diff --git a/RX_FSK/RX_FSK.ino b/RX_FSK/RX_FSK.ino
index 8391f95..fea214b 100644
--- a/RX_FSK/RX_FSK.ino
+++ b/RX_FSK/RX_FSK.ino
@@ -14,7 +14,8 @@
 #include <Scanner.h>
 #include <aprs.h>
 #include "version.h"
-#include <geteph.h>
+#include "geteph.h"
+#include "rs92gps.h"
 
 // UNCOMMENT one of the constructor lines below
 U8X8_SSD1306_128X64_NONAME_SW_I2C *u8x8 = NULL; // initialize later after reading config file
@@ -407,9 +408,13 @@ struct st_configitems config_list[] = {
   {"tcp.idformat", "DFM ID Format", -2, &sonde.config.tcpfeed.idformat},
   {"tcp.highrate", "Rate limit", 0, &sonde.config.tcpfeed.highrate},
   {"---", "---", -1, NULL},
-  /* RS41 decoder settings */
+  /* decoder settings */
   {"rs41.agcbw", "RS41 AGC bandwidth", 0, &sonde.config.rs41.agcbw},
   {"rs41.rxbw", "RS41 RX bandwidth", 0, &sonde.config.rs41.rxbw},
+  {"rs92.rxbw", "RS92 RX (and AGC) bandwidth", 0, &sonde.config.rs92.rxbw},
+  {"rs92.alt2d", "RS92 2D fix default altitude", 0, &sonde.config.rs92.alt2d},
+  {"dfm.agcbw", "DFM6/9 AGC bandwidth", 0, &sonde.config.dfm.agcbw},
+  {"dfm.rxbw", "DFM6/9 RX bandwidth", 0, &sonde.config.dfm.rxbw},
   {"---", "---", -1, NULL},
   /* Hardware dependeing settings */
   {"oled_sda", "OLED SDA (needs reboot)", 0, &sonde.config.oled_sda},
@@ -857,7 +862,7 @@ void sx1278Task(void *parameter) {
       resetup = false;
       sonde.setup();
     }
-    Serial.println("rx task: calling sonde.receive()");
+    //Serial.println("rx task: calling sonde.receive()");
     sonde.receive();
     delay(20);
   }
@@ -1481,7 +1486,7 @@ void wifiConnect(int16_t res) {
 static int wifi_cto;
 
 void loopWifiBackground() {
-  Serial.printf("WifiBackground: state %d\n", wifi_state);
+  // Serial.printf("WifiBackground: state %d\n", wifi_state);
   // handle Wifi station mode in background
   if (sonde.config.wifi == 0 || sonde.config.wifi == 2) return; // nothing to do if disabled or access point mode
 
@@ -1648,6 +1653,7 @@ void loopWifiScan() {
     sonde.updateDisplayIP();
     wifi_state = WIFI_CONNECTED;
     geteph();
+    get_eph("/brdc");
     delay(3000);
   }
   enableNetwork(true);
diff --git a/RX_FSK/data/config.txt b/RX_FSK/data/config.txt
index a937d8d..a1c864c 100644
--- a/RX_FSK/data/config.txt
+++ b/RX_FSK/data/config.txt
@@ -2,8 +2,8 @@
 # Hardware depending settings
 #-------------------------------#
 # pin: 255=disabled; x=button x+128=touch button
-button_pin=0
-button2_pin=255
+button_pin=130
+button2_pin=142
 # LED port
 led_pout=9
 # OLED Setup is depending on hardware of LoRa board
@@ -38,9 +38,17 @@ call=N0CALL
 passcode=12345
 #-------------------------------#
 # Sonde specific settings: bandwidth
+# valid values: 3100, 3900, 5200, 6300, 7800, 10400, 12500,
+# 15600, 20800, 25000, ...
+# other values will be rounded up to the next valid value
+# rs92.alt2d: default altitude used by RS92 decoder if only 3 sats available
 #-------------------------------#
-rs41.agcbw=6300
+rs41.agcbw=12500
 rs41.rxbw=6300
+rs92.rxbw=12500
+rs92.alt2d=480
+dfm.agcbw=20800
+dfm.rxbw=10400
 #-------------------------------#
 # axudp for sending to aprsmap
 #-------------------------------#
diff --git a/libraries/SX1278FSK/SX1278FSK.cpp b/libraries/SX1278FSK/SX1278FSK.cpp
index d6dde01..a9f2bfd 100644
--- a/libraries/SX1278FSK/SX1278FSK.cpp
+++ b/libraries/SX1278FSK/SX1278FSK.cpp
@@ -542,7 +542,7 @@ int32_t SX1278FSK::getFEI()
 {
 	int32_t FEI;
 	int16_t regval = (readRegister(REG_FEI_MSB)<<8) | readRegister(REG_FEI_LSB);
-	Serial.printf("feireg: %04x\n", regval);
+	//Serial.printf("feireg: %04x\n", regval);
 	FEI = (int32_t)(regval * SX127X_FSTEP);
 	return FEI;
 }
@@ -554,7 +554,7 @@ int32_t SX1278FSK::getAFC()
 {
 	int32_t AFC;
 	int16_t regval = (readRegister(REG_AFC_MSB)<<8) | readRegister(REG_AFC_LSB);
-	Serial.printf("afcreg: %04x\n", regval);
+	//Serial.printf("afcreg: %04x\n", regval);
 	AFC = (int32_t)(regval * SX127X_FSTEP);
 	return AFC;
 }
diff --git a/libraries/SondeLib/DFM.cpp b/libraries/SondeLib/DFM.cpp
index 1243b69..34c9b1f 100644
--- a/libraries/SondeLib/DFM.cpp
+++ b/libraries/SondeLib/DFM.cpp
@@ -36,14 +36,14 @@ int DFM::setup(float frequency, int inv)
 	Serial.println(br);
 #endif
 
