Modern intelligent transport solutions can achieve an improvement of traffic flow on motorways. With lane-specific measurements and lane-specific control, more measures are possible. Single frequency precise point positioning (PPP) is a newly developed and affordable technique to achieve an improved position accuracy compared with global positioning system (GPS) standalone positioning. GPS-PPP allows for sub-meter accurate positioning, in real time, of vehicles on a motorway. This paper tests this technique in real life; moreover, it presents a methodology to map the lanes on a motorway using data collected by this technique. The methodology exploits the high accuracy and the fact that the most driving is within a lane. In a field test, a GPS-PPP equipped vehicle drives a specific motorway stretch 100 times, for which the GPS-PPP trajectory data are collected. Using these data, the positions and the widths of different lanes are successfully estimated. Comparison with the ground truth shows a dm accuracy. With the parametrized lanes, vehicles can be tracked down to a lane with the GPS-PPP device.

Precise Point Positioning (PPP) is a popular Global Positioning System (GPS) processing strategy, thanks to its high precision without requiring additional GPS infrastructure. Single-Frequency PPP (SF-PPP) takes this one step further by no longer relying on expensive dual-frequency GPS receivers, while maintaining a relatively high positioning accuracy. The use of GPS-only SF-PPP for lane identification and mapping on a motorway has previously been demonstrated successfully. However, the performance was shown to depend strongly on the number of available satellites, limiting the application of SF-PPP to relatively open areas. We investigate whether the applicability can be extended by moving from using only GPS to using multiple Global Navigation Satellite Systems (GNSS). Next to GPS, the Russian GLONASS system is at present the only fully functional GNSS and was selected for this reason. We introduce our approach to multi-GNSS SF-PPP and demonstrate its performance by means of several experiments. Results show that multi-GNSS SF-PPP indeed outperforms GPS-only SF-PPP in particular in case of reduced sky visibility.

Through the advent of more and extended GNSS constellations, Single Frequency (SF) positioning gains much in performance and applicability. In this contribution we explore the role SF GNSS can play for driver assistance, cooperative driving and fully autonomous vehicles. A convoy experiment was conducted with three vehicles, driving behind each other on a straight road. Each of the three vehicles was equipped with a SF GNSS receiver (u-blox M8T) and a patch antenna, and at the side of the road a fourth identical SF GNSS receiver with a patch antenna was setup. Raw data logged with these receivers were processed in several modes, exploring their possible use for different types and levels of vehicle automation. SF-PPP is considered for driver assistance, moving base (MB) differential processing (i.e. combined processing of the data from two or more moving vehicles) is considered in the light of cooperative driving, and RTK is considered for self-driving vehicles. In each of these modes, the data were processed as if it were in real-time. Reference data were collected with a professional robotized total station for land-surveying (Leica), setup at the road side independently measuring absolute vehicle positions with centimeter precision. Additionally, the second vehicle was equipped with a laser disto-meter (Leica) to independently measure the distance between the first two vehicles, with millimeter-precision. Results show that the accuracy requirements are met for each of the three applications considered. Availability is also high, and the advantages of a multi-constellation approach are highlighted. The results also contained evidence of a well-known weakness of GNSS, e.g. its sensitivity to RFI due to the low received signal power.

Autonomous vehicles require accurate position at all times in different environments at an affordable price. This accurate position can only be achieved when combining multiple positioning methods. One of these methods is presented in this paper: positioning based on a Global Navigation Satellite System (GNSS) to obtain absolute position. This solution should be at an affordable price with sub-meter position accuracy. At the University of Delft, the Netherlands, a low cost solution was developed in Matlab for open areas which is called Single Frequency Precise Point Positioning (SF-PPP). It uses a low cost receiver with single frequency, single antenna and single GNSS constellation (GPS). The receiver provides raw measurements to the SF-PPP algorithm which corrects them for different kind of errors. This method was ported to a low cost Commercial Off-The-Shelf (COTS) embedded platform in C++. The selected platform is a Raspberry Pi version 2 with a u-Blox NEO 7P GPS receiver. The corrections for the raw measurements are received from a network service via a 4G modem. The PPP method is validated with an RTK system which is cm accurate. We evaluated the PPP method in different environments and conditions, with focus on open area, but also for harsh conditions on the highway and in an urban environment to know the current limitations of the method. For the open area environment a horizontal root mean square error (RMSe) of 0.5 m on position coordinates was achieved which fulfills our target of submeter accuracy. In harsh environments we suffer from reflections (caused by multipath receptions) and poor satellite availability due to obstructions from trees and buildings which makes the accuracy varying from 0.5 m up to 3 m. Future plans to improve the results involve using more satellites from other constellations like GLONASS, using the Doppler shift to estimate the vehicle speed, using dual frequency receiver for ionosphere removal and closer integration with other low-cost sensors and vehicle model.

In this contribution we study the strength of the single-receiver, single-channel GNSS model for instantaneously resolving integer cycle-slips. This will be done for multi-frequency GPS, Galileo and BeiDou, thereby focusing on the challenging case that the slip is due to a simultaneous loss of lock on all frequencies. The analytical analysis presented is supported by means of numerical results.