A new release of Trimble Mobile Manager (TMM) is adding key functionality to make global navigation satellite system (GNSS) receiver positions more usable and to aid real-time decision-making in the field.
The latest version of Trimble Mobile Manager—a simple app for configuring and controlling connections to supported Trimble GNSS receivers—adds support for in-field orthometric height calculation and advanced geodetic functionality.
New Version Makes Orthometric Height Computation Easier
GNSS receivers can output elevations relative to sea level by using a “grid file” to calculate the difference between the GNSS ellipsoidal height and the mean sea level (MSL) at any given location. This grid takes into account the irregularities of the earth’s surface, however, due to the massive size of the earth and the relatively small amount of storage space available in a GNSS receiver, the built-in grid file on most GNSS devices is low resolution and, as a result, fairly imprecise. So while MSL heights calculated onboard the GNSS receiver are easy to understand compared to (the much more accurate) receiver ellipsoid heights, they have limited use in high accuracy workflows.
The solution is to compute an MSL elevation using a more localized and highly accurate model of the earth’s surface for a given location. This type of elevation is known as orthometric height, and the calculation uses a combination of the precise Height Above Ellipsoid (HAE) determined by the GNSS receiver and a precise local grid of parameters that are specific to a local area to accurately model the undulation of the Geoid in the local area. Using a local Geoid model to calculate orthometric height, the elevation output by the receiver is accurate, as well as being presented in a usable and human-understandable form (relative to sea level).
Real-Time Values In the Field Increase Productivity
Traditionally, orthometric height calculation required manual processing of GNSS data once field data had been sent back to the office, but now Trimble Mobile Manager enables Trimble GNSS receivers to be configured to compute orthometric height in the field, and for those values to be displayed in real-time. This workflow means field users can now act on the data in real-time—which is a major productivity benefit.
New Feature Enables Regional Specifications
In another feature enhancement, Trimble Mobile Manager has even greater ability to specify regionally optimal coordinate systems or reference frames (including applying time-dependent transformations). These configuration parameters can also be fully leveraged by partner applications using Trimble Precision SDK (Software Development Kit). Trimble Mobile Manager also lets the user set a specific epoch for the coordinate system of the correction source, which is of particular interest to users in tectonically active regions.
Trimble Mobile Manager provides a simple interface for configuring the receiver and downloading and applying a Geoid grid file all directly in the app. The app then creates a configuration file which is used by Trimble Precision SDK (TPSDK) partner apps such as Esri Collector for ArcGIS for Android which has been updated to incorporate support for these new features in its latest Android release (version 20.1.0).
TMM Adds Data Confidence to Any Location-Enabled App
In addition to providing a standardized GNSS configuration interface for TPSDK partner apps, Trimble Mobile Manager can also be used to connect to and manage the GNSS receiver connection to any location-enabled app without the need for custom development. In this workflow, by using the Trimble Mobile Manager “Location Sharing” feature, any app can benefit from the confidence delivered by Trimble GNSS receiver solutions.
For more information, view the Trimble Mapping and GIS Solutions Community blog post.