how to estimate the relative pose between robots?

[NatureLan-sudo]

after read your paper , I met a little question.
In the paper ,once two robot meet , we can determine a Tab, the equation is :

how can we get the zab under the b Coordinate System？
if we use ICP we can get zab ， but it not under any coordinate.
I don't know if I'm right to think this way, hope to get your help
@yeweihuang @jinkunw

[yeweihuang]

Hi @lantianran,
When solving the problem, we first roughly transferred xa into robot b’s frame with the initial rotation guess from ScanContext. And since their ScanContext features get matched, we define a zero translation initial. Then we set xb as target cloud in ICP, and get the fixation of xa in robot b’s frame from ICP. Finally we calculate zba using xb and the fixed xa in robot b’s frame.

[goldqiu]

Hi@lantianran, where is your dataset？