omlox

omlox is a technology standard that enables the provision of location data independent of technology and manufacturer. The term omlox is derived from the Latin terms "omni" = omnipresent and "locus" = location.

Logo of the omlox technology

The omlox standard essentially describes two core components:

  • A location middleware ("omlox hub") that brings together location data from the various technologies and makes it available to other applications via standardised APIs.
  • An open location infrastructure ("core zone") based on ultra-wideband radio technology, in which devices can be located or locate themselves independently of manufacturer.

All other positioning technologies (such as RFID, BLE, WLAN, etc.) are not standardised by omlox itself, but can be connected to an omlox hub as so-called "complementary zones". The technology standard is managed by the industry association Profibus and Profinet International.

Architecture

Omlox refers to location technologies that cover different spatial areas in a factory as zones. Omlox distinguishes between two different types of zones:

  • Core zone - is an area where an interoperable ultra-wideband system is installed that allows vendor-independent location. The omlox standard defines how assets in industrial environments can be located with the necessary accuracy using ultra-wideband technology.
  • Complementary zone: In addition to ultra-wideband technology, there are a variety of other technologies that allow location inside or outside buildings. These include Wi-Fi, BLE, RFID and, in the future, 5G. Since omlox does not exert any standardising influence on these technologies, but simply makes them accessible, the areas in which such technology is used are named complementary zones.

Above the zones, the location data is brought together by a location middleware, the omlox hub. This hub makes the data available to various applications, such as the enterprise resource planning (ERP), warehouse management system (WMS), production planning or transportation management system (TMS), via uniform interfaces and in a standardised format.

omlox architecture at a glance
Industrial applications Enterprise resource planning Warehouse management Production planning Transport management etc
Location middleware omlox hub

omlox hub API

Location technologies omlox core zone

UWB

 Complementary zone

RFID

 Complementary zone

BLE

 Complementary zone

SLAM

 Complementary zone

5G/GPS

Location middleware: omlox hub

The omlox hub decouples industrial applications that process positioning data from the actual positioning technologies and their manufacturers. This middleware architecture principle simplifies the integration of positioning technologies into applications and enables any combination of technologies and manufacturers.

The omlox hub aggregates the positioning data, puts it into a uniform data format and provides some core spatial functions that are needed again and again. The positioning data is provided in 3D with x, y and z coordinates. Modern APIs enable easy integration of the omlox hub. An omlox hub is designed as a lightweight software that can also meet the requirements of real-time data processing of automation.

The specification of the omlox hub can be obtained from Profibus and Profinet International (PI).[1]

Trackable as a moving object

In an omlox hub, moving things (assets, tools, vehicles, people) can be described as trackables. A trackable is characterised by a unique identifier, a spatial extent, further attribute data and the dynamic combination of different positioning technologies. Depending on the application, spatial constellation or available positioning technology, positioning data can be dynamically assigned to a trackable via APIs. Software applications can thus simply query the last known location of a trackable via an API. The actual tracking technology thus recedes into the background and becomes interchangeable.

Geo-referencing

An omlox hub transfers location data from the different, usually locally installed zones, to a global coordinate reference system. This means that industrial applications always receive uniform data and seamless outdoor/indoor tracking is made possible. Depending on the application, different levels of location accuracy are required and since an omlox hub application can be used in different locations around the world, an omlox hub supports different coordinate reference systems. In doing so, omlox uses the EPSG nomenclature to describe coordinate reference systems.

An omlox hub also supports the reverse, in that position data can be translated from a global coordinate back to a locally installed positioning system, with its local coordinate system.

Functional areas

In addition to the concept of trackables and geo-referencing, the omlox hub supports two core spatial functions.

Fencing

It is often of interest to know whether an object is inside or outside a fence. Fences can be defined via the omlox hub fence API and an omlox hub calculates whether a trackable enters or leaves a fence. An important difference to classic tracking systems is the fact that fencing also works independently of the tracking technology and that cross-technology fences can be defined. To ensure maximum interoperability between different omlox-hub implementations, the framework parameters for calculating a fence entry or exit are also defined within omlox, e.g. time intervals to compensate for fluctuations in the tracking data.

