the central processing node to the router
  3. Power the Beaglebone; wait for it to connect to the network
  4. Power the motor controller and the SDR


Location of Measurements

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Location of Measurements

Simulation of Position Points

Simulation.gif

Future Developments