The GPS board mentioned in my latest blog has now been put through the reflow soldering oven. Only component missing now is the GPS receiver from uBlox. As it cannot tolerate the reflow soldering process, it will be soldered by hand during the weekend.

The initial test, applying power to the board (aka smoke test) was performed without incident. I will leave the “hello world”-test to the GPS team.

The only leaded component on the board is the connector used to program the processor. The GPS team specified an ATMEGA2560 processor, as it is equipped with 4 UARTs. The rest of the through-hole pads on the board are for discrete wires.

The GPS box will contain two GPS receivers.

The main GPS receiver is a Novatel model, kindly donated by Gomspace in Aalborg. This receiver is used in the companys nanosatellites, and should be able to maintain a position fix at the acceleration levels expected during the powered part of the Nexø II flight.

The secondary GPS is a uBlox receiver from their NEO8-series. We wish to find out if this receiver is able to maintain a position fix during powered flight, as this is a problem for most commercially available GPS receivers.

A barometric pressure sensor is also incorporated in the system. This MEMS sensor will be mounted in a connector shell, enabling us to place it outside the closed GPS box. We are interested in learning about it’s usability as an altitude indicator.

Below are a couple of pictures from the soldering process.

The GPS board with solder paste applied. Most of the passive components are placed. Photo: Bo Brændstrup.

The GPS board with solder paste applied. Most of the passive components are placed. Photo: Bo Brændstrup.

Here all semiconductors have been placed as well. Only the connector for the uBlox antenna is missing. Photo: Bo Brændstrup.

Here all semiconductors have been placed as well. Only the connector for the uBlox antenna is missing. Photo: Bo Brændstrup.

The board immediately after reflow soldering. The fine pitch parts will need some rework, but there is no tombstoning. Photo: Bo Brændstrup.

The board immediately after reflow soldering. The fine pitch parts will need some rework, but there is no tombstoning. Photo: Bo Brændstrup.

Categories: Blog

Published by Bo Braendstrup on

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