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GF-8801/02/03 
Multi-GNSS Disciplined Oscillator
- 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
Ultra-small size form factor featuring atomic clock level frequency stability with 24h holdover.
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.
Combined with ultra-miniature OCXO, GF-8802 / 8803 (approx. 34mm x 27mm) builds up a holdover function which can maintain within 10μs / 24 hours(ex.GF-8803) in case that GNSS falls into unlock. There is also low-profile module called GF-8801 embedded with TCXO on the same form factor. 3 available models 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.
GF-88 series have embedded solutions against;
- Multipath in Urban area
- Jamming (interference wave)
- Spoofing
- 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 3 compact size models of "Short" form factor.
GF-8801, GF-8802, GF-8803 are small and low-profile models for size oriented users. 3 models are all pin compatible with same output, the only difference is the holdover performance.
For very high accuarcy end users, GF-8804 and GF-8805 provides superlative holdover function (i.e. Grande form factor).
[Specification]
| Form factor | Model | 1PPS Accuracy | 10MHz Short Term Stability (Root Allan variance ( =1s)) | Size (mm) | |
|---|---|---|---|---|---|
| Lock State | Holdover | Lock State, Holdover | |||
| Short | GF-8801 | < ±40ns | - | < 5×10-10 | 34×27×11 |
| GF-8802 | < ±40ns | < ±50μs/24h | < 5×10-11 | 34×27×15.5 | |
| GF-8803 | < ±40ns | < ±10μs/24h | < 2×10-11 | 34×27×20 | |
| Grande | GF-8804 | < ±40ns | < ±5μs/24h | < 1×10-11 | 100×52×20 |
| GF-8805 | < ±40ns | < ±1.5μs/24h | < 1×10-11 | 100×52×20 | |
1PPS Timing Accuracy <± X μs continued from start of holdover.
* Reference information only, values not guaranteed.
| Form factor | Model | 1PPS Accuracy | |||||
|---|---|---|---|---|---|---|---|
| < ±0.1μs | < ±0.4μs | < ±1.1μs | < ±1.5μs | < ±5μs | < ±10μs | ||
| Short | GF-8802 | - | - | 1h | 2h | 8h | 16h |
| GF-8803 | - | 1h | 3h | 4h | 16h | - | |
| Grande | GF-8804 | - | 2h | 6h | 8h | - | - |
| GF-8805 | 2h | 6h | 18h | - | - | - | |
Coherent behavior between time pulse (jitter less 1PPS) and frequency (10 MHz)
Single satellite tracking capable operations (except Navigation Mode)
Synchronization with external pulse
・Usable to synchronize to time information such as IEEE1588 or SyncE obtained through the network
・Improves robustness of the system
T&F_Gx-88_WP2
White Paper : High stability of 4.5ns (1sigma) using a single band GNSS timing receiver
Download (550.83k)T&F_Gx-88_WP5
White Paper : “Holdover function” as a countermeasure against GNSS reception interruptions
Download (1016.72k)| Description | Part-Number |
|---|---|
| GF-8801 [Holdover : 1 PPS none ; 10MHz less than 5x1e-10] | GF-8801 |
| GF-8802 [Holdover : 1 PPS less than ±50μs/24h ; 10MHz less than 5x1e-11] | GF-8802 |
| GF-8803 [Holdover : 1 PPS less than ±10μs/24h ; 10MHz less than 2x1e-11] | GF-8803 |
| GF-8801 Evaluation Kit | VF-81 |
| GF-8802 Evaluation Kit | VF-82 |
| GF-8803 Evaluation Kit | VF-83 |