-	if(sx1278.setAFCBandwidth(25000)!=0) {
-		DFM_DBG(Serial.println("Setting AFC bandwidth 25 kHz FAILED"));
-		return 1;
-	}
-	if(sx1278.setRxBandwidth(12000)!=0) {
-		DFM_DBG(Serial.println("Setting RX bandwidth 12kHz FAILED"));
-		return 1;
-	}
+        if(sx1278.setAFCBandwidth(sonde.config.dfm.agcbw)!=0) {
+                DFM_DBG(Serial.printf("Setting AFC bandwidth %d Hz FAILED", sonde.config.dfm.agcbw));
+                return 1;
+        }
+        if(sx1278.setRxBandwidth(sonde.config.dfm.rxbw)!=0) {
+                DFM_DBG(Serial.printf("Setting RX bandwidth to %d Hz FAILED", sonde.config.dfm.rxbw));
+                return 1;
+        }
 	// Enable auto-AFC, auto-AGC, RX Trigger by preamble
 	if(sx1278.setRxConf(0x1E)!=0) {
 		DFM_DBG(Serial.println("Setting RX Config FAILED"));
diff --git a/libraries/SondeLib/Display.cpp b/libraries/SondeLib/Display.cpp
index 8da9785..b5488a0 100644
--- a/libraries/SondeLib/Display.cpp
+++ b/libraries/SondeLib/Display.cpp
@@ -32,11 +32,12 @@ static unsigned char kmh_tiles[] U8X8_PROGMEM = {
 static unsigned char ms_tiles[] U8X8_PROGMEM = {
    0x1F, 0x02, 0x04, 0x02, 0x1F, 0x40, 0x20, 0x10, 0x08, 0x04, 0x12, 0xA4, 0xA4, 0xA4, 0x40, 0x00
    };
-static unsigned char stattiles[4][4] =  {
+static unsigned char stattiles[5][4] =  {
    0x00, 0x1F, 0x00, 0x00 ,   // | == ok
    0x00, 0x10, 0x10, 0x00 ,   // . == no header found
    0x1F, 0x15, 0x15, 0x00 ,   // E == decode error
-   0x00, 0x00, 0x00, 0x00 };  // ' ' == unknown/unassigned
+   0x00, 0x00, 0x00, 0x00 ,   // ' ' == unknown/unassigned
+   0x07, 0x05, 0x07, 0x00 };  // ° = rx ok, but no valid position
 
 
 //static uint8_t halfdb_tile[8]={0x80, 0x27, 0x45, 0x45, 0x45, 0x39, 0x00, 0x00};
diff --git a/libraries/SondeLib/RS41.cpp b/libraries/SondeLib/RS41.cpp
index cccb489..033fca7 100644
--- a/libraries/SondeLib/RS41.cpp
+++ b/libraries/SondeLib/RS41.cpp
@@ -103,11 +103,11 @@ int RS41::setup(float frequency)
 #endif
 
