Edge 530 not recording accurate distances

You would need a speed sensor if not using a suitable smart trainer

Thanks Peter. I'm using a KICKR which I see on other threads is compatible for speed.

The problem is that I have the same distance errors for Indoor activities, whether the smart trainer is paired or not, so the error is coming from the Garmin 530 unit.

I'm not wanting to spend more money on sensors when I don't need or want speed/distance for indoor rides. You'd think activities could just show 0km for Distance as per previous models like the 520; rather than what seems to be a poorly estimated guess. 

Can I turn off Distance/Speed readings for Indoor and then the unit just records Power/Time/Heart Rate?

I’ve not used mine indoors, so not I’m not sure of your options.

However, it might be worth checking if the speed reading is coming from the Virtual Partner. It’s always running in the background even if its screen isn’t turned on in your user profile. You could try adjusting the speed to zero or at least something sensible for you.

I'm surprised you're getting a reading at all tbh. I use my Edge 530 indoor all the time (to dual record my powermeter when Zwifting), so I can keep track if the numbers coming from my Kickr Core are approx the same as my Assioma's. 
I use a different profile for indoor than outdoor, and have the GPS disabled on the indoor profile. At first I only recorded HR and powermeter, but as I like to have some kind of speed recording, I mounted a speed sensor on the inside of the wheel that drives the flywheel, and calibrated the wheel diameter in the edge so that the speed value is about what I would expect when doing a certain power effort at a certain rpm. It's not perfect, but at least I have some speed data that makes kinda sense. The Zwift data only goes to Strava, while the Edge data goes to Garmin Connect and from there to Intervals and TP. 

Garmin is not estimating the distance.  The speed is from the KICKR and if it's like my KICKR Core, it is completely useless.  Unless you're using a wheel-on trainer and you have a speed sensor on your rear wheel.  In that case, the speed will still be (mostly) useless, especially in erg mode.

I use Vector power pedals as the power source when riding indoors, not the KICKR.  I don't get any distance or speed recorded.  I use training hours these days to compare periods, not distance, because of this very reason.

When I start pedaling, I get a message on the Edge saying that it saw the vectors, and do I want to switch power source.  When I say yes, then at that time, the speed goes to "--".

The topic starter is not using a Kickr but a crank PM. My Kickr is connected to Zwift and not my Garmin. Zwift is calculating the speed, it's not coming from the kickr. I have a speed sensor on the kickr to get some kind of speed rating for my Garmin, where also my Assume PM is connected to.

Unless the smart trainer is completely removed from the Edge for both ANT+ and BTLE profiles, it is the one sending speed to the Edge.  Or a speed sensor if it's a wheel on trainer. 

The point of my reply is that the Edge is not "making up" the speed or distance,  It must come from some external sensor. So the Edge 530 works the same way as the 520.  If no speed sensor is connected, it won't record distance or speed. The 530 probably supports getting speed from a trainer, that the 520 didn't (guessing here).

Thanks Kokketiel. I'll keep trying. Appreciate thhe response.