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What is the Arianna system?

1-What is the Arianna system?

The Arianna system is an indoor localisation and tracking system for GPS-denied environments.

It can also be augmented by ancillary wearable sensors (e.g. heart pace, carbon dioxide sensor), becoming a wearable safety system, conveying information about the location, health status and nearby environmental hazards (see Sec. 22).

What kind of infrastructures does it need?

2-What kind of infrastructures does it need?

The Arianna System doesn’t need the deployment of any infrastructure.

It is only based on a small-size, lightweight Smart Sensor that logs the data and processes them to estimate the user path. It can transmit the data outside, to let an external user know/view the position/track in real-time, along with (if equipped) the data coming from biometric and environmental sensors.

How does Arianna work?

3-How does Arianna work?

The Arianna System is based on the SmartSensor:

  • a small sensor that the user (walker) to be fastened on the shoe or inside it.

  • a computation unit (Master Control Unit) with an internal battery, in charge of performing the processing and manage the communication.

  • A software on the PC that allows the display of the path on a map view in real time (AriannaMap).


The sensor (in the red frame) and the Master Control Unit -> SmartSensor


The AriannaMap software interface

Wearing the Arianna SmartSensor

4-Wearing the Arianna SmartSensor

To wear the Arianna system is enough to fix the sensor on the shoe with tape, laces, strips, metallic clamp or any fixing system and place the MCU at the belt.


The Arianna system: a) the MCU can be placed on the belt; b) the sensor must be fixed on the shoe

DoI need training on "how to walk"

5-Do I need a training on “how to walk”?

No training is required on how to walk is required.

Arianna performance does not depend on the specific user and has no need of user-specific calibration.

You need only to wear the sensor, power it on and start to walk.

Can I run, crawl, jump, sweep, climb stairs, use lifts?

6-Can I run, crawl, jump, sweep, climb stairs, use lifts?

Yes: you can walk and move freely.

You can also run, but in some circumstances, this might increase the error, depending on the speed.

The movements not currently handled by ARIANNA are: swimming, skating, skiing (and similar).   

What is the Arianna localization accuracy?What is the Arianna localization accuracy?

7-What is the Arianna localization accuracy?

It depends on the optional modules added to ARIANNA.

7.1-No modules: basic ARIANNA

The position error estimation linearly increases with the length of the walked path, being the increasing rate very dependent on the shape (geometry) of the walked track.

In a generic large environment, the is less than 1% of the walked length, but in limited and closed spaces the error can drop below 0.1% of the walked distance.

In the following image, a real test (6:30 hours, 7.35 Km) is reported.


ARIANNA (no add-on modules): 6:30 h and 7.350 m path length test: the larger and smaller red circles represent the 1% and 0,5% confidence error; the small green circle and the little black man icon represent the start and end points, respectively.

7.2-ARIANNA + FLOOR module

The FLOOR module exploits the availability of the floorplan (map) of the intervention area, by adding a “map matching” processing layer on the top of the ARIANNA position estimation.

This allows for a constant position accuracy, independent of both the mission time and walked path; being only dependent on the reliability and accuracy of the employed floorplan.

REMARK: the FLOOR module is suitable for the real-time tracking, but it is not it not a pre-designed, stand-alone module, because it must be always customised on the user’s specific needs and the nature of his available floorplans. The customisation cost (deeply varying as a function of the requirements) are a non-recurring cost, charged on the module cost. 


ARIANNA-FLOOR: 6:00 hours test in a large mall; the position error in nearly constant throughout the whole experiment, basically depending on the map reliability/accuracy.

7.3-ARIANNA + CTX module

The CTX module has been designed for post-processing and post-mission analysis applications; therefore, it is not designed for real-time applications, at least in its current version.

It doesn’t rely on the availability of floorplans, but exploits the multiple crossings of the same points of the track, statistically occurred many times in real operations. A proprietary processing technique dramatically shrinks the error accumulation, leading to a high-accuracy track, with a precision as low as 1 m, independent of the mission time and walked path length.   

The next figure illustrates one experiment carried out by the Italian Firefighters in an ancient underground cave, comparing the achieved “purely inertial” result and the one achieved by adding the CTX post-processing module.    