 	if(sx1278.setAFCBandwidth(sonde.config.rs41.agcbw)!=0) {
-		RS41_DBG(Serial.println("Setting AFC bandwidth 25 kHz FAILED"));
+		RS41_DBG(Serial.printf("Setting AFC bandwidth %d Hz FAILED", sonde.config.rs41.agcbw));
 		return 1;
 	}
 	if(sx1278.setRxBandwidth(sonde.config.rs41.rxbw)!=0) {
-		RS41_DBG(Serial.println("Setting RX bandwidth 12kHz FAILED"));
+		RS41_DBG(Serial.printf("Setting RX bandwidth to %d Hz FAILED", sonde.config.rs41.rxbw));
 		return 1;
 	}
 	// Enable auto-AFC, auto-AGC, RX Trigger by preamble
diff --git a/libraries/SondeLib/RS92.cpp b/libraries/SondeLib/RS92.cpp
index d7c931f..3559b94 100644
--- a/libraries/SondeLib/RS92.cpp
+++ b/libraries/SondeLib/RS92.cpp
@@ -76,6 +76,20 @@ static void Gencrctab(void)
    } /* end for */
 } /* end Gencrctab() */
 
+
+static byte data1[512]={0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x10};
+static byte data2[512]={0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x10};
+static byte *dataptr=data1;
+
+static uint8_t rxbitc;
+static int32_t asynst[10]={0};
+static uint16_t rxbyte;
+int rxp=0;
+
+static int haveNewFrame = 0;
+static int lastFrame = 0;
+static int headerDetected = 0;
+
 int RS92::setup(float frequency) 
 {
 #if RS92_DEBUG
@@ -84,7 +98,7 @@ int RS92::setup(float frequency)
 	if(!initialized) {
 		Gencrctab();
 		initrsc();
-        	get_eph("/brdc.19n");
+        	// not here for now.... get_eph("/brdc.19n");
 		initialized = true;
 	}
 
@@ -105,15 +119,15 @@ int RS92::setup(float frequency)
 	Serial.print("Exact bitrate is ");
 	Serial.println(br);
 #endif
+        if(sx1278.setAFCBandwidth(sonde.config.rs92.rxbw)!=0) {
+                RS92_DBG(Serial.printf("Setting AFC bandwidth %d Hz FAILED", sonde.config.rs92.rxbw));
+                return 1;
+        }
+        if(sx1278.setRxBandwidth(sonde.config.rs92.rxbw)!=0) {
+                RS92_DBG(Serial.printf("Setting RX bandwidth to %d Hz FAILED", sonde.config.rs92.rxbw));
+                return 1;
+        }
 
-	if(sx1278.setAFCBandwidth(sonde.config.rs41.agcbw)!=0) {
-		RS92_DBG(Serial.println("Setting AFC bandwidth 25 kHz FAILED"));
-		return 1;
-	}
-	if(sx1278.setRxBandwidth(sonde.config.rs41.rxbw)!=0) {
-		RS92_DBG(Serial.println("Setting RX bandwidth 12kHz FAILED"));
-		return 1;
-	}
 	// Enable auto-AFC, auto-AGC, RX Trigger by preamble
 	if(sx1278.setRxConf(0x1E)!=0) {
 		RS92_DBG(Serial.println("Setting RX Config FAILED"));
@@ -345,8 +359,10 @@ void RS92::decodeframe92(uint8_t *data)
 	//int calok;
 	//int mesok;
 	//uint32_t calibok;
-	Serial.printf("rs corr is %d\n", corr);
-	print_frame(data, 240);
+	lastFrame = (dataptr==data1)?1:2;
+	Serial.printf("rs corr is %d --- data:%p data1:%p data2:%p lastframe=%d\n", corr, data, data1, data2, lastFrame);
+	dataptr = (dataptr==data1)?data2:data1;
+	//print_frame(data, 240);
 #if 0
 	/* from sondemod*/
 	int p=6;
@@ -458,19 +474,10 @@ static uint8_t scramble[64] = {150U,131U,62U,81U,177U,73U,8U,152U,50U,5U,89U,
 		193U};
 #endif
 
-static byte data[5000]={0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x10};
-
-static uint8_t rxbitc;
-static int32_t asynst[10]={0};
-static uint16_t rxbyte;
-int rxp=0;
-
-static int haveNewFrame = 0;
-static int headerDetected = 0;
 
