GPSimply
a very simple software for straight-line GPS navigation
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FAQ (Frequently Asked Questions)
Mio Navigators have already their software. Why I should use GPSimply?

The navigation software that comes with the Mio Navigators is for road navigation. Road navigators are not suitable for straight-line navigation. GPSimply is for straight-line navigation. Stop.
Why the "compass" is turning in an apparently random way?

There are two possibilities:
  1. You are moving very slowly. (see 'Why the graphic part of the GPSimply main screen "is not exactly a compass"');
  2. The GPS signal that you are receiving is very poor.
What kind of course GPSimply calculates? How accurate are the displaied data?

GPSimply calculates, at the rate of once per second, the istantaneous bearing for an orthodromic course. In my opinion, since GPSimply is not conceived as the primary navigation mean (see the Disclaimer), the difference between orthodromic and lossodromic courses remain only of theoretical value in this context; but the calculation is made as said. The distance from the waypoint is also computed accordingly. Note that this calculations are based on a spherical Earth model, with a radius which has an intermediate value between the equatorial radius and polar radius.

As for the accuracy: - for the data directly derived from the NMEA messages, the accuracy of the displaied data is substantially the same of the data contained in the messages; - for computed data (Bearing, Distance), the approximation derives from:
What is the meaning of "type of GPS fix"?

The "fix" is your current position as computed by the GPS receiver contained in your hand-held device.The type of fix that the GPS receiver can compute depends on the number of usable GPS satellites in view: The GPS fix displaied comes from the "GSA" message of the NMEA protocol.
This is related with the fact that, while the clocks of GPS satellites are perfectly synchronized, the clock of the GPS receiver is not so; if it was, the propagation times of the GPS signal of three satellites to the receiver could be computed and the receiver position determined as intersection of three spheres centered on the three satellites and of known radii (propagation times multiplied for the speed of light); but, since the clock of the GPS receiver is not (a priori) sychronized, the radii are only known less an additive constant (the GPS receivers clock "error", unknown, multiplied for the speed of light); in order to solve also for this unknown, at least one more equation is needed; the best thing is to have four satellites instead of three, but also a (known or assumed) value for the height can solve the problem.
What is the exact meaning of "Height"?

This should be, as far as I know, the height above the local mean sea level (see GGA message of NMEA protocol, sixth field). Note that a GPS receiver does not compute directly this height; the height above the earth ellipsoid is computed first, and then the geoid height is (algebrically) subtracted; some GPS receivers might not perform this calculation, which requires a geoid model to be built in the receiver. The difference between the two heights can amount (approximately) to +/- 300 ft.
Why GPSimply uses nautical_miles/knots/feet units instead of Kilometers/etc. ?

The intended use of GPSimply is straight-line navigation, which is suitable for boats and planes (but see the Disclaimer). For this purpose the nautical_miles/knots/feet are still the commonly used units.
Why the graphic part of the GPSimply main screen "is not exactly a compass"?

A common compass (magnetic compass), installed on a plane or on a ship, indicates towards which direction the prow is oriented (heading).
A GPS receiver is able, by computing the difference between successive positions, to indicate towards which direction it is moving (course). The calculation accuracy is poor when the receiver is moving slowly, and the direction becomes totally undefined when the receiver is at rest.

The two directions are rarely coincident, due to deflections caused by winds, currents, etc. Note that the use of a GPS receiver (i.e. keeping the course coincident with the waypoint bearing) make unnecessary to take explicitly into account the deflections caused by wind and/or currents.

Also the reference direction (North) is different: for a compass it is the compass North (ideally the magnetic North), while for the GPS receiver it is the true North.
Why there is an empty band in the lower part of the GPSimply screen?

Frankly speaking, I don't know. I tried to use also that part, but without success. Eventually I decided that this was not so important and gave up (After all, this part of the screen is normally used by the taskbar; in this way there is no or little interference...).
When running GPSimply the screen flickers...

Yes. The screen flickers a lot - but ONLY for a couple of seconds - at start. Afterwards, during normal operation, there is also a LITTLE flickering every second (every time that the display is upated).
The fact is that the software environment of GPSimply (Visual Basic) does not provide the double buffering technique which is normally used to prevent these effects. A kind of double buffering might be implemented programmaticaly, but this would be at the cost of a significant effort and with some wasting of system resources.
Since in my opinion this is not a big annoyance, I decided to leave it as it is.

Sometimes most (or all) of fields of the GPSimply screen are empty...

Obviously, in order to display data, the data shall be available. Sometimes the GPS receiver requires a lot of time to get locked, and therefore it can not deliver any data in the mean time. This is not a problem of GPSimply, it affects all the GPS receivers (see the manual of your device).
Sometimes the data are partially available: for instance, until you select a waypoint, the "Bearing", "Distance", "ETE", "ETA" field and the "Off-course" indicator can not be displaied. "ETE" and "ETA", also, are not displaied when "ETE" should show more that 24 hours (e.g. when you are at rest...).
ETE and ETA are often too optimistic...

ETE is calculated once per second on the basis of your distance from the waypoint and of your current speed. ETA is simply Current Time + ETE. You will obtain realistic results if you look for them when you are enroute at the cruising speed, and you are able to mantain the route and the speed.
Recovering after an hard reset

It is known that the Mio navigators, upon each hard reset, make some cleaning operations and re-lock the device. "Cleaning" means also that many files that you may have installed (including GPSimply) are deleted.
The good news are that it is possible to setup the device so that it automatically unlocks again and restores the installed software.
My preferred method requires the usage of a program called C310Auto.exe, and an SD card.
See http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=75889&whichpage=1 for the downloading the program and for general instructions on how to use it.
For GPSimply in particular, you can also have a look in http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=95647&whichpage=2

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