Marvelmind Beacon HW v4.9 User manual

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Marvelmind Indoor Navigation System
Operating instructions for beacon
V2017_05_02
www.marvelmind.com
User Manual
Beacon HW v4.9
915MHz

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Table of contents
1. Executive summary................................................................................................................................................. 3
3. Basics of the system.................................................................................................................................................... 5
3.1 What’s in the box .............................................................................................................................................. 5
3.2 Indoor GPS architecture .................................................................................................................................... 6
3.3Indoor GPS – beacon’s inside view.................................................................................................................... 7
3.4 System elements ............................................................................................................................................... 8
3.4.1 Stationary beacons ....................................................................................................................................... 8
3.4.2 Mobile beacon (“hedgehog”) ....................................................................................................................... 9
3.4.4 Charging beacons and other details ........................................................................................................... 10
4. Setting up the system .......................................................................................................................................... 11
4.1 The very first setup routine of your device ..................................................................................................... 11
4.2 Setup software (Dashboard) ........................................................................................................................... 12
4.3 Using the system after the very first setup ..................................................................................................... 16
5. Interfaces ............................................................................................................................................................... 17
5.1 Beacon HW v4.9 external interface 4x4 pinout........................................................................................ 18
6. Advanced system settings and optimization .................................................................................................. 19
6.1 Using oscilloscopes.......................................................................................................................................... 19
6.1.1 Monitor ultrasonic signal from one beacon to another ............................................................................. 19
6.1.2 Proper ultrasonic signal detection .............................................................................................................. 20
6.2 Using hedgehog.log file............................................................................................................................... 21
6.3 Important aspects and hints ........................................................................................................................... 22
6.4 Deep hints ....................................................................................................................................................... 23
6.5 Table: Power consumption ............................................................................................................................. 24
6.6 Different colors in the Dashboard menu......................................................................................................... 25
6.7 Ultrasonic coverage......................................................................................................................................... 25
6.8 Submaps.......................................................................................................................................................... 25
4. Frequently Asked Questions .............................................................................................................................. 26
5. Contacts................................................................................................ .................................. 26
................................6. FCC Statement................................................................................................ .................................. 26

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1. Executive summary
Marvelmind Indoor Navigation System is off-the-shelf indoor navigation system designed for
providing precise (+-2cm) location data to autonomous robots, vehicles (AGV) and copters.
It can also be used for tracking other objects, where the mobile beacon can be installed, for
example, in virtual reality (VR) systems.
The navigation system is based on stationary ultrasonic beacons united by radio interface in
license-free band. Location of a mobile beacon installed on a robot (vehicle, copter, human,
VR) is calculated based on the propagation delay of ultrasonic signal (Time-Of-Flight or
TOF) to a set of stationary ultrasonic beacons using trilateration.
Key requirement for the system to function properly is:
- An unobstructed sight by a mobile beacon of three or more stationary beacons
simultaneously - for 3D (X, Y,Z) tracking
- An unobstructed sight by a mobile beacon of two stationary or more stationary
beacons simultaneously – for 2D (X,Y) tracking

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Key capabilities:
−Distance between neighboring beacons: up to 50 meters. Recommended distance in real-life
environment – up to 30m *
−Coverage area:
oUp to 1000 ㎡for Starter Set
oCoverage for larger areas is done similar to cellular networks; can be much larger, than
1000 ㎡and depends on the radio interface that can be further extended
−Location precision:
o1-3% of the distance to the beacons (without calibration)
oDifferential precision: ±2 cm
−Location update rate:
o0.5-45Hz
Can be set manually
Depends on the distance between mobile beacon and stationary beacons (smaller
distance – higher update rate)
Depends on the number of beacons
−Beacons form the navigation system automatically – no manual coordinates measurements or
entering required (except of height)
* Sensor 4 to sensor 4 direct line; all other sensors are disabled
Parameter Technical Specifications
Distance between beacons Up to 50 meters; Recommended - 30 meters (Transducer4 to Transducer4 looking
straight to each other and other transducers are off)
Coverage area Up to 1000 m
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for Starter Set configuration
Coverage for larger territories done similar to cellular networks
Location precision - Absolute: 1-3% of the distance to the beacons
- Differential precision: ±2 cm
Power supply Internal: LiPol battery 1000mAh
External: microUSB
Weight Mobile beacon from Starter set:
- 55 grams (including battery 1000mAh and housing)
- 27 grams (bare board w/o battery)
Beacon size Size: 55x55x33 mm (with antenna: 55x55x65mm)