 void RS92::stobyte92(uint8_t b)
 {
-	data[rxp] = b;
+	dataptr[rxp] = b;
 	if(rxp>=5 || b=='*') rxp++; else rxp=0;
 	if(rxp==6) { // header detected
 		headerDetected = 1;	
@@ -478,7 +485,7 @@ void RS92::stobyte92(uint8_t b)
 	if(rxp>=240) { // frame complete... (240 byte)
 		rxp=0;
 		//printRaw(data, 240);
-		decodeframe92(data);
+		decodeframe92(dataptr);
 		haveNewFrame = 1;
 	}
 } /* end stobyte92() */
@@ -506,9 +513,9 @@ void RS92::process8N1data(uint8_t dt)
                                 int rssi=sx1278.getRSSI();
                                 int fei=sx1278.getFEI();
                                 int afc=sx1278.getAFC();
-                                Serial.print("Test: RSSI="); Serial.println(rssi);
-                                Serial.print("Test: FEI="); Serial.println(fei);
-                                Serial.print("Test: AFC="); Serial.println(afc);
+                                Serial.print("Test: RSSI="); Serial.print(rssi);
+                                Serial.print(" FEI="); Serial.print(fei);
+                                Serial.print(" AFC="); Serial.println(afc);
                                 sonde.si()->rssi = rssi;
                                 sonde.si()->afc = afc;
 			}
@@ -516,14 +523,14 @@ void RS92::process8N1data(uint8_t dt)
 			rxbitc = (rxbitc+1)%20;
 			if(rxbitc == 0) { // got startbit, 8 data bit, stop bit
 				//Serial.printf("%03x ",rxbyte);
-				data[rxp++] = (rxbyte>>1)&0xff;
-				if(rxp==7 && data[6] != 0x65) {
-					Serial.printf("wrong start: %02x\n",data[6]);
+				dataptr[rxp++] = (rxbyte>>1)&0xff;
+				if(rxp==7 && dataptr[6] != 0x65) {
+					Serial.printf("wrong start: %02x\n",dataptr[6]);
 					rxsearching = true;
 				}
 				if(rxp>=240) {
 					rxsearching = true;
-					decodeframe92(data);
+					decodeframe92(dataptr);
 					haveNewFrame = 1;
 				}
 			}
@@ -602,6 +609,19 @@ int RS92::receive() {
 
 #define RS92MAXLEN (240)
 int RS92::waitRXcomplete() {
+	// called after complete...
+	Serial.printf("decoding frame %d\n", lastFrame);
+	print_frame(lastFrame==1?data1:data2, 240);
+
+	SondeInfo *si = sonde.sondeList+sonde.currentSonde;
+	si->lat = gpx.lat;
+	si->lon = gpx.lon;
+	si->alt = gpx.alt;
+	si->vs = gpx.vU;
+	si->hs = gpx.vH;
+	si->dir = gpx.vD;
+	si->validPos = 0x3f;
+
 #if 0
 	int res=0;
         uint32_t t0 = millis();
diff --git a/libraries/SondeLib/Sonde.cpp b/libraries/SondeLib/Sonde.cpp
index dc0c08a..b7acb08 100644
--- a/libraries/SondeLib/Sonde.cpp
+++ b/libraries/SondeLib/Sonde.cpp
@@ -67,8 +67,12 @@ Sonde::Sonde() {
 	config.marker=0;
 	config.showafc=0;
 	config.freqofs=0;
-	config.rs41.agcbw=25000;
-	config.rs41.rxbw=12000;
+	config.rs41.agcbw=12500;
+	config.rs41.rxbw=6300;
+	config.rs92.rxbw=12500;
+	config.rs92.alt2d=480;
+	config.dfm.agcbw=20800;
+	config.dfm.rxbw=10400;
 	config.udpfeed.active = 1;
 	config.udpfeed.type = 0;
 	strcpy(config.udpfeed.host, "192.168.42.20");
@@ -145,6 +149,14 @@ void Sonde::setConfig(const char *cfg) {
 		config.rs41.agcbw = atoi(val);
 	} else if(strcmp(cfg,"rs41.rxbw")==0) {
 		config.rs41.rxbw = atoi(val);
+	} else if(strcmp(cfg,"dfm.agcbw")==0) {
+		config.dfm.agcbw = atoi(val);
+	} else if(strcmp(cfg,"dfm.rxbw")==0) {
+		config.dfm.rxbw = atoi(val);
+	} else if(strcmp(cfg,"rs92.alt2d")==0) {
+		config.rs92.alt2d= atoi(val);
+	} else if(strcmp(cfg,"rs92.rxbw")==0) {
+		config.rs92.rxbw = atoi(val);
 	} else if(strcmp(cfg,"axudp.active")==0) {
 		config.udpfeed.active = atoi(val)>0;
 	} else if(strcmp(cfg,"axudp.host")==0) {
@@ -326,23 +338,20 @@ rxloop:
 	}
         rxtask.receiveResult = 0xFFFF;
         Serial.printf("waitRXcomplete returning %04x (%s)\n", res, RXstr[res&0xff]);
-#if 0
-//currently not used...
-{
-	int res;
-	switch(sondeList[rxtask.currentSonde].type) {
+	// currently used only by RS92
+	// TODO: rxtask.currentSonde might not be the right thing (after sonde channel change)
+	switch(sondeList[/*rxtask.*/currentSonde].type) {
 	case STYPE_RS41:
-		res = rs41.waitRXcomplete();
+		rs41.waitRXcomplete();
 		break;
 	case STYPE_RS92:
-		res = rs92.waitRXcomplete();
+		rs92.waitRXcomplete();
 		break;
 	case STYPE_DFM06:
 	case STYPE_DFM09:
-		res = dfm.waitRXcomplete();
+		dfm.waitRXcomplete();
 		break;
 	}
-#endif
 	memmove(sonde.si()->rxStat+1, sonde.si()->rxStat, 17);
         sonde.si()->rxStat[0] = res;
 	return res;
diff --git a/libraries/SondeLib/Sonde.h b/libraries/SondeLib/Sonde.h
index 5f4e3ec..bc7326b 100644
--- a/libraries/SondeLib/Sonde.h
+++ b/libraries/SondeLib/Sonde.h
@@ -7,7 +7,7 @@
 // RX_TIMEOUT: no header detected
 // RX_ERROR: header detected, but data not decoded (crc error, etc.)
 // RX_OK: header and data ok
-enum RxResult { RX_OK, RX_TIMEOUT, RX_ERROR, RX_UNKNOWN };
+enum RxResult { RX_OK, RX_TIMEOUT, RX_ERROR, RX_UNKNOWN, RX_NOPOS };
 #define RX_UPDATERSSI 0xFFFE
 
