Can I use graph slam to solve this problem?
However, the problem with graph slam is it is an offline algorithm that requires huge memory space. So, are there any other graph-based algorithm is available which is suitable for this problem?
Actually memory is less of a problem than processing speed.
Secondly, If I need to implement the same problem ...
Ok, just to answer this and close the question. I asked the lab people to test my node with prediction only, and it turned out that it is ok.. So my conclusion is that for some reason, the simulation in my computer is giving me wrong velocities (I don't know why exactly).
My solution to this, was to record a bag in the lab's computer, and use that to ...
Is this a problem that is accounted for in the EKF SLAM algorithm from the book?
It is. If you look at the pseudo code implementation you posted you will notice that the update only works for the observed features.
For all your matrices,jacobian,$H$ matrix, Kalman gain. The parts related to the unobserved landmark is 0. Therefore the update will be 0, and ...