PointPerfect L-band Configuration
In this guide, we will review the hardware requirements and device configuration to receive and use PointPerfect service via L-band. The instructions on how to configure NEO-D9S and ZED-F9P for this purpose are explained in the respective configuration sections of the modules. The diagram below shows the L-band solution architecture.
If you are interested to evaluate PointPerfect L-band solution, you need to have a u-blox L-band receiver NEO-D9S to receive PointPerfect L-band corrections, in addition to the high precision receiver supporting SPARTN format. The NEO-D9S receives the PointPerfect encrypted L-band stream and passes it to ZED-F9P.
The NEO-D9S and ZED-F9P receivers follow the u-blox configuration concept. The UBX-CFG-VALSET, UBX-CFG-VALGET, and UBX-CFG-VALDEL messages can be used to configure the SPARTN L-band correction data reception.
NEO-D9S and ZED-F9P can be connected via UART2. Using the UART2 connection is common practice and recommended for customer designs, while UART1 or USB are the most convenient interfaces for monitoring and configuring both modules, using u-center, for instance.
It is important to check the UART2 communication to ZED-F9P, e.g., using the UBX-MON-TXBUF message as shown in image below.
Configuration item Value
CFG-SPARTN-USE_SOURCE 1 - LBAND
Configuration item Value
L-Band Dynamic Keys and Decryption
The decryption of the SPARTN messages happens inside ZED-F9P module. ZED-F9P needs to have the proper L-band dynamic keys to decrypt the encrypted SPARTN data stream. The device can subscribe to the /pp/ubx/0236/Lb topic via MQTT to get the L-band dynamic keys in UBX format and transfer to the receiver at it is. Please contact firstname.lastname@example.org if you need help with getting the L-band keys to ZED-F9P receiver.
Note: The keys are not stored in non-volatile memory and will be deleted on every module reset or restart. In such cases, the keys need to be passed to ZED-F9P again.
The user has established communication with the ZED F9P module (e.g. via u-center 22.07 through UART1 or USB)
The L-band and keys configuration has been done for ZED -F9P as described above. UBX-RXM-SPARTNKEY message can be enabled to verify the module has L-band dynamic keys. The description of UBX-RXM-SPARTNKEY message can be seen in the applicable interface description.
ZED-F9P UART2 has been connected to the NEO-D9S UART2.
UBX MON COMMS messages can be enabled now to verify that UBX messages, including UBX-RXM-PMP, are received on the ZED-F9P UART2:
Check the correction streams at ZED-F9P connected to u-center by viewing the UBX-RXM-COR message as shown in below image.