ARIANNA-CTX: experiment carried out by the Italian Firefighters in one ancient underground cave. Left: result achieved by purely inertial tracking. Right: the same track, but with the CTX post-processing module activated.

Is a communication device included in Arianna?

8-Is a communication device included in Arianna?


However, ARIANNA has been designed as an open system; its estimated position (plus ancillary data) are made available over a number of  standard interfaces (see Communication Channel section).

Arianna System uses any private server?

9-Arianna System uses any private server?

No. The MCU can send the track information to a user computer without passing through any server or private infrastructure. It is a point to point connection. For the connection type see Communication Channel section.

Communication Channel

10-Communication Channel

Arianna SmartSensor does not include a long-range communication cannel/device.

However, it can use any proprietary or public communication channel because it supports:

  • Bluetooth LE 4.2;

  • WiFi;

  • RS232 (+/-12V);

  • RS232 over USB;

Therefore, it can be connected with any of the following communication devices:

  • RS232 (e.g. point to point Radio modem);

  • smartphone (SMT, GSM, 4G, 5G);

  • portable HotSpot (GSM, 4G, 5G);

  • Infrastructured area with WiFi;

  • Custom communication device.

Transmission payload

11-Transmission payload

The Arianna system transmits only few bytes per second.

It can be configured to transmit up to 74 bytes @1Hz

This is enough to reconstruct the user position and its path in real time.

Does Arianna support “holes” in the communication?

12-Does Arianna support “holes” in the communication?

The position estimation algorithms run inside the SmartSensor; therefore, the estimation is totally independent of the reliability (or even the presence) of a communication channel.

However, any message transmitted by Arianna (say, one per second) contains the estimation of the last position, along with a set of correction factors. This implies that a long-lasting lack of communication could reduce the capability of properly displaying the user track in real-time at the receiving site.

Because of this, ARIANNA can support, upon request, the re-transmission of all the lost messages, because of a long communication gap (see section 13).

Does the MCU support messages re-transmission?

13-Does the MCU support messages re-transmission?

Re-transmitting the lost data is usually a waste of the communication bandwidth; anyway, the device internally stores all the messages history. If the communication channel supports (also on spot) the bandwidth needed for the lost data re-transmission, ARIANNA, upon request, can send again all the lost messages.

How many users are supported?

14-How many users are supported?

It depends on:

  1. the computer displaying the tracks.

  2. the communication channel bandwidth.

  3. the polling and routing criteria of the employed communication standard.

If each user had its own independent communication channel and the simultaneous display of all the user on the same map is not required, the number of supported users is virtually infinite.

What happen if I do not have any map?

15-What happen if I do not have any map?

The map is not required at all for the ARIANNA system to work. It is just an option to provide the operator with the visual aid of the map background, but the estimated track is fully meaningful also without the background map.

The map (floorplan) is only required by the ARIANNA FLOOR add-on (see section 2).

Can I include floorplans?

16-Can I include floorplans?

Yes, the Arianna software GUI (AriannaMap) can import any common raster image format (e.g. JPG, PNG), to be placed on the map as reference.

The floorplan map can be scaled and rotated to better fit the ground truth.  Floorplan transparency can be managed as well, to maintain the visibility of the underlying map. 


ARIANNA-MAP (visual tool of the system): example of a floorplan image imported, scaled, rotated and made transparent, preserving the visualisation of the background map.

Without GPS, how can I place the path on a map?

17-Without GPS, how can I place the path on a map?

At the mission start, the user can select the address or the Lat/Lon coordinates of the starting point; in addition, he can move in real time the track on the map, to better fit the ground truth.

Does it also estimate the elevation?

18-Does it also estimate the elevation?

Yes, the reconstructed track is in Latitude, Longitude and relative Elevation. The next figure reports the vertical position estimated by ARIANNA, including elevators and stairs in a 6 floors building.


ARIANNA: experiment showing the estimated vertical position, with one elevator and stairs climbed and waked down.

Is there any 3D view?

19-Is there any 3D view?

Yes, there is the option to display the track in a 3D view.


ARIANNA: example of 3D view: track and background street map (left) and satellite map (right).

