A free tool to monitor GPS output
An advanced PC GPS time synchronization
Legacy VisualGPS application
A PC GPS time synchronization tool
VisualGPS XP (Legacy)
Legacy VisualGPS application
Clock Maze Screen Saver
A Free screen saver that sloves a maze and shows the time
VisualGPSView (Freeware) incorporates many advanced features that show the status of the GPS receiver via the NMEA 0183 protocol. Its sole purpose is to display graphically specific NMEA 0183 sentences for GPS and position analysis.
- GPS Receiver connected to a RS-232 port or USB with NMEA 0183 output
- Windows 7 to Window 10
VisualGPS decodes the following NMEA 0183 sentences:
- GPGGA and GLGGA
- GPGSA and GLGSA
- GPGSV and GLGSV
The price for NMEATime2 is $20.48USD If you purchase NMEATime2, we will send you a registration key via email within 48 hours.
NMEATime2 is very different from the original. It’s set up as a system service where the PC clock is disciplined to the NMEA string from the GPS. The control loop uses the same techniques in disciplining OCXO oscillators and atomic Rubidium clocks. By charactering the arrival of NMEA messages, NMEATime2 uses advanced digital filters to minimize communication jitter and achieve the best reference to train the PC clock to.
Because of this, there are some requirements that need to be met. Specifically, the rate output of NMEA message GPGGA and GPRMC.
It’s getting more difficult to find a PC with a native RS-232 serial communication port, most GPS receivers that interface to a PC use a USB. The majority of the USB GPS receivers will look to the PC as if it is a serial port. However, the modern USB GPS looks to the PC as a USB to Serial driver that emulates the serial port. In the USB world, it’s referred as a CDC (communication device class) device.
NMEATime2 will use the NMEA string (GPGGA) transmitted from the GPS, time tag the first character of the that command and use this as a timing reference. As you would expect, there are delays between the 1PPS epoch and the RS-232 causing software jitter. The delay can be calibrated out. NMEATime2 will use digital filtering (the red line you see in the Time Difference Plot - see below) and discipline the PC clock to this reference.
The minimum NMEA sentence requirements matter. The most important is that the GPGGA and GPRMC message output once per secnd.
- GPGGA - must be at least once/second
- GPRMC - must be at least once/second
- GPGSA - every two seconds
- GPGSV - every two sconds
Please note to access NMEATime control panel, simply right click on the tray bar icon and select show panel
GPS Receiver Notes
The following are GPS receivers have been tested and the notes at accompany them. If you find that another receiver is working well, please let us know and we can list it here.
- BU-353-S4 - USGlobalsat - This USB SiRF Star IV based receiver seems to work well and has no issues.
- Navibe GM 720 - USB SiRF Star III based GPS works with no issues
- Holux M-215+ - This USB receiver will function, however it causes Windows 10 to BSOD when connecting/disconnecting the USB physically from the computer. Not recommended.
- Generic USB GPS from Amazon (link) - This USB receiver seems to work well. No issues.
The above plot is showing the GPS receiver under a startup condition, cold start. Consumer GPS receivers will not indicate cold start, however it will still navigate and produce time when tracking satellites. The problem is when in this mode, the GPS may not have a full almanac (all the data from the satellites) and the time may be referenced to GPS time or something close. When the timing portion of the almanac is received, you may notice a jump in timing as depicted above. This jump usually happens within 13 minutes from the time the GPS starts tracking satellites. This is the approximate time it takes to download an almanac from the satellites. The plot shows the GPS jumping two seconds taking just a less than five minutes to occur from the start of tracking satellites.
It’s recommended to wait for at least 15 minutes before using the PC for any critical timing application when first powering up the GPS.
The test setup was using a GlobalSat BU-353-S4 USB GPS with the PC referenced to a NTP server. The data was taken using NMEATime2 with the control loop turned off and the control loop logging enabled. You can perform the same test with your GPS receiver. The control loop log will produce a comma separated value file (CSV) where you can perform analysis. The value to use is the Raw Time Difference.
If you like VisualGPS and would like to support more products like these, please donate. Suggest donation $5 USD
Currently VisualGPS is over 10 years old! NMEA support is only limited to GPS NMEA strings (Not GLONASS or Galileo). We recommend that you download VisualGPSView.
VisualGPS (Freeware) incorporates many advanced features found in professional programs. Its sole purpose is to display graphically specific NMEA 0183 sentences and show the effects of selective availability (SA).
- GPS Receiver connected to a RS-232 port with NMEA 0183 output - NMEA demo file included for those who do not have a GPS receiver
- Windows 2000 sp4, Windows XP, Vista or Windows 7
- 486 100MHz or higher microprocessor
- SVGA at least 1024X768 resolution
- 16 megabytes of RAM
- 6 megabytes of disk space
- One available RS-232 port (or captured NMEA text file - included)
VisualGPS decodes the following NMEA 0183 sentences:
Download a free copy of VisualGPS program. It is a 32 bit program written for both the Windows 2000, XP and Vista environments. This software is freeware and there is not charge for it.Download
Purchase NMEATime for $15.00USD
Currently NMEATime is over 10 years old! It only supports GPS NMEA string (Not GLONASS or Galileo). We recommend that you download NMEATime2
NMEATime will automatically set your PC clock using a GPS receiver connected to the serial port of a PC or to the National Institute of Standards and Technology (NIST) time servers over the Internet. Using network time or the time from a GPS receiver, NMEATime will keep your computer referenced to an atomic time standard.
|Also included with NMEATime is a NASA type desktop clock configurable to show day of year, 24 hour time or local time, color and size.|
- Digital desktop time code clock - like NASA has!
