Does using multiple gps tracker use much more battery?
The GPS itself probably won't use much more power – after all it doesn't matter if 1 or 100 apps ask for the location: it's obtained once and then handed to all. Actually there's even a "location cache": if you're now at e.g. Trafalgar Square in London, you're unlikely to be in Manhattan the next second (exaggerating a little) – so that's what subsequent requests within a short interval access. And that's also what's used when you e.g. enter a tunnel and temporarily have no location info.

A little more power of course will be required as the device is kept awake "more aggressively": one app probably would update the location once per second (or fewer times) – while multiple apps won't do that "unisono" (at the exact same time). But compared to the overall load while tracking (or navigating), that's most likely rather a little indeed.

Which reduces your question to: "Does using multiple apps use much more battery". The answer to that is "it depends". It certainly uses more – but how much depends on what those apps do, how well they are written, etc. Also think of ads they may draw, or data uploads they might perform.