 // Events that change what is displayed (mode, sondenr)
@@ -70,6 +70,14 @@ struct st_rs41config {
 	int agcbw;
 	int rxbw;
 };
+struct st_rs92config {
+	int rxbw;
+	int alt2d;
+};
+struct st_dfmconfig {
+	int agcbw;
+	int rxbw;
+};
 
 typedef struct st_rdzconfig {
 	int button_pin;			// PIN port number menu button (+128 for touch mode)
@@ -96,6 +104,8 @@ typedef struct st_rdzconfig {
 	char call[9];			// APRS callsign
 	char passcode[9];		// APRS passcode
 	struct st_rs41config rs41;	// configuration options specific for RS41 receiver
+	struct st_rs92config rs92;
+	struct st_dfmconfig dfm;
 	// for now, one feed for each type is enough, but might get extended to more?
 	struct st_feedinfo udpfeed;	// target for AXUDP messages
 	struct st_feedinfo tcpfeed;	// target for APRS-IS TCP connections
@@ -103,7 +113,7 @@ typedef struct st_rdzconfig {
 
 typedef struct st_sondeinfo {
         // receiver configuration
-		bool active;
+	bool active;
         SondeType type;
         float freq;
         // decoded ID
@@ -116,7 +126,7 @@ typedef struct st_sondeinfo {
         float alt;			// altitude
         float vs;			// vertical speed
         float hs;			// horizontal speed
-		float dir; 			// 0..360
+	float dir; 			// 0..360
         uint8_t validPos;   // bit pattern for validity of above 6 fields
         // RSSI from receiver
         int rssi;			// signal strength
@@ -128,7 +138,7 @@ typedef struct st_sondeinfo {
 	uint32_t viewStart;		// millis() timestamp of viewinf this sonde with current display
 	int8_t lastState;		// -1: disabled; 0: norx; 1: rx
 } SondeInfo;
-// rxStat: 0=undef[empty] 1=timeout[.] 2=errro[E] 3=ok[1]
+// rxStat: 3=undef[empty] 1=timeout[.] 2=errro[E] 3=ok[1] 5=no valid position[°]
 
