Great question.
GPS signal relies on clear line of sight and the less interreference the better. If your GPS is facing the wrong way - like down/sideways instead of upwards, it can bounce around .
If indoors, truth be told actually, it is very difficult to get GPS without assistance indoors however, the AirBolt GPS can in some cases manage to obtain it in even this situation. However, the downside is essentially, that the limited signal you do get indoors has bounced around significantly and hence, your location bounces around. Whilst it gets you an idea of where it is and some assurance, I understand that this may confuse a little, however, when you move outdoors, this is when it shines which will be perfect should your Dog be off leash.