STL functionality

Overview

The Iridium-STL version of the RockSTAR provides the majority of the existing tracker functions that you expect from Ground Control trackers with the additions and performance variations noted on this page.

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Key features

• Robust handheld device for navigation, automated tracking and messaging.
• Emergency alert button
• Messaging and configuration achievable via the R7 connect app (IoS and Android)
• Live positioning and accuracy reporting.

important

Features in the RockSTAR STL is undergoing continuous development. Watch this space for further updates regarding more recent firmware developments. This page was last updated on 28th Feb 2025 to add changes made in firmware StarSTL7

Summary

The STL (Satellite Time & Location) version of the tracker utilises new hardware for Positioning Timing and Location. The primary source of location is driven by the highly powerful(up to x1000 higher) Iridium STL signals delivered from their Low Earth Orbit satellite constellation.

STL positioning can provide reasonable levels of accuracy ( less than 25m ) in areas where traditional GNSS/GPS signals are being spoofed or blocked. The high power STL signaling can even penetrate buildings and covered areas.

Key points to NOTE

The reception and processing of STL signals requires increased power so as a result the battery life is significantly reduced compared to our traditional GNSS based tracking products. If the STL tracker is left continuously activated then the battery capacity will be limited to approximately 15hrs.

In order to calculate position the processing of STL signals needs significantly more time than traditional GNSS/GPS. It improves accuracy as signals arrive from each passing satellite. The user needs to be aware that in most cases the reporting of a reasonably accurate position may take around 20 to 30 minutes after activation.

The firmware in RockSTAR STL trackers CANNOT be upgraded using the R7 Connect app. Refer to: Updating via USB

Due to the higher strength of the STL positioning signal bursts the tracker will often be able to store valid positions when indoors or if there is a restricted view of the sky. When this is happening the count of stored position reports will be shown in the bottom left hand corner of the home screen. These stored reports will be sent when the tracker has a good enough view of the sky for Iridium SBD to work correctly.

Activation and Deactivation

When not in use the RockSTAR Iridium-STL tracker should be DEACTIVATED. In this state the STL electronics are not powered and the tracker is effectively in 'Stand by' mode. Battery life in this deactivated mode can be many weeks. Due to the lower background power consumption, users can achieve faster charging (Mini USB) while DEACTIVATED.

The position screen

The Iridium-STL version of the RockSTAR has expanded functionality compared to the standard version. When there is a valid STL position data stream available this screen will update every second and display 'LIVE' in the bottom left hand corner. If ‘LIVE’ is not displayed, the position will be the LAST recorded before the live STL feed was lost. The user needs to be aware that this position could be many hours or days old and may not represent the current position.

Irrespective of the age of the displayed position the processed STL burst rate will show the current state so that the user is aware of the quality of reception and move the tracker improve the rate.

Position screen for firmware StarSTL7

Position screen for firmware StarSTL6

Position Figure Of Merit (PFOM)	Estimated Position Error (EPE)	Guideline time (Mins) to be within EPE (FAST+STATIC Modes)	Guideline time (Mins) to be within EPE (ECO+STATIC Mode)
1	< 25m	20+	80+
2	< 50m	10 - 20	40 - 80
3	< 75m	5 - 10	20 - 40
4	< 100m	-	-
5	< 200m	3 - 5	5 - 20
6	< 500m	-	-
7	< 1000m	-	-
8	< 5000m	1 - 3	2 - 5
9	>= 5000m	-	-

The Guideline times to be within the estimated position error are based on testing in the Ground Control Labs. There are many factors that effect the timing including - handset velocity, location, view of the sky, handset temperature and orientation of handset.

STL Geolocation Mode

Available from version StarSTL7 (Preset to STATIC in StarSTL6) there are two options for the STL geolocation mode.

STATIC - suitable if the user is remaining in the same location for around 10 minutes or more and would like a more accurate position reported.

DYNAMIC - suitable for improved tracking whilst on the move. However, reported EPE may remain in the 100 - 200m range.

Extending Battery lifetime

Battery lifetimes quoted here are based on position reporting every 30mins. More frequent reporting will further reduce the lifetime.

Default mode is 'Fast' (fastest arrival at the most accurate position - NO power saving) Battery life may be limited to about 15hrs in this mode.

Can be set to 'Eco' which will extend battery lifetime to approximately 20hrs. In 'Eco' mode there is a reduction in STL positioning performance which may increase the time taken to arrive at more accurate positions.

Setting is available in the 'Tracking' Menu.

Setting the Iridium-STL Tracker in limited power mode will also extend battery life.

STL Sensitivity

The setting of the STL receiver sensitivity can be adjusted from within the 'Tracking' menu. Default mode is High.

High sensitivity will give the best results when indoors or in areas with a restricted view of the sky. However, when a very high rate of STL bursts are available there can be advantages in lowering the sensitivity as this helps to reject bursts that have a degraded measurement quality. This will improve timing and positioning accuracy.