Repeatable performance testing with truly representative real-world GNSS signals
A self-contained, versatile and easy to use system for recording GNSS signals and replaying them in the lab.
Spirent’s GSS6400 is a complete, standalone record and playback system, designed for recording live GPS L1, GLONASS L1, Galileo L1 and QZSS signals in the field, and playing them back in the lab with optimal fidelity and performance.
The GSS6400 records not only the GNSS signals (including SBAS where present), but also the background noise or interference, making the replayed signals truly representative of the real-world conditions.
Repeatable, representative testing
Testing performance against real-world signals is a crucial stage in the R&D of any location-aware technology. But real-world GNSS signals and environments are, by their nature, constantly changing—and as a result, the value of testing against a live sky is inherently limited.
By recording live GNSS signals for repeated playback in the lab, the GSS6400 not only makes truly meaningful, comparative testing possible, it accelerates R&D and drives down test costs by eliminating the need for repeated trials in the field.
The GSS6400 has a wide range of applications:
- Chipset and GNSS product design
- Evaluating receiver variants
- Performing vendor selection
- Developing navigation algorithms
- Performance characterization in difficult environments
- Production testingTesting telematics, and finding faults in multimedia and control BCM units
The GSS6400’s 2-bit encoding provides optimum signal quality for testing applications, OCXO playback is also included at no extra cost, and its 500GB SATA drive (a SSD option is also available) supports approximately 30 hours of recording time.
For extended record capacity you can use an external SATA drive, or take advantage of the convenient USB ports to move files onto other media such as pen-drives.
To complement the GSS6400, Spirent also offers a live sky global data set subscription. The data sets give you access to a broad range of representative GNSS environments recorded at locations worldwide, without you ever needing to leave the lab.
The GSS6400 can also record and playback serial data from a wide range of data sources:
- CAN Bus
- Inertial sensors
- DR sensors (gyros and wheel speed sensors)
- reference receivers
- 1pps signals
The system supports the synchronous/asynchronous record and playback of two channels of this serial digital data alongside the GNSS signals, giving you the power to design and test integrated GNSS devices.
The GSS6400 can also start and stop both record and playback on a pulse, enabling easy integration of the GSS6400 with other test applications and systems.
The GSS6400 can also start and stop both record and playback on a pulse, enabling easy integration of the GSS6400 with other test applications and systems.
Videos
GSS6400 Record & Playback
Spirent’s GSS6400 Record Replay System is a complete, standalone system, designed for gathering data in the field and replaying it with optimal fidelity and performance back in the lab.
On-Demand Webinars
Record & Playback for GNSS Testing
Presenter: Steve Hickling
Duration: 60 minutes
Saving Costs with GNSS Record & Playback
Presenters: John Pottle, Steve Hickling and Rahul Gupta
Duration: 60 minutes
eBooks
Find out more about how Spirent’s GSS6400 can help you by downloading our eBooks.
An Introduction to GNSS RF Record & Playback Systems Pt2
This ebook introduces the additional benefits offered by a Record Playback System (RPS) approach, describing the key testing areas where such an approach can add value.
GSS6400 RPS Applications & Testing Examples
Spirent describes the applications, uses and results that can be obtained when using the GSS6400 GNSS Record and Playback System for the development and test of GLONASS and GNSS receivers.
GSS6400 Help Sheets
GSS6400 "How To" Help Sheet #1
This help sheet explains the use of the Built-in Attenuator in the GSS6400 Record Playback Systems
GSS6400 "How To" Help Sheet #2
This help sheet explains the repeatability of GPS position fixes using the GSS6400 Record Playback System
GSS6400 "How To" Help Sheet #3
This help sheet explains the Repeatability Test using the GSS6400 RPS (Static GPS Signals)
GSS6400 "How To" Help Sheet #4
This help sheet explains how to Extract a Section of Data from a Recorded File in the GSS6400 Record Playback Systems
GSS6400 "How To" Help Sheet #5
This help sheet explains how to control the GSS6400 remotely
GSS6400 "How To" Help Sheet #6
This help sheet explains the use of FTP to Transfer Files Between GSS6400 and External Devices
Hyundai
When Hyundai was developing its innovative Blue Link® service in 2011, they turned to Spirent’s GNSS6400 to resolve some of their testing issues. Find out more.
