Student TM

Manual for preparation of the Student Telemetry Station forStudent Rocket Operations

Student Telemetry

Station Manual

Amund Nylund and Kjetil Henninen Page 1 of 16Last update: 13.6.2006


1. Introduction

At Andøya Rocket Range (ARR) we use two telemetry stations for receiving and processing data from student rockets. The Main Telemetry station (or Main TM station) uses a 10’ and a 20’ parabolic antenna for receiving signals from the rocket. These antennas are commonly used by ARR under scientific rocket campaigns. During the student rocket campaign some of the Main TM station will be set up and operated by ARR staff, and some of the preparations will be done by students under supervision of a group leader. The Student telemetry station is used as back up under student rocket campaigns, and for educational purposes in off-campaign matters. The Student TM station will be completely prepared and operated by students during the student rocket campaign (under supervision of a group leader).

Figure 1 shows a typical block scheme for a telemetry station with the most important equipment needed to receive and process data from a sounding rocket. This manual will give a description on how to set up the Student telemetry station for a student rocket launch. An introduction to the main components of a telemetry station will be given before the telemetry station is prepared.

Figure 1



2. Scope of Work

This manual describes how to set-up and configure the Student Telemetry station to receive, visualize and record sensor and housekeeping information transmitted from a Student Rocket.

The Student Rocket carries a payload section with various sensors, a data encoder and an S-Band radio transmitter. The radio will transmit on 2279.5 MHz.

Further information on the Rocket Payload can be obtained from the Payload Manual distributed to the Payload Group.

3. Available Equipment

The student telemetry station has all the equipment necessary to receive and process data from the Student Rocket.

The main components of the Student TM station are:

Horn antenna. Antenna gain: about 17 dBi. Antenna Controller Microdyne 1100 Receiver EMR 720 PCM Bit Synchronizer Bell&Howell VR-3700B Tape Recorder VikinX Video Distributor PC with Eidel EE352 Camera & control unit with monitor TV Monitor for Countdown clock Operations Intercom NOGO/ GO- status panel

4. Equipment interfacing

- Antenna signals (RF) to Down Converter: Left Hand Circular Polarized to Downconverter Channel 1 (RF IN)Right Hand Circular Polarized to Downconverter Channel 2 (RF IN)

Down Converter signals to Receiver:Intermediate Frequency (IF) OUT Ch 1 from Downconverter to RF IN at Receiver.

- Receiver signals to Bit Synchronizer:



Video Out J15 from Receiver to Source Input (SCE 1) at Bit Synchronizer.This connection should be done via a distribution amplifier.

- Receiver signals to Tape Recorder:Video from Receiver 1 to Tape Recorder (via a Video distributor).

- Receiver Signals to Main Telemetry Station:Video Out to Patch Panel(See patching description below)

- Bit Synchronizer to Eidel PC:NRZ-L to NRZ-L0º to Clock Pulse (Cp)

- Main Telemetry Station Signals to Tape Recorder:Clock Signal (IRIG B) from Main TM via Patch Panels to Tape RecorderOperation Intercom (Voice) from Main TM via Patch Panels to Tape Recorder(See patching description below)

NB If you need more parallel signals then available on receivers you can use the Video distributor. Always remember to use a 50Ω termination plug on the “LOOP” connector whenever inputting signals to any of the channels on the Video distributor.

The Antenna Controller and Camera / Camera controller are already connected up and ready for use.



5. Patching signals to / from other locations

There are patch boards in NAROM LAB (Figure 2) and in the Student TM Station (Figure 3). These are used to send and receive signals to / from various location around the rocket range.Use coaxial cables with BNC plugs to patch signals according to the listing above.You will need information from the Main TM Group on where signals are received / transmitted.

On the patch board on NAROM LAB the Student TM patch board is marked NAROM TM.

NB! The patching in the pictures are just examples.

Figure 2 Figure 3



6. Set-up of all equipment

- EMR 720 PCM Bit Synchronizer

1. Set SOURCE according to input connector used.2. Set INPUT CODE to “BIØ-L”3. Set DATA POLARITY to “NORM”4. Set DETECTOR to “I/D”5. Set LOOP WIDTH to “0.3”6. Set PROGRAM to “LOCAL”7. Set BIT RATE to “256.0 KB”



Receiver setupThere are two Microdyne 1100 receivers (Figure X) in this telemetry station. One for right-hand circulated polarized (RHCP) signals, and one for left-hand circulated polarized (LHCP) signals. The horn antenna receives both kinds of signals on 2279.5 MHz from the rocket antennas. The frequency is down converted with a frequency of 1985 MHz in the down converter located below in the rack. Subtract this frequency from the received frequency and set the receiver to the right frequency.

Tasks: Switch on the receivers. Tune in to the correct frequency. Make sure the demodulation is set to FM. Set 2nd LO mode to XTAL. Set AGC Time Constant to 100 ms

Figure X



- Eidel EE315 PC

The EE315 interface card and software is used to visualize data from the rocket. The encoder in the rocket payload codes data from the various sensors in the rocket. This code is called Pulse Code Modulation (PCM). This code has to be decoded by the visualization software. The PCM code for the student rocket is BiØ-L. How this and another code called NRZ represent binary codes are shown in Figure 4.

