Test 1.1.2 Instructions¶

• Test 1.1.2 Instructions
  • Test Hardware
  • Test 1: Lab Test
  • Test 2: Field Test
  • Test 3: From Orbit Test

Test Hardware¶

• Ground Sphere Test Rig
• Computer, min system reqs: Windows 7, 1GHz, 1GB RAM

Test 1: Lab Test¶

Lab test using low power transmitter at 915 MHz to confirm signal reception and system gain (not an AX.25 signal, but close enough). These instructions assume that the receiver is already assembled and most recent software is installed. If not, accomplish the next 2 steps.

1. Follow the instruction for "GroundSphere Kit assembly"
2. Follow the instructions for Operations Manual - "Getting Started and Set up"

Test Date: _________________________ Test Location: ___________________________________

Record Test Conditions: _________________________________________________________________

Additional Tools Needed:
Tape Measure

Safety concerns:
_________________

Outcome

• Partial verification of technical requirement 1.1.2,
• Confirmation of Ground Sphere performance in best case laboratory conditions
• Confirmation of Ground Sphere performance in simulated orbital conditions

Instructions:

1. [ ] Turn on computer
2. [ ] Turn on the transmitter
3. [ ] Plug the GroundSphere USB data connector into an open USB port
4. [ ] Plug the GroundSphere power cord into a standard 120v power outlet
5. [ ] Measure and record the distance between transmitter and receiver: 1 meter
6. [ ] Launch the SeeDeR version 0.1 software
7. [ ] Tune the SeeDeR version 0.1 software to receive 915 MHz
8. [ ] Position the cursor (red vertical bar) at 915 MHz on the horizontal axis
9. [ ] Record the noise floor signal level: ___ dBm
10. [ ] Tune the transmitter to 915 MHz. Instructions
11. [ ] Set transmitter power to -20dBm. Instructions _NOTE: (This is a reasonably strong terrestrial signal, and is an unrealistically high power to expect from SkyCube. See Lab Test Link Budget figures here
12. [ ] Observe and capture/record the transmitted signal received by GroundSphere
13. [ ] Position the cursor (red vertical bar) at the center peak of the displayed radio signal on the horizontal axis
14. [ ] The signal should be plainly obvious as a strong peak above the noise floor. If this is not the case, abort the test and troubleshoot.
15. [ ] Measure and move the transmitter 3 meters from the GroundSphere antenna ensuring a clear line of sight.
16. [ ] Set the transmitter power level to -60dBm. NOTE: (at this power level, the intent is to get as close as possible to the signal strength that we expect to receive form SkyCube as it flies directly overhead of the antenna, given its orbital parameters <link to TLE file used in calculations> )
17. [ ] Observe the transmitted signal received by GroundSphere
18. [ ] Position the cursor (red vertical bar) at the center peak of the displayed radio signal on the horizontal axis
19. [ ] Record the radio signal level: ___ dBm
20. [ ] Subtract the noise floor figure recorded earlier from the radio signal level recorded in the step above.
21. [ ] Record the difference between the signals: ___ dBm
22. [ ] The difference between the signal and noise floor should be at least 17dBm. If this is not the case, abort the test and troubleshoot.

<insert image of laboratory setup>
<insert screenshot image of computer screen showing high power 915 MHz signal>
<insert screenshot image of computer screen showing low power 915 MHz signal>

TEST PROCEDURE COMPLETE

Test 2: Field Test¶

Long range field test using low power transmitter at 915 MHz to verify the predicted link budget (which comes from <insert link to spreadsheet> analysis) and confirm signal reception. It is recommended to conduct this test with at least 2 individuals. These instructions assume that the receiver is already assembled and most recent software is installed. If not, accomplish the next 2 steps.

1. Follow the instruction for "GroundSphere Kit assembly"
2. Follow the instructions for Operations Manual - "Getting Started and Set up"

Test Date: _________________________ Test Location: ___________________________________

Record Test Conditions: _________________________________________________________________

Additional Tools Needed:
Laptop computer meeting or exceeding the minimum system requirements.
Portable table or truck bed (on which to set up receiver equip and computer)
Access to 120V a/c power for preamp (generator or car inverter) or DC adapter (vehicle power jack to 2.1mm preamp power jack).
Tape measure or distance finding equipment (GPS?)

Safety concerns:
Weather caution
Traffic caution
Portable power for equipment(?)

