Joined: Aug 2008
Posts: 13,140
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From: Ann Arbor, MI
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Without knowing what kind of "GPS" unit we're talking about, all that can really be done to resolve this problem-- insofar as it is one at all-- is to get a high-accuracy satellite receiver which uses both GPS and GLONASS and samples at high speed, like 10Hz. You may be able to find somehing which uses the super accurate GNSS/Galileo satellite network and/or maybe BeiDou network as well as GPS and GLONASS. Maybe we're simply talking about upgrading from an iPhone 6 to iPhone 12, or maybe you need to get a unit with killer antennae like the Garmin GPSMAP 66ST, but with the info we have, there's no way to say much other than that getting around a 50' cul de sac at 10mph does not seem like a data-intensive undertaking.