gps with pci 1426

[sandeepchinni]

Hi,

I am doing image acquisition with NI PCI 1426. I have written a program which is acquiring the images which is working fine. My next requirement is to get the GPS time when the image is captured. I only know that PCI 1426 has two ports on it (one is being used by the camera).

I would like to know how I can get the GPS time using a GPS receiver and the second avaialable port.

Thanks & Regards,

Sandeep

[SMeserve]

Hi Sandeep,

Hi again!  What kind of output does the GPS receiver give?  That is, what is the connection type (serial, etc)?  Once we know that, we can move forward.

[sandeepchinni]

Hi Stephen,

Currently I am using a GPS device which gives out parallel output. But since my computer doesnt have a parallel port I have a parallel to serial converter and then use a Radio Shack cable to convert the serial to USB1.1. I did not build the current system, so I dont know why it was built that way. The GPS signal acquisition is triggered by a pulse from the flash of a Nikon camera which is being used to do image acquisition(built using .NET). The idea being the GPS time to be logged at the instance of image capture.

I am building a similar application in LabVIEW where I need to capture images and get the GPS time at the instance of the image capture. I can use the above GPS which gives out parallel output or

a) Use Topcon Hiper Lite receiver which has Bluetooth 1.1, USB 1.1 and serial port

b) OEM receiver which has a serial port

Thanks & Regards,

Sandeep

[SMeserve]

Hi Sandeep,

I think that either of these solutions will work out for you, but the key element is the format in which the signal will arrive.  You will need to read whatever manuals come with your device to be able to decode the signal that you are receiving.

[sandeepchinni]

Hi Stephen,

Thanks for your response. I have one more question regarding the same. How can I trigger the GPS time acquire at the same time as image capture? Should I be connecting a cable from the PCI card to the GPS devices or from the camera to the GPS device or would it depend on the device that I am using?

Can you also let me know what tool kits I would require to do the communication with the GPS device?

Thanks & Regards,

Sandeep

[SMeserve · Accepted solution]

Hi Sandeep,

You can trigger the acquisition off the 1426 board using the Digital I/O connectors on the card.  You can simply send a digital logic high when an image is acquired to the GPS.  Of course, again, it depends what sort of input your GPS device will accept as a trigger.   If it can accept a TTL digital signal, you will be fine.  If not, you may be facing some conversion between the board and the GPS device.

As far as I know, you shouldn't need any special toolkits to interact with a GPS device.  A GPS Toolkit does exist for LabVIEW, but it sounds like the things you are trying to do will not require it.

[sandeepchinni]

Thanks Stephen!

Sandeep

[sandeepchinni]

One more question...how can i send a TTL signal to the GPS device when I am acquiring a series of images using IMAQGrab?

[SMeserve]

Hi Sandeep,

You can place a DAQ Assistant in the loop to just send a logic high over the digital line.  You can check out example finder for some great examples of digital input/output.  It is under Help»Find Examples... in LabVIEW.

[sandeepchinni]

Thanks again Stephen! You have been a lot of help. 🙂

Sandeep