Can I add to the 3D view a 3D CAD of a building?

20-Can I add to the 3D view a 3D CAD of a building?

Yes, but the 3D view SW only supports Microsoft 3MF file format.  See the next figure.


ARIANNA: importing a 3D CAD in 3MF format.

Can I add extra information linked to the track?

21-Can I add extra information linked to the track?

Yes, standard photo and 360° photo panoramic photos can also imported, along with other information, such as (but not limited to) Note, spotted Instrument measurements, continuous measurements; all can be related (contextualised) to the track, by relying on match between the time tags of the imported information and the track.


ARIANNA: contextualisation of heterogeneous information in the right location of the track.

Does it support also others sensor data?

22-Does it support also others sensor data?

Yes, for instance, ARIANNA can handle and show in real time also the heart pace, measured by a standard BLE HRM.

External sensors (e.g. heart pace, poisonous gases detectors) are not included in the system, but ARIANNA is compatible with virtually any external sensor equipped with BT or WiFi data transfer channel.


ARIANNA: example of track inside a large building: the blue track is the real-time representation of the heart pace of the user.


23-Is it possible to integrate Arianna System into a proprietary system?

Yes, the Arianna software (AriannaMap) can share either the last estimated position or the whole track over a TCP/IP connection to any external server. The output data format can be customised, to fit user specifications. The shared data format can be CSV,XML,JSON,KML,… and can be adapted to meet the user’s needs.

The current version supports an XML format with the last 500 steps (refreshed on 1 second base) over a TCP/IP channel to a remote server. The user has to enable the function into the Arianna SW and set the appropriate information (Address & Port).

What are size, weight, and specs?

24-What are size, weight, and specs?


BT/WiFi Specifications


Output channel USB 2.0 on type C connector
Radio modem connection: RS-232 ( levels +/- 6V)

Scatolotti e connessioni-01.png
Can you provide one system for testing purposes?

25-Can you provide one system for testing purposes?

Basically no.

You can have a complete ARIANNA system only after placing a purchase order and, whenever applicable, the clearance for the “dual use” given by the National Authorities.

However, you can have, for a limited and fixed time a reduced-scale ARIANNA for testing purposes. The testing version of ARIANNA is the same as the full version, but with some disabled functionalities (e.g. does not manage movements like crawling, sweeping).

The release of the testing version needs the signature of one NDA and one “use agreement” before the delivery.



The Arianna system is an autonomous system that collects the data from a sensor on the shoe and perform internally in the MCU all the calculation to reconstruct the path of the walker.

This path and the original data are stored internally into a flash disk and can also be transmitted to a remote computer.

The communication channel between the MCU and the remote computer is not intrinsically part of the Arianna system.

The MCU can use any standard communication device to send the messages.

The payload is less than 74Bytes @ 1Hz (a message any second).

Examples of the supported communication devices are: Smartphone, Portable HotSpot, any kind of Radio Modem that supports the RS232 connection and is capable of at least 30Byte/second of payload.

Integrating the Arianna System into a proprietary system is easy. It is enough to create a TCP/IP server on the same computer (or an a different one) and pass the connection information to the AriannaMap SW.

The shared data format can be CSV, XML, JSON, KML, and can be adapted to the user specification.

1:General consideration on using Dune SmartSensor

Any com Basically, must be considered that, at the power on, the SmartSensor is slave and wait for a command to start. After receiving the “start” command, the SmartSensor unit emits autonomously a message any second (@1Hz).


Each message should arrive to the AriannaMap SW even if holes (messages lost) in the transmission can be managed.


The file is also saved internally into the Flash memory and can be also downloaded after the mission to be imported and visualized.


This file can be imported by using the menu option File -> Import track file and selecting a street address close to the real starting point, (the track can be easily moved after the import to fit the real starting position).


In the following an example of a messages log, the file will look like:







Each line is a message.


2:General consideration on using a communication equipment

Any communication equipment that behave as a “wireless wire” can be used.

Usually it is based on two units.

The first one is the mobile transmitting unit and it is connected to the SmartSensor.

The second unit (the fixed receiving unit) it is connected to the PC usually by using a USB cable or RS232.


