NEPAL-PQ1 LINK BUDGET

UPLINK BUDGET

Modulation Type: GFSK at 500 bps and Fdev=1kHz

Table 1: Uplink Budget Analysis

 Frequency:437.5MHz 
 Distance:815kmat 35 Degrees
 Transmit Power:14W 
  11.46128036dBW 
GSTransmit Antenna Gain:12dBi 
EIRP:23.46128036dBWPower+Antenna Gain
Transmission Loss at GS2dB 
Uplink PathFree Space Path Loss:143.4727133dB32.4+20log(d)+20log(f)
Antenna Pointing Loss:1dB 
Antenna Polorization Loss:1dB 
Atmospheric Loss:2dB 
Ionospheric Loss:1dB 
Rain Loss:0dB 
SpacecraftIsotropic Signal Level at Spacecraft-127.011433dBEIRP-Losses
Spacecraft Antenna Pointing Loss0.2dB 
Spacecraft Antenna Gain2.2dBi 
Spacecraft Line Loss1dB 
Receiver Sensitivity-115dBm 
Receiver Sensitivity-145dBW 
Received Power-126.011433  
 Link Margin18.98856703dB 

Table 1 shows the uplink budget during the communication.  The analysis is done at 437.5 MHz with satellite antenna gain of 2.2 dBi and Ground Station antenna gain of 12 dBi with the transmission power of 14W for the tele-commands. The link margin thus obtained is 18.9 dB.

Downlink Budget

Nepal-PQ1 Down Link Budget Analysis using SNR Method

Table 2 : Downlink Budget Analysis

 Frequency:437.5  MHz 
Orbital Altitude500  km 
Elevation Angle35  Deg 
Distance:815.08896  
km
 
Transmit Power:0.1  WPt
-10  dBW 
   
   
SpacecraftSpacecraft Antenna Gain2.2  dBi 
Spacecraft Line Loss1  dB 
EIRP-8.8   Transmit Power-Gain-Loss
       
  GFSK(2K00F1D)CW Morse (500H A1A)RTTY FSK (515H F1B)  
Downlink PathFree Space Path Loss:143.47366143.4736614143.4736614dB32.4+20log(d)+20log(f)
Antenna Pointing Loss:111dB 
Antenna Polorization Loss:111dB 
Atmospheric Loss:222dB 
Ionospheric Loss:111dB 
Rain Loss:000dB 
       
       
Ground StationIsotropic Signal Level at GS-157.2736614-157.2736614-157.2736614dBEIRP-Losses
GS Antenna Pointing Loss0.20.20.2dB 
GS Antenna Gain121212dB 
GS Transmission Loss222dB 
Ground Station Effective Noise Temperature:635635635K 
Ground Station Figure of Merrit (G/T):-18.22773725-18.22773725-18.22773725dB/K(=Gain-Losses-Noise temperature) in dB
Signal Power at Input of LNA-147.4736614-147.4736614-147.4736614dBW(=Signal Level at GS-Gain-Losses)
Boltzman’s Constant-228.6-228.6-228.6dbW/K/Hz 
Receiver Bandwidth2000500515Hz 
Receiver Noise Power-167.5619628-173.5825627-173.4541905dBWPn = K + 10log(Ts) + 10log(B)
SNR at Receiver20.0883013826.108901325.98052905dBSignal Power-Noise Power
Required SNR12.81010dB 
       
 Link Margin7.28830138416.108901315.98052905dB 

Table 2 shows the downlink budget analysis for the communication. The analysis is done at 437.5 MHz with satellite antenna gain of 2.2 dBi and Ground Station antenna gain of 12 dBi with the transmission power of 100mW. The link margin thus obtained for GFSK, CW Morse and RTTY FSK are 7.2 dB, 16 dB and 15 dB simultaneously.

Leave a Reply