shaken Sepentrio PolaNt-x-MF antenna

Robust positioning

LOCK+ is a set of techniques to guarantee robust tracking under rapid signal changes such as those caused by mechanical vibrations or shocks, earthquakes or ionospheric scintillations. Traditionally, GNSS receivers need some time to react to changes in the GNSS signals.  If, for example, the antenna position changes suddenly after a shock, it takes some time for the receiver to sense the change and report the new position. LOCK+ technology ensures that the true position is always accurately reported.

Surface blast holes - vertical drilling (c) Flanders - Anglogold Amanti tropical mine
Surface blast holes - vertical drilling (c) Flanders - Anglogold Amanti tropical mine

Handling heavy machinery

Large construction machines are often subject to strong shocks and heavy vibrations due to movement on tracks, rough terrain and heavy engines. An excavator boom can be jerky, with the GNSS antenna along for the ride. Not every receiver can handle such a rollercoaster where the signals are changing at such short intervals. LOCK+ technology has been designed and implemented on hardware and software level of Septentrio receivers to withstand mechanical vibrations, ensuring accurate positioning calculation at all times.


GPS GNSS positioning without LOCK+


LOCK+ significantly decreases the latency and overshoot effects.  The next figure shows the results of the same test performed with a Septentrio receiver. The measured position now accurately follows the true position.


GPS GNSS positioning with LOCK+


As another example, the following figure shows the change of latitude reported during strong antenna vibration in the north-south direction.  Without LOCK+ (in green) the receiver has difficulties following the rapid changes and the position eventually diverges due to cycle slips.   LOCK+ (blue) allows continuous and accurate tracking.