LMS-6 Radiosonde for Tornado Probe

Community Projects
1

The project I am a part of was donated a LMS-6 Radiosonde manufactured by Lockheed Martin in order to record atmospheric properties inside of a tornado. The problem is we don’t have the receiver equipment required to receive the data via radio frequencies like the National Weather Service does. Documentation of the actual Radiosonde regarding sensors is pretty scare, most likely because it is proprietary to Lockheed Martin. Does anyone have any idea how we might be able to receive the data another way. Maybe we could remove the sensors we need from the board, and use them on a board we design?

We could have used hobby grade sensors, but they wouldn’t have the range we need. For example the barometric pressure sensor on the Radiosonde has a range from 3 millibars to about 1020 millibars. There is also a GPS transmitter that we would like to utilize, but I understand that the receiving on our end is going to be the problem.

If anyone has ideas or input, it would be greatly appreciated. We would like to have the project ready to fly by April, but obviously that might not be possible.

If we end up having to use a separate board build, using different sensors, let me know where I can find sensors that would have the same range as what the National Weather Service has access to.

This might be way out there as well, but would there be any way we could get the sensors to talk to an Arduino, or something of the sort.

Thanks in advance!

2

Reverse engineering the RF signal might be pretty tough. But at some place in the system, there must be a stream of digital bytes to be transmitted. Perhaps you could find that spot, cut out the current RF system and replace it with one that you do have the specs for.

3

Do you (@OP) have any idea of the vintage of the LMS-6 Radiosonde ? That makes a huge difference.

4

I will have to check the serial number. I presume it was manufactured recently. The LMS-6 is a new model that is replacing the older Radiosondes (according to the NWS).

Skye, I was thinking the same thing. It will take some time to pin point everything on the board since I do not have access to any schematic documentation.

In the mean time I will be ordering some sensors for a custom sensor package build based on an Arduino.

Here are the sensors on the list so far (Let me know if these should be suffice for this application):

(Barometric Pressure Sensor) - MPX5100D

http://www.mouser.com/ProductDetail/Fre … dhXoDf8w==

(Temperature Sensor) - TMP102

https://www.sparkfun.com/products/11931

(Humidity Sensor) - HIH-4030 Breakout

https://www.sparkfun.com/products/9569

(GPS) - 50 Channel GP-635T GPS Receiver

https://www.sparkfun.com/products/11571

The GPS will not only enable us to locate the probe after the intercept, but will hopefully give us a ballpark wind speed reading as well.

Is there anything else I should consider for the probe? I think that covers the meteorological element, but is there anything else I should use with this set up?

I will also need a reliable power supply that can run the probe for several hours, and will transmit the final LON LAT coordinates when it comes to a rest. Any suggestion on a power supply set up would be very helpful as well.

I am a Mechanical Engineer and Forecaster, so I am getting familiar with the electrical aspect of the project!

Thanks,

Warren

5

What do you have for receiving gear ? So far as I can find radiosondes output pressure, temp and humidity … with an option for GPS data. The newer ones are digital, tx’ing at 1680 MHz* (settable via dip switches), although I’m less certain that the GPS data is in that stream. A high altitude balloon project (amateur) was using an LMS-6, using it’s GPS as a backup for the APRS tracking. The tx freq was listed as 400+ MHz. I saw other sites listing that as 403 MHz.

http://patkilroy.com/simsat/3/

My point is you may be able to figure out the simple PTH data by examination w/your existing gear. Moreover if your plan is to recover the probe, perhaps a datalogger is all you need, vs a telemetry system ?

OTOH see this link re: US radiosondes and the RS92SGP digital protocol …

Seems odd to me that the US would have 2 incompatible systems (LMS-6 and Vaisala RS92-NGP) to replace the older MarkIIA’s. So does the LMS-6 also follow the RS92SGP digital protocol ?

http://www.rtl-sdr.com/tag/rs92sgp/

*Perhaps it’s a case of all the older MarkIIA’s (and ???) using 400+ MHz for downlink.

http://www.sippican.com/stuff/contentmg … smark2.pdf

6

Thanks for all of the support.

I visited the NWS and they couldn’t tell us anything about the software they use to decode the data. Quite frankly they didn’t know too much of anything regarding the technical aspect of the radiosonde. “We simply launch it and use the data, that’s about as far as we go.”

I’ll see if we can pick up a signal with our receiving gear. Another member of our team handles that aspect. He has a long range FPV system and some other things we can probably utilize. We also have an SD data logger for after we retrieve it.

I will probably order those sensors as back up.

I would assume the LMS-6 follows the same protocol, however the NWS said they updated all of their receiving equipment.

I’m trying to wrap my head around all of this so bare with me!

Thanks!