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Accubeacon Andrew Gans, Spencer Curran, Shreyank Amartya, Alex Fouss, John Bullock.

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Presentation on theme: "Accubeacon Andrew Gans, Spencer Curran, Shreyank Amartya, Alex Fouss, John Bullock."— Presentation transcript:

1 Accubeacon Andrew Gans, Spencer Curran, Shreyank Amartya, Alex Fouss, John Bullock

2 Winter backcountry recreation has become increasingly popular. Thousands of skiers and sledders put themselves in dangerous avalanche zones each year 90% are caused by a victim or someone in their party. Personal Account of Avalanche Video Avalanche Hazards background Spencer

3 include data on life expectancy Avalanche Hazards Spencer


5 Probe line - A technique used with an abundance of searchers K9 search team - Avalanche dogs are trained to sniff out buried victims Proper Shoveling - There are several methods for fast and swift extractions Air Bag - A backpack air bag that can be deployed when victim triggers an avalanche to prevent being buried. Avalanche Rescue Methods Spencer

6 Spence

7 Use of sensors 1. Knowledge about the state of the victim; survival chances, urgency, vital signs. 2. Orientation of victim in snow 3. Depth of buried victim. Multiple Buried victim markers Other Innovations

8 Accubeacon Avalanche Transceiver System Overview

9 To design a set of avalanche transceivers that can communicate with each other to allow for more accurate pinpointing of buried victims and multiple burial detection Statement of Purpose Spencer

10 Requirements-Primary LevelRequirementDependencies PrimaryP1Triangulate relative location of buriedS1,S2,S3 PrimaryP2Display victim location in an easy to read formatS4 PrimaryP3Supply enough power for extended use in the backcountryS5 PrimaryP4Meet all standard specifications and functionality of current transceivers S7,S8 PrimaryP5Detect multiple burialsS6 Spencer

11 LevelRequirement SecondaryS1Calculate distance between user beacon and buried beacon using 457kHz wireless signal SecondaryS2Calculate distance between user beacon and other searching beacons using other wireless protocol SecondaryS3Receive distance data from other searching beacons SecondaryS4Place relative location of buried victim onto visual display SecondaryS5Provide a sufficiently sized battery pack to meet power requirements SecondaryS6Determine the event of multipal burials SecondaryS7Transmit at standard 457kHz frequency SecondaryS8Incorporate standard signal strength indicator search functionality Requirements-Secondary Spencer

12 1. 457 kHz RF Transmits/receives standard 457kHz frequency signal and processes associated RSSI signal 2. ZigBee Wireless Transmits in the ISM band and uses RSSI or RTOF (round trip time of flight) to get triangulation information 4.User Interface/Data Processing Provides clear and concise information about the location of burial Subsystems Alex


14 Processing and User Interface Subsystem Accubeacon Avalanche Transceivers

15 Collects data from 457khz and zigbee subsystems Uses data to run required algorithms for multiple burial detection, localization and trilateration Processing and User Interface

16 Trilateration Localization Multiple Burial Detection Algorithms

17 Uses distances between three or more searching beacons to determine relative x,y positions of other searchers Requires accurate distance measurement between searching beacons x,y positions of other searchers allows for triangulation using 457khz signal Localization

18 -Localization determines relative position of other searchers -Trilateration uses localized distance vectors from other searchers to compute buried location -Buried location presented to searcher via user interface Trilateration Process Shreyank

19 Trilateration Diagram Shreyank

20 System Setup Alex

21 Use 457khz signal strength from multiple antenna and multiple beacons to determine distance from buried victim(s) Multiple Burial Detection




25 Requirements o Processor that can run all required algorithms o User interface that displays results of algorithms User Interface and Hardware

26 Atmel xmega 256-A3 microcontroller Power Conversion Serial Connectors 4.5V Battery Jack Test Pads USB connector Power and Serial LED's PDI interface for AVR ISP mkii Development Board

