A key aspect of the autonomous vehicle of the future is that it will be able to position itself precisely on a map. For this to be possible, two things must happen:
- First of all, the car must be able to situate itself in its environment starting from a known and universal position, which in technical terms is referred to as an absolute position.
- Second, the position of the vehicle must be estimated with high precision and accuracy.
The only technology that can provide absolute positioning information is that based on GNSS systems, so the efforts of the industry to develop increasingly reliable systems with this end has been capitalized in recent years.
In sectors other than automotive, the use of GNSS receivers capable of processing more than one frequency band has been consolidated for a long time. In these sectors, there are not too many limitations in the mechanical and electronic design of GNSS receivers, or at least, they are not limitations that have an impact on the performances that can be obtained with these receivers. However, the automotive case is quite different, since the market demands make the implementation of high-performance GNSS receivers very difficult. On the one hand, the size and consumption of silicon must be significantly reduced, and on the other, the cost of the devices must be well-bounded also.
Dual-frequency GNSS receiver chipsets are one of the several initiatives specially designed for today’s automotive market and adopted by the industry in recent years. However, connecting a common automotive antenna to a dual-frequency GNSS receiver blurs the full potential of the latter. In the best case, in this situation, we could find an antenna able to receive several frequency bands but whose radio-frequency characteristics produce a degradation of the quality of the signal. In the other hand, we can find antennas with a good radio-frequency response but whose bandwidth is very limited.
When the GNSS antenna bandwidth barely covers two bands, the most adopted solution by the antenna manufacturers are clearly L1 of GPS and L2 of GPS, because the GPS system has been in operation for many years and this gives it a high level of reliability from users perception. In addition, the proximity of both bands facilitates the design of these antennas.
However, by increasing the frequency bands that are offered to the GNSS receivers of the vehicles, we are facilitating the adoption of advanced positioning techniques, which in turn give the vehicle the ability to position itself responding to the demanding requirements of autonomous driving.
Moreover, supporting the E6 band of Galileo will offer more accurate positioning compared to the Open Service available in the E1 and E5 bands, and of course compared to the service provided by other systems such as GPS. Apart from the promising performances of the High Accuracy Service offered by Galileo in this band, the resources to provide authentication to the service available in the same must be highlighted. It cannot be forgotten the fact that safety is a must for autonomous driving, so supporting this band that covers from 1261 MHz to 1300 MHz could eventually become mandatory for vehicles.
The deployment of the advanced dual-frequency receivers (and their subsequent advanced positioning techniques) is technically possible with antennas that exist today since other sectors already provide antennas with the desired features. However, the autonomous car that we are imagining today shall be a vehicle accessible for a large part of the population, a vehicle that is mass-produced. The adoption of these cars will not be possible while the systems that are integrated into autonomous car prototypes are not able to reach the market price.
This is precisely one of the main objectives of this project, to design an antenna that, besides being technically competitive for the most advanced systems, is a cost-competitive antenna for the automotive market that fulfils mechanical and electronic design requirements of the automotive sector. The proposed antenna will increase the frequency bands that are offered to the GNSS receivers of the vehicles. It will include the E6 band of Galileo offering, in this manner, not only more accurate but also safer positioning due to the authentication service.
The final idea behind MAGICA project is to develop a more accurate antenna to be used in the Autonomous Car framework.