diff --git a/build.sh b/build.sh
index a00a31b..cd5f84c 100755
--- a/build.sh
+++ b/build.sh
@@ -29,6 +29,7 @@ java -jar "../tools/yuicompressor-2.4.8.jar" --type=js --disable-optimizations -
 java -jar "../tools/yuicompressor-2.4.8.jar" --type=js --disable-optimizations --nomunge colour-map.js >> mobile.js
 java -jar "../tools/yuicompressor-2.4.8.jar" --type=js --disable-optimizations --nomunge format.js >> mobile.js
 java -jar "../tools/yuicompressor-2.4.8.jar" --type=js --disable-optimizations --nomunge flight_doc.js >> mobile.js
+java -jar "../tools/yuicompressor-2.4.8.jar" --type=js --disable-optimizations --nomunge suncalc.js >> mobile.js
 
 #compile plot lib and config
 java -jar "../tools/yuicompressor-2.4.8.jar" --type=js --disable-optimizations --nomunge _jquery.flot.js >> init_plot.js
diff --git a/js/format.js b/js/format.js
index 547c5b7..b8e2b8f 100644
--- a/js/format.js
+++ b/js/format.js
@@ -145,6 +145,28 @@ function formatData(data) {
                         }
                     }
 
+                    // Payload data post-processing, where we can modify / add data elements if needed.
+
+                    // Determine if this payload is a WSPR payload
+                    // We determine this through either the modulation field, or comment field.
+                    var wspr_payload = false;
+                    if (data[key][i].hasOwnProperty("modulation")){
+                        if(data[key][i].modulation.includes("WSPR")){
+                            wspr_payload = true;
+                        }
+                    }
+                    if (data[key][i].hasOwnProperty("comment")){
+                        if(data[key][i].comment.includes("WSPR")){
+                            wspr_payload = true;
+                        }
+                    }
+
+                    // For WSPR payloads, calculate solar elevation.
+                    if(wspr_payload){
+                        dataTempEntry.data['solar_elevation'] = (SunCalc.getPosition(stringToDateUTC(dataTempEntry.gps_time), dataTempEntry.gps_lat, dataTempEntry.gps_lon).altitude/rad).toFixed(1);
+                    }
+
+
                     dataTemp.push(dataTempEntry);
                 }
             }
diff --git a/js/suncalc.js b/js/suncalc.js
new file mode 100644
index 0000000..fec2ec3
--- /dev/null
+++ b/js/suncalc.js
@@ -0,0 +1,78 @@
+// Sun Position Calculations from https://github.com/mourner/suncalc
+
+// shortcuts for easier to read formulas
+
+var PI   = Math.PI,
+    sin  = Math.sin,
+    cos  = Math.cos,
+    tan  = Math.tan,
+    asin = Math.asin,
+    atan = Math.atan2,
+    acos = Math.acos,
+    rad  = PI / 180;
+// date/time constants and conversions
+
+var dayMs = 1000 * 60 * 60 * 24,
+    J1970 = 2440588,
+    J2000 = 2451545;
+
+function suncalc_toJulian(date) { return date.valueOf() / dayMs - 0.5 + J1970; }
+function suncalc_fromJulian(j)  { return new Date((j + 0.5 - J1970) * dayMs); }
+function suncalc_toDays(date)   { return suncalc_toJulian(date) - J2000; }
+
+
+// general calculations for position
+
+var suncalc_e = rad * 23.4397; // obliquity of the Earth
+
+function rightAscension(l, b) { return atan(sin(l) * cos(suncalc_e) - tan(b) * sin(suncalc_e), cos(l)); }
+function declination(l, b)    { return asin(sin(b) * cos(suncalc_e) + cos(b) * sin(suncalc_e) * sin(l)); }
+
+function suncalc_azimuth(H, phi, dec)  { return atan(sin(H), cos(H) * sin(phi) - tan(dec) * cos(phi)); }
+function suncalc_altitude(H, phi, dec) { return asin(sin(phi) * sin(dec) + cos(phi) * cos(dec) * cos(H)); }
+
+function siderealTime(d, lw) { return rad * (280.16 + 360.9856235 * d) - lw; }
+
+// general sun calculations
+
+function solarMeanAnomaly(d) { return rad * (357.5291 + 0.98560028 * d); }
+
+function eclipticLongitude(M) {
+
+    var C = rad * (1.9148 * sin(M) + 0.02 * sin(2 * M) + 0.0003 * sin(3 * M)), // equation of center
+        P = rad * 102.9372; // perihelion of the Earth
+
+    return M + C + P + PI;
+}
+
+function sunCoords(d) {
+
+    var M = solarMeanAnomaly(d),
+        L = eclipticLongitude(M);
+
+    return {
+        dec: declination(L, 0),
+        ra: rightAscension(L, 0)
+    };
+}
+
+var SunCalc = {};
+
+
+// calculates sun position for a given date and latitude/longitude
+
+SunCalc.getPosition = function (date, lat, lng) {
+
+    var lw  = rad * -lng,
+        phi = rad * lat,
+        d   = suncalc_toDays(date),
+
+        c  = sunCoords(d),
+        H  = siderealTime(d, lw) - c.ra;
+
+    return {
+        azimuth: suncalc_azimuth(H, phi, c.dec),
+        altitude: suncalc_altitude(H, phi, c.dec)
+    };
+};
+