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3. Basics of the system
3.1 What’s in the box
Starter Set:
- 4xStationary beacons
- 1xMobile beacon (aka “hedgehog”)
- Deleted part
* Exact appearance may wary depending on the Hardware version. Characteristics are kept the same or better
unless specially noted

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3.2 Indoor GPS architecture
Marvelmind Indoor Navigation System provides high-precision (± 2 cm) indoor coordinates
for autonomous robots and systems (“indoor GPS”). Brief description of the key elements of
the system is given on scheme below:

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3.3 Indoor GPS – beacon’s inside view

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3.4 System elements
3.4.1 Stationary beacons
- Shall be mounted on walls and ceilings – usually, above the robot and ultrasonic sensors facing
down – to provide the most robust unobstructed coverage of ultrasonic signal to robot. However,
for automatic landing and indoor navigation of copters, for example, it is recommended to place
beacons on the floor/ground and install the mobile beacon horizontally downwards looking on
the belly of the copter
- Position for the beacons and angles of
positioning shall be chosen in such a way that
maximum coverage in ultrasonic is provided for
the maximum territory. Proper ultrasonic
coverage is the utmost important element for the
system to function effectively
- Stationary beacons emit and receive ultrasound,
when the map is being formed. And they only
receive the ultrasound, when the map is formed
and frozen
- Stationary beacons have no exterior difference
with mobile beacons
- Inertial measurement unit aka IMU is not
installed on the stationary beacons
- The mobile and stationary beacons can be easily
interchanged by selecting the option (Except
IMU) in the Dashboard
- There is 915MHz version available. Proprietary radio protocol is used for communication and
synchronization. Other ISM bands are available upon request too

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3.4.2 Mobile beacon (“hedgehog”)
-The mobile and stationary beacons can be easily interchanged by selecting the option in the
Dashboard
-The mobile beacons are designed to be placed on the robot vehicle or copter/drone or AGV
or helmet to trace its location. Formally speaking, location of the mobile beacon is traced –
not the robot itself. Since the sizes and the location of the central point of the mobile beacon
and the robot are different, the difference
has be taken into account in the robot’s
SW
-The mobile beacon has to be placed
horizontally to provide optimal ultrasonic
coverage – upper hemisphere
-Its sensors must not be closed with
anything that can reduce the strength of
ultrasonic signal
-The beacon’s coordinates are updated
according to the rate set in the Dashboard
-System may contain one or more mobile
beacons. Current implementation relies on
time division multiple access approach.
Thus, if two mobile beacons are activated,
they share the time. It means that, if 16 Hz
update rate is selected and there are 2
mobile beacons in the system, each beacon’s location will be updated with the rate of
16Hz/2 ~ 8Hz. If there are 3 mobile beacons => 16Hz/3 ~ 5Hz, etc. Future SW
implementation will contain different solution that will improve update rate in the setup with
multiple mobile beacons.
-Location data is obtained either from the “hedgehog” via USB (virtual UART), UART, SPI.
More on interfaces: http://www.marvelmind.com/#Interfaces
-Data from the beacon is sent in a streaming format identical that of GPS (NMEA 0183)
-There is 915MHz version available. Proprietary radio protocol is used for communication
and synchronization
-The “hedgehog” has been successfully integrated with Windows PC, Linux machines,
Raspberry Pi, Arduino boards, Intel boards, etc:
http://marvelmind.com/pics/supported_interfaces.png

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3.4.4 Charging beacons and other details
- The Beacon has 5 sensors (transducers) RX1, RX2, RX3, RX4, RX5
- DIP switch modes:
1) Power OFF, DFU OFF: charging is possible; beacon is disconnected from power. This
mode is recommended, if you want to keep the battery fully charged for many months
2) Power ON, DFU OFF: normal working mode for beacon. The beacon is fully powered
and wakes up every a few seconds. Power consumption is still minimal, if the beacon
sleeps and the battery can last for many weeks or a few months. It is recommended to
keep the beacon in this mode and to not touch the DIP switch at all, unless you want
to store the beacon on the shelf. Then, the mode 1) is better and recommended
3) Power ON, DFU ON: DFU programming mode. It is used for the very initial SW
uploading or when the HEX SW cannot be uploaded from the Dashboard for some
reasons
- Charge your board from USB
- Charging is done automatically every time, when the USB charger is attached to the board. It takes
1-2h to fully charge the board’s battery
- If you plan using charger for permanent power of the beacon, make sure that it is not noisy. The
performance can be monitored by Dashboard => View => Oscilloscope, visit oscilloscope paragraph
- When the board is charged and turned on LED 2 is blinking every few seconds.