Recent results from CYGNSS measurements over land show the importance of coherent scattering. It is envisioned that future GNSS-R instruments will have the ability to separate and detect coherent scattering and downlink complex-valued coherent DDM measurements. This additional information will allow carrier phase altimetry, the separation of coherent and non-coherent scattered power, and the evaluation of geo-physical phenomena at along-track resolutions 10x greater than current spaceborne instruments, such as TDS-1 or CYGNSS. In this paper, we will present a prospective design for the on-board detection of coherent reflections. We also investigate how to achieve enhanced along-track resolution.

Adaptive antenna arrays have become the system of choice for protecting Global Navigation Satellite Systems (GNSS) receivers in strong radio frequency interference environments. GNSS receiver adaptive antenna arrays have small aperture (of the order of a wavelength) and few (e.g., less than 10) elements. In the near future, even smaller vehicles will be equipped with protected GNSS receivers. Therefore, future GNSS receiver antenna arrays will be even smaller in size. At the same time, requirements for availability, accuracy, and integrity monitoring will increase. Novel array signal processing techniques need to be developed and deployed to meet these requirements. This paper presents state-of-the-art GNSS adaptive antenna array signal processing techniques. Some drawbacks of the current GNSS antenna signal processing techniques are also discussed in this paper, and new ideas for further research and development in GNSS adaptive antennas are presented.

A signal processing technique is developed to reduce clutter due to ground bounce in ground penetrating radar (GPR) measurements. This technique is especially useful when a GPR is used to detect subsurface antipersonnel mines. The GPR clutter is modeled using a simple parametric model. Buried mine and clutter contributions are separated through a pair of coupled iterative procedures. The algorithm outperforms existing clutter reduction approaches and also yields target features that are useful for detection and identification of these mines. The proposed technique effectively reduces clutter resulting in a significant decrease in false alarm rates.