 
 #define MAXSONDE 99
diff --git a/libraries/SondeLib/nav_gps_vel.cpp b/libraries/SondeLib/nav_gps_vel.cpp
index 97e4c1f..89084f8 100644
--- a/libraries/SondeLib/nav_gps_vel.cpp
+++ b/libraries/SondeLib/nav_gps_vel.cpp
@@ -384,6 +384,20 @@ EPHEM_t *read_RNXpephs(const char *file) {
         ephem.week = 1; // ephem.gpsweek
 	Serial.printf("Reading ephem for prn %d\n", ui);
 	if(ui<33) {
+#if 0
+		// no need to do it the difficult way, most recent data is at end of file :-)
+		double tdiff;
+		if(te[ui].prn!=ui) {
+			tdiff = WEEKSEC;
+		} else {
+			tdiff = now - te[ui].toe;
+			if(tdiff>WEEKSEC/2) tdiff -= WEEKSEC;
+			if(tdiff<-WEEKSEC/2) tdiff += WEEKSEC;
+		}
+		double td = now - ephem.toe;
+		if(td>WEEKSEC/2) td -= WEEKSEC;
+		if(td<-WEEKSEC/2) td += WEEKSEC;
+#endif		
 		te[ui] = ephem;
 	} else {
 		Serial.printf("bad prn: %d\n", ui);
diff --git a/libraries/SondeLib/rs92gps.cpp b/libraries/SondeLib/rs92gps.cpp
index b788d88..7365329 100644
--- a/libraries/SondeLib/rs92gps.cpp
+++ b/libraries/SondeLib/rs92gps.cpp
@@ -50,28 +50,10 @@
 
 #include <SPIFFS.h>
 #include "nav_gps_vel.h"
-
-#ifdef CYGWIN
-  #include <fcntl.h>  // cygwin: _setmode()
-  #include <io.h>
-#endif
+#include "rs92gps.h"
+#include "Sonde.h"
 
 
-typedef struct {
-    int frnr;
-    char id[11];
-    int week; int gpssec;
-    int jahr; int monat; int tag;
-    int wday;
-    int std; int min; float sek;
-    double lat; double lon; double alt;
-    double vH; double vD; double vU;
-    int sats[4];
-    double dop;
-    int freq;
-    unsigned short aux[4];
-    double diter;
-} gpx_t;
 
 gpx_t gpx;
 
@@ -91,6 +73,7 @@ int option_verbose = 0,  // ausfuehrliche Anzeige
     rawin = 0;
 double dop_limit = 9.9;
 double d_err = 10000;
+//double fixalt2d = 480; // bei mir zu Hause :-) TODO: make it configurable
 
 int rollover = 0,
     err_gps = 0;
@@ -550,6 +533,7 @@ int get_GPStime() {
     gpstime /= 1000;
 
     gpx.gpssec = gpstime;
+    Serial.printf("GPS time is %04x (%d)\n", gpstime, gpstime);
 
     day = (gpstime / (24 * 3600)) % 7;        // besser CRC-check, da auch
     //if ((day < 0) || (day > 6)) return -1;  // gpssec=604800,604801 beobachtet
@@ -901,6 +885,8 @@ const double df = 299792.458/1023.0/1024.0; //0.286183844 // c=299792458m/s, 102
 //           dl = L1/(chips/sec)/4
 const double dl = 1575.42/1.023/4.0; //385.0 // GPS L1 1575.42MHz=154*10.23MHz, dl=154*10/4
 
+double pr_ofs;
+double GPSsatAlt = 20200e3;
 
 int get_pseudorange() {
     uint32_t gpstime;
@@ -919,10 +905,12 @@ int get_pseudorange() {
     memcpy(&gpstime, gpstime_bytes, 4);
 
     // Sat Status
+    Serial.print("Sat status: ");
     for (i = 0; i < 12; i++) {
         sat_status[i] = framebyte(posGPS_STATUS + i);
-	Serial.printf("sat status %d: %d\n", i, sat_status[i]);
+	Serial.printf("%d:%d ", i, sat_status[i]);
     }
+    Serial.print("\n");
 
     // PRN-Nummern
     for (i = 0; i < 4; i++) {
@@ -953,7 +941,7 @@ int get_pseudorange() {
             pseudobytes[i] = frame[posGPS_DATA+8*j+i];
         }
         memcpy(&chipbytes, pseudobytes, 4);
-	Serial.printf("Chipbytes(%d): %04x\n",j, chipbytes);
+	//Serial.printf("Chipbytes(%d): %04x\n",j, chipbytes);
 
