QC Symbol codes for ASCII plot:

Symbol codes for "SV":
(hierarchy is left-to-right, top-to_bottom)
C  receiver clock slip                m  n-msec multipath jump              
I  ionospheric phase slip             M  multipath MP1 and MP2 slips        
1  multipath MP1 slip only            2  multipath MP2 slip only            
3  write switch case                  4  write switch case                  
-  SV above elev mask, but no data    +  SV data, but below elev mask       
^  partial SV data and below elev mask.  A/S off; L1 C/A                    
:  A/S off; L1 P1                     ~  A/S off; L1 C/A L2 P2              
*  A/S off; L1 P1 L2 P2               ,  A/S on; L1 C/A                     
;  A/S on; L1 P1                      o  A/S on; L1 C/A L2 P2               
y  A/S on; L1 P1 L2 P2                L  Bit 0 of LLI set (rx lost lock)    
_  no SV data and below elev mask     

Symbol codes for "Pos" (position):
(hierarchy is left-to-right, top-to_bottom)
^  large position change              X  code position inverse failed       
C  position did not converge          H  large horizontal uncertainty       
V  large vertical uncertainty         T  large total uncertainty            
>  kinematic survey is OK             o  static survey is OK                
O  insufficient observables           E  insufficient ephemerides           
S  insufficient SV set                

Symbol codes for "Clk" (receiver clock):
(hierarchy is left-to-right, top-to_bottom)
-  reset by - msec                    +  reset by + msec                    
^  missing observation epoch(s)