27 Past experience with Atmel microcontrollers and AVR Studio Can easily switch to a different series of Atmel microcontroller Easily accessible drivers and libraries for different peripherals and modules Can be easily programmed through PDI using Atmel mkii In System Programmer Microcontroller - ATxmega 256A3U

28 Push Buttons to power on, switch between search and transmit mode LCD module to display the grid and relative positions of the searchers and victims User Interface

29 Zigbee Wireless Subsystem Accubeacon Avalanche Transceivers

30 Sends data between searching beacons Detects RTOF/RSSI from received signal to calculate distance Tasks and Responsibilities

31 ZigBee -Received Signal Packer from Other Searchers -Distance correlation (RTOF/RSSi) ZigBee Modem Distance Data to Microcontroller Transmitted Signal Packet to Other Searchers Display/Processing Processing and Display -Triangulates burial location -Displays to screen -Distances between searchers -Distance/Angle to buried victim -Mode information Alex

32 ModuleZigbee Wireless Transceiver Level 2 Input48 bit packets using TOA (Time of Arrival) or RTT (Round Trip Time) Output48 bit packets using TOA (Time of Arrival) or RTT (Round Trip Time) FunctionalityProvide adequate signal to determine distance from other searchers and transmit own 457 kHz signal to aid in trilateration. As well as receive the distance of other searchers in order to locate them compared to own reference location. Determine their 457 signal of the buried victim to aid in trilateration.

33 RSSI(Received Signal Strength Indicator) -RSSI is the measurement of power present in the received radio signal. RSSI is directly proportional the distance as follows RSSI 10 log (P/Pref) Wireless Distance Measurement Shreyank

34 Time of Arrival - Using synchronized clocks and time stamps to record signal travel time -Travel time can be correlated with distance -More accurate than RSSI but requires precise timing Wireless Distance Measurement Shreyank

35 -Currently we are using XBee libraries to transmit packet arrays amongst other searcher. -The packet contains the following data 1. Sender's XBee ID 2. 1st RF distance 3. 2nd Searchers RF distance 4. 3rd Searchers RF distance 5. Distance from 3 to 1 6. Distance from 3 to 2 7. Distance from 2 to 1 -Each individual XBee processes this data and extract all relevant data for their own array. Wireless Packet

36 457 kHz RF Subsystem The backbone of avalanche transceivers

37 The 457 kHz subsystem is the bare minimum needed for a working avalanche beacon Other marketed beacons only have this system. Some beacons use digital signal processing and 3 axis antennas to eliminate false readings No current beacon uses communication with other searchers to correlate information and further eliminate error

38 457 kHz Transmitter Transmit on (Oscillators / Filtering) USER INPUT (device power on) Analog Front End (Filtering, Multiplexing, A/D) Directional Information to Microcontroller 457 kHz Receiver USER INPUT (device switched to search mode) Ferrite Rod Antenna (2x, orthogonal) Outputs Radiation Pattern Ferrite Rod Antenna (2x, orthogonal) Determines Orientation Alex

39 457 kHz Transmitter (Level 3) Module457 kHz Transmitter Level 3 InputPower Output457 kHz pulsed RF power on either of two antennas FunctionalityProvide adequate radiation to allow for detection when buried ~50m away Crystal Oscillator RF Filters Buffer AMP MUX RF PWR AMP Demu x Counter Frequency Divider Frequency Divider RF Choke Power 457 kHz pulse Gnd Pulsed 457 kHz Antenna selection

40 457 kHz Receiver (Level 3) Module457 kHz Receiver Level 3 InputRF Radiation (tuned to 457 kHz), power OutputAnalog signal to be processed by microcontroller FunctionalityProvide a meaningful analog voltage that represents signal strength for each antenna orientation Power 457 kHz tunning Mux RF Choke RF AMP Band pass filter buffer RectifierSignal Conditioning Out to CPU Pulsed 457 kHz Antenna selection (sync with Tx) Creates a DC voltage relative to received RF signal strength

