We are doing a project that requires constant 1hz position updates. But we are finding that at times position updates are smooth and other times they are sluggish. When we queried Garmin about this they gave the following response:
The sluggishness of the GPS 18x and GPS 10x products when moving slowly is due to using very long integration times for the position calculation when the observed dynamics indicate that the unit is likely being operated at a fixed position. Over a period of time, that results in a better and better estimate of position on units that are operated from a fixed location. The downside is that after looking like a unit that is operating in a fixed location, it takes some significant velocity for several seconds or a signficant change in postion, more than just a few feet, to determine that the unit is no longer operating at a fixed location. I think you’ll find that as long as the unit is in more or less continuous motion, you’ll never encounter the types of symptoms you are reporting below. So what makes the units suitable for use in one scenario also makes them more difficult for you to use in your non-typical scenario.
There is no provision to implement external control over the use of longer integration times for GPS receivers that seem to be operated from a fixed position.
So the question is do any of the GPS modules available through Sparkfun have provision to implement external control over the use of longer integration times for GPS receivers that seem to be operated from a fixed position? Or are there any that do not employ this algorithm?