What is Atlas?
Launched in January 2017, Atlas Native is the first Sigfox location service, solely based on the Sigfox Network location. The service is available for every device equipped with the simplest Sigfox module, without GPS or any other additional hardware/software component.
Following the launch of this service, Sigfox has been working on the development of Atlas Suite to enable all type of use cases involving asset location – by choosing the right technology(ies) for the right balance between cost, energy and accuracy.Let’s have a look to the 2 live Atlas services:
- Atlas Native, providing Sigfox Network based location only
- Atlas WiFi, providing WiFi Positioning & Sigfox Network location (fallback)
Atlas Native
Atlas Native is solely based on the Sigfox Network location service, aiming to provide the geographic coordinates (latitude/longitude) and an estimated radius of a device message delivered through a callback or a standard Sigfox API.
How does it work?
- The Sigfox Cloud platform receives the different frame replicas.
- Replicas are transferred to the Geomodule.
- The Network location is computed by the Geomodule.
- The Data advanced service callback is generated by the Sigfox Cloud platform with the location information (latitude, longitude & radius).
- The Data advanced service callback is received by customer infrastructure.
As explained above, the Data Advanced Callback provides the location information of the corresponding device to the customer system when receiving a new message from the device.
The Sigfox infrastructure receives in a limited time frame, the different replicas of an original message sent by a device. The Geomodule waits 25 seconds to capture the different replicas and analyzes them to define the device’s location. Once defined, the location information is sent back to the Sigfox infrastructure. If the Sigfox infrastructure does not receive an answer from the Geomodule after 15 seconds, it can execute a retry after one minute. Once received, the Sigfox infrastructure generates the Data advanced service callback.
You can have all details regarding the format of the Data Advanced Callback and how to retrieve location information through API here.
Atlas WiFi
Atlas WiFi is the combination of two location technologies – Sigfox Network and WiFi Positioning - into one single location service.
Same as Atlas Native, the service provides the geographic coordinates (longitude, latitude and radius) and an estimated radius of a device message delivered through a callback or a standard Sigfox API.
By default, the coordinates are provided by the WiFi location service, while Network location is used as a fallback solution (due to its low accuracy) and as a mean to check WiFi location relevance – what we call “consistency check” (due to possible WiFi infrastructure update).
What about the WiFi positioning?
Google and HERE Technologies have the largest databases with several billions of WiFi access points recorded and frequently updated worldwide. In March 2018, Sigfox chose HERE as its main provider for the WiFi location service.
Since November 2018, HERE provides a WiFi location with only 1 MAC@ sent by the device, while most WiFi providers (including Google) impose to collect and send to their platform at least 2 MAC@ for data privacy purpose. However, this regulation imposes HERE to lower the level of accuracy of the WiFi location when only 1MAC@ has been sent by the device (+500meters on the radius value).
How does it work?
The high-level workflow is the following:
- Step 1: The device detects, selects and sends one message with 2 MAC Addresses (ID of WiFi access points).
- Step 2: The Sigfox Cloud recognizes the message and sends it to the external WiFi platform, which translates the MAC Addresses into geographic coordinates (longitude, latitude, radius).
- Step 3: In the meantime, the Network location is computed by the Geomodule, based on the RSSI contained in the metadata.
- Step 4: The Geomodule compares and chooses the best coordinates. It provides a consistency check between the location provided by the WiFi platform and the location computed through the Sigfox 0G network. It allows detecting potential issues that could appear on the WiFi side due to the fact that it is a public infrastructure that could change with WiFi access points moving from one location to another.
- Step 5: The customer receives the service through the Data Advanced Callback directly in its IT system.
Success rate increase with Access Points Machine Learning
In case the third party WiFi database provider is unable to locate the WiFi MAC Addresses the geomodule provided, a built-in Machine Learning-based recovery mechanism is activated.
The unknown Mac Addresses are constantly getting processed in the background by an algorithm that attempts to position them based on how often they are scanned along with known Mac Addresses that are properly located themselves.
This Machine Learning model builds a complementary worldwide database of Mac Addresses that allow us to recover failed attempts at locating assets with third party providers. This results in up to double digits WiFi geolocation improvements in some areas and countries, ensuring a homogeneous quality of service across entire integrated markets.
Location source selection with the Geomodule
The geomodule in the Sigfox Cloud has three functions:
- Compute Network location
- Request to the WiFi Platform to compute WiFi location
- Do a consistency check between the two geographic coordinates from Network and Wifi locations to select the best one:
- If the distance between the two is less than 3 times the local radius of Network, the consistency check is approved and the computed Wifi location is chosen.
- Otherwise, the consistency check is failed and the Network location is chosen.
You can have all details regarding the format of the Data Advanced Callback and how to retrieve location information through API here.