Inbuilt versus External GPS
First, some facts:
Some of your Nokia phones have an embedded GPS chipset, most or all are built by Texas Instruments. It’s of good quality and has a very low power demands. However, it requires long acquisition times and finds less satellites, providing lower overall fix qualities. Nokia make up for these deficiencies by providing a software solution in the way of A-GPS.
For noobs, A(assisted)-GPS software uses the GPS data acquired by your provider’s ubiquitously placed network coverage relay “cells”. Every cell has its own GPS chipset, broadcasting its position along with unique cell identifiers. All phones receive this omnipresent data, compliant with emergency services regulations, but A-GPS software gives user access to it. When coupled with data from your embedded GPS chipset, A-GPS software “completes” the package by providing faster connections and supplemental positioning data.
External GPS receivers use more robust GPS chipsets giving faster TTFT (time to first fix) times, and access to more satellites, providing better overall fix qualities. The SiRFstarIII chip is a prime example.
Power management:
Naturally, having everything under one hood is convenient. But running the embedded GPS chip, A-GPS processes and the targeted application, in our case NST, has an obvious effect on battery performance. At the same time you are sacrificing a measurable amount of satellite fix quality, albeit rather insignificant because Nokia’s TI GPS chip does a fine job.
Using an ext GPS receiver requires the use of your phone’s BT radio spectrum to communicate positioning data with your phone. Nevertheless, this draws less overall power than the embedded chip plus A-GPS processes. Of course it also has its own power supply. The caveat here being that you have to purchase, charge and carry an additional appliance with you on your workouts.
Summary:
If you want better fix qualities, faster TTFT and better power management, then an ext BT GPS receiver is the better option.
Nevertheless, no matter how good your ext BT GPS configuration is, the problems of interference always remain. Extreme spikes in X and Y data seem inevitable no matter the environment you’re in.
Discuss.
-David
Current setup: e61 unbranded product code 0529654 Euro-B1 Silver. Firmware: 3.0633.09.04. Theme: Ovi blue. Service provider: 3 Sweden. Peripherals: Bluemax ext BT GPS module
