Hello from u-blox

Hi Everyone,

My name is Nabeel Khan and I work at u-blox. Reading through some posts here, it looks like many of you have implemented systems integrating the ZED-F9, and we are very impressed in the effort that has gone into this project and the success you have achieved.

I’d like to learn more about your experience with OpenAgGPS and using u-blox GNSS receivers. Any feedback on how we can improve our next generation products and firmware is welcome.

I’d also love to talk to anyone that has implemented an OpenAgGPS system using a u-blox receiver, as I’m working on a short story on Precision Agriculture. I want to learn more about your experience of implementing auto-steering. If you’re available for a 30 minute phone call, I’ll provide a $20 amazon gift card for your time.

If you happen to be in Florida and are willing to let me swing by and check out your setup, that would be even better! I’m based in Orlando but don’t mind driving.

If you’re interested, please shoot me an email at nabeel.khan@u-blox.com or send me a message on here.



Hi Nabeel.
It is nice of you to take interest in AOG. I think there are several who would be interested in anything U-Blox could offer.
I dont want to sound direct, but AOG has had its share of people who weren’t what they represented themselves to be. Could you give some helpful information about yourself to help the community to verify that you are with U-Blox ?
If so, I believe there are several who would be glad to share with you.
Thank you



Anyone interested can contact me via LinkedIn: https://www.linkedin.com/in/nfkhan/
or via my u-blox email: nabeel.khan@u-blox.com

I’m open to a mod or admin sending me an email to verify this account.


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Glad you are here, your company makes a great product. F9P is a great performer, light years ahead of the previous M8’s.

I am excited to see in future how far your company can push this technology.


Two things ublox could do:

Make a receiver like the F9R with the IMU that calculates a virtual reference point on the vehicle (terrain compensation) but can do it with rtk fix. The F9R is quite close to what we need if it could do that.

Second, produce an integrated product that has two antennas and is preconfigured to send heading and declination information. Two F9Ps can already be configured to do this but one package that’s preconfigured would be nice. Some farmers find the double antenna system works quite well. Heck maybe an integrated IMU would be of value in this configuration also to get very accurate, fast, readings that are fully adjusted for the tilt of the tractor.


With an intergrated udp port


having the Imu integrated maybe it is possible to compute the NMEA HDT string


Welcome to the forum Nabeel. Here you will find I am sure smart and creative people pushing your product to the extreme of its capabilities and even maybe beyond. ArduSimple has been an excellent partner allowing the popular form factor of the arduino and its connector system to be able to quickly build prototype and PCB style GPS units and now even a full steering system with both single and dual options on the same board.

We do have some key challenges and we look forward to working with you to overcome some of them. Market potential in this area of industry is quite large - and also is an exciting time for precision ag not only in steering but robotics, automation, and computer vision.


Great product! I haven’t tried the f9P on WAAS/SBAS. We currently have commercial units running on WAAS. And get along fine for most operations in the IL area.

I was a bit disappointed with the F9P on WAAS.

Is the F9R as good on WAAS as the commercial Ag units?


Thanks Brian. I agree that there is a lot of potential for open source projects like AOG to enable autonomous functions for the mass market. I believe this will especially have a large impact on emerging markets with limited resources.

I’m still getting up to speed on the technical details of AOG but am looking forward to understanding your challenges and how we can help.

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I need to do some research on this and will follow up with my thoughts.

@PotatoFarmer Thank you
More than 2 user mentions are limited on my account - sorry.

Regarding several comments on the ZED-F9R, we have recently made optimizations in the firmware to adapt to slower moving heavy machines and robotics systems. So it is now possible to use the integrated sensor fusion system, which can significantly improve performance in high multipath environments such as being close to trees or buildings. The IMU data is accessible by the external host, so it may be possible to use this directly with the AOG System.

It’s not clear to me what you mean by calculating virtual reference point for terrain compensation. I’ll look into this in the docs but more detail would help me understand.
The ZED-F9R reference points for the antenna and IMU are both configurable.

