High speed GPS.

Hi,

I've been asked to help with a project that involves GPS logging of vehicles going around a track.

The GPS modules I've seen (sparkfun etc) typically work at 5 or 10hz. For a vehicle travelling at 100mph (approximately 45m/s) that equates to one GPS fix every 5 meters.

I'd like to log positions more closely, so I need a GPS that works at a higher frequency (maybe 50Hz or 100hz). Can anyone recommend anything suitable - hopefully a relatively cheap hobby solution, not an ultra expensive professional one.

Alternatively, does anyone know if it's possible to somehow synchronize multiple cheap GPS modules, if I could round-robin the GPS modules I could take my 1st fix from GPS A, my 2nd from GPS B, my third from GPS C etc etc and then back to the first GPS unit, but this does require forcing each module to operate in sequence. Is this possible?

Cheers

This post explains the maths and the low pass filtering.

You won't get 100 Hz.

In addition, a single location fix will only be accurate to within about 5 meters due to the fundamental design of the GPS system and the natural variability of atmospheric conditions.

Perhaps look at the low cost GPS/IMU boards used by autonomous model aircraft.

Fulliautomatix:
Can anyone recommend anything suitable - hopefully a relatively cheap hobby solution, not an ultra expensive professional one.

If there was a 'cheap hobby solution' why would people be buying 'ultra expensive professional' ones ?

a single location fix will only be accurate to within about 5 meters due to the fundamental design of the GPS system

True, but for this sort of work what's often more important is the relative accuracy from one point to the next - and judging from what I've done with 10Hz GPS it's pretty good.

If there was a 'cheap hobby solution' why would people be buying 'ultra expensive professional' ones ?

Dunno. why do people spent 40k on car when a 15k one will still get you from A to B?

Fulliautomatix:
from what I've done with 10Hz GPS it's pretty good.

... and so the interpolation between points is also pretty good. The mass of the car guarantees this. 10Hz is good enough.