Category: Sensors

Enabling Extended Kalman filter (EKF) on IRIS+

IRIS+ runs the opens-oruce flight control software APM:Copter. With version 3.2 – which was released on November 7th, 2014 – an interesting new feature was introduced: Extended Kalman filter (EKF).

High HDOP values when flying IRIS

In the IRIS forums at DIYDronres, Ardupilot, and the IRIS Facebook group I have seen reports from various users who have complained about low HDOP (Horizontal Dilution of precision) reported by their IRIS when trying to arm in Loiter or Auto mode (Both are GPS assisted modes). In these cases the HDOP value determined and reported by Arducopter is higher than 2.0 after powering up IRIS. This value is higher than the default value of 2.0 for the GPS_HDOP_GOOD paramter value. As a result the pre-arm checks fail and IRIS is not able to arm in a GPS-assisted flight mode.

Copper shield for IRIS’ GPS module

Various folks in the IRIS forums at DIYDronres, Ardupilot, and the IRIS Facebook group have complained about poor GPS performance on their IRIS. Others (including myself) weren’t quite sure if there was something wrong with their GPS module, but weren’t quite stunned with the performance either. So I decide to shield my GPS module with a piece of copper shield and find out what difference it makes.

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