UWB Assisted GPS RTK in Hostile Environments

This paper presents initial results of an experiment to augment RTK GPS with an additional range from an ultra-wideband ranging radio system. The UWB radios used for this study are the Time Domain PulsON 210 development kit. The ranging accuracy of the UWB radio pair is evaluated prior to using the ranging radio to augment a short baseline RTK float solution. One test was conducted to assess UWB range accuracies and results from a prior test performed by Ebeling (2007) are reproduced here for comparison. In the first test, it was found that UWB ranges were accurate to 0.011 m, when compared to a GPS short baseline and to a range deduced from known coordinates. This is compared to a second test, performed by Ebeling (2007), that shows that UWB range accuracy is dependent on two factors: distance and visibility. UWB to UWB radio Line-ofSight (LOS) distances of 5 m, 10 m, 15 m, 20 m, and 25 m revealed that a general linear trend existed between precision and range. RMS values ranged from 0.017 m to 0.071 m for the 5 m and 25 m scenarios, respectively. Non-Line-of-Sight (NLOS) range accuracy was evaluated by taking 5 m ranges through a door, as well as through a wall. Ebeling (2007) found 0.037 m and 0.431 m UWB RMS error values through a door and through a wall, respectively.