Tag's location got movement when more than 200 stationary tags in one cell

we use dw1000 for indoor location. And we are now test a specification that our product must support more than
600 tags in one cell which has 4 anchors for our TDOA solution. The cell is about 10mx10m. A serious problem is encountered that some of the
stationary tags’s location is moving from here to there, and the moving direction is uncertain.

we do not have 600 real tags. So we use some real tags to simulate some virtual tags, for example, one real tag for 50 virtual tags. This is
how we send the blink packet. for one real tags, every minutes it send 50 blink packets with different address so they can be tell from the
applicaiton. Every blink packet is sent after a random delay,[0,20]ms. We watch two different phenomenon:

  1. if we use only one real tag for 200 virtual tags with random delay[0,5]ms between each blink packet, every virtual tag’s location is almost stationary.
  2. if we use 4 tags for 200 virtual tags, which 1 real tags for 50 virtual tags. There will be some virtual tag’s location move from here to there even
    the tag is stationary. This phenomenon will be obvious if the virtual tags add to 600.
  3. During the test, the real tags are all stationary.

from the log we get from the test, when tag A’s location is located to somewhere, maybe 6m from its real location, its timestamp read from the anchor is uncorrectly
bigger than normal. So we doubt that whether tag A’s time is stamped by the following tag B? how should we handle this situation.

can some help to analyze this problem? we are now stuck here. Thanks a lot.