Servers by jDrones

UBlox ZED-F9P L1/L2 GNSS Unit

(Josep Olivart) #61

Hi Mirko,
Production is on going and we expect to have full stock available by the end of the month, pre-order is available.

(Mirko Zhou) #62

Thank you so much, Does this component have the integrated compass ?

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(Josep Olivart) #63

No, it has not an integrated compass (magnetometer).

If two simpleRTK2Blite are combined (or one simpleRTK2B+simpleRTK2Blite), you can get extremely accurate heading based on a moving base configuration.
As far as I know, the parser for the specific message containing this information is not yet implemented in Ardupilot software.

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(curt carroll) #64

I cut this from another thread…

Ok now that I am looking at the right GPS…Yes it has a compass. you can see the orientation
Also it’s listed in the description


I also watched a video that said the Here Pro will have full FC capabilities.

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(Mirko Zhou) #65

Thank you for your help.
But I’m not quite understand the moving base configuration ? Does it mean the combined GPS board (Ardusimple + Ardusimplelite) all installed on the vehicle ? Or one of them still need to be set on a specific location on the ground as static base ?

(Josep Olivart) #66

With the moving base configuration, both simpleRTK2B+simpleRTK2Blite are installed in the vehicle.
With this units, you will get high accuracy heading without the need of a static base station or NTRIP corrections (the longer the distance between the antennas the higher the accuracy).

If you also want to have cm level position, you can either:

  • Use an additional static base (in the ground)
  • Use NTRIP corrections

Let me know if you have any doubts

(Mirko Zhou) #69

Thank you Josep, can I use the moving base configuration with Pixhawk ? Also since the two antennas will be installed on the vehicle, so the distance between them cannot be very far. How accurate it will be if two antennas are very close with each other (around 300mm ) ?

(Mirko Zhou) #70

Hi Josep,

For the Ardusimplelite, does it also support standalone & SSR correction ?

(Josep Olivart) #71

Hello Mirko,

Right now and as far as I know, Pixhawk doesn’t support the moving baseline functionality, although is relatively easy to implement for the developers.
The heading accuracy can be defined as:
heading_accuracy = atan(2/distance), where distance is the distance between antennas in cm.

30cm: 3.8deg
1m: 1.14deg
10m: 0.11deg

This is an approximation, but the final numbers should be the same order of magnitude.

simpleRTK2Blite will support standalone operation + RTCM corrections.
SSR corrections will be supported in a future firmware release by u-blox (no dates available yet).

(Josep Olivart) #72

Hello everyone,

I need your help to list the cables and connectors used by the most common autopilots.
Pixhawk 4 uses JST-GH male-male 6 pin not-crossed cable.

What about other autopilots?


(Mirko Zhou) #73


This is what I can find. Anyone else can help with this ?

(Mirko Zhou) #74

Another question I have is that how Ardusimplelite connects with Internet to receive NTRIP corrects when it is moving on the vehicle ? I understand it can connect with Internet using USB cable and a laptop, but when it’s moving on the vehicle, I don’t think it is suitable to still use the USB cable

(James Pattison) #75

The ntrip corrections are passed up to the vehicle over mavlink from the gcs - so you need a telemetry datalink.
It would be possible to do it directly on the vehicle if the vehicle has a companion computer and 3/4/5G internet link, but that’s more complex than most people need or want

(Josep Olivart) #76

@Mirko_Zhou thanks for the cable information!

Apart from the options mentioned by @james_pattison, you can also use a dedicated radio link only for receiving corrections.

(Liang Tang) #77

F9p RTK fixed is unstable, especially when braking suddenly, satellite is lost and positioning status is lost. But height and location data seem to be continuous.

Comparing a uBlox F9P with a M8P with RTK
(Liang Tang) #78

Comparing a uBlox Zed-F9P GPS with a M8P without external corrections
(curt carroll) #79

I have some setting suggestions for you. In ucenter under nav5 - change your elevation mask to 15 -13 degrees, set the SNR value to 35-40db. You do not need more than 13-18 sv’s for a good RTK fix. If you are in harsh GPS environments use the slightly lower settings. In the open stay with 15 deg & 40db SNR.
If your signals are low in the sky, they are too weak to use reliably.
When you pitch your vehicle the ground plane will also effectively cut off part of the sky causing a loss of lock.
You may also have a radio issue. I never see my status drop to 4.

(Liang Tang) #81

thanks very much, i’ll have a try tomorrow.

(Liang Tang) #82

test log file. could you have a look on it?

(curt carroll) #83

I have made changes to the default settings here.
You can to save these parameters to GPS rover. Same for the base but you can let the elevation mask down a bit say 10deg. This insures the rover and base get the same sv signals.