iHUD

Why does iHUD know the attitude when no GPS signal is received!
The iPhone has built-in 3-axes accelerometers, which allow to register any movement of the device. iHUD makes use of this wonderful feature, therefore being able to show attitude and attitude changes.

Does this really work?
Yes!
GPS:The iPhone 3G integrates a high performance AGPS (assisted GPS receiver) baseband processor and a low-noise GPS RF front end. It comes packed with new software features such as advanced multi-path mitigation that avoid large errors in urban environments caused by reflected signal in buildings and other structures. Data provided by the iPhone interface are coordinates of the position (longitude and latitude) each with a unique time stamp. Displayed speed, heading, altitude, and vertical speed are significantly depending on accuracy of the position data form the GPS and the time stamp delivered by the iPhone. We observed that erratic data supplied by the interface are not uncommon. Therefore, you may observe variation on the graphical display of the parameter mentioned. Note that for best GPS data signal, line of sight to the GPS satellites is required!

Accelerometer: The iPhone and iPod Touch have a fairly good accelerometer and more than enough processing capability to run the measurements and computations needed to make iHUD practical. With proper calibration and settings, iHUD can be quite accurate. Regardless of the absolute accuracy, g-Meter offers very good precision and repeatability, making it a great tool to look for performance increments from factors like engine and chassis modifications and driving style.

Does iHUD require an iPhone 3G with GPS?
Yes, iHUD does make use of GPS for speed, heading, altitude, and vertical speed information.

The accelerometer part of iHUD showing acceleration (G-loads), however will work with any iPhone or iPod Touch running iPhone OS 2.1 or later.

The display orientation is fixed and can not be rotated - why?
iHUD works the same on iPhone or iPad, always in landscape orientation with home button to the right (landscape-right in terminology). It has never supported any other orientation.

iHUD requires a known default orientation because it measures angles from this orientation, and the calibration needs some basic assumptions about the references. The app cannot use rotation as a cue to spin the screen, since rotation actually constitutes roll. We obviously don't want the screen spinning every time someone did a hard bank. Therefore, the app does not monitor screen rotation notifications and will not respond to them. Any rotation of the screen is interpreted as roll. Landscape-right is the default landscape orientation for apps and accessories.

Does iHUD work with the iPhone 4 ?
yes, extremely smooth and fast graphics due to the way faster processor. Unfortunately, the higher resolution of the retina display has the processor work to the limits and slows down rendering. Therefore, we have an automatic switch that will block the app from using gradients for the sky and earth.

Also, the onboard magnetic compass has been implemented for use as a alternate way to GPS of displaying heading information.

Does iHUD's Augmented Reality visualization work with the iPhone 3G ?
yes, but you need at least OS 3.1