  • F1 Fixed communication equipment receiving unit.

  • M1 Mobile communication equipment transmitting unit.

  • SS1 SmartSensor

In order to use a communication equipment with AriannaMap these requirements have to be satisfied:

  • The communication equipment should act as a “wireless wire”, so each SS1 message should arrive to the AriannaSW “as it is”. Extra messages can be also present and will be discarded.


  • The F1 unit must be connected to the PC by using an RS232 connection (for example RS232 over USB like for dune Radio Modem or RS232 over BT). Other approaches (like USB management different from RS232, UDP, … ) can be implemented but are not implemented now. It is also possible to open a TCP/IP server connection to receive the sensor messages.


  • The M1 unit has to take care of letting start the SS1 Smart sensor by emitting the “start” command “aaa” at the power on.


So, if the M1 <–> F1 equipment behaves as a transparent RS232 connection between the SS1 dune smart sensor and the AriannaMap SW, it is enough to open the connection by using the menu item:


Connection -> Open connection


Then selecting a street address close to the real mission starting point (the track can be easily moved after the import to fit the real starting position)


And, if required, selecting the right port:


After that, the AriannaMap SW will manage any message received from the sensor and will display graphically the track and log it into a file in the directory …\Documents\AriannaMap Data.

3.First scenario Radio Modem: Single user.

No furthermore specific requirement is present.


4:Second scenario Radio Modem: Multi users.

In this scenario it is important to preserve the Message integrity.


So, it is required that the M1->F1 connection is independent off the M2 -> F1 connection.

The AriannaMap will manage automatically the presence of many users.


If this is not possible (as for the new dune Radio Modem where all the user share the same radio channel) you could use the Time Division approach. The message length is small enough to send the message in a slot of 100ms on any second.


5:Alternative scenario: Smartphone & PC connected to the net


By using a smartphone as M1 unit, it is enough to put the AriannaMap SW in “waiting status” by opening a server connection (Connection -> Open server). Now the M1 unit has to open a connection with the address ([PC TCP/IP] address: [13000] port) for example


Also in this case, the AriannaMap SW will manage any message received from the sensor and will display graphically the track and log it into a file in the directory …\Documents\AriannaMap Data.

Again, any message of SS1 that M1 sends to the remote PC over the network, will appear on the AriannaMap sw.


Pay Attention on how Smartphone and the PC are connected to the net.

  1. Both on the same private WiFi network

  2. PC on the net office/domestic net and the Smartphone on the 4G cellular net


In scenario 1) it should work if AP isolation is not enabled on the net,

in scenario 2) depends on many aspects like firewall, public vs private address (check if you can PING the PC from the smartphone).


On the Android Smartphone, the AriannaApp receives the SmartSensor data over the BT connection. AriannaApp could also work by using a cable and a cabled RS232 connection between SmartSensor and the smartphone.

AriannaApp and AriannaMap both can manage a TCP/IP connection. You have to put the remote PC public address (also in a URL format) into the AriannaApp field and perform the connection into the App before connecting the BT device.

On the AriannaMap open Connection->Open server.

Then AriannaApp will send to the remote server (AriannaMap) any received (74H) string and works exactly like for the RS232 connection.


Pay Attention:

  1. If the network is a public network the windows firewall can disable some feature and the connection does not work


  1. The AriannaMap server IP address has to be Public and not under NAT or you have to use a service that behave as a tunnel between your address and a public address. AriannaApp manages the connection to the service ngrok ( as a demonstration of the tunnel possibility.
    If you are interested, follow the instruction on the ngrok site and install it on the AriannaMap computer.

  2. The SmartSensor does not have any GPS so there are two option: you have to use a “new Smart BT dongle” that collects these data from the sensor and the GPS data and adds them to the 74H formatted stream or you have to use the dune dongle (or any equivalent one) to send the sensor data (74h format) to the Smart phone that have to add its GPS data to the 74h stream. At the moment this is not done but it can be done.



6:Alternative scenario: Hotspot & PC connected to the net

In the same way the SmartSensor can use a standard hotspot WiFi device to access directly on the net to the AriannaMap software. In this case no Android application is required.

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