Outcome

• Partial verification of technical requirement 1.1.2,
• Confirmation of Ground Sphere performance in optimal fielded conditions
• Confirmation of Ground Sphere performance at a far distance to simulate orbital conditions

Instructions:

Mission Control Set Up

1. [ ] Set up receiver and computer on portable table or in a vehicle with the antenna outside.
2. [ ] Turn on computer
3. [ ] Plug the GroundSphere USB data connector into an open USB port
4. [ ] Plug the GroundShpere power cord into a standard 120v power outlet
5. [ ] Launch the SeeDeR version 0.1 software
6. [ ] Tune the SeeDeR version 0.1 software to receive 915 MHz
7. [ ] Position the cursor (red vertical bar) at 915 MHz on the horizontal axis
8. [ ] Record the noise floor signal level: ___ dBm
9. [ ] Move to a distance 2650 meters away from the receiver set up with a clear line of sight, then set up the transmitter
10. [ ] If not exactly the above distance, record the distance between transmitter and receiver: _______(in m)

Remote transmit site Set Up

1. [ ] Power on and tune the transmitter to 915 MHz [[https://opendesignengine.net/projects/groundsphere-test-rig/wiki/Operating_Manual]]
2. [ ] Set transmitter power to 0dBm NOTE: (This is a reasonably strong terrestrial signal, and is an unrealistically high power to expect from SkyCube)
3. [ ] Tune the SeeDeR software to receive 915 MHz
4. [ ] Observe and capture/record the transmitted signal received by GroundSphere from the test transmitter
5. [ ] Position the cursor (red vertical bar) at the center peak of the displayed radio signal on the horizontal axis
6. [ ] The signal should be plainly obvious as a strong peak above the noise floor. If this is not the case, abort the test and troubleshoot.
7. [ ] Set the transmitter power level to -20dBm. NOTE: (at this power level, we are simulating the signal that we expect to receive form SkyCube as it flys directly overhead of the antenna, given its orbital parameters <link to TLE file used in calculations> )
8. [ ] Observe and capture/record the transmitted signal received by GroundSphere from the test transmitter
9. [ ] Position the cursor (red vertical bar) at the center peak of the displayed radio signal on the horizontal axis
10. [ ] Record the radio signal level: ___ dBm
11. [ ] Subtract the noise floor figure recorded earlier from the radio signal level recorded in the step above.
12. [ ] Record the difference between the signals: ___ dBm
13. [ ] The difference between the signal and noise floor should be at least 17dBm. If this is not the case, abort the test and troubleshoot.

<insert image of receiver setup>
<insert image of transmitter setup>
<insert screenshot image of computer screen showing high power 915 MHz signal>
<insert screenshot image of computer screen showing low power 915 MHz signal>

TEST PROCEDURE COMPLETE

Test 3: From Orbit Test¶

acquire signal from orbiting cubesat operating on 915 MHz (NPS just launched two cubesats which use the same radio and configuration as SkyCube). Orbital prediction software will need to be used to calculate the appropriate timing for this test. It is only possible to conduct the steps below in anticipation of a 915 MHz signal source flying overhead. These instructions assume that the receiver is already assembled and most recent software is installed. If not, accomplish the next 2 steps.

1. Follow the instruction for "GroundSphere Kit assembly"
2. Follow the instructions for Operations Manual - "Getting Started and Set up"

Test Date: _________________________ Test Location: ___________________________________

Record Test Conditions: _________________________________________________________________

Tools Needed:
Ground Sphere test rig
Computer meeting min system reqs
Skycube satellite pass within range of receiving station.

Safety concerns:
Weather caution
Traffic caution *

Outcome
Verification and completion of Technical requirement 1.1.2

Instructions:

1. [ ] Set up receiver and computer on portable table or in a vehicle with the antenna outside
2. [ ] Turn on computer
3. [ ] Plug the GroundSphere USB data connector into an open USB port
4. [ ] Plug the GroundShpere power cord into a standard 120v power outlet
5. [ ] Launch the SeeDeR version 0.1 software
6. [ ] Tune the SeeDeR software to receive 915 MHz
7. [ ] Position the cursor (red vertical bar) at 915 MHz on the horizontal axis
8. [ ] Record the noise floor signal level: ___ dBm
9. [ ] Await Skycube satellite pass as predicted by gpredict or other prediction software
10. [ ] Observe and capture/record the transmitted signal received by GroundSphere
11. [ ] Record the closest approach as shown by the polar plot (sky view) on GPredict: degrees elevation
12. [ ] Position the cursor (red vertical bar) at the center peak of the displayed radio signal on the horizontal axis
13. [ ] Record the radio signal level: ___ dBm
14. [ ] Subtract the noise floor figure recorded earlier from the radio signal level recorded in the step above
15. [ ] Record the difference between the signals: ___ dBm
16. [ ] If the difference between the signal received from Sky Cube and noise floor is 17dBm or greater, the AX-25 packet should be decoded by the SeeDeR software. Save a screenshot of this event.
17. [ ] Find the anticipated signal strength in the link budget given the elevation of the closest approach and compare this figure to the received signal.
18. [ ] Record any substantial difference: ______________________________________________________

<insert screenshot image of computer screen showing signal received from satellite>
<insert pic of Test hardware set up>

TEST PROCEDURE COMPLETE