Experimental studies of wireless communication and GNSS kinematic positioning performance in high-mobility vehicle environments

摘要: In order to support intelligent transportation system (ITS) road safety applications such as collision avoidance, lane departure warnings and keeping, Global Navigation Satellite Systems (GNSS) based vehicle positioning has provide lane-level (0.5 1 m) or even in-lane-level (0.1 0.3 accurate reliable information users. However, current navigation systems equipped with a single frequency GPS receiver can only road-level accuracy at 5-10 meters. The be improved sub-meter higher the augmented GNSS techniques Real Time Kinematic (RTK) Precise Point Positioning (PPP) which have been traditionally used in land surveying slowly moving environment. these techniques, corrections data generated from local regional global network of ground stations are broadcast users via various communication links, mostly 3G cellular networks satellites. This research aimed investigate precise performances when operating high mobility environments. This involves evaluation both RTK PPP using: i) state-of-art dual receiver; ii) low-cost receiver. Additionally, this evaluates effectiveness several operational strategies reducing load on due correction transmission, may problematic for future wide-area ITS services deployment. These include use different transmission protocols, format standards, less-frequent interval. A series field experiments were designed conducted each task. Firstly, evaluated static kinematic (highway speed exceed 80km) experiments. solutions achieved RMS precision 0.09 0.2 meter tests, while reported 0.5 1.5 meters 1.8 tests by using RTKlib software. values could further if better algorithms adopted. results also showed that more suitable positioning. professional grade (dual frequency) mass-market (single receivers tested their performance modes. analysis shown good solution continuity, although overall is worse than receivers. In an attempt reduce network, we firstly evaluate namely RTCM version 2.x 3.0 format. A 24 hours test was compare throughput. 66% throughput reduction newer 3.0, comparing older Secondly, examine two TCP UDP, through Telstra network. method analysed terms packet latency, dropout, throughput, retransmission rate etc. latency UDP 76.5% 83.6% remains same level. Additionally, nature it found 0.17% packets lost during but loss doesn't lead significant quality results. experimental mobile blocked couple seconds, kept required level setting Age Differential. Finally, effects (transmitted 1, 5, 10, 15, 20, 30 60 seconds interval) system. As time interval increasing, percentage ambiguity fixed gradually decreases, error increases 0.1 meter. position still up 20 transmission.