begin hw4

hw4.Rmd

@@ -0,0 +1,56 @@
+# HW 4
+Write an R script to calculate the output of the Klobuchar model.
+Provide a GUI means for entering input data, and the name and the
+path to navigation message file with coefficients of the Klobuchar
+model. Load the coefficients of the Klobuchar model from the given
+RINEX n file using a dedicated function in the R script. Provide a
+feature to calculate the value of the ionospheric delay of the GPS
+signal during 24 hours of a given day, in 1-minute increments, with
+the given coefficients of the ionospheric model. Verify the correctness
+of the algorithm implementation with a given numerical example. After
+that, conduct a 24-hour simulation of the GPS ionospheric delay in 1-
+minute increments for the position φu = 45.33709°, λu = 14.42496°, E
+= 90°, A = 180°. Store the estimated 24-hour simulation data set in a
+dedicated file on the local disc.
+
+The problem description, method, R script and implementation results
+should be presented in a single HTML document, which should be
+sent to the subject teacher's e-mail by May 21, 2026 at 23:59 CEST.
+
+
+```{r read-file}
+# Function to extract Klobuchar parameters from a RINEX navigation file
+extract_klobuchar_parameters <- function(rinex_file) {
+  ion_alpha <- numeric(4)
+  ion_beta <- numeric(4)
+
+  # Read the file line by line
+  con <- file(rinex_file, "r")
+  while (length(line <- readLines(con, n = 1)) > 0) {
+    if (grepl("ION ALPHA", line, fixed = TRUE)) {
+      # Extract the 4 numeric values from the line
+      ion_alpha <- unlist(strsplit(line, "\\s+"))[2:5]
+    }
+    if (grepl("ION BETA", line, fixed = TRUE)) {
+      # Extract the 4 numeric values from the line
+      ion_beta <- unlist(strsplit(line, "\\s+"))[2:5]
+    }
+    # Stop reading if we've reached the end of the header (END OF HEADER)
+    if (grepl("END OF HEADER", line, fixed = TRUE)) {
+      break
+    }
+  }
+  close(con)
+
+  # Return the parameters as a named list
+  list(
+    ION_ALPHA = ion_alpha,
+    ION_BETA = ion_beta
+  )
+}
+
+rinex_file <- "brdc0930.26n"
+klobuchar_params <- extract_klobuchar_parameters(rinex_file)
+
+print(klobuchar_params)
+```