Collisions

For many use cases it is also of interest to be able to calculate the distance between moving objects and to receive a notification when the distance falls below a defined minimum distance. This behaviour is defined within omlox as a collision API. The frame parameters that define a collision are mapped within the specification.

Interfaces

The omlox standard currently supports the following access methods:

An MQTT interface is also planned for a future version of the omlox standard. The data within the omlox-hub API is described in a JSON notation.

The omlox hub API defines the following services:

  • The zone API describes the setup of a zone, including associated spatial operations like geo-coordinate transformation.
  • The trackable API deals with handling of trackable things within the omlox ecosystem.
  • The provider API describes the setup of a location provider and the advertisements of location updates to an omlox hub.
  • The fence API handles the creation, update and deletion of fences.

The open UWB system: omlox core zone

The omlox core zone is an open real-time locating system (RTLS), the specification of which is jointly developed and refined by all omlox partners.[2] It basically uses a time of flight (ToF) measurement of pulse-shaped signals transmitted wirelessly via radio channels with high bandwidth and low transmission power. This is often referred to as IR-UWB (impulse-radio ultra-wide-band).[3] The omlox core zone specification is available from the Profibus and Profinet International (PI) organisation[4] and is subject to continuous adaptation.[note 1]

Ultra-wideband (also: UWB) is a short-range radio technology that uses extremely large frequency ranges with a bandwidth of at least 500 MHz.[5] UWB works with a low transmitting power (0.5 mW / -41.3 dBm/MHz) in order not to disturb already occupied frequency ranges. Only special UWB receivers can detect the signal. The frequency range of ultra-wideband is between 3.1 and 10.6 GHz. It is based on the IEEE 802.15.4.z standard,[6] which deals with the communication of sensors and accuators in wireless networks.

The omlox core-zone differs from other real-time positioning systems by:

  1. Full manufacturer independence thanks to standardised radio interface.
  2. Unlimited number of self-locating objects (no bandwidth limitation)
  3. Deterministic behaviour thanks to time-triggered system behaviour
  4. Very robust thanks to true trilateration and use of the 4 GHz band group
  5. Perfectly matched to the data connection via the omlox hub

Satellites as building infrastructure

The realisation of the omlox core-zone requires a building infrastructure. Specifically, permanently installed transmitters are necessary, which are called satellites in reference to GPS. In omlox V2, these are three different types of satellites:

  • Full Blown Satellite (FBS) is equipped with a fixed power supply and can exchange information with local servers via an additional data network.
  • Mains Powered Satellite (MPS) is equipped with a fixed power supply and has no access to an additional data network.
  • Battery Powered Satellite (BPS) is powered by a local battery and has no access to an additional data network.

At least three satellites are required for positioning. Additional satellites may be required depending on the area and accuracy required. Only one FBS can collect the information and forward it to a local server. Depending on the measurement method used, different satellites must be used. In omlox V1 only FBS are used.

Measurement methods for location determination

With the different satellites and tags, different measurement methods for location determination can be realised:

  • Downlink Time Difference of Arrival (DL TDOA): A tag can measure the signals of the surrounding synchronised satellites and thus determine its own position via TDOA and the known positions of the satellites. This method is comparable to GPS technology.
  • Uplink Time Difference of Arrival (UL TDOA): A tag regularly transmits signals and thus allows the synchronised satellites to determine the ToA (Time of Arrival). With these collected arrival times, a location server can estimate the position of the tag from the differences between the ToA and the known positions of the satellites.
  • Reconstructed Time of Flight (RToF): Not only the satellites, but also the tag is precisely synchronised with two-way communication. Thus, in addition to the arrival time, the transmission time can also be measured and thus the transmission time (ToF = Time of Flight) can be calculated. With this calculated ToF, a location server can now determine the position of the tag.
  • Timestamped Time of Flight (TsToF): Here, too, all satellites and tags are synchronised. The tag exchanges signals with all satellites, which also contain the transmission time of the signals. This enables the most accurate determination of the position to within 10 to 30 cm.
Summary of the measurement methods for determining the location
MethodsObjectiveSatellitesTags
DL TDOA (similar to GPS)Locate themselveFBS, MPS, BPSRxT, TRxT
UL TDOATrackingFBSTxT, TRxT
RToFTrackingFBS, MPSTRxT
TsToFTrackingFBS, MPSTRxT

Complementary Zones
Further information: Indoor positioning system § Wireless technologies

Within an omlox architecture, all other locating technologies can be connected to an omlox hub as complementary locating zones.