LOCOSYS
LOCOSYS needed a flexible GPS platform for their own, and their customers testing requirements, they chose Spirent. Find out more.
Septentrio
When Septentrio were looking for a new way to characterise their new algorithms, they turned to Spirent. Find out more.
ST-Ericsson Case Study
ST Ericsson was looking to reduce time and travel costs incurred during extensive testing and development phases of their GPS and GNSS receiver chipsets. Find out more.
Q. What is the longest single recording possible?
A. In theory the largest possible file is 16TB (about 45 days of GPS data) this is limited by the size of the hard drive which for a 500GB drive gives around 30 hrs.
Q. How can I use the GSS6400 to evaluate sensitivity?
A. Record a signal with a known C/No and at least 10dB higher than the expected sensitivity. Replay into the receiver under test and increase the attenuation setting once signal are acquired until they are lost. Note that the result is repeatable and comparable between units however absolute accuracy depends on the noise figure of the receiver under test.
Q. Why 2 bits instead of 1 bit?
A. Recording at 2 bits adds just less than 1 dB of noise compared to the true signal. Recording at 1bit adds 3db, and is therefore not as good if you are trying to test sensitivity. 2 bits also improve the dynamic range to help cope with jammers.
Q. Can the output be split for distribution?
A. Yes. Please use the DC block provided if the splitter provides DC for an antenna.
Q. The GSS6400 can use passive or active antenna. What is the range of antenna gain that can be accommodated?
A. Up to 27dB gain antennas are supported.
Q. Can I use a splitter before the RF input during record to allow a reference receiver to log NMEA messages?
A. Yes, a dc block may be required on one of the splitter outputs depending on the dc arrangement of the splitter.
Q. Can files be managed remotely? For example if a recorder was left unattended but networked could a remote user start / stop recording and then collect the files?
A. Yes. The web server can be accessed remotely via the internet, depending on you local IT policy. You can also VNC into the box … which is a PC.
Q. Can the username and password be modified by the user?
A. The password can be modified, but the username cannot.
Q. If I want to control a unit from a local laptop what is the best way of doing this?
A. The easiest way is to connect them via an Ethernet hub or switch.
Q. Please confirm that there are 6 ways of controlling the unit:
- Front panel
A. Yes playback/record etc.
- Keyboard/Monitor/Mouse at the rear panel
A. Yes but to control the pc run scripts, or open a browser and go to http://localhost to run the Webserver interface.
- Webserver via the internet (using dynamically assigned IP address)
A. Yes playback/ record etc.
- Webserver locally using crossover cable
A. Yes playback/record etc. Currently the manual does not include instructions on how to do this. An application note will be produced to detail the process.
- VNC remote desktop
A. Yes but to control the pc run scripts, or open a browser and go to http://localhost to run the Webserver interface.
- Linux shell scripts
A. Yes
Q. If I transfer files to an external hard drive (via SATA or USB) can I then retrieve those files using a PC running Windows OS?
A. Yes
Q. Can I use the USB ports for a flash drive/memory stick?
A. Yes
Q. Can this unit be used for production test?
A. Yes. If for example you take the unit outside and track satellites with a clear view of the sky you can replay this data into the unit under test. The UUT should give the same position or C/No on every receiver under test.
Q. Should I see the same performance on my receiver as I would have done in the real world?
A. Yes. The only difference is that the C/No will be a little lower than in the real world due to the noise figure of the two receiver front ends that have been used, typically <1.5dB.
Q. Can I record L2?
A. No. L2 is a different frequency and the GSS6400 operates at L1 only.
