107 - Ultra high spatial resolution GNSS receiver for automotive industry

The ability of exploiting the spatial dimensions has allowed array antennas to be exploited in various applications. Over the past years, array antennas have been deployed in GNSS receivers either to provide a spatial filter or to improve the signal-to-noise ratio (SNR) using beamforming techniques. 

To achieve a high spatial resolution, a large array antenna aperture should be used. The manufacturing process of a large array antenna aperture, with fully synchronized and phase-coherent radio frequency (RF) chains, is very expensive and complex. 

Lately, synthetic aperture techniques and the supercorrelator have been proposed in the literature to provide spatial diversity. Those techniques rely on the movement of a single antenna receiver. This single antenna movement in space will create a linear virtual array, and accordingly, a directional ambiguity should be resolved. On the other hand, the supercorrelator technique relies on a long coherent correlation time.

In this activity a moving array antenna instead of a single antenna receiver is proposed. Furthermore, the deployed antenna should support simultaneously Right Hand and Left Hand Circular Polarization to increase the degrees of freedom without increasing the physical array antenna aperture. By exploiting the vehicle movement, the aperture of the array antenna (with a limited number of antennas) can be virtually expanded to provide the virtual effect of hundreds of antennas.

This will enable the following:

• Ultra-high beamforming gain, beyond any current HW
• Unlimited jamming and spoofing cancellations
• Very deep nulls towards interference, spoofing and multipath effect
• Very accurate spoofing and jamming direction finding
• The high spatial resolution array antenna should enable new applications using GNSS signals, e.g., refraction index of the ionosphere layer, dynamic mapping, obstacle detection, etc.

The objective of this activity is to implement a compact system (i.e. a hardware and a software) that is suitable to be embedded in vehicles. The hardware solution should include an array antenna to provide spatial and polarization diversities for GNSS signals. The software solution, on the other hand, should exploit the vehicle movements to increase the spatial resolution of the compact array antenna.

 

The proposed technique in this activity can be distinguished from the synthetic aperture and supercorrelation techniques as follows:

• The proposed activity aims to deploy a dual polarization array antenna 
• In case of static receiver, the array antenna will keep providing beamforming applications, though the resolution is limited to the amount of the deployed physical antennas multiplied by two (for dual polarization)
• In case of mobile receiver, the aperture of the deployed array antenna will be increased due to the movement of the vehicle, i.e. achieving a synthetic aperture that is 2*N times larger than single antenna synthetic aperture techniques (N being the number of physical antennas that will be deployed) 

The tasks to be performed shall include:

• Study, design, and demonstrate the use of a compact dual polarization array antennas in vehicles. The spatial movement of the vehicle should be captured by an accurate IMU device and modelled to create a virtual array antenna with an ultra-large aperture. 
• Design the system with the following characteristics: 
  • Phase coherency among antenna elements
  • Multiple frequency channels and dual polarization antenna elements
  • Accurate measurement of the vehicle movements
• Model the spatial movements to create an ultra large array antenna aperture
• Exploit the ultra large aperture to provide new applications, e.g. refraction index of the ionosphere layer, debris detection, dynamic mapping, obstacle detection, etc.

The main outputs of the activity will consist of:

• a GNSS receiver (hardware and a software) 
• a compact moving platform that can resemble the vehicle movement to test, verify and validate the proposed GNSS receiver
• verification report.