This Starting Guide introduces installation and operation of the fully scalable RTLS TDoA system . It describes operation with REST and Websocket API, data storage and Introduces Sensmap, a monitoring and visualization application, step by step.
- Server with Ubuntu OS and preloaded RTLS software
- Client’s computer with Ethernet socket
- Google Chrome browser
- Prepared floor plan
- Anchors (preloaded with TDOA firmware)
- Tags (preloaded with TDOA firmware)
- Power Source: PoE adapter 24V-48V DC or Mini USB power supply
- Ethernet cabling with switch
The Sewio RTLS TDOA system utilizes Time of Flight (ToF) distance measurement . Mobile Tag sends a signal in a predefined regular manner. Once the signal is processed by at least three adjacent Anchors, the position of the Tag can be estimated on server. The system requires sub-nanosecond synchronization of Anchors. Synchronization is done wirelessly between Anchors and it is managed by a configuration application referred to as RTLS Manager. The position calculation is done by RTLS software running on RTLS server. The position of Tag is visualized in Sensmap, a web based visualization and monitoring application running within RTLS software on the server. Location data may be stored in database and they are accessible through HTTP API (REST/Websocket).
|Tag||Mobile locator device being localized||UWB Radio 3 – 7 GHz|
|Anchor||Static device with known position. Anchors come with predefined settings that need to be changed, see section 4.||UWB Radio 3 – 7 GHz
Backhaul Ethernet UDP Port 5000,5001
HTTP interface TCP Port 80
|RTLS Manager||Web based software for RTLS device management and synchronization configuration||UDP Port 5000,5001,5100|
|RTLS Server SW||Software for positioning, data manipulation and filtering.||UDP 5100
HTTP 80, Web-sockets 8080
|Sensmap Server||Web based software which provides data access and storage place.||HTTP 80, Web-sockets 8080|
|Sensmap API||Application protocol interface for RTLS via Web Sockets or REST HTTP interface||HTTP 80, Web-sockets 8080|
|Sensmap Visualization||Client based web application for real-time RTLS visualization||HTTP 80, Web-sockets 8080|
Network diagram of RTLS TDoA system is depicted in Figure 1. The entire RTLS infrastructure is designed to be integrated seamlessly in local TCP/IP network. RTLS Software can be installed on Ubuntu Linux operating system machine; recommended machines are listed below:
- HP ProLiant MicroServer Gen8
- HP ProLiant DL60 Gen9.
In order for the system to run correctly UDP ports 5000, 5001, 5100 and TCP 80 and 8080 must be allowed in the network
The Anchors consists of three user interfaces:
- Mini USB interface for to supply power from battery pack or USB power adapter
- LED for device status indication
- Ethernet socket to connect the Anchors into the network
Anchor Power Supply
There are two options how the Anchors can be powered: 1) By USB, 2) By Passive PoE Ethernet. Detailed information about the powering of the Anchors are provided in the Anchor’s datasheet.
Never connect USB and POE at The same time! They are not galvanic isolated.
Table 1. Power options
|USB Adapter||DC USB adapter with rating 1A, cable USB mini, maximum length 1.8m.|
|USB Power Bank||Power Bank with USB output, cable USB mini, maximum length 1.8m.
Capacity at least 10000mAh is recommended.
|Passive PoEDC 24V-48V||DC Source with rating at least 1.5W per Anchor. Power supply is delivered in spare pairs of RJ-45 10/100Base-T. Passive injector/splitter is recommended.
Pair 4,5 is 24V-48V
Pair 7,8 is GND
Not compliant with IEEE 802.3af.
2.1.Changing Anchor's default configuration
In the following tables, the default configuration for both Anchors and Tags is shown. There is no need to change the radio settings during this step but the Anchor’s IP settings need to be modified.
Table 2 Default Anchor Settings
|Master||RF Profile Syncs||Sync Channel||RF Profile Blinks||Blink Channel||Tx Power||IP Address|
|No||RF 0||5||RF 0||5||18,5||192.168.225.100|
Table 3 Default Tag Settings
|RF Profile Mode||RF Channel||Random deviation||Accelerometer mode||Tx Power|
|RF 0||5||Yes||Mode 6||33,5|
You change the Anchor’s IP settings by using a dedicated web interface. To use this interface, connect the Anchor to the power supply by using USB and then connect the Anchor to your PC/Laptop with an Ethernet UTP cable as in the following figure:
Figure 5 Connecting the Anchor to the host computer
The Anchor and your PC/Laptop must be in the same network in order to open the web interface. Since the Anchor is predefined with an IP address of 192.168.225.100, you need to change your computer’s IP settings. If you do not know how, see paragraph 1) in section 4. If you have changed the IP settings, type the Anchor’s IP address (default is 192.168.225.100) into your web browser. You should see the Anchor’s website as shown at Figure 6.
You need to setup an IP address for each Anchor manually, since they all come with the same preconfigured IP address. Otherwise there will be an IP address conflict in the network. Each Anchor must have its own unique IP address.
