Whether developing navigation algorithms, performing vendor selection, evaluating receiver variants or establishing the performance of a PND under real world conditions, you will need a repeatable representative high quality GNSS signal. Testing using real world signals is the only way to confirm performance in the presence of real world impairments or operational challenges.
Spirent’s GSS6400 Record Replay System is a complete, standalone system, designed for recording live GPS L1, GLONASS L1 and QZSS signals in the field and re-playing them with optimal fidelity and performance back in the lab. Both the wanted GNSS signals, including SBAS where present, and the background noise (or interference), are recorded making the replayed signals truly representative of the real-world conditions.
The loss of signal integrity inherent in 1-bit systems is greatly reduced by use of 2-bit encoding whilst the in-built 500GBs SATA drive provides approximately 30hrs 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. For those customers who prefer a solid state drive in the place of the standard hard drive, an SSD option is available.
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 and 1pps signals can be recorded coherently with the GNSS signals. These are embedded within the same data file to guarantee synchronisation during playback.
To complement the GSS6400, a data set subscription is also available. The data sets are accompanied by reference “truth” position data, recorded using a high grade inertial (INS) aided receiver.
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 #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
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, 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:
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Front panel
A. Yes playback/ record etc.
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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.
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Webserver via the internet (using dynamically assigned IP address)
A. Yes playback/ record etc.
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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.
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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.
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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.
