This article first appeared in the Railway-News magazine Issue 3 2023.
In a previous Railway-News article, ‘Precise Positioning for Railway Vehicles’, some of the fundamentals of Global Navigation Satellite System (GNSS) operation were described, including pseudo-random noise (PRN) code-based and carrier phase-based measurement methods for position calculations.
Also discussed was the use of real-time kinematic (RTK) corrections via base/rover GNSS receiver pairing to achieve sub-6cm accuracy. RTK accuracy is required to improve rail safety and productivity, especially in autonomous systems.
Briefly recapping, GNSS antennas require a stable phase centre, predictable phase centre variation, a design that mitigates multi-path and supports deep out-of-band filtering of interfering RF signals (e.g. 5G cellular signals). At the same time, the antenna must be capable of receiving GNSS and augmentation (correction) signals broadcast from medium earth orbits and geostationary satellites, respectively.
Traditional GNSS installations placed the GNSS antenna on the roof or a mast and ran a coaxial RF cable to the receiver. This design is suitable for installation where the antenna and antenna cable are not subject to RF noise. Today’s installations are increasingly complicated, and often, sensors are collocated; therefore, both the antenna and RF cables are subject to interference from these sensors or vehicle communications (RF signals).
In a Smart Antenna, the GNSS antenna and receiver are in the same enclosure, often on the same PCB, and are shielded from these other sensors and RF noise. A smart antenna design provides the cleanest and purest signal to the receiver. With a clean and pure signal, the receiver can estimate the most accurate and precise measurements.
Tallysman’s TW5390 smart GNSS antenna integrates the TW3972, American Association of Railways (AAR) certified GNSS antenna and the u-blox F9x family of GNSS receivers. The antenna has many key features such as multi-constellation, multi-band correction support (including L-band options), a low axial ratio that provides excellent multi-path mitigation, a precisely calibrated phase centre, Tallysman’s eXtended Filtering (XF), a low-noise amplifier that ensures a low noise figure and strong signal to noise ratio (C/No).
u-blox and Tallysman Wireless Inc. have announced they have signed a design partner agreement for the development of the PointPerfect PPP-RTK.
Tallysman® Wireless Inc. is excited to announce the dual-band low-profile HC871SXF to its industry-leading line of helical GNSS antennas.
Tallysman Wireless Inc. has announced a new distribution partnership with Mouser Electronics for its high-precision GNSS Antennas.
Tallysman® Wireless is excited to announce the new lightweight and low-profile SSL889XF dual-band GNSS antenna.
Tallymatics recently co-hosted a webinar focused on Global Navigation Satellite System Augmentation Technology, alongside GPS World.
Tallysman® Wireless has announced that it has added the housed SSL990XF full-band survey-grade GNSS antenna to its line of GNSS products.
Tallysman® Wireless is excited to introduce the housed AJ977XF triple-band antenna, with anti-jam technology.
TALLYMATICS Inc., a division of Tallysman Wireless, is excited to introduce its latest Smart Antenna to the market, the TW5390 Smart Antenna.
Tallysman® Wireless adds the housed TW3885T dual-band (L1/L5) timing antenna to its industry-leading line of GNSS products.
Tallysman® Wireless is excited to announce that it has added eXtended Filtering (XF) to their helical antennas.
Tallysman's new HC885EXF and HC885XF helical antennas are ideal for a variety of applications, including UAV's for land, sea and air.
Tallysman® Wireless announced that it has added eXtended Filtering (XF) to the full line of VeroStar® precision GNSS antennas.
Tallysman® has added Galileo-E6, QZSS-L6, and BeiDou-B3 support to the TW7000 line of surface-mount antennas.
Tallysman® Wireless Inc. announces the addition of its first full-band GNSS antenna to its industry-leading line of Helical antennas.
Tallysman Wireless is excited to announce new eXtended Filtering (XF) features to the TW3900 series of Accuntena® precision antennas.
Airspan Networks has selected Tallysman timing antennas for its innovative Cloud-Native, Open Radio Access Network (O-RAN) solutions.
Tallysman Wireless Inc. has been acquired by Calian Group Ltd, a publicly owned Canadian company listed on the Toronto Stock exchange (CGY).
Tallysman® is excited to announce that the TW3972 has added European Rail Certification to its already impressive list of qualifications.
Use the form opposite to get in touch with Tallysman Wireless Inc. directly to discuss any requirements you might have.