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LD5P and PPS synchronization




  • TDY_Kevin
    Community team
    Expert (Gold)

    First of all, please take a look of our KB Using PPS to Synchronize with External GPS | Teledyne FLIR

    The LadybugImageInfo contains the timestamp and shutter time information.
    In trigger mode, the GPS timestamp is stored at the end of integration. The timestamp accuracy has a positive offset of 45 μs ±8 μs.
    In free running mode, the GPS timestamp is stored at the start of integration.
    To calculate the mid point of a frame's timestamp:
    Mid Point = Timestamp - 45 μs - 0.5 x Shutter Time"



  • TDY_Kevin
    Community team
    Expert (Gold)

    Let me explain a bit further in details:
    - the actual timestamp that gets stored, whether at the beginning of the Exposure (free run mode) or at the end of the Exposure (trigger mode) will ALWAYS be the Camera Time. This is basically a counter that takes the host PC time when ladybug unit connects to power and start to increment on its own. When you set up a PPS synchronization, this Camera Time is synced on every seconds according to your GPS Time (UTC Time) to prevent time drift over a long period.
    - PPS sync is only reached when
    GPS Status = 1
    PPS Status = 1
    Fixed Quality = 1 / 2
    You can take a look of the ladybugGPS.h header file located in C:\Program Files\Teledyne\Ladybug\include
    It is possible that your GPS device is not compatible with the Ladybug. In this case PPS sync will never be reached.
    - The GPS NMEA sentences are interpolated in the Ladybug SDK, on the host computer side. The ladybug unit does not contain the hardware/software to interpolate them. The UTC Time, is the timestamp that your GPS sends to the host PC at pre-configured frequency of your GPS device. This timestamp is not related to the image capture time, but shows that your host PC can get/read the timestamp from your GPS device. If the UTC Time is 0, PPS sync is not reached.


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