- Analog desktop clock
- Uses GPS Time to set your PC clock
- NMEA 0183 v2.20 - 3.01 compatible
- Software generated IRIG-B Output (requires sound card)
- Two Network time Protocols - Daytime NIST ACTS compatible and SNTP compatible
- Programmable time setting rate
- Selectable GPS NMEA message for time reference
- Random time server select mode from an editable server list
- Accepts 1 Pulse Per Second (1PPS) input in to RS-232 DSR or CTS port
- BONUS SCREEN SAVER! (ClockMaze)
- Transparent Clock! See what is behind the clock (XP and Win2000 only).
- For GPS time: GPS Receiver connected to a RS-232 port with NMEA 0183 output
- For network time: Access to the internet
- Windows 95/98, Win2000/XP, WinNT4.0 or higher with Internet Explorer 4.0 or higher
- Pentium 166MHz or higher microprocessor
- SVGA at least 800X600 resolution
- 16 megabytes of RAM
- 2 megabytes of disk space
- One available RS-232 port (for GPS time)
- Sound board for IRIG output
NMEATime decodes the following NMEA 0183 sentences:
- GPGGA or GPRMC or GPZDA
- Compatible with NMEA 0183 version 2.01 - 3.01
Purchase VisualGPSXP for $9.95 USD
Welcome to the VisualGPSXP multipurpose GPS utility. Please note that VisualGPSXP uses specific NMEA sentences to display data graphically.
VisualGPSXP is a general purpose utility for monitoring the output of a GPS receiver. Using the NMEA data from the GPS receiver, VisualGPSXP will display various statuses graphically. Tools such as a survey utility average the position and shows accuracy of the GPS receiver in a static application. Other features such as analog gauges show altitude, speed, vertical speed and direction. One additional feature is the capability to connect and share a GPS receivers data over the Internet.
If you like our software, please donate! Suggested donation: $2USD
ClockMaze is a simple screen saver that creates a maze, solves it, and shows the current time. You can setup itemse such as solve color, maze color, and solve speed. It's free. Enjoy.
VisualGPS is located in Anaheim California, USA. If you have any questions or comments or simply send us a email or twitter.
info @ visualgps.net.
Application End User License
"[THESOFTWARE]" software application will be referred as “software application” through the remainder of this document. You should carefully read the following terms and conditions before using this software. Unless you have a different license agreement signed by VisualGPS, LLC your use, distribution, or installation of this copy of this software application indicates your acceptance of this License.
If you do not agree to any of the terms of this License, then do not install, distribute or use this copy of software application. If you paid VisualGPS, LLC for this copy individually, you may return it unused, within thirty (30) days after purchase, for a full refund of your payment.
This copy of software application may either be used by a single person who uses the software personally on one or more computers, or installed on a single workstation used non-simultaneously by multiple people, but not both. This is not a concurrent use license.
You may access this copy through a network, provided that you have obtained an individual software application license for each workstation that will access software application through the network. For instance, if 8 different workstations will access software application on the network, each workstation must have its own software application license, regardless of whether they use software application at different times or concurrently.
This software, and all accompanying files, data and materials, is distributed "AS IS" and with no warranties of any kind, whether express or implied. Good data processing procedure dictates that any program be thoroughly tested with non-critical data before relying on it. The user must assume the entire risk of using the program. This disclaimer of warranty constitutes an essential part of the agreement.
Any liability of VisualGPS, LLC will be limited exclusively to refund of purchase price. In addition, in no event shall VisualGPS, LLC, or its principals, shareholders, officers, employees, affiliates, contractors, subsidiaries, or parent organizations, be liable for any incidental, consequential, or punitive damages whatsoever relating to the use of software application, or your relationship with VisualGPS, LLC.
In addition, in no event does VisualGPS, LLC authorize you to use software application in applications or systems where VisualGPS, LLC failure to perform can reasonably be expected to result in a significant physical injury, or in loss of life. Any such use by you is entirely at your own risk, and you agree to hold VisualGPS, LLC harmless from any claims or losses relating to such unauthorized use.
This Agreement is the complete statement of the Agreement between the parties on the subject matter, and merges and supersedes all other or prior understandings, purchase orders, agreements and arrangements. The laws of the State of California shall govern this Agreement. Exclusive jurisdiction and venue for all matters relating to this Agreement shall be in courts and located in the State of California, and you consent to such jurisdiction and venue.
All rights of any kind in software application which are not expressly granted in this License are entirely and exclusively reserved to and by VisualGPS, LLC. You may not rent, lease, modify, translate, reverse engineer, decompile, disassemble or create derivative works based on software application. There are no third party beneficiaries of any promises, obligations or representations made by VisualGPS, LLC herein.
In no event shall VisualGPS, LLC be liable for any loss of profit or any other commercial or private damage, including but not limited to special, incidental, consequential or other damages, resulting from or in any way connected with the use of this software. VisualGPS, LLC specifically disclaims any other warranties expressed or implied, including but not limited to the implied warranties of merchantability and fitness for a particular use.
Do not operate software application while driving a vehicle. software application is not designed as a primary navigational aid. Failure to pay full attention while operating the vehicle and road conditions while operating the vehicle could result in an accident or collision with property damage and personal injury.