41 Using cross-searcher data communication reduces guesswork and ambiguity with ultimate goal of eliminating a coarse search Trilateration (Triangulation) Quick and precise pinpointing of multiple buried victims (even with unintended signal modulation - overlap)

42 Tasks Transmit RF signal within margin of error up to current standards (457 kHz ± 80 Hz) Differentiate signals of multiple buried victims Relay analog information to microcontroller when in search mode

43 Features Backwards Compatibility Receive RF signals within a large margin of error (457 kHz ± 200 Hz) o Covers range of frequencies for 1970's era beacons If all else fails (one searcher, no xbee communication, etc) the transceiver will function as a regular ("digital”) beacon

44 Prototyping & Testing Multiple searcher tests done Differences in signal waveform (BCA Tracker DTS) give signature characteristics based on buried beacon’s orientation Use the differences in signal to communicate between beacons and determine instantaneous location of buried victim This method can be extrapolated for multiple burials

45 Prototyping & Testing Digital signal processing Differentiate between signal overlap and no signal overlap Smooth out signal modulation when overlapping

46 Prototyping More information is needed to reduce degrees of freedom Searcher inputs number of burials Digital compass used to find magnetic north


48 Transmitting Antenna (Buried Person) Receiving Antennas Arrangement (BCA Tracker DTS) Antenna 1 Antenna 2


50 Two Transmitters Same Relative Distances


52 1 Transmitter Closer to CH. 2 CH. 2 CH. 1


54 90 Degree Triangle




58 In H-Plane Closer to CH. 2




62 In H-Plane Tx, Rx CH.1,Rx CH.2 Orientation


64 Same Configuration with Rx CH.2 Rotated 90 Degrees


66 Both CH. 1 and CH. 2 90 Degree Offset

67 Development Plan (Multiple Burials) Input data into microcontroller Analog voltages converted to sampled digital signal Signal processed using differential algorithms Vectors assigned to signals and output to high-res matrix display

68 Milestones 1. Proof of Theory 2. Rev A. - Proof Of Concept 3. Rev. B 4. Final Rev. Design Approach Wheeler

69 Completed required background research to show that the concept is feasible - Used existing beacon as test platform Incorporated Zigbee wireless: -data transmission -distance measurement Algorith Implementation on arduino Design So Far Wheeler

70 Arduino Uno Xbee Point to Point network RSSI -Distance Measurement BCA Tracker Beacon RSSI pulled from 7-Segment Display Allows for easy implementation of algorithms Current Setup


72 -First PCB Revision -Atmel Microcontroller on “development board” -Multiple Burial Algorithm Implemented -Lower Level Input from Existing Beacon -RTOF implementation Revision B Wheeler

73 -Integration of our own 457kHz Transceiver -Finalized Zigbee System -Finalized Multiple Burial Determination System -Finalized Processing/Display Revision C - Final Rev. Wheeler

74 Team/Project Management Wireless Communication RF Communication Multiple Burial Determination User Interface/Data Processing SpencerXXX WheelerXXX JohnXX AlexXXX ShreyankXX John

75 Along with our bi-weekly scheduled lab time, we have weekly "scrums" to discuss progress and updates on Monday nights. We do our best to set up 2 week sprints, in which we set goals and task to accomplish in order to stay on track with our milestone goals. Scheduling Tasks John

76 Budget Estimated Costs Research$102 Rev A$133 Rev B$294 Rev C$294 Total$823 John Applied for UROP and using Personal Funds.

77 1. RSSI accuracy has not been proven, RTOF should prove to be more accurate, but we have been unsuccessful implementing 2. RF 457 kHz implementation 3. Expandability to function with N searching beacons 4. Multiple Burial Determination Risks and Contingencies John

78 -Current beacon technology is decades old -Accuracy is going to be our biggest concern and goal -Through 2-way communication we project to minimize search time to save lives and hopefully carve out a spot in the market not yet realized Conclusion John

79 Questions & Comments

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