Introduction
The Firehose is a GNSS RF front end and digitizer. It provides three 50 MHz RF channels (and two auxiliary baseband channels), supporting signals from GPS, GLONASS, Galileo, Beidou and SBAS. Signals are transmitted on a gigabit Ethernet link using two bits for I and two bits for Q; this format provides high-quality wideband signals to any downstream software receiver or recorder.
Each of the RF channel of 50 MHz is independently tunable. That provides the multi-constellation and multi-frequency capability, since any of the GNSS frequencies can be used: L1/L2/L5, E5a/E5b, 1191 MHz (E5a+b), E6, GLONASS L1/L2/L3, any of the BeiDou bands, etc. Each RF channel is digitized at 70 Msample/s, 2 bits for I and 2 bits for Q. The samples from all three channels are then broadcast on a gigabit Ethernet port (total payload approx. 840 Mbit/s). Each RF input has a bias tee with 3.3 V for convenient antenna interfacing.
There are two auxiliary baseband inputs for 10 MHz and PPS inputs, designed for timing applications using an external high-quality clock such as an OCXO or Rb, or synchronizing multiple Firehose receivers.
The Firehose receiver can be used in many applications such as raw signal record playback, multipath mitigation modeling, timing, jamming and spoofing environments. Although the Firehose was built with an educational purpose in mind to allow students to create their own application and experiment with different signals and constellations, it can also be used for commercial receiver development.
Features and Technical Specifications
- Three 50 MHz RF channels (by default set to L1, L2, and E5a+b; tunable from 925 MHz to 2175 MHz)
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Two-bit complex sampling (70 Ms/s), 840 Mbit/s total payload
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Supports command and status over Ethernet
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Lightweight
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All GNSS signals available: GPS, GLONASS, Galileo, BeiDou, SBAS
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Compatible with any GNSS software receiver
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Open source hardware and firmware (https://github.com/pmonta/
GNSS_Firehose/) -
Firmware in C, running on a RISC-V soft CPU; can be customized by the user with open tools KiCAD for schematic and PCB layout
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Two baseband channels for 10 MHz and PPS inputs to support timing receivers
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Each RF channel provides a bias tee with 3.3 V, 50 mA
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Power: 5V DC, 2 A
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Weight: 220 g (0.5 lb)
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Dimensions: 12.5 x 10 x 3 cm (5” x 4” x 1”)
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Connectors: SMA, 1000baseT, coaxial DC power
- Ports: 3 RF and 2 Auxiliaries
- Communication: Ethernet
Firehose Package Content
- Receiver
- Power supply
- Ethernet cable, 1000baseT, 1 meter
- Antenna not included; compatible with any GNSS antenna
Want to learn more?
If you would like to learn more about the Firehose receiver and what it can do for you, visit Peter Monta’s blog: http://pmonta.com/blog/.
Ordering
To request pricing information, click on the Pricing button.
