GPS Speed is a free iPhone app developed by 逸鸣 赵. It falls under the category of Travel & Navigation and provides users with a convenient way to track their speed and distance while on the go.

With GPS Speed, users can easily switch between different units of measurement including MPH, KM/H, and KNOTS, allowing them to view their speed in their preferred format. The app features a digital speedometer and HUD (Head-Up Display) which provides a clear and easy-to-read display of the user's current speed.

In addition to speed tracking, GPS Speed also offers distance measurement, allowing users to keep track of the distance they have traveled. The app also includes a compass display, providing users with a quick reference to their current direction.

One notable feature of GPS Speed is its ability to track altitude. This can be particularly useful for outdoor enthusiasts and hikers who want to keep track of their elevation changes during their journeys.

Overall, GPS Speed offers a user-friendly interface and provides essential features for speed and distance tracking. It is important to note that continued use of GPS running in the background can significantly impact battery life.