GNSS Correction Data Receiver (NEO-D9S) Hookup Guide
bboyho, 
PaulZC 
u-Blox Thingstream Services
There are three key steps to be able to achieve centimeter positioning accuracy using the ZED-F9P and NEO-D9S.
- Register with u-blox Thingstream and sign up for a PointPerfect L-band plan (data stream)
- Configure the NEO-D9S to receive the u-blox PointPerfect correction data stream
- Configure the ZED-F9P with encryption key(s) so it can decrypt and use the correction data
By default, the ZED-F9P is configured such that the correction data is passed from the NEO to the ZED using the UART2 interface. However, it is also possible to read the correction data from the NEO and push (write) it to the ZED using I2C. We just need to configure the modules so that the I2C port is enabled and set the protocol.
Thingstream and PointPerfect Services
The NEO-D9S was designed to receive correction data from an L-band satellite and push it to a high precision GNSS module like the ZED-F9P. You will need to use u-blox Thingstream and PointPerfect service to provide dynamic keys in order to decrypt the correction data.
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Thingstream is u-blox service delivery platform for IoT Communication-as-a-Service, IoT Security-as-a-Service and IoT Location-as-a-Service.
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PointPerfect is u-blox GNSS augmentation service which is designed to provide high-precision GNSS corrections to suitable receivers with decimeter-level location accuracy. The following webinar from u-blox has an excellent explanation of the service and how the system works.
PointPerfect data is delivered through Thingstream. The first step is to register with Thingstream and then request an L-Band plan:
You can find the current pricing on u-blox portal. Select IoT Location-as-a-Service and then PointPerfect.
You may need to contact u-blox first, to enable the option to purchase an L-Band plan through your Thingstream account.
The PointPerfect L-band plan provides unlimited access to the L-band satellite correction data stream (via the NEO-D9S).
If you have an internet connection, you can also receive PointPerfect corrections via IP (MQTT). The PointPerfect L-band and IP plan may be a better choice if you think you may want to receive correction data via both satellite and Internet.
Once L-band permissions are enabled on your Thingstream account, you will be able to add a new L-band Location Thing and view its credentials:
- Login to Thingstream
- Select Location Services and then Location Things
- The Add Location Thing button (top right) will allow you to select and activate an L-Band plan
- Once your L-band plan is active, you will be able to monitor your Activity and view your Credentials via the appropriate tabs
u-blox have written a comprehensive application note which describes in detail: the configuration of both NEO and ZED; and how to interpret the expiry date for the L-band encryption keys. In the following sections, we describe how to configure the NEO and ZED using our u-blox GNSS Arduino Library.