Figure 4

The data is transmitted from the rocket to the TM stations in a pre-configured format.To be able to decode the data again the PC program needs to be set up with the correct format description. The format configurations is shown in Table 1

Bitrate 256 kbit/sPCM code BiPhase-Level (Biφ-L)Sync-word 16 bit, hex:EB90, bin:1110 1011 1001 0000Frame counter 16 bitWords per Frame 14Frame per Format 1Analogue channels 8Analogue word length 8 bitDigital channels 2Digital word length 8 bit

Table 1



Start-up the Eidel program:(Switch on the PC and Monitor)- Type “cd dec315” and “enter”- Then “ee315” and “enter”. You are now in the main menu.

Key functions:Use digital book (www.romteknologi.no) chap. 5.5.1 to get familiar with the different functions keys. Try the functions keys step by step from F2 to F9 (do not use F8 here. It will only bring you back to DOS). Elsewhere F8 will bring you one step back. In digital book a more detailed description is given.

Importent files:Format setup file (name.FOR)Data & Setup file (name.SIG)Recorded data file (name.DAT)

Project directoryFrom the main menu press F6 to get access to project directories. Here you can also make your own project directory.

Copying of filesKeep in mind that you also include the project name when the old and new file are located on different project directories (see below):Copy directory name\file name.file type (ex. FOR) new name(copy pro\pulsaur.FOR stud\newname.FOR)

Format setup:Press F2. To get an exiting format file (from your current project directory) press F2.Now you can select a proper format file (name.FOR).

Data Display setup:Press F3. To get an exiting signal file (from your current project directory) press F2.

Preparation for recording to a data file (name.DAT):Press F3, Data Setup and Display.Press Ctrl F2 for setup of new storing file. Press F6 and type the name of your group. Push F8 for return to main menu.

Press enter. Use the arrow buttons one step down to decide block size in the column for block format. Press F5 to edit this size. Put in “500” and press enter. Then press F8 to exit.Now the bottom line should turn red. Check it!

Use the arrow buttons down the last data line. Press Ctrl F1 for “untagging” of data storing. You will now observe that the “D” disappear from the line. Do this for the 3 data lines above as well. Now you are ready to record data from the rocket payload!

When we are receiving signals via the telemetry station the red blinking in upper right corner


http://www.romteknologi.no/


of the screen will turn green. This indicated that we have “lock” on the signal.

When there is about 2 minutes before lift off of the rocket, press Ctrl F3 to start recording.Stop recording by pressing Ctrl F3 again (when we tell you).

Playback:

(Now you need to be in “data setup & display”-mode. From the main menu press F3)To get access to playback of rocket data press Ctrl F5. Use the arrow keys to select the xxx.dat-file you stored (group name).

Now you are able to make a playback of the recorded data by use of “F7” for start/stop.

Press Alt F1 to toggle some of the signals. This means to select which of the signals you will monitor. Its only possible to monitor 4 signals at the time in this mode. It might be convenient to toggle the magnetometer ( to watch the spin of the rocket) and accelerometer (acceleration). When these are toggled, press F4 to monitor them graphically.

Use the arrow buttons to adjust the size of the graphs (200ms, and 20s). Press F7 to start.



The PCM format is shown in Table 2. Word Allocation Data Comment

00 Frame Sync (EB)01 Frame Sync (90)02 Frame Counter MSB03 Frame Counter LSB04 Analogue Ch 0 Temperature PCB-card05 Analogue Ch 1 Temperature Nose06 Analogue Ch 2 Magnetometer Spin07 Analogue Ch 3 Pressure Sensor08 Analogue Ch 4 Accelerometer Z09 Analogue Ch 5 Accelerometer Y10 Analogue Ch 6 Photo Transistor11 Analogue Ch 7 Payload Battery Voltage12 Digital Ch 013 Digital Ch 1 First bit pulled high at

lift-offTable 2

Run the Eidel program and choose “F2 – Format Setup”. The screen in Figure 5 appears (parameters in the figure is only an example). Set the correct parameters according to Table 1.



Figure 5

Choose the “Data Setup and Display” on EE315 to set the rest of the parameters in Table 3. Set up your displays in such way that the analogue channels first show its decimal value, and then the special scale value. (In EE315 the special scale edit comes up if you push F9). The special scale value refers to the sensors voltage output level. This voltage has to be converted to a different value, e.g. bar, meter, g, tesla or gauss. To visualize the sensor output in a special scale you will need to put in some scaling formulas. Calculation of these formulas must be based on the bit resolution and sensor output. Thus, study the different sensor data sheets and try to figure out what the formula means. The different formulas and constants are listed in the table below. Note that these formulas have to be calibrated when the payload and experimental group are finished with the sensors.



