SSR (22-05-18) Flashcards
What is the principle of operation of SSR?
Ground station has interrogator
Aircraft has a transponder
Uses slant range by pulse timing.
What is the relationship between power and range of an SSR?
Range prop root(P)
As well as receiving aircraft position info, what other into can SSR receive?
Identity
Altitude
freind or foe on military designs
How does an SSR work out aircraft azimuth?
From the position of the array when the signal is coming back
What is the operating frequency range of the SRR?
1030 - 1090MHz
A/C Tx - 1090Mhz, Rx- 1030MHz
Ground Tx - 1030MHz, Rx - 1090MHz
What do mode A and mode C of SSR provide?
Mode A gives identification (SQUARK)
Mode C gives automatic height readout
What are the 3 pulses of SSR?
P1 and P3 are signal frame pulses
P2 is a sidelobes suppression pulse
What is the spacing between P1 and P3 of SSR for mode A and C?
Mode A - 8microseconds
Mode C - 21 microseconds
What is the PRP of the aircraft repsonse in SSR?
20.3 microseconds
In SSR what is the altitude step size for mode C?
100ft (+/- 50ft)
What does the ident button do in SSR?
Sends 7777 for 20 seconds
should only be done when asked to do so.
What are the SQUARK codes and their meanings in SSR?
7700 emergency
7600 radio failed
7500 unlawful interference and hijack
2000 A/C entering FIR with code assigned
7000 conspicuity code used to simply appear on SSR display
0000 used for mode C failure
7007 open skies agreement (legal spying)
How does side lobe suppression work for an SSR?
The P2 pulse signal strength is compared with that of the P1 - P3 pulses.
If the P1 - P3 signal is stronger then the interrogation is valid and the transponder will respond
In SSR, what is garbling?
overlapping replies from 2 or more aircraft within 1.7nm
In SSR, what is FRUITing?
False Response from Unsolicited Interrogation Transmission
where the transponder omits its response but is picked up by another SSR ground station.
