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GF-8804/05

Multi-GNSS Disciplined Oscillator

More details

  • Wide product range in terms of size and holdover performance
  • Concurrent reception of GPS/GLONASS/Galileo/QZSS/SBAS
  • In conformity with G.8272 PRTC-A, PRTC-B (GF8801 : PRTC-A complied only)
  • TRAIM, Single Satellite Tracking, Multipath Mitigation, Anti-Jamming and Anti-Spoofing

Atomic clock class stability GNSSDO 24-hour holdover performance comparable to Rubidium.

GF-88 series is a full-featured multi-GNSS disciplined oscillator (GNSSDO), embedded with multi-GNSS receiver, OCXO, LDO regulator and antenna detection circuit in a compact pin-header module.
It provides outputs of one-second pulse (1PPS), synchronized with Coordinated Universal Time (UTC), and reference frequency (10MHz) signal.

GF-8805, equipped with a high quality OCXO, has a frequency stability equivalent to that of an atomic oscillator of 1.5 μs / 24 hours, not only during reception of GNSS signals, but also during holdover when GNSS falls into unlock. Another module called GF-8804 shares the same form factor with excellent cost performance. It is recommended either model based on designers request could save significant time and effort during product design.Features

Generates UTC-synchronized 1PPS (pulse per second) and continuously disciplined 10 MHz

One-module combining a GNSS receiver, crystal oscillator and peripheral circuits that dramatically reduces design cycle (time-to-market) of wireless system.

GNSS Receiver manufacturer featured one-package solution (no need external CPU)

Extremely high stability of 4.5ns (1sigma) using a single band receiver in conformity with G.8272 PRTC-A, PRTC-B

FURUNO technology made it possible to achieve 5G performance with 4.5ns (1 sigma) stability by single band receiver. For example, GF-8803 is in conformity with G.8272 PRTC-B. This is achieved by an improved and advanced position estimation algorithm. It optimizes position calculations using several different GNSS satellite constellations. It allows users to achieve 5G-required performance without changing existing single band GNSS antennas.


Suitable for various RF・Broadcasting applications. Designed functions aiming to solve usual troubles on site.

The number of radio stations applied with GNSS time synchronization, ex. PMR, local 5G, and V2X, has been increasing year by year. Especially in urban area, users have to face problems such as urban canyon (signals blocked) and multi-path (signals reflected) etc.

GF-88 series have embedded solutions against;

  1. Multipath in Urban area
  2. Jamming (interference wave)
  3. Spoofing
  4. Interruption of GNSS signal (holdover)

In addtion, as a longterm supplier of major mobile base venders, Furuno keeps the same carrier grade quality on GF series as well.

1.GNSS antennas can be mounted on walls and windows of tall buildings
The Dynamic Satellite Selection™* minimizes deterioration of time synchronization performance by choosing only the high quality satellite signals
* a new satellite signal selection algorithm developed by NTT



* GF-880x : GT-88 + OCXO/TCXO
2.Jamming (interference wave)

If GNSS receiver is interfered by jamming signals, it can mitigate the negative impact and prevent GNSS signal loss or failure. It also helps investigate the source by detecting and monitoring frequency and power level from the jamming signals.

3.Spoofing

Malicious spoofing signals intentionally mislead the position and timing calculation of the GNSS receiver. Therefore it is designed to detect and cancel such effects and protect the system from spoofing attack.

4.Interruption of GNSS signal (holdover)

Even if the receiving satellites are all lost due to antenna failure, jamming, signal interruption, the timing function keeps working for a holdover period of time.
・In case GNSS positioning is interrupted, it predicts and corrects oscillator performance through exclusive adjusting technology.
・Excellent cost performance as replacement for atomic oscillator.

A lineup of 2 holdover-highlighted models of "Grande" form factor.

GF-8804, GF-8805 have same pin assignment and output as GF-8801~03. They are designed for applications that request different holdover ability.

For size oriented users, GF-8801, GF-8802, GF-8803 are also available as small, low-profile model (i.e. Short form factor).

[Specification]

Form factorModel1PPS Accuracy10MHz Short Term Stability
(Root Allan variance ( =1s))
Size (mm)
Lock StateHoldoverLock State, Holdover
ShortGF-8801< ±40ns-< 5×10-1034×27×11
GF-8802< ±40ns< ±50μs/24h< 5×10-1134×27×15.5
GF-8803< ±40ns< ±10μs/24h< 2×10-1134×27×20
GrandeGF-8804< ±40ns< ±5μs/24h< 1×10-11100×52×20
GF-8805< ±40ns< ±1.5μs/24h< 1×10-11100×52×20

[Test data]

1PPS Timing Accuracy <± X μs continued from start of holdover.
* Reference information only, values not guaranteed.
Form factorModel1PPS Accuracy
< ±0.1μs< ±0.4μs< ±1.1μs< ±1.5μs< ±5μs< ±10μs
ShortGF-8802--1h2h8h16h
GF-8803-1h3h4h16h-
GrandeGF-8804-2h6h8h--
GF-88052h6h18h---

Coherent behavior between time pulse (jitter less 1PPS) and frequency (10 MHz)

Single satellite tracking capable operations (except Navigation Mode)

Synchronization with external pulse

Enables synchronizing to time pulse from an external source
・Usable to synchronize to time information such as IEEE1588 or SyncE obtained through the network
・Improves robustness of the system

T&F_Gx-88_WP1

White Paper : Measures against GNSS jamming (jamming wave)

Download (637.75k)

T&F_Gx-88_WP2

White Paper : High stability of 4.5ns (1sigma) using a single band GNSS timing receiver

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T&F_Gx-88_WP3

White Paper : World class synchronization accuracy in urban areas

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T&F_Gx-88_WP4

White Paper : Measures against GNSS spoofing signals

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T&F_Gx-88_WP5

White Paper : “Holdover function” as a countermeasure against GNSS reception interruptions

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T&F_Gx-88_GNSS-Timing-catalog

Furuno Gx-88 GNSS Timing Catalog

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T&F_GF-880x_PS

Furuno GF-880x Protocol Specifications (eSIP)

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T&F_GF-8804_05_HS

Furuno GF-8804/GF-8805 Hardware Specifications

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DescriptionPart-Number
GF-8804 [Holdover : 1 PPS less than ±5μs/24h ; 10MHz less than 1x1e-11]GF-8804
GF-8805 [Holdover : 1 PPS less than ±1.5μs/24h ; 10MHz less than 1x1e-11]GF-8805
GF-8804 Evaluation KitVF-84
GF-8805 Evaluation KitVF-85