How can I use a GPS sensor for obtaining ground-truth on a mobile robot?

Question

I have a GP-635T sensor which I am reading using the nmea_navsat_driver package (which provides the nmea_serial_driver node). The sensor does not seem to work as easily as the GPS sensor on a smartphone: it takes a long-time to lock-in and gets lots very easily. At the moment, I haven't been able to obtain very good and stable readings such as those obtained on smartphones. How does a GPS sensor need to be used to get more stable and precise readings? Do I need to fuse this with other information such as odometers or an IMU, using EKF or similar? Is it feasible to use this type of GPS sensors for outdoor ground-truth?

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Originally posted by Matias on ROS Answers with karma: 122 on 2014-05-12

Post score: 0

Answer 1

A single GPS is not suitable for ground truth outdoors. Even the very best autonomous systems will have a position error of around 1m.

If you really need accurate ground truth, you may want to look into a differential GPS system.

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Originally posted by ahendrix with karma: 47576 on 2014-05-12

This answer was ACCEPTED on the original site

Post score: 1

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Original comments

Comment by Matias on 2014-05-19:
the position errors are quite large and erratic. I'm not sure if it is due to this particular sensor, or the fact that GPS sensors are generally fused with other inertial sensors, as I suspect is the case for smartphones. What would be the correct way to use a gps sensor in ROS?