Backtracking with Particle Filter

Question

I have just implemented a particle filter for Indoor Tracking. It looks good but at some points the particles go in a room and are trapped there.

What's a smart way to do backtracking? I save the state of the particles for their last 10 movements.

Thank you

Answer 1

It is completely normal that particles get distributed everywhere. Otherwise it is not a probabilistic approach. In addition, note that the particles are sampled based on the posterior probability at time t-1 and the current motion distribution. However, even if it is not recommended in filtering but you can restrict your research space in the sampling step.

For backtracking, you may use at each time t the same approach of fortracking, with changing only the direction of the velocity (on all axies). You can start from the state which maximise the probability distribution. Finaly, you compare the obtained trajectories (result of for/backtracking) and you decide based on the result which further filtering is needed to get the best result.