GPS-ABC has been thououghly tested by it's designers to ensure that it will give time, accurate to +/-0.001 seconds of UT.
provided that a) the A-OK LED is lit and b) a better than 4 satellite fix is maintained at all times. Reference devices.
GPS-ABS's rate of going was compared with IOTA-VTI, KIWI-OSD and KIWI-PC by using 25 frame (50 field) per second video cameras and then by selection of specific frames to highlight details, like the lighting of LEDS and the sounding of the piezo buzzer. For example: shown above is an image of two consecutive video fields (No. 72349 and 72350) of IOTA-VTI (on top) and GPS-ABC#1 (on bottom), that shows consistency of the lighting of each device's 1pps LEDs.
The video frames and fields, as well as the audio beeps were analysed using LiMovie and Tangra. Shown above is a LiMovie analysis;
on the left, a pair of video fields, the top one showing the 1pps LED lighting.
and on the right - the LiMovie Audio Channel Display.
This shows consistency of the audio beep with the flash of the 1pps LED.
The full details of the testing regime are available here (235Kb)
The designers would welcome independent testing of the device, contact Dave to discuss this if you are interested.