'Moving base' functionality for position+heading

Q&A forumCategory: Questions'Moving base' functionality for position+heading
amorosik asked 4 months ago

Starting with Ublox firmware version 1.10, the Zed-F9p has “moving base” functionality
How exactly is this feature used?
Have any of you already tried this setup?
What is the correct hardware connection and which software configuration to adopt on the first and second card?
How are differential corrections provided?
How do you read the direction in addition to the position?


Ardusimple Staff replied 4 months ago

Hi amorosik,

Yes we have tested the feature and it’s quite impressive. For your info we are testing now a new ardusimple product that will make it plug-and-play to use it. In a few weeks we will know if it’s material for sale or not ūüôā
There’s a good explanation on how to enable this feature in the integration manual: https://www.u-blox.com/sites/default/files/ZED-F9P_IntegrationManual_%28UBX-18010802%29.pdf . Look for Base and rover configuration for moving base RTK operation.

One zed-f9p with be a “moving base”, sending corrections to the second zed-f9p that allows you to have accurate heading or accurate relative position between 2 moving objects (e.g. uav landing on a moving platform like a boat, or “follow-me” modes for autonomous vehicles).

For the heading use case, in addition, this “moving base” can receive corrections from a static base to have it’s position with rtk precision.

1 Answers
jsampson answered 4 months ago

I followed the instructions here: https://github.com/u-blox/ublox-C099_F9P-uCS
I used two ArduSimple boards. I connected the UART1 connections between boards (Swapping TX and RX). I connected ioref of both boards to 3.3V. And connected the grounds. I ran two copies of u-center, one for each F9p-USB port. You just follow the instructions and load the configuration files they supply. The test results are here: https://youtu.be/QNQJIevoI0Y
Now I have to figure out how to do it without u-center. (I.e., how to get CORS correction data into the base unit. How to get the POSRELNED UBX message out of the rover and decode it. And the base unit (and maybe that is mirrored on the rover) should be outputting a valid 1-2cm fix.
Here is another approach. He uses two receivers in rover RTK mode. Then computes the angle between the two RTK fixes. https://www.youtube.com/watch?v=W1JhgKakhBE

clive1 replied 4 months ago

Had a dual stack configuration, with an 2.42″ OLED on top, running from an STM32 LoRa DISCO board.
UART2 pins bent out, and cross routed on the two Rover boards.
UART1 of primary has default connection via Arduino header, UART1 of secondary bent out and routed to secondary Arduino position.
RTCM3 pushed from Base via LoRa into UART1 of primary rover. RTCM3 from primary rover output via UART2 into UART2 of secondary rover.
Output of position and angle to OLED display, and tertiary UART of LoRa board.

Here with the smaller screen

clive1 replied 3 months ago

The build with the large screen, https://portal.u-blox.com/s/contentdocument/0692p000007DlYxAAK
This is entirely self-contained, just needs power and two antenna, solves at 5 Hz, outputs NMEA style attitude/orientation data, and RTK position of primary antenna.