GPS Toolkit 1.5 Trajectory Scripts

[howmean]

Hi,

I've encountered a few problems when trying to understand how the Trajectory Scripts in GPS Toolkit 1.5 work. 

1) There are a few ways to construct the Trajectory Scripts and there are several commands that could be used.

         For e.g.: 

         Syntax for straight command: straight heading_type distance duration

         Syntax for waypoint command: waypoint heading_type latitude longitude altitude speed

    Questions:

    - Why is speed parameter needed instead of duration parameter in waypoint command?

    - In a normal NMEA data, duration between two points is 1 second apart.

      But in waypoint command, duration parameter is not used. How could we determine duration between each point then?

      Is there some calculation in background to retrieve duration to stay at a waypoint based on the provided speed?

2) According to the Help file, great_circle is defined as "the largest circle around a sphere. A great circle cuts a sphere into two equal halves. Therefore, a great circle has the same circumference and center as the sphere."

    Questions:

    - I tried out a motion script that contains a series of waypoints with heading_type set to great_circle. While the binary is generating, I received an error.

      By using the same motion script, but changed the heading_type to constant_heading, the binary could be generated successfully.

      Did anyone encounter the same problem?

    - So how does constant_heading and great_circle affect the binary that I'm generating?

3) When generating a single point binary, "Frame" needs to be specified.

    When Trajectory Script is used, "Frame" is no longer needed. Is it because a default "Frame" size is set?

4) It looks like there is no way for me to verify the binary that I've generated other than using a GPS device to receive the signal.

Really appreciate if someone could answer my questions as I couldn't find all these detail information neither in the Help file nor NI website.

Thanks.

How Mean

[Meadow]

Hello How Mean, Answering your questions below:

1. To set up Trajectory scripts, there are few functions that can be used to create the trajectory. In the case that you would like to set up the trajectory by providing a certain duration instead of speed at a specific position, you can use straight command instead of waypoint command. Since the usage of the straight and waypoint is different, there is no access to the duration to stay at a waypoint based on the the provided speed. If you read the manual, waypoint determines what is the speed at the waypoint location.

2. May be you can describe or copy the script that you are trying to do using the waypoint _great_circle parameters for us to start with.

3. When you use trajectory script setting, the function will automatically create the frame based on the standard, hence you don't need to.

4. I think so.

Regards,

James