Another variable is exactly how MerginMaps is getting its position.
From your screenshot, it appears you're running it on Android. If this is the case, do you have "Location Sharing" in Trimble Mobile Manager turned on? Do you have TMM set as the Mock Location Application under Developer Settings? It appears so, given the estimated accuracy shown on the screen recording.
The next question is about the method used by MerginMaps for getting positions from the Android OS. Many applications today are using what's called the Android 'FusedLocationProvider' API which can result in application behavior like you've observed. Under the hood, locations come from a variety of sources (internal GPS, a-GPS, WiFi-assisted positioning, mock provider, etc.) and are then "fused" by the operating system and then delivered to the operating system.
Trimble provides several options to bypass the uncertainty caused by the FusedLocationProvider in applications which demand unwavering location accuracy. If you have a contact at MerginMaps we'd be happy to discuss those options with them.
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Dan Colbert
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Original Message:
Sent: 01-05-2024 19:06
From: Chen Zi Yan
Subject: Accuracy and Consistency of DA2 Catalyst 1
Hi,
I subscribed to Catalyst 1 and began collecting points using a third-party app (MerginMap). The DA2 was connected to the RTX service and converged to cm accuracy before I initiated the work. I collected the coordinates of 10 points and repeated the process for four rounds to test the consistency and accuracy of RTX. However, I observed that the coordinates of each point varied in every round I surveyed them. The variation between each round for each point could exceed 1 meter, with the smallest difference being 5 cm. I made sure to achieve <2 cm accuracy before recording the coordinates of each point. I am puzzled as to why this issue occurs, as I anticipated obtaining cm-accurate positions with repeatable results when I subscribed to Catalyst 1.
Additionally, I noticed that when I stood still at a point, the GPS location would jump around within a range of 20 cm, even though the DA2 was corrected to approximately 2 cm accuracy. Is this considered normal?
Positions of the same point, which were collected in 4 separate rounds.
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Chen Zi Yan
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