         // delta_pseudochips / 385
         for (i = 0; i < 3; i++) {
@@ -985,9 +973,9 @@ int get_pseudorange() {
             continue;
         }
 */
-	Serial.printf("j=%d: prns=%d status=%d  dist=%f\n", j, prns[j], sat_status[j], dist(sat[prns[j]].X, sat[prns[j]].Y, sat[prns[j]].Z, 0, 0, 0));
-	int o=prns[j];
-	Serial.printf("x=%f y=%f z=%f\n", sat[o].X, sat[o].Y, sat[o].Z);
+	Serial.printf("j=%d: prns=%d status=%d  dist=%f\n ", j, prns[j], sat_status[j], dist(sat[prns[j]].X, sat[prns[j]].Y, sat[prns[j]].Z, 0, 0, 0));
+	//int o=prns[j];
+	//Serial.printf("x=%f y=%f z=%f\n", sat[o].X, sat[o].Y, sat[o].Z);
         if (  (prns[j] > 0)  &&  ((sat_status[j] & 0x0F) == 0xF)
            && (dist(sat[prns[j]].X, sat[prns[j]].Y, sat[prns[j]].Z, 0, 0, 0) > 6700000) )
         {
@@ -1020,12 +1008,13 @@ int get_pseudorange() {
         prj = sat[prn[j]].pseudorange + sat[prn[j]].clock_corr;
         if (prj < pr0) pr0 = prj;
     }
-    for (j = 0; j < k; j++) sat[prn[j]].PR = sat[prn[j]].pseudorange + sat[prn[j]].clock_corr - pr0 + 20e6;
+    for (j = 0; j < k; j++) sat[prn[j]].PR = sat[prn[j]].pseudorange + sat[prn[j]].clock_corr - pr0 + GPSsatAlt;
     // es kann PRNs geben, die zeitweise stark abweichende PR liefern;
     // eventuell Standardabweichung ermitteln und fehlerhafte Sats weglassen
     for (j = 0; j < k; j++) {                      //  sat/sat1s...             PR-check
-        sat1s[prn[j]].PR = sat1s[prn[j]].pseudorange + sat[prn[j]].clock_corr - pr0 + 20e6;
+        sat1s[prn[j]].PR = sat1s[prn[j]].pseudorange + sat[prn[j]].clock_corr - pr0 + GPSsatAlt;
     }
+    pr_ofs = pr0;
 
     return k;
 }
@@ -1049,6 +1038,80 @@ int get_GPSvel(double lat, double lon, double vel_ecef[3],
 
 double DOP[4];
 
+int naiv_2Dfix(int N, SAT_t sats[], double alt) {
+// simple 2D fix: 3 Sats & Alt above ellipsoid
+//
+// - fuer 3 unbekannte lat, lon, t braucht man mind. 3 Satelliten
+// - fuer Iteration braucht man jedoch einen Startwert
+// - es gibt direkte Methoden
+// - hier werden die vorhandenen Funktionen benutzt:
+//   - der 4. Satellit im Erdmittelpunkt
+//   - seine pseudorange(+clock) wird grob geschaetzt
+//     (pseudochips liefern erst Rueckschluesse, wenn man Position kennt)
+//   - dann approximieren, bis Hoehe stimmt
+// - bei 3-4 Satelliten ist die DOP-Konstellation oft schlecht
+// - moeglicherweise ist in einigen Faellen die 2. Loesung besser
+
+    double radius = 6371e3 + alt; // wird dann approximiert
+    double lat2d, lon2d, alt2d,
+           pos_ecef[3], rx_cl_bias,
+           dpos_ecef[3];
+    //double d;
+    double rofs = 200000.0, rdiff = 0.0;
+    int k, k_limit;
+    double gdop = -1;
+
+
+    sats[3].X = sats[3].Y = sats[3].Z = 0;
+
+    k = 0;
+    k_limit = 100;
+
+    if (N >= 3) {
+
+            do
+            {
+                // PR = pseudorange + clock_corr - pr_ofs + GPSsatAlt
+                sats[3].X = sats[3].Y = sats[3].Z = 0;
+                sats[3].PR = radius - rofs;
+                sats[3].pseudorange = sats[3].PR + pr_ofs - GPSsatAlt;
+
+
+                NAV_bancroft1(4, sats, pos_ecef, &rx_cl_bias);
+                //NAV_bancroft3(4, sats, pos_ecef1, &rx_cl_bias1, pos_ecef2, &rx_cl_bias2);
+
+                ecef2elli(pos_ecef[0], pos_ecef[1], pos_ecef[2], &lat2d, &lon2d, &alt2d);
+                rdiff = alt-alt2d;
+
+                rofs -= rdiff*1.2;
+                k += 1;
+
+            } while (k < k_limit  &&  fabs(rdiff) > 1.0);
+
+            NAV_LinP(4, sats, pos_ecef, rx_cl_bias, dpos_ecef, &rx_cl_bias);
+            //  for (j=0;j<3;j++) pos_ecef[j] += dpos_ecef[j];
+            //  NAV_LinP(4, sats, pos_ecef, rx_cl_bias, dpos_ecef, &rx_cl_bias);
+            //  d = dist(0, 0, 0, dpos_ecef[0], dpos_ecef[1], dpos_ecef[2]);
+
+    }
+
+    if (calc_DOPn(4, sats, pos_ecef, DOP) == 0) {
+        gdop = sqrt(DOP[0]+DOP[1]+DOP[2]+DOP[3]);
+    }
+    //if (gdop > 2*dop_limit) gdop = -1;
+    //if (gdop < 0) gdop = -1;
+
+    gpx.lat = lat2d;
+    gpx.lon = lon2d;
+    gpx.alt = alt2d;
+    gpx.dop = gdop;
+
+    if ( fabs(alt2d-alt) > 1000.0 ) return -1;
+    if ( k == k_limit ) return 0;
+    return 1;
+}
+
+
 int get_GPSkoord(int N) {
     double lat, lon, alt, rx_cl_bias;
     double vH, vD, vU;
@@ -1281,8 +1344,8 @@ int get_GPSkoord(int N) {
 