Further positioning technologies can be e.g.

  • Satellite-based positioning technologies such as GPS, Galileo, GLONASS, etc.
  • Bluetooth-based positioning technologies
  • RFID-based identification and tracking
  • Optical positioning via camera-based systems
  • Ultrasound-based positioning
  • Magnetic field-based positioning

The open architecture concept of omlox - based on the different zones (core zone and complementary zones) and their integration into an omlox hub - allows for a holistic, transparent positioning across technology boundaries. omlox is therefore retro-fit capable, as existing positioning technologies can be used in the future.

  1. Retro-fit-capable, as existing positioning technologies can still be used.
  2. Future-proof: because further tracking technologies can be connected to an omlox hub without fundamentally changing the overall system.

Use cases
Further information: Indoor positioning system § Types of usage

The omlox positioning standard addresses a very broad spectrum of use cases, which are particularly relevant in industry and logistics.[7] In summary, the following categories of use cases can be distinguished:

  • Tracking of things, e.g. means of production, goods, tools, orders, vehicles or persons.[8]
  • Automatic logging and documentation of process progress in IT systems, e.g. for paperless production.
  • Location-based information and control, e.g. for machine control or machine maintenance.
  • Autonomous transport, e.g. in the orchestration of internal factory traffic by autonomous transport robots.
  • Safety-related applications, e.g. for lone worker monitoring in the process industry.

History

The start of open tracking was initiated by TRUMPF Werkzeugmaschinen GmbH + Co KG at the beginning of 2018. The background to this was that all the tracking systems available at the time were proprietary and could not be widely used because of the lock-in. The TRUMPF company then looked for other supporters of open tracking and was quickly able to win over more than 20 companies in the German-French region. Under the working title "initiative LoTUS", this loose association then worked out the loads and performance data of such an open system and then realised it in an agile development. After successful testing, the first standard was then derived and the result transferred to PI in June 2020.[9]

Notes
  1. The current version 1.x of the omlox standard was developed before the standardisation of UWB chips within IEEE802.15.4z and requires a defined chipset. Version 2.x of the omlox standard is only available as a draft in 2021 and contains the new UWB standard IEEE802.15.4z as a basis.

References
  1. "omlox HUB Specification API and Behavior". profibus.com. Profibus and Profinet International. 2021-06-17. Retrieved 2021-12-06.
  2. "omlox partners and members". omlox.xom. Retrieved 2021-12-07.
  3. "Ultra-Wideband (UWB): Here's everything you need to know". bleesk.com. Retrieved 2021-12-08.
  4. "omlox Core Zone Specification". profibus.com. Profibus and Profinet International. 2021-10-05. Retrieved 2021-12-07.
  5. "Exploring Ultra-Wideband Technology for Micro-Location-Based Services". microwavejournal.com. Microwave Journal. 2021-06-14. Retrieved 2021-12-07.
  6. "IEEE 802.15.4z-2020 - IEEE Standard for Low-Rate Wireless Networks--Amendment 1: Enhanced Ultra Wideband (UWB) Physical Layers (PHYs) and Associated Ranging Techniques". ieee.org. IEEE Standard. Retrieved 2021-12-07.
  7. "Omlox benefits for manufacturers". controleng.com. Control Engineering. 2021-05-08. Retrieved 2021-12-06.
  8. Wahl, Eberhard (2021-03-10). "Healthcare Digitalization Needs Standards to Get Low Total Cost of Ownership". mddionline.com. Medical Devices and Diagnostics Industry. Retrieved 2021-12-06.
  9. "Omlox off to flying start at PI". profibus.com. Profibus and Profinet International. Retrieved 2021-12-08.
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