Thursday 19 March 2009

Market Weighton

This market town in the middle of East Yorkshire is place who's name is often mispronounced, it should be "weeton" not "wayton". Since the bypass was built I've rarely been into the town, though I've driven past it hundreds of times. The bypass has cut a couple of small roads in half. Housing estates have sprung up around these roads filling towards the bypass. We mapped about a third of the town, with a couple of schools which were easy to estimate because of the surrounding roads. There is a fairly new Tesco which I can't remember what was there before. It has not been a very inspiring place so far, but I think the best bit may yet be to come. The Hudson way ends in the town, so the existing trace from the OoC map needs tidying up.

One thing I spotted again today was the quality of the GPS signal was once again superb. Today we saw the accuracy as 7 feet for a few minutes. My Garmin eTrek was showing the symbol for WAAS - the D above the satellite bars, though it is EGNOS (European Geostationary Navigation Overlap Service) . I've seen this a few times recently, though usually only for a few minutes at a time. I think the service is due to be fully available this year so better accuracy in Europe for GPS looks promising. Spring seems to be here too.


Anonymous said...

I was seeing accuracy down to 9 feet whilst mapping Saltaire the other day, which I'd put down to either being on the Leeds/Bradford glidepath or the high pressure system we currently have.

The two countries I do mapping in are theoretically at either ends of the coverage area for EGNOS. Surprisingly though Turkey has much better coverage then I've ever had in the UK, perhaps it's because of the wide open spaces there.

Spring being here means it's time to get into training for my planned ride across Europe this Autumn.

Chris Hill said...

The glide path of airports make no difference to GPS reception, except for a couple of trial sites in Spain, and even then only briefly. It is illegal to land an aircraft in the UK only using GPS. The biggest problem is the very poor accuracy of height. All instrument landings use radio beacons installed at airfields specifically for the purpose.

The weather, especially atmospheric water, can affect some (most?) receivers. Leaf cover is often cited as reducing the signal, but the water in the leaves is the biggest contributor to this. In leafless winter woods the signal is still weakened if the twigs are wet.