Guest blog by Thomas Scherrer of Copenhagen Suborbitals

Rocket positioning and height indication using GPS is not a new thing. At Copenhagen suborbitals we have been using GPS units from the very beginning for all our flying projects.

But now, Copenhagen Suborbitals can obtain altitude data from space - above 100 km using GPS.

All normal GPS receivers got two limits build into them since the GPS system was released for public usage. The US military, who build and own the GPS, has placed a speed and height limit so no receivers can be used in automatic guided weapons - good idea of course.

Due to more relaxed rules, we now have the possibility to use GPS signals at higher altitudes and speeds. The problem is people normally don’t know how to either construct their own receivers or disable/modify the limits inside ready available modules (until now).

As an electronics design engineer I got in contact with all sorts of distributors, who were also looking at new and interesting parts. It is not the first time one of them got interesting GPS modules - but this time they where actually able to work together with the software engineers of the GPS and deliver a sample unit to me really fast - with no limits inside.

I expect they only got the OK to create this software modification for us since we are clearly a peaceful organization with not sinister objectives - and also in a very limited number of units. Basically removing the limits is a matter of getting into the hardware changing the code or get the manufacturers to do it. Needless to say, diplomacy and trust is the key to unlock this.

The final product to be flown (without limits) by Copenhagen Suborbitals. Image: Thomas Scherrer

Together with my friend DZL I have previously experimented with balloon altitude testing using GPS with a regular 18 km limits flying from Denmark to Sweden on a 100 km track going as high as 29 km (by altitude curvature estimation).

Balloon altitude experiment reaching 29 km. Image: DZL

Now the limits are gone and Copenhagen Suborbitals hope to fly this unit up to new heights already next summer - and hopefully into space in the future to come.

Thomas Scherrer

Thomas Scherrer is an communications expert working at a private company in Denmark. He has been a part of Copenhagen Suborbitals from the very beginning working link-budgets, systems design and communication hardware. Learn more about Thomas´ private work on his site.