GF-8805 holdover experiment (test environment, transition of time accuracy)
- GNSS for Time Sync
Multi-GNSS Disciplined Oscillator
Model GF-8804/05
Atomic clock class stability GNSSDO
24-hour holdover performance comparable to Rubidium
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, 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.
New product: High robustness with dual frequency band reception of L1 and L5. The GT-100 can also deliver programmable frequency clock outputs.
- GNSS (Timing, Automotive/Industrial)
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 compliant 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. GF-8804 and GF-8805 are both compliant 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;
- 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 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 factor | Model | 1PPS Accuracy | 10MHz Short Term Stability | Size (mm) | |
|---|---|---|---|---|---|
Lock State | Holdover | Lock State, Holdover | |||
Short | < ±40ns | - | < 5×10-10 | 34×27×11 | |
< ±40ns | < ±50μs/24h | < 5×10-11 | 34×27×15.5 | ||
< ±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 | |
[Test data]
1PPS Timing Accuracy <± X μs continued from start of holdover.
- Reference information only, values not guaranteed.
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
Enhance performance in combination with recommended antenna
AU-300 Multi-GNSS Timing Antenna delivers both high stability and high robustness.
Specifications
General
GNSS Reception Capability
GPS L1C/A, GLONASS L1OF, Galileo E1B/E1C, QZSS L1C/A, QZSS L1S, SBAS L1C/A
GNSS Reception
32 channels
Sensitivity
GPS
Tracking: > -162 dBm
Acquisition: > -148 dBm
GLONASS
Tracking: > -158 dBm
Acquisition: > -144 dBm
Galileo
Tracking: > -146 dBm
Acquisition: > -136 dBm
QZSS
Tracking： > -147 dBm
Acquisition： > -131 dBm
*Measurement platform with recommended active antenna
ITU-T Recommendation
Compliant with G.8272 PRTC-A, PRTC-B
Initial Stabilization Time
< 5 minutes (until lock state)
10 MHz Output
Square pulse, Sine wave
10MHz Output (Lock State)
10MHz Long Term Stability (24h average): < ± 1 × 10⁻¹²
10MHz Short Term Stability (Root Allan variance ( =1s)): < 1 × 10⁻¹¹
1PPS Output (Lock State)
1PPS Accuracy: < ± 40ns (vs UTC)
1PPS Stability: < 4.5ns（1 σ）
*Open sky
10MHz Output (Holdover)
GF-8804
10MHz Long Term Stability (24h average): < ± 1 × 10⁻¹⁰
10MHz Short Term Stability (Root Allan variance ( =1s)): < 1 × 10⁻¹¹
GF-8805
10MHz Long Term Stability (24h average): < ± 3 × 10⁻¹¹
10MHz Short Term Stability (Root Allan variance ( =1s)): < 1 × 10⁻¹¹
1PPS Output (Holdover)
GF-8804
1PPS Accuracy: < ± 5μs/24H
（< ± 400ns/1H(TYP))
GF-8805
1PPS Accuracy: < ± 1.5μs/24H
（< ± 400ns/1H(TYP))
Supply Voltage
5.5 VDC
Current Consumption
400 mA(Typ)
*When supply voltage is stabilized
Operating Temperature
-40°C to +85°C
Antenna Detection
Short and Open Detection
Outer Size
100 mm x 52 mm x 20 mm
Protocol
eSIP (NMEA 0183 Standard Ver 4.10)
Functions
Anti-Jamming (BCW), Multipath Mitigation (Dynamic Satellite Selection™), Anti-Spoofing, T-RAIM, Synchronization with external pulse
Countermeasure for GNSS receiver failure
We provide technical white papers for each of the typical failures caused by GNSS receiver. For each failures, our experts in time synchronization explain details about countermeasures on receiver side, using diagrams to show the effectiveness, and how to select products. If you are considering a GNSS receiver for the first time, please take a look.
- High stability with single band receiver
White Paper: High Stability of 4.5ns (1 sigma) using a single band GNSS timing receiver - Multipath in Urban area
White Paper: Industry-leading multipath mitigation in urban canyon environments - Jamming (interference wave)
White Paper: Measures against GNSS jamming (jamming wave) - Spoofing
White Paper: Measures against GNSS spoofing signals - Interruption of GNSS signal (holdover)
White Paper: "Holdover function" as measures against GNSS reception interruptions
Evaluation Kit
P/N VF-84 :Evaluation kit for GF-8804
P/N VF-85 :Evaluation kit for GF-8805
P/N VF-85 :Evaluation kit for GF-8805
Contents: GNSS antenna, CD (GNSS Conductor GF), USB cable
- Output time pulse (1PPS) and 10 MHz reference frequency (selectable) from a SMA terminal.
- Simple use by connecting the GNSS antenna with the power supply.
- Connect the PC with a USB port to communicate.
Our Customers
GF-88 series is selected as a core part of Grandmaster Clock (GMC), which plays key role in synchronization of network devices.
Quote Request
Please fill out the quote form and our staffs will respond to you shortly.
This is a quote form only for GNSS receivers for time synchronization.
For other contents, please contact us using the respective inquiry form.
Downloads
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| Dec 13, 2024 | |
| Dec 13, 2024 | |
| Oct 6, 2022 | |
| May 24, 2019 |
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Inquiries about GNSS Products
- Specifications subject to change without notice.
GNSS for Time Sync Product List
Timing Multi-GNSS Receiver Module
Model
GT-100
Timing Multi-GNSS Receiver Module
Model
GT-90/GT-9001
Timing Multi-GNSS Receiver Module
Model
GT-88
Multi-GNSS Disciplined Oscillator
Model
GF-8801/02/03
Multi-GNSS Disciplined Oscillator
Model
GF-8804/05
GPS Disciplined Oscillator
Model
GF-8048
Field Time Sync Generator
Model
TB-1There are no products that meet the conditions.
GNSS for Time Sync
GNSS for Automotive & Industrial
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Coaxial lightning arrestor TVA-03C/TVA-03V
GNSS Surge Protector TVA-05V
Multi-GNSS antenna AU-18
GPS Antenna AU-15