CF having trouble reciveing over 4 lightouses.

Topics related to the Lighthouse positioning system, configuration and use
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cafeciaojoe
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Posts: 83
Joined: Mon Jun 18, 2018 2:37 am

CF having trouble reciveing over 4 lightouses.

Post by cafeciaojoe »

Hi all,

The cf can recieve and fly from 4 basestations. But over 4 is causing it to recieve nothing at all.
It can recieve 5 sketchily, but cannot fly.
6 and above it completley checks out. the board goes yellow.
the tab says none of them are being recieved.
the KALMAN task is at 15% when 4 are on , but drops down to 8% when 5 or more are on.
Perhaps the sensors are being bombarded by light?

Is this a hard limit on what the cf can do? or is there a way around this.


******EXTRA INFO******
We are using such a ridiculous number of lighthouses because we have motrless drones on the back of the hand that are being used as markers that the drone follows. So we want good coverage. Most of the time the flying drone or the hand drone will not see all BS, but still, it needs to for the calibration postion. (see this thread that explains why the CF must see all BS at calibration)


(firmware build 340:6a0f79c84766 (2020.09 +340)
Relevant change here is

Code: Select all

#define PULSE_PROCESSOR_N_BASE_STATIONS 8
TASK DUMP (with 4 BS being received)
SYSLOAD: Load Stack left Name
SYSLOAD: 0.85 230 Tmr Svc
SYSLOAD: 60.64 127 IDLE
SYSLOAD: 0.38 213 CRTP-RX
SYSLOAD: 0.0 74 PWRMGNT
SYSLOAD: 0.0 256 CMDHL
SYSLOAD: 0.0 115 PLATFORM-
SYSLOAD: 0.0 255 LOG
SYSLOAD: 0.0 223 MEM
SYSLOAD: 0.05 91 PARAM
SYSLOAD: 0.58 93 LEDSEQCMD
SYSLOAD: 0.20 107 CRTP-SRV
SYSLOAD: 0.44 100 SYSTEM
SYSLOAD: 0.08 61 CRTP-TX
SYSLOAD: 0.82 176 SYSLINK
SYSLOAD: 5.46 368 STABILIZE
SYSLOAD: 6.06 159 SENSORS
SYSLOAD: 15.89 283 KALMAN
SYSLOAD: 8.48 67 LH
SYSLOAD: 0.0 114 USBLINK

SYSLOAD: Task dump (with 5 BS turned on)
SYSLOAD: Load Stack left Name
SYSLOAD: 2.16 230 Tmr Svc
SYSLOAD: 62.02 127 IDLE
SYSLOAD: 1.11 213 CRTP-RX
SYSLOAD: 0.0 74 PWRMGNT
SYSLOAD: 0.0 256 CMDHL
SYSLOAD: 0.0 115 PLATFORM-
SYSLOAD: 0.0 251 LOG
SYSLOAD: 0.0 217 MEM
SYSLOAD: 0.04 91 PARAM
SYSLOAD: 0.40 100 SYSTEM
SYSLOAD: 0.08 61 CRTP-TX
SYSLOAD: 1.74 176 SYSLINK
SYSLOAD: 1.65 93 LEDSEQCMD
SYSLOAD: 0.67 107 CRTP-SRV
SYSLOAD: 5.15 368 STABILIZE
SYSLOAD: 7.74 151 SENSORS
SYSLOAD: 7.39 283 KALMAN
SYSLOAD: 9.78 67 LH
SYSLOAD: 0.0 114 USBLINK

SYSLOAD: Task dump (with 6 BS turned on)
SYSLOAD: Load Stack left Name
SYSLOAD: 2.81 181 Tmr Svc
SYSLOAD: 55.50 127 IDLE
SYSLOAD: 1.41 213 CRTP-RX
SYSLOAD: 7.20 151 SENSORS
SYSLOAD: 0.0 74 PWRMGNT
SYSLOAD: 0.0 115 PLATFORM-
SYSLOAD: 0.0 251 LOG
SYSLOAD: 0.0 217 MEM
SYSLOAD: 0.0 91 PARAM
SYSLOAD: 0.08 100 SYSTEM
SYSLOAD: 0.07 61 CRTP-TX
SYSLOAD: 2.13 176 SYSLINK
SYSLOAD: 2.08 93 LEDSEQCMD
SYSLOAD: 0.87 107 CRTP-SRV
SYSLOAD: 6.68 368 STABILIZE
SYSLOAD: 8.59 283 KALMAN
SYSLOAD: 12.50 67 LH
SYSLOAD: 0.0 114 USBLINK
SYSLOAD: 0.0 256 CMDHL
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RMIT University
School of Design
http://www.cafeciaojoe.com
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kristoffer
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Re: CF having trouble reciveing over 4 lightouses.

Post by kristoffer »

Ha ha, now I saw this post, I already answered in the other one about base stations facing up.
Moving the answer here instead.

It is not unlikely that it does not work very well (or at all) with more than 4 base stations in the current implementation. It is pretty much untested and this is also one of the reasons we officially only support 2 base stations for now.

The rotors in the base stations run at slightly different rotation speeds (based on their channel) and the purpose is to avoid that the sweeps from two base stations interfere at the same point all the time. With different speeds the interference area will change over time and a receiver will only lose position information from time to time. The current implementation of decoding the lighthouse data works "OK" but when sweeps from two base stations interfere we loose a bit more data than should be necessary. This is not a problem for two base stations, but when the numbers increase you get more and more interference. It is possible that the limit for a functional system is at 4 base stations?

Note that the problem only occurs if the base stations are illuminating the same point, if they are at different parts of the tracked space and do not overlap everything if fine.

The observation that the CPU load of the kalman filter goes down with 5 base stations matches the theory above, there is simply less useful data that is decoded and sent to the filter.
cafeciaojoe
Member
Posts: 83
Joined: Mon Jun 18, 2018 2:37 am

Re: CF having trouble reciveing over 4 lightouses.

Post by cafeciaojoe »

Ah ok. Yeah this seems like a hardware issue rather than a software issue? I cant tell from that response.

But anyway something to look forward to in the future!
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RMIT University
School of Design
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kristoffer
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Re: CF having trouble reciveing over 4 lightouses.

Post by kristoffer »

I think it can be improved slightly with software but there will be an upper limit somewhere.
A clue might be that it is limited to 4 base stations in Valve's (Steam) set up
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