Antennas as Precise Sensors for GNSS Reference Stations and High-Performance PNT Applications on Earth and in Space

Satellite navigation is more and more important in a plethora of very different application fields, ranging from bank transactions to shipping, from autonomous driving to aerial applications, such as commercial avionics as well as Unmanned Aerial Vehicles (UAVs) . In very precise Positioning, Navigation and Timing (PNT) applications, such as in reference stations and precise timing stations, it is important to characterize all errors present in the system, in order to possibly account for them or calibrate them out. Antennas play an important role in this respect: they are indeed the “sensor” that captures the signal in space from Global Navigation Satellite Systems (GNSS) satellites and thereby strongly contribute to the overall achievable performance. This paper reviews the currently available antenna technologies, targeting specifically reference stations as well as precise GNSS antennas for space applications, and, after introducing performance indicators, summarizes the today achievable performance. Finally, open research issues are identified and possible approaches to solve them are discussed

A Miniaturized All-GNSS Bands Antenna Array Incorporating Multipath Suppression for Robust Satellite Navigation on UAV Plattforms

Nowadays, an increasing trend to use autonomous Unmanned Aerial Vehicles (UAV) for applications like logistics as well as security and surveillance can be recorded. Autonomic UAVs require robust and precise navigation to ensure efficient and save operation even in strong multipath environments and (intended) interference. The need for robust navigation on UAVs implies the necessary integration of low-cost, lightweight and compact array antennas as well as structures for multipath mitigation into the UAV platform. This article investigates a miniaturized antenna array mounted on top of vertical choke rings for robust navigation purposes. The array employs four 3D printed elements based on dielectric resonators capable to operate in all GNSS bands while being compact enough for mobile applications such as UAV

A Multi-Band Conformal Antenna Array for GNSS Applications

The position accuracy in satellite navigation is enhanced when low elevation satellites are included in the triangulation due to the contribution of satellite geometry. Moreover, improved reception of low elevation signals leads to a higher overall system availability. However, the receiving antenna characteristics usually suffer from low-gain and high axial ratios at low elevations. In this contribution, an antenna array conformal to a spherical cap is presented. The array consists of a single antenna on top of the cap and six, radially directed, equally spaced elements on a ring. The manufactured antenna achieves a gain between 0 dB and 4 dB with low axial ratio in the forward hemisphere at the E5a/b and E1 center frequencies of 1.176 GHz, 1.207 GHz and 1.575 GHz, respectively

Analysis of Circular Polarization Properties of 4x4 Arrays at Ka-band

This paper investigates polarization properties of circularly polarized 4x4 patch arrays at Ka-band for classical arrangement and sequential rotation of elements. The investigations are performed for various values of axial ratio of array elements and different steering angles. The simulated results are validated by measurements of fabricated arrays

Design and Installed Performance Analysis of a Miniaturized All-GNSS Bands Antenna Array for Robust Navigation on UAV Platforms in GNSS Denied Environments

Global navigation satellite systems (GNSS) are vital technologies of our age and serve a plethora of industries that rely on precise positioning for automation, efficiency and safety. Emerging applications of unmanned aerial vehicles (UAV) in critical applications like security, surveil-lance, critical logistics and defense demand precise and robust navigation capabilities even in challenging environments with high multipath or (un-)intended interference and jamming. The design of robust GNSS receivers for UAV applications, capable of suppressing interfering sig-nals, is challenging due to the need for multi-antenna systems and the stringent requirements on hardware to be lightweight and miniaturized enough to fit onto small mobile platforms. In or-der to overcome these limitations, the present article details a four-element wideband antenna array, fitting into a 100mm diameter footprint. The array is capable to operate across all GNSS frequency bands while incorporating a miniaturized vertical choke ring multipath mitigation solution. The antenna performance is evaluated in terms of its radiation pattern via installed an-tenna simulations and measurements in an anechoic chamber. The effect of vertical choke rings and different installation heights above the UAV on the antenna pattern is studied. Furthermore, GNSS measurements, carried out with the array alone and mounted on the UAV are presented

An active phased array for mobile satellite communication at Ka-band in LTCC technology

To transfer broadband services to mobile users by satellite communications a large bandwidth is required. Because the frequency spectrum at lower frequencies is very crowded with different services, free broad frequency bands can be found only at Ka-band or at higher frequencies. The user terminal antenna for satellite communication should have preferably low profile so that it can be conveniently integrated into e.g. aircraft, ship or vehicle. Antennas based on the reflector technology have necessarily high profile. Antennas with lower profile are based on array technology. They can be fully electronically steered or offer a combination of electrical and mechanical scanning in elevation and azimuth respectively. The lowest profile offer fully electronically steered antennas