Steve Reutebuch
New Member
We are using TR2 units to get approximate coordinates for forest inventory plots. These plots are always in areas of heavy tree canopy and very high multipathing. We have found through testing (against a circuit of hubs surveyed with a total station in a dense forest) that if we have 12 or more sats and we collect at least 15 minutes of static data at a point and then post-process with a nearby GNSS (GPS+GLONASS), that we can usually get point horizontal accuracy of approx. 1m, which is our target accuracy for forest inventory plots.
If we process the same plots with DPOS, often the majority of basestations that DPOS selects are GPS-only rinex. The solutions have much poorer accuracy (compared to processing in Justin using only GNSS basestations). This is likely because in DPOS, the GLONASS signals aren't used in the GPS-only basestation solutions and the number of sats drops to the point where multipaths are not being detected and removed, resulting in poor solutions.
Would it be possible to add an option to DPOS that allows the user to specify that DPOS only use GNSS (GPS+GLONASS) basestations in solutions?
I'm attaching an example DPOS output for a 15 min static occupation (T6P6jps) that illustrates this issue.
The GPS-only basestations only use 9 sats in solutions; whereas, the GNSS basestations use 15-17 sats. The horizontal error for T6P6 is 5.79m. When I process the same file in Justin using only GNSS basestations and a cut off mask of 20 degrees , the error is 0.60m.
If we process the same plots with DPOS, often the majority of basestations that DPOS selects are GPS-only rinex. The solutions have much poorer accuracy (compared to processing in Justin using only GNSS basestations). This is likely because in DPOS, the GLONASS signals aren't used in the GPS-only basestation solutions and the number of sats drops to the point where multipaths are not being detected and removed, resulting in poor solutions.
Would it be possible to add an option to DPOS that allows the user to specify that DPOS only use GNSS (GPS+GLONASS) basestations in solutions?
I'm attaching an example DPOS output for a 15 min static occupation (T6P6jps) that illustrates this issue.
The GPS-only basestations only use 9 sats in solutions; whereas, the GNSS basestations use 15-17 sats. The horizontal error for T6P6 is 5.79m. When I process the same file in Justin using only GNSS basestations and a cut off mask of 20 degrees , the error is 0.60m.