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--- project:weathersonde:telemetry_decoding [2016/07/16 12:01] – fix GPS structure size pinky
+++ project:weathersonde:telemetry_decoding [2017/02/19 16:58] (current) – [SUBFRAME structure] update doc for CRC polynom pinky
@@ Line 12: / Line 12: @@
 | 1 | 1 | SUBFRAME_LEN | Length of subframe payload |
 | 2 | 2*SUBFRAME_LEN | SUBFRAME_PAYLOAD | subframe payload |
-| 2*SUBFRAME_LEN+2 | 2 | SUBFRAME_CRC | CRC 16 of subframe payload, polynom = 0x11021 |
+| 2*SUBFRAME_LEN+2 | 2 | SUBFRAME_CRC | CRC 16 of subframe payload, polynom = 0x11021 (0x1021 withought leadeing 1) |
 ==== Known subframe types ====
@@ Line 20: / Line 20: @@
 | 0x69 | Measurement data |
 | 0x67 | GPS data |
-| 0x68 | typ of content not indentified |
+| 0x68 | RADAC (radiation measurement) / O3 (ozone) |
 | 0xff | padding ? |
@@ Line 65: / Line 65: @@
 | 21 | 3 | int24 | MEAS_REF4 | reference lower bound |
-Humidity value equations:
+<code>
+ref = (MEAS_REF3 + MEAS_REF4) / 2;
+p_rel = 1.0 / ((MEAS_P - ref) / (MEAS_REF1 - ref) - 0.0655) * 0.9053 + 0.08778;
+# pressure in hPa
+P = p_rel * ((((CALIB_COEFF[15] * p_rel + CALIB_COEFF[14]) * p_rel + CALIB_COEFF[13]) * p_rel + CALIB_COEFF[12]) * p_rel + CALIB_COEFF[11]) + CALIB_COEFF[10];
-  * ref_lo = (MEAS_REF3 + MEAS_REF4) / 2
+ref4 = MEAS_REF2 - ref;
-  * ref_hi1 = MEAS_REF1 - ref_lo
-  * ref_hi2 = MEAS_REF2 - ref_lo
+u1_rel = 1.0 / ((MEAS_U1 - ref) / ref4);
-  * U1_rel = ref_hi2 / (MEAS_CH1 - ref_lo)
+u2_rel = 1.0 / ((MEAS_U2 - ref) / ref4);
-  * U2_rel = ref_hi2 / (MEAS_CH2 - ref_lo)
+# humidity
-  * U1 = cal[40] + cal[41]*U1_rel + cal[42]*U1_rel^2 + cal[43]*U1_rel^3 + cal[44]*U1_rel^4 + cal[45]*U1_rel^5
+U1 = (
-  * U2 = cal[50] + cal[51]*U2_rel + cal[52]*U2_rel^2 + cal[53]*U2_rel^3 + cal[54]*U2_rel^4 + cal[55]*U2_rel^5
+    (u1_rel * CALIB_COEFF[43] + CALIB_COEFF[42]) * \
-  * U = max(U1, U2)
+    u1_rel + CALIB_COEFF[41]) * u1_rel + ALIB_COEFF[40];
+U2 = (
+    (u2_rel * CALIB_COEFF[53] + CALIB_COEFF[52]) * \
+    u2_rel + CALIB_COEFF[51]) * u2_rel + CALIB_COEFF[50];
+U = max(U1, U2)
+rt = (1.0 / (CALIB_COEFF[37] - 1.0) + 17.99418) * \
+.079298 / (((MEAS_T - ref) / ref4) - 0.15791);
+# temperature °C
+T = ((((
+    rt * CALIB_COEFF[35] + \
+    CALIB_COEFF[34]) * rt + \
+    CALIB_COEFF[33]) * rt + \
+    CALIB_COEFF[32]) * rt + \
+    CALIB_COEFF[31]) * rt + \
+    CALIB_COEFF[30];
+</code>
-Similar set of equations, but with some aditional tricks should work for P, and T.
 ===== GPS subframe payload (0x67) =====
@@ Line 115: / Line 134: @@
 | 7 | 1 | ??? | number, min/max: < -38, 39 > usually -5..10 |
-===== Unknown subframe payload (0x68) =====
+===== RADAC / O3 (radiation and ozone measurement) (0x68) =====
 expected payload length: 10
-No clue what this means.
+No usefull values available to decipher this frame, have someone something?
 ^ offset (B) ^ length (B) ^ description ^