The American Surveyor

Nine GNSS Frequencies Available through New JAVAD GNSS Receiver

January 28, 2014 – The 864-channel TRE-3 receiver, just announced by JAVAD GNSS, can simultaneously access all current GNSS signals, with room to spare for multiple-channel tracking of select signals, according to the company. The new product offers many features, including:
• Three ultra wide-band (100 MHz) fast sampling and processing, programmable digital filters and superior dynamic range. After 12-bit digital conversion, nine separate digital filters are shaped for each of the nine GPS L1/Galileo E1, GPS L2, GPS L5/Galileo E5A, GLONASS L1, GLONASS L2, Galileo E5B/BeiDou B2/GLONASS L3, Galileo altBoc, Galilee E6/BeiDouB3/QZSS LEX, and BeiDou B1 bands.
• Each band consists of a combination of a digital cascaded integrator-comb (CIC) filter and a digital finite impulse response (FIR) filter (up to 60-th order) where signal selection is performed.
• Two types of digital in-band anti-jamming filters (automatic 80-th order and “user selectable” 256-th order).
• Multiple channels to acquire and track each satellite signal. For example, 20 channels can be assigned to acquire the GPS L1 signal, each spaced one millisecond apart. Up to 5 channels can be assigned to track each signal, each with different filter parameters and tracking strategies. This supports acquiring and tracking weaker signals in difficult conditions, especially under trees and canopy — potentially using up to the 864 channels available in the receiver! Several patents are pending.
• 80 dB out-of-band interference rejections: high dynamic range of wide RF bands and highly rectangular digital filters make the receiver much more resistant to out-of-band jamming.
• High-speed high-dynamic automatic gain control (AGC) to respond to interferences and signal variations.
• Programmable filter width (by commands).
• Highly stable digital filters (band characteristics do not change with age, input voltages, or temperature).
• Improved GLONASS inter-channel bias performance (due to a flat digital filter shape).
• New multipath rejection technique.
• 60-MHZ-wide Galileo altBoc band takes advantage of the full benefit of this signal. Its multipath resistance is improved even beyond that of the company’s new multipath reduction technique, it asserts.
• 864 GNSS channels allow tracking all current and future satellite signals.
• Three wide-band RF sections enable monitoring spectrums and interferences in three 100-MHz-wide bands.
• TRE-3 can track and decode the QZSS LEX signal messages, making it a unique product on the market in this regard, according to the company.
• Features for time -transfer applications: In time sources where the zero crossing of the input frequency defines the exact moment of the time second, the receiver monitors zero crossings and accurately defines the moment of the time second. An external time interval measurement unit is not required to measure zero crossing and 1-PPS offset.
• Embedded calibrator measures phase and code delays of each of the nine bands in timing applications. External calibration is not required.

TRE-3 is form, pin-out, and command compatible with the company’s earlier TRE-G3T receiver. It uses 8-Watts of power, compared to 4-Watts of the TRE-G3T

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