 
 int print_position() {  // GPS-Hoehe ueber Ellipsoid
-    int j, k, n = 0;
-    int err1, err2;
+    int j, k = 0, n = 0;
+    int err1, err2, fix2d = 0;
 
     err1 = 0;
     if (!option_verbose) err1 = err_gps;
@@ -1293,13 +1356,22 @@ int print_position() {  // GPS-Hoehe ueber Ellipsoid
   //err2 |= get_GPSweek();
     err2 |= get_GPStime();
 
+#if 0
     Serial.printf("ephem=%d\n",ephem);
+    Serial.printf("print_position: ephs is %p\n", ephs);
+#endif
+
     if (!err2 && (almanac || ephem)) {
         k = get_pseudorange();
 	Serial.printf("k=%d\n", k);
         if (k >= 4) {
             n = get_GPSkoord(k);
         }
+	if (k == 3) {
+	    SAT_t Sat_A[4];
+	    for (j = 0; j < 3; j++) { Sat_A[j] = sat[prn[j]]; }
+	    fix2d = naiv_2Dfix( 3, Sat_A, sonde.config.rs92.alt2d);
+	}
     }
 
     if (!err1) {
@@ -1316,7 +1388,11 @@ int print_position() {  // GPS-Hoehe ueber Ellipsoid
         fprintf(stdout, "%s ", weekday[gpx.wday]);  // %04.1f: wenn sek >= 59.950, wird auf 60.0 gerundet
         fprintf(stdout, "%02d:%02d:%06.3f", gpx.std, gpx.min, gpx.sek);
 
-        if (n > 0) {
+	if (k == 3  &&  fix2d > 0  &&  gpx.dop > 0  &&  gpx.dop < 2*dop_limit) {
+             fprintf(stdout, "  2D  lat: %.5f  lon: %.5f  alt: %.1f ", gpx.lat, gpx.lon, gpx.alt);
+             fprintf(stdout, " DOP[%02d,%02d,%02d,0] %.1f ", prn[0], prn[1], prn[2], gpx.dop);
+        }
+        else if (n > 0) {
             fprintf(stdout, " ");
 
             if (almanac) fprintf(stdout, " lat: %.4f  lon: %.4f  alt: %.1f ", gpx.lat, gpx.lon, gpx.alt);
@@ -1386,7 +1462,8 @@ void print_frame(uint8_t *data, int len) {
         }
         fprintf(stdout, "\n");
     }
-    else print_position();
+    //Serial.printf("print_frame: ephs is %p\n", ephs);
+    print_position();
 }
 
 void get_eph(const char *file) {
@@ -1395,7 +1472,7 @@ void get_eph(const char *file) {
             ephem = 1;
             almanac = 0;
         }
-	Serial.printf("reading RNX done, result is %d\n", ephem);
+	Serial.printf("reading RNX done, result is %d, ephs=%p\n", ephem, ephs);
         if (!option_der) d_err = 1000;
 }
 
diff --git a/libraries/SondeLib/rs92gps.h b/libraries/SondeLib/rs92gps.h
index 229c2ea..a780b78 100644
--- a/libraries/SondeLib/rs92gps.h
+++ b/libraries/SondeLib/rs92gps.h
@@ -1,3 +1,21 @@
 
+typedef struct {
+    int frnr;
+    char id[11];
+    int week; int gpssec;
+    int jahr; int monat; int tag;
+    int wday;
+    int std; int min; float sek;
+    double lat; double lon; double alt;
+    double vH; double vD; double vU;
+    int sats[4];
+    double dop;
+    int freq;
+    unsigned short aux[4];
+    double diter;
+} gpx_t;
+
+extern gpx_t gpx;
+
 void print_frame(uint8_t *data, int len); 
 void get_eph(const char *file);