GPS travelled Distance error

Projects General Guidance
1

hi, i am on a project that calculate travelled distance. firstly i had a standing error. in other word device thought that i am travelling while i was standing still because of gps uncertinity. i fixed it by adding minimum 30 meters threshold. but now my device calculates approximately %6 less then actual travelled distance. is there any way to lower this error? or is it natural. i am waiting for your comment. thank you.
i am using arduino nano
neo 7m gps module
gps antenna
satellite count generally above 7
related part of my gps distance

 //distance measurement
  currentMillis=millis();
  if(currentMillis - previousMillis >= 2000){ //calculate disance one in every 2 sec
    distance = TinyGPS::distance_between(flat, flon, slat, slon);
    distance=300;
    
    
    if(distance>30){
      slat=flat;
      slon=flon;
      sum_distance1=sum_distance1+distance;

      if (taksimetrepressed==1) sum_distance3=sum_distance3+distance; //taksimetre pressed but passenger didnt sit
      
      if (sensor1>350 || sensor2>350 || sensor3>350 || sensor4>350 || ((millis()-previousMillis6)<6000) )  { // anlık kesilme önlemesi
        sum_distance2=sum_distance2+sum_distance3+distance;        
        taksimetrepressed=0;
        sum_distance3=0;

        //kısa mesafe uzun mesafe
        
        sum_distance4=sum_distance4+distance;
               
        }
      
     
      
      Serial.print("sum_distance1: "); Serial.println(sum_distance1);
      Serial.print("sum_distance2: "); Serial.println(sum_distance2);
      Serial.print("sum_distance3: "); Serial.println(sum_distance3);
      }
    
      Serial.print("distance "); Serial.println(distance);
    

    
    previousMillis=currentMillis;
  }

all my code,

#include <SoftwareSerial.h>

#include <TinyGPS.h>



TinyGPS gps;
SoftwareSerial ss(3, 4);

//distance
float slat=39;
float slon=27;
unsigned long age=0;
unsigned long sum_distance1;
unsigned long sum_distance2;
unsigned long sum_distance3; //taksimetre basıldıktan sonra müsteri oturuncaya kadar geçen süre
unsigned long sum_distance4; //uzun yolcu kısa yolcu sayar
int distance=0;

//kısa mesafe uzun mesefe
int kyolcu=0;
int uyolcu=0;

//timer
unsigned long previousMillis = 0;
unsigned long currentMillis = 0;
unsigned long previousMillis3=0; //save distance
unsigned long previousMillis4=0; //secure gps cable
unsigned long previousMillis5=0; // taksimetre sıfırlama
unsigned long previousMillis6=0; //uzun yolcu kısa yolcu sayar

//--sensors and taksimetre
#define sensor1pin A0
#define sensor2pin A1
#define sensor3pin A2
#define sensor4pin A3

int sensor1;
int sensor2;
int sensor3;
int sensor4;

#define taksimetrepin 2
bool taksimetrepressed=0;

#include "U8glib.h"
U8GLIB_SH1106_128X64 u8g(U8G_I2C_OPT_NONE);

//--------------RFID
#include <SPI.h>                          //SPI kütüphanemizi tanımlıyoruