GPS and Ultrasonic sensors

Manny

Hi I'm looking for help with a project I'm building. Can any one point me it the right direction on this, I am building a tracked hull (tank) that I would like to be able to navigate from point·"A" to point "B", "C" or "D" (up to 6 waypoints) and avoid anything·that might get in its way.·I'm using the parallex GPS receiver, ultrasonic sensors and stamp to process the imputs and then would like to output to a GE Fanic PLC to control the·drives (DC Motors via OSMC h-bridges).·This my frist venture into·GPS and any help would help.


Manny
manny_d2410@msn.com·····

Franklin

First you should read and to a certain extent understand the material that came with the gps or can be found on the page selling the gps. next do the same for the ultrasonic. Cobble some simple code to test those devices then start to combine them. If you have questions come back here and ask.

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- Stephen

Chris Savage

Manny,

I would recommend breaking your problem down into something more specific. I have seen this discussion come up before and there are knowledgeable folks on here that could help with specific questions.

I think the most popular question is how to calculate a new heading based on the target coordinates in relation to the current coordinates. This is the basis of the Robo-Magellan competitions and it would be interesting to see the community come up with some simple GPS navigation code. There is a project posted in our Completed Projects forum for a GPS Boat. There may be some information there or the author may be able to share his findings.

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Chris Savage
Parallax Tech Support

SRLM

Hi. I did something similar with an RC car. The method of navigation that I settled on was a combination of GPS and compass. The compass is needed since the GPS has a poor accuracy (at least at the small scale robotics). I had the program create a desired heading from the two GPS coordinates and a real heading from the compass. I then had the program compare, and then the ping looks in that dirrection (desired heading) if it is clear, then it goes that way. One thing to keep in mind is that you want to use the format of the GPS strings dirrectly as it comes from the GPS. If you convert it to something else, such as decimal degrees, the BS2 trunacates values and you lose precision.

One more thing: what tank treads are you using? I wanted to use treads for one of my projects, but the only ones I could find were either Parallax's or a $4000 model.