Harry's GPS Suite Forum

Hi HArry, did you actually test this device before recommending it with 5 stars?
It looks like you read the spec sheet, and recommended it on their claimed ability to use L1 and L2 frequencies - which is supposed to deliver superior positioning - and therefore speed data compared to L1.
I have been testing this extensively - and the speed display - in particular is very laggy - only changing at seemingly 1 hz - even though the device has been switched to 5hz. When compared to the Racebox Mini and Dual XGPS 160 (which virtually always agree on speed at any moment in time) the Columbus lags way behind. I haven't yet looked at lap times, but for anyone creating videos of their laps - the speed data is way too slow updating. When accelerating hard - the displayed speed can be 10mph behind the Dual and RAcebox - and that is from testing it in a VAN!!. Goodness knows how laggy the speeds readout would be in a fast car.
SO far I've been very disappointed with the performance of the Columbus. In fact it struggles to keep a signal in some environments too.
I'll see if i can post a video I created to prove the point.
I bought it based on reccomendation from your accessories page - but now wish I hadn't and am looking to contact Columbus for a refund.
My own mobile phone Chipset (Samsung S9+) is more responsive and less laggy than the Columbus - despite being 1Hz.

The GPS speed lag is a function of update rate, position accuracy, and the amount of smoothing that is applied to speed measurements.

GPSes in the consumer segment apply strong smoothing. This results in a big lag for speed changes. Opposed to this, there are GPSes applying a very low level of smoothing. One example is the VBOX Sport. Low smoothing results in a small lag but a lot of "noise" in measurements. So for these sensors, one needs to apply some "after the fact" filters to get good values. Position accuracy is often used to control the level of smoothing with more smoothing for lower accuracy.

I have no data on Racebox speed smoothing. Most probably it will apply a lower level and comes with 5 times the rate. But it costs a multitude of what a Columbus devices costs too. In case you are not satisfied because you focus on speed, I suggest to return it.

Well possible the Columbus smoothes speed more than others. This may disturb you, but it has no influence on precision of lap timing - which is the priority over speed accuracy in our rating.

In case you have a precise data comparison, I'm happy to add a comment to the compatibility pages too.

- Harry