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TPSDK for Android and iOS

Overview

Trimble Precision SDK (TPSDK) is available in different flavors depending on the targeting operating system.

The default outputs are

  • Objective-C for iOS
  • Java for Android
  • Xamarin for Android

Although the same core is shared between all outputs the actual interface changes per platform due to the platform specific technologies.

A simple example is Bluetooth communication - which is quite different between Android and iOS and hence requires platform specific adoption.

Before starting with the actual implementation it may be worth considering the different integration strategies offered by TMM and TPSDK. Based on the application needs a web socket approach might prove to be more convenient and effective compared to e.g. the SDK integration.


Options

Before diving into any of the offered TPSDK APIs a developer should pick his preferred way to handle Trimble technology. Therefore different options are available - based on the needs of the application:

  • Android mock locations and location extras (Android only)
  • Web socket server (ws and wss)
  • TPSDK Facade on iOS and Android
  • TPSDK on Android

Generally speaking apps that only need a position typically work nicely with either the mock location framework (if available) or websockets.

Applications which aim for higher control want to look into the facade layer - which is a wrapper around the SDK encapsulating the most common use cases.

Applications going for full control or less common receiver features want to extend the facade by implementing the missing functionality or just implement the SDK.

Each approach has different pros and cons.


Feature overview

A none-extensive overview can be found in the following comparison

Integration Mock locations WebSocket server TPSDK
Supports Trimble receivers yes yes yes
Position access Android location API localhost ws and json API
Position meta data Check documentation Check documentation Check documentation
Complexity low low med-high
Access to all features no no yes
Allows datum transformation yes, via TMM yes, via TMM yes, via the API and/or TMM
Allows going static no, just 1Hz snapshot positions no, just 1Hz snapshot positions yes
Allows undulation values yes yes yes
Allows tilted measurements no no yes

 


Mock locations

WebSocket example

WebSocket example

Many applications are in need of precise positions - but can happily live with the information detail level as provided via the Google Mock locations aka the corresponding the location object.

To overwrite mock locations you can enable the corresponding feature in Trimble Mobile Manager (TMM). This approach requires no development effort on your part - your application behaves just as it normally would, and can benefit from receiving higher accuracy positions from the Trimble GNSS receivers.

TMM also adds additional meta information to the location extras - accessible via known Android techniques. Detailed information on the available data can be found in the TMM developer documentation.

 


Web sockets

Web sockets are from a data perspective identical to TMMs mock location output plus location extras - although combined in a single object.

The advantage of web sockets are that the Android OS does not inject fused locations - in some cases applications find it tricky to distinguish positions from a GNSS receiver vs fused positions by Google (fused means a mix of cell phone triangulation, Wifi and GPS/ GNSS).

Additionally progressive web apps often have issues accessing mock locations as they can’t define the location provider. For those apps the web socket server is ideal as it provides a json based output stream that can be easily parsed by apps.

More details on the web socket and its behavior can be found in the TMM developer documentation or the TPSDK documentation

 


TPSDK and the Facade

Facade

The term facade is used quite heavily within the context of TPSDK. In short the facade is a wrapper layer around several components of TPSDK. This wrapper exposes the most common functions like connecting via Bluetooth and starting a NTRIP survey. It also acts as sample as it shows how to use the interfaces exposed by TPSDK.

The facade ships in source code form for Android and as component for iOS - so ideally the facade project is copy/ pasted to the solution. This allows drop-in replacements when new version of TPSDK go live.

Enhancements to the facade ideally happen in a derived class so that the drag & drop update process still works.

 

TPSDK

TPSDK and its core components Sensor Software Interface (SSI) and Licensing Software Interface (LSI) create the foundation of all SDK related things. SSI exposes a vast set of GNSS receiver features ranging from the configuration of the receiver internal UHF radio to tilted measurements and more. The SDK has a component oriented design based on interfaces. In essence this means that feature are linked to an interface. For example, say the possibility to start RTK - if this is supported or not depends on the availability and properties of the corresponding ISsiStartRtkSurvey interface.
The availability is determined dynamically during runtime.

For more details please take a look at the TPSDK documentation.