Civil Engineering Reference
In-Depth Information
Figure 6.39 The flowchart for the Integrated Tracking System algorithm
be the drift accumulated during the mobile user's walk in a GPS denied environ-
ment. The constant correction being applied by the ITS to the PDR location in GPS
denied environment makes sure that it nullifies the effect of drift accumulated in
the user's walk until the very last time the user has entered the particular GPS
denied environment. The algorithm of the ITS is illustrated as a flowchart in
Figure 6.39. Once the user steps out of the GPS denied environment, the ITS regains
the RTK-GPS signal. However, this may not happen immediately as the user steps
into a location with available GPS positioning because it takes some time to
establish the connection with the RTK-GPS.
Once the GPS is regained, the correction is adjusted and the PDR drift becomes
zero as the adjusted PDR location would once again become equal to the RTK-GPS
location due to the new corrections. This updated correction manifests itself as a
“jump” in the location of the position of the user from the ITS at that point in time
when the ITS switches taking command from the newly available RTK-GPS
instead of the PDR position. When the accuracy of the ITS falls below desired
levels, the mobile user can step outside, recover the RTK-GPS signal, correct his/her
Search WWH ::
Custom Search