Getting an accurate heading ... using a digital compass?

I use two very small GPS units and ready the differential when making robots that are about a meter across in some direction. Earlier I used a single GPS with two antennas and switched them- this yielded two positions and a heading angle. Well, I know the angle of the two antennas on the robot, so I can add so many degrees offset and get the actual direction the robot is facing. But for smaller robots, a digital compass is okay- just use the type that yields an angle, not the 8 point variety. Note- if you are using the Dinsmore compass, you can mount two of them at slightly different angles to double the resolution. Just a thought.

Cheers!

Chip Shults My robotics, space and CGI web page -

Hi all. I was just wondering about different ways to determine the direction (preferably a compass heading) that a bot platform is moving. I have seen projects that use the Devantech compass and a couple of others, but it seems that (from what I have read) getting a reading from those units can take two or three seconds, which, if a bot is moving even at a relatively slow speed of 6, 8 or ten inches per second, seems to be quite a long time to obtain an accurate reading. Isn't it?

Are there other digital compass units that anyone here has tried, that are accurate and FAST that are used in a (somewhat) autonomous system?

Just wondering.

Thanx