I found out that my phidgets motor then also must have a short circuit somewhere cause when I disconnect it the motor runs free when not engaged but when I hook it up it doesn’t run as smooth. I also have a noise on the radio when it’s plugged in but I can’t find where the short circuit should be. Everything else works fine…
Possibility that PWM frequency from arduoino low from that motor , test motor with 6V or 12V .
I have the gps in my tractor operating at 10hz, does the RTK base station need to run that fast aswell?
No, the main correction messages are typically sent once per second. Some can be sent less frequently, depends on the message type.
Not aware what motor driver you are using, but Cytron specifies this feature:
- Regenerative Braking
- Brakes the motor when PWM pin is low (logic low)
Would this mean motor will brake when PWM is zero?
When i send my data from base station to rtk2go for ntrip the support team told me that 0,2Hzis enough for rtk. It is one sending every five seconds.
Depends on the receiver how old correction data it accepts. My Topcon AGI-4 quits after 60 seconds and loses accuracy before that. In this sense 0.2 Hz sounds good but if you work in areas where the correction data link is temporarily lost at times, you would prefer another few seconds of recovery time. Going from 0.2 Hz to 1 Hz gives an additional 4 seconds.
The one providing free service (like rtk2go), a lower rate is preferable. If you pay a lot per byte for the rover internet connectivity, a lower rate might be of interest. I pay less than 10 Euros per year per rover for NTRIP data delivery and I pay 10 Euros even if I did not send RTK corrections at 1 Hz. Obviously lower rate would not give me any advantage.
The best rate is not the same for everyone.
I tested it with 12 v. The noise disappeared from the radio and the motor still has power enough for turning my steering wheel so I will continue with that setup. But there’s still more resistance in the motor when not engaged than when it’s completely shut off. Might be the cytron as SjaakA mentioned.
FYI motor acts as a generator when connected. Thats why it turns hard. If you turn just motor by hand slowly it works, but as soon as you turn it abit faster the lights on your cytron come on and motor turns harder. Motor works good at 12v for straight driving but not fast enough for uturn.
It will only be hard to turn if the cytron is putting a load on the motor so I assume it does. Useful in some situations, not in ours. AFAICS the IBT2 doesn’t do this.
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Potentially dumb question alert
Does anyone have any ballpark figures for how quickly an ardusimple board working on a base / rover setup updates the GPS?
I’m looking at running a vehicle that travels at 1MPS or around 2.2MPH and want to track and record its position as accurately as possible. If (say) its position is being updated every 5 seconds, then am I right in thinking that the coordinates will be out by up to 5m?
Mine is 8Hz.
Have you ever [had any cause to] measure this? Are you really getting 8 updates per second?
Edit: 8 accurate updates / fixes per second?
VTG and GGA data can be seen running into AOG at speed and it’s set up for 125ms intervals in U-Centre. Why would that not be the case?
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My u-blox F9P calculates an accurate position at 10 Hz. As a rover it could do it even faster but only when a subset of GNSS constellations are used. My base supports GPS and GLONASS which is why the FP9 also runs GPS and GLONASS only and could do faster than 10 Hz.
My Topcon AGI-4 runs at 10 Hz too.
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Because I’ve worked in networks for 20 odd years and one thing I do know is that claimed throughout is not equal to real life throughput, usually not even close!
But this is all new to me so perhaps we have an exception. The ardusimple does appear to buck this trend.
Fantastic, thanks guys.
Your position would be bouncing all over the place if it was unstable. Especially standing still. If there were misses the screen would stutter as fixes were dropped from bad data. Ublox i believe can do 20 hz as well.
10 isn’t a stretch at all.
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That was my initial problem with standard GPS; drift. Trying to follow an AB Line is lots of fun when your vehicle thinks it’s at x, then thinks it’s 5m to the east, then 2m to the north, etc.
What were you using before your F9P that was so inaccurate?
I first tested AOG with a £12 patch receiver that actually wasn’t bad at all.
If you’re an expert in networking could you answer this one for me please?