On the first page, you can see the addresses and statistics of the Anchor. You can also reboot the Anchor by the “Reboot” button located at the bottom of the page. To change the IP settings, navigate to the Network Settings tab. To change the IP address of the Anchor, select Static IP mode and type in the new address. The result can look like this:
Figure 7 Changing the Anchor IP address
As shown in the figure above, we changed the address to 192.168.225.17. To confirm the changes, press the “Submit” button. Once the IP address is changed, you can try reloading the page with the new address or try to ping the new address by using the command line. If the results are successful, then the new address has been set up correctly. You can then repeat the same process for each Anchor, until they all have been assigned with a new IP address.
When the IP addresses of the Anchors have been setup correctly, the initial IP setup is finished. There is no need to change the Tag’s IP settings.
It is recommended not to place the Anchor directly on a wall. The Anchor should be placed at least 10 cm from the wall due to the affection of signal emission. It is better to use a holder with adjustable arm in order to easily adjust anchor position in case of need, see Figure 2.
Figure 2 Knee holder.
Please record Anchors MAC addresses before you start the deployment process. Before installation please consider the following recommendation:
- Maximum line of sight distance between two Anchors is 15 meters
- In order to calculate position, Tag must be readable at least by three adjacent Anchors to perform 2D positioning, for 3D positioning four Anchors is required
- In scenario with several office rooms, it is not necessary to place the Anchors in every room. The Anchors signal is transmitted through the dry walls even several of them. However signal is not transmitted through several floors
- Place the Anchors in height of at least 2 meters, ceiling height recommended.
- Deployment of the Anchors in rectangular space is acceptable. However, it is recommended that ratio between length and width of the room should not exceed 3:1(1:1 is optimal), otherwise please try to place the Anchors into a square shape. The higher the ratio the higher the positioning error.
- Please avoid installation of the Anchors into areas where metal obstacles may corrupt signal transmission between the Anchors and the Tags. Distance measurement and accuracy might be affected for example by human bodies, metal parts or other obstacles containing signal absorbing material.
- The Anchors should be deployed in the same height, otherwise accuracy can be affected. The Anchors should be placed above people in order to reduce signal attenuation. There should not be any obstacle in radius of 20 cm in front of the Anchors.
- The difference between height level of the Tags and the Anchors should not exceed 3 meters, otherwise accuracy and stability of positioning might be decreased. If the Anchors height level is dramatically bigger that height level of the Tags, please use 3D positioning.
The examples of the Anchors deployment are depicted in Figure 3.
The Anchors deployment for 2D positioning:
The Anchors deployment for 3D positioning:
The Anchors must be deployed in different heights, the bigger the difference in height the more accurate are the positioning results. For example top-bottom diagonal placement as depicted in Figure 4. Do not place the Anchors too close to the floor, height above 30 cm from the floor is recommended. For 3D location, cubic anchors deployment should be chosen.
Now you can place Anchors to the desirable locations. For proper mounting of Anchors use an Anchor holder.
The networking scheme of the entire system is depicted in Figure 5. For data transmission from the Anchors it is recommended to deploy a dedicated Ethernet network. The RTLS Server, either as a software image or a hardware server, comes with preconfigured DHCP Server.
Please be aware that if you connect the Anchors to the existing network, DHCP server operating in this network may cause an IP address misconfiguration.
Figure 8 Networking scheme of RTLS TDoA system
3.1.Powering the Anchors with PoE
In order to power the Anchors with Power over Ethernet, please use the PoE splitter, see Figure 6. UTP cables are used to power the Anchors ad also to connect PoE splitter to the network switch. No USB cables are needed.
Figure 9 Networking diagram with PoE
This PoE splitter has two type of socktes: Data and Power+Data. Use Data sockets to connect PoE splitter to the switch. Use Power+Data socket to connect the Anchors. Data goes from the Anchors to the dedicated port Power+Data and continues through the appropriate Data port to the switch. For example data from Power+Data port number 2 goes through the Data port number 2 to the switch.
In this step, all the Anchors should be connected with the server, if that is the case, you can…turn on the power supply. The Anchors indicate correct powering with green LED light, see Figure 8.
Note: You should wait at least 15 minutes to let the Anchors warm up properly. Otherwise the system will not be fully functional and the accuracy will be affected.
As the next step please connect a computer into the network, connect computer to the switch by using a UTP cable. There are two IP addressing options: 1) Setup a static IP address, 2) Obtain an IP address from a DHCP server
1. Configuration of static IP address
IP address: 192.168.225.5, Mask: 255.255.255.0, Gateway: blank
Note: In Windows OS this setting can be done by using “Network and Sharing Center”, press CTRL+R and type “ncpa.cpl” and hit the Enter button. Select the Ethernet network interface, click the right mouse button and select Properties and then IPv4 settings.
2. Obtaining an address from DHCP server
Please follow the steps from the paragraph above to access to the IPv4 protocol configuration window. In such window check the box “Obtain IP address from DHCP Server automatically”
Now access the RTLS server by opening Chrome internet browser and typing (or copy-paste) the following URL:
If you can access the following webpage, the server is ready to use.
For more information on RTLS Manager, see the RTLS Manager section: https://www.sewio.net/rtls-tdoa/rtls-manager/.