I flew from my home in south Seattle this past Sunday to Tucson, Arizona where I'll be spending the rest of the winter. Brought my Spark with me. I always had decent satellite strength in Seattle to the point where it only took a minute or 2 at most to get the GPS connected, ready to fly signal. And, I always had good connectivity. Here in NW Tucson it's a different story. Got the Spark out for the first time today and it took 2 - 3 minutes to get the GPS connected signal. I glanced at the satellite bar chart and I was only connected to 9 satellites and all of them were weak. I was still GPS connected so I went ahead and launched but I kept it at about 2-3M just to see what would happen. Sure enough, after about a minute the voice told me I was now in ATTI mode, i.e. I had lost my GPS connectivity meaning I would have no RTH function if I went real high. At this point I lost my courage and landed. I was down to 50% battery anyway. Did I do the right thing or should I have been brave and forged full speed ahead? As a beginner, I read all of the unintended fly-away posts and I just didn't want to be in that position. Was I too cautious?