Sensor Formula Scale name

Notes Scale Min value

Scale Max value

Low limit

High limit

Constants

Temperature PCB

((A/e)*g)/f C (Celcius degrees)

f = 0.05 -10 120 0 100 A = word nre = 256f = see notesg = 5h = 44307.69396i = 38*10-3

j = 0.190284k = 130l = 3.2m = -0.48

1 n = 0.0045o = 5

Temperature Nose

((A/e)*g)/f C (Celcius degrees)

f = 0.05 -10 120 0 100

Magnetic Field

((A/e)*g)*o kA/m 2

Optional3 -10 10 -10 10

Pressure (((A/e)*g)-m)/n

mbar (millibars)

Optional4 0 1100 0 1015

Acceleration Z

(((A-k)/e)*g)/i

g (m/s2) -60 60 -50 50

Acceleration Y

(((A-k)/e)*g)/i

g (m/s2) -60 60 -50 50

Photo Transis.

((A/e)*g)*l Intensity

Battery Voltage

((A/e)*g)*l V (Volts) 4 16 5.2 12

Altitude h*((1-((((A/e)*g)-m)/n)^j)

m (meter) 0 10000 0 9000

Battery Voltage

((A/e)*g)*l V (Volts) 4 16 5.2 12

Umbilical A IN (marks lift-off)

Mask first bit

0 1 0 1

Table 3

During the payload testing you will see if the Eidel computer is correctly configured.

Remember to save all your work. Consult the F1 help page!

1 This value must be corrected for the barometric pressure at launcher during the rocket campaign. The correction formula is based on the linear scale pressure output from the pressure sensor datasheet. This formula is: m = ((Output voltage) – 0.0045*(Known Pressure))2 1 kA/m = 1.25 mTesla (in air), 1 mT = 10 Gauss. In this formula the value is not concurrent with units.3 The magnetometer used on this sensor is only to register rocket spin variations.4 Altitude is calculated from the pressure value.



Bell&Howell VR-3700B Tape Recorder

Prior to operation, the tape recorder heads need to be cleaned and demagnetized.Then you need to load the recorder with a tape.The Group leader will instruct you how to prepare the tape recorder for use.

1. Set PHASE LOCK SELECTOR to “TACH”2. Set RECORD TEST SELECTOR to ”NORM”3. Set TAPE SPEED SELECTOR to “60”

The tape recorder has seven available channels for recording, you can select any channel to record any of the available signals. Remember that the purpose of the recording is to store data for the future, and to have the possibility to replay the rocket data if there are any errors in the set up of the decoding software.Note: You will need to document on which channels you have recorded the various data!!

- Horn Antenna and Antenna Controller

Switch on antenna controller and power to the Low Noise Amplifier (LNA) in the antenna pedestal. To be able to control the antenna you need to switch on the Elevation and Azimuth motor power as well.

NB. Be aware of the “LEFT SECTOR” / “RIGHT SECTOR” lights next to the Azimuth display. Normally you should always turn the antenna towards the illuminated lamp to avoid twisting the internal cables in the pedestal.



- Camera and Camera Controller

Switch on the Camera controller and Monitor. You might need to wipe off the camera lens if it has been raining lately. You can zoom in / out with the “Tele” and “Wide” buttons, the other buttons on the camera controller are not used.

- TV with countdown clock

You will need to set up a TV in the Student TM to receive campaign information and countdown clock.

- Operations Intercom

The Operations Intercom is used during countdown to communicate between the various stations around the rocket range. Please be quick and to the point when using the Operations Intercom. Also note that the whole rocket range can hear you when you are using this Intercom.

7. Test and preparation

After all equipment has been connected and configured you need to test the system. This is done in cooperation with the Payload group.The rocket payload will be switched on, and you can test that you have :

- Reception of signal on both Receivers (note signal level)- Sync lock on Bit Synchronizer- Sync lock on Eidel315 system- Display of data on Eidel315 system

You should also practice using the antenna controller, as you will need to manually track the rocket during part of the flight. Group leader will demonstrate how this is done. You will be given a table listing the expected rocket trajectory.



8. Countdown and Launch

When you are satisfied that all the equipment are working, you are ready for Countdown and Launch. The group will have to nominate dedicated personnel to operate the various systems during the operation.

Tasks during the operation are:

- Pre-pointing the antenna.

Nominal launcher settings are given during the pre-flight meeting; the antenna is directed according to these settings and pre-computed trajectory listing.

- Report status and Go / No Go indication according to Countdown Procedure.

The Countdown procedure will be handed out during pre-flight meeting.

- Start recording according to Countdown Procedure.

- Track the rocket manually from the rocket reaches apogee to impact in the ocean.

- Stop recording according to Countdown Procedure.

9. End of Operation

After completion of the Rocket operation you will need to shut down all equipment, and tidy up the Student Telemetry Station. Remember to make copies of all data recorded

Remember to make notes on all configuration settings and interfacing before you power off units and / or remove cables.

Please remove any temporarily installed equipment or cables.

Please remove all waste or any other items you have brought with you to the Student Telemetry Station.


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