We’re keeping an eye on market potential for a dual antenna module. This could especially be a good fit for PCB size constrained like drones. Generally ground based vehicles have been ok with using two modules, but this is good feedback.

giotoma I will look into this

Kevin I would make sure you are running the latest firmware on your ZED-F9 as SBAS was added in an update about a year ago. Also ensure you disable SBAS in other continents as you can sometimes pick up satellites in other regions, degrading your performance.
ZED-F9R gives you the advantage of integrated dead reckoning, but ultimately either ZED-F9P/R standalone will both give you meter-level accuracy with SBAS. RTK is required for applications requiring cm level accuracy. Generally, our commercial applications leveraging ZED-F9 are using RTK corrections using either a local base or our PointPerfect SSR-RTK service that is delivered via either L- band satellite (using a NEO-D9S module) or IP (via a hotspot, cellular module, ISM forwarding from a gateway, etc). This is a continental stream that eliminates the need for a local base: https://www.u-blox.com/en/product/pointperfect.This can get you sub 5cm CEP95 in all of the US and EU with a good antenna. Disclaimer: It is a paid service, but I think it’s very competitively priced. Pricing details are on the web here: Thingstream

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You are very good at outdoor positioning, but we expect indoor positioning devices from you :slight_smile: best regards.

I don’t know the proper terminology. In the farming world we call it Terrain Compensation. Basically the antenna is on the roof, or otherwise above the ground on the vehicle and is subject to pitching and rolling as the tractor moves over uneven ground. In order to steer the vehicle we need to know what the GPS position is on the ground under the axle. In other words translated from the roof position to the ground position, with a lateral offset added that is proportional to the tilt of the tractor. This is what I referred to as a “virtual reference point.” That was a terminology that came from the F9R documentation. In AOG we don’t have a huge need for dead reckoning. Rather we require RTK fixes at all times. That’s why the F9R is not sufficient presently. RTK Float just isn’t good enough.

If the receiver could do the terrain compensation internally and output the GPS coordinates as if they were on the ground (translated by user-defined variables such as distance from axle and height above ground which vary from machine to machine), then AOG wouldn’t have to do any of that kind of calculation itself, or try to synchronize the IMU readings with the GPS fixes, as the receiver would do that internally all by itself.

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Thanks for the explanation. This makes sense. I am meeting with the product team next week and will discuss this topic. Will follow up with any updates.


We have indoor positioning products now too! Using Bluetooth 5.1 Angle of Arrival, you can achieve ~1m accuracy with “anchors” placed in a grid about 10 meters apart.

For more precision, anchors can be placed closer, but there are diminishing returns. Applications could include indoor drone landing, vehicle parking, and general asset tracking.


I checked out your 5cm correction pricing, but its not very clear how it is priced. This could be a great service for many who do not want to maintain a base.

But what is the cost in real terms like $/month or $/hour. Commercial corrections are usually priced in day/ month/ hour/ increments.

“0.00001cents per event” Im not sure how to price check that.

RTK is awesome, but this would greatly simplify things for broad acre applications and really hilly land.

Our pricing is available on the web here in the Location-as-Service - PointPerfect tab: Thingstream

We have plans where you purchase a fixed number of hours of streaming, or unlimited plans.

Ex) For corrections streaming via IP, the unlimited plan is $19 per device per month.
Hourly plans start at $3.90 for 60 hours of operation.

We also have pooled plans but these are targeted to large fleets of vehicles in the tens of thousands of hours of operation per month

Another possibility, given how well AOG already does terrain compensation with good IMU data, would be just a receiver with an onboard IMU (which automatically calibrates based on GPS heading, and fuses gyro and accelerometer readings) that outputs NMEA where the IMU pitch, roll, and yaw rate numbers are synced to the time of the GPS fix. This is what the Panda arduino sketch is trying to do.