Hi,
My UAVs (with dwm1000) use ardupilot and are controlled by ground controll station.
I'm trying to use lps nodes as tdoa positioning system.
There are communications absolutely needed in tdoa?
I was searching the code but it's really easy to miss things, is there documentation on the subject?
Communication between lps and ground control
Re: Communication between lps and ground control
Hi,
Currently the main documentation for TDoA is the code (since this is still work in progress).
The way the algorithm currently work is:
- The anchors send packets in sequence
- Each packet contains the transmit timestamp of the current packet and RX timestamp of all the previously received packet by this anchor
- These data are enough information for a receiver (ie. the Crazyflie) to synchronize the anchors and calculate the TDoA of the packets.
The ground station has no part in that, the TDoA measurements are used by the kalman filter to estimate a position and this position estimate is used by the controllers to follow the setpoint.
I hope I answer the question.
Currently the main documentation for TDoA is the code (since this is still work in progress).
The way the algorithm currently work is:
- The anchors send packets in sequence
- Each packet contains the transmit timestamp of the current packet and RX timestamp of all the previously received packet by this anchor
- These data are enough information for a receiver (ie. the Crazyflie) to synchronize the anchors and calculate the TDoA of the packets.
The ground station has no part in that, the TDoA measurements are used by the kalman filter to estimate a position and this position estimate is used by the controllers to follow the setpoint.
I hope I answer the question.
Re: Communication between lps and ground control
Thank you for the answer,
I did understand that tdoa is separate from the ground station.
With my question I was mostly referring to the set up and the crazyradio.
Once I put the anchors on place anchors positions are strictly needed, than is there something else?
I did understand that tdoa is separate from the ground station.
With my question I was mostly referring to the set up and the crazyradio.
Once I put the anchors on place anchors positions are strictly needed, than is there something else?
Re: Communication between lps and ground control
I do not understand your question. Since the ground station is not involved in the positioning, Crazyradio is not involved in positioning.
The tag needs to know the position of the anchor in order to estimate its position from TDoA measurements. The position of the anchor can either be sent at startup upon connection or be compiled in the source code.
The tag needs to know the position of the anchor in order to estimate its position from TDoA measurements. The position of the anchor can either be sent at startup upon connection or be compiled in the source code.
Re: Communication between lps and ground control
Basically I just wanted a confirmation that aside anchors position there's no needed communication.
I apologize for being unclear, in my head sounded right.
I apologize for being unclear, in my head sounded right.
Re: Communication between lps and ground control
So I can confirm that: in order to get a position from TDoA all you need is to know the anchor position and to receive the TDoA packets using a DW1000 (or other 802.15.4a) radio.