Improving the automotive satellite navigation experience: Page 4 of 5

November 10, 2017 //By Florian Bousquet, u-blox
Satellite navigation doesn't always produce the results you want as a user – and as a designer of navigation systems. This article shows how to improve the accuracy.

Figure 4: UDR approach used by the NEO-M8 module from u-blox.

Another important aspect of UDR’s approach is that it has the capability for delivering a high refresh rate of positional data, or a real time high navigation rate (HNR) output. When relying on GNSS signals alone, there is an inherently large latency in the calculation of the position. Typically using GNSS systems in the mass market, this allows a maximum of 10 fixes per second, a refresh rate of 10 Hz. This would reflect the position the vehicle was in when the satellite data was acquired. UDR can double the refresh rate, up to 20 Hz, significantly improving the navigation rate.


Figure 5: Real time high navigation rate comparing GNSS versus UDR approach.

Figure 5 illustrates the impact of latency on the navigation between using GNSS alone versus a UDR solution, the later using the sensor data to complement that received from GNSS. Latency as low as a few milliseconds is achieved, which is key for use in safety applications such as anti-collision systems based on V2X infrastructure and positioning of vehicles against each other. Low latency and high navigation rate are absolute must requirements for V2X applications, to achieve the required reactivity in case of alert.

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