Hi Geomaticist,
If you don't have PPK on board yet, no need to buy a new drone. Consider the V-Map system which is completely platform independent and weighs only 120g (about 4oz). If your drone can handle the extra 120g and has a space for the dual frequency antenna, you should be able to mount it on your existing drone. The only requirement is that the camera has an external flash hot shoe connector that delivers a pulse at mid-exposure. The V-Map system comes with free post-processing software that takes you through the whole work flow from RINEX conversion to trajectory computation to event position calculations to geo-tagging. You can use your existing survey grade GNSS receiver, a VRS, a network service or a second V-Map receiver as reference station.Have a look at
www.v-map.net. There's a white paper there as well. Feel free to leave an enquiry. We will respond with technical info and pricing.