Discussion
Ruxpin said:
Driving up the M1 this morning my Garmin Nuvi Satnav recorded a maximum of 209mph!!
Anyone have a good explanation, as somehow i don't think the skoda managed it....
Never underestimate the Econoskode... if yours is anything like the Mrs', then it'll overtake everything and give you 60mpg at the same time!!
It could be due to changing/dropping satellites etc but it didn't appear to lose satellite coverage and i was in the open - no bridges / buildings.
It happened just as i passed a Volvo XC90 - was registering correct speed as i was following and accelerated to pass. Then flicked up to the 209mph only for a moment as i passed. Then immediately returned to normal showing correct speed. Was too quick for it to have totally lost satellites and recovered.
Just wondered if these are regular glitches and if they affect all GPS based satnav's / performance meters etc
It happened just as i passed a Volvo XC90 - was registering correct speed as i was following and accelerated to pass. Then flicked up to the 209mph only for a moment as i passed. Then immediately returned to normal showing correct speed. Was too quick for it to have totally lost satellites and recovered.
Just wondered if these are regular glitches and if they affect all GPS based satnav's / performance meters etc
These type of stand-alone/handheld GPS units can have errors if they drop a number of satellites and can lead to momentary short-term errors (quite large as you have seen). This is obviously then recorded if the unit keeps max speed. I have had this in years past on handheld Garmins, which is why I sold it and replaced it with a a proper data-logger (AX22).
In terms of VBox/AX22 the differences that removes this error are:
1. 5Hx or 20Hz GPS rather than 1Hz, so greater sampling rate.
2. Roof mounted professional GPS antennas rather than simpler internal intennas that are inside the car (ie a metal box that blocks signals) - that reduces the chance of dropped satellites.
3. The data is stored every 1/100th of a second to memory, so there's a full data record of speeds with literally millions of data points, so any error points would be obvious on the data download if they had occurred.
4. The AX22 also has acceleromters from which the data is overlaid onto the GPS derived data, thus removing the risk of large errors.
So in short the answer is NO, the proper data-loggers do not suffer from the errors that can easily afflict the more basic units that are designed for navigation.
Guy
In terms of VBox/AX22 the differences that removes this error are:
1. 5Hx or 20Hz GPS rather than 1Hz, so greater sampling rate.
2. Roof mounted professional GPS antennas rather than simpler internal intennas that are inside the car (ie a metal box that blocks signals) - that reduces the chance of dropped satellites.
3. The data is stored every 1/100th of a second to memory, so there's a full data record of speeds with literally millions of data points, so any error points would be obvious on the data download if they had occurred.
4. The AX22 also has acceleromters from which the data is overlaid onto the GPS derived data, thus removing the risk of large errors.
So in short the answer is NO, the proper data-loggers do not suffer from the errors that can easily afflict the more basic units that are designed for navigation.
Guy
Edited by GuyR on Tuesday 3rd October 11:35
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