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Session A10: Complementary PNT: PNT from LEO 2

Collins Aerospace User Equipment Results and Analysis for the Xona PULSAR System
Dave Anderson and Michael Armatys, Collins Aerospace
Location: Ballroom B
Date/Time: Wednesday, Jun. 4, 2:30 p.m.

Collins Aerospace is a leading manufacturer of military and commercial avionics based on flexible, Software Define Radio (SDR) platforms. One such SDR is the Secure Common Data Link (CDL) Intelligence, Surveillance and Reconnaissance (SCISR) radio. Originally designed as a low-Size, Weight and Power (SWaP) tactical datalink, the SCISR is also well-suited as a demonstration platform for emerging Positioning, Navigation and Timing (PNT) applications with its flexible Xilinx Field Programmable Gate Array (FPGA) processor.
Xona Space Systems is developing the PULSAR, the first commercial PNT service based on Low-Earth Orbit (LEO) satellites. The PULSAR signal is much like traditional GNSS in its signal structure, but with higher signal power, signal authentication and time distribution capability. PULSAR presents a unique opportunity for military as well as commercial applications and Collins Aerospace has chosen to develop an SDR-based PULSAR receiver for incorporation into future Collins PNT and communications products.
Leveraging decades of Global Navigation Satellite System (GNSS) software development for the commercial avionics market, the Collins team transformed the SCISR radio into a Xona PULSAR receiver. With PULSAR’s GNSS-like signal structure, existing GNSS receivers are obvious candidates for early PULSAR User Equipment (UE) platforms. The Collins team extensively used the code base for the Collins GLU-2100 commercial GNSS receiver, a certified GNSS receiver on roughly 80% of commercial air transport platforms, porting the code to the SCISR’s FPGA target hardware.
The PNT Assessment Experiment (PNTAX) 2024 presented the first opportunity to test the Collins PULSAR receiver. Xona Space Systems deployed a terrestrial transmitter at the White Sands Missile Range (WSMR) experiment site, providing a first-look at the PULSAR signal in an Over-The-Air (OTA) environment. The Collins PULSAR receiver collected acquisition data in a jamming environment as well as high-rate RF samples that can be played back for future receiver testing.
Following the successful PNTAX 2024 test and data collection campaign, Collins continued the PULSAR receiver development, including tracking, demodulation and measurement generation of the PULSAR signal. With launch of the first operational PULSAR satellite scheduled for mid-2025, testing the Collins PULSAR receiver is limited to simulator testing and use of PNTAX RF collected data. To that end, Collins Aerospace purchased a Spirent SimXona RF simulator to enable robust testing of the Collins PULSAR receiver. One special consideration for LEO UE developers is the increased Doppler shifts over which acquisition and tracking must occur relative to traditional Medium Earth Orbit (MEO) GNSS signals. SimXona enables testing of the larger Doppler range and to begin certification processes prior to Initial Operation Capability (IOC) of the PULSAR constellation.
This paper presents results for early acquisition testing at the PNTAX 2024 field event as well as results from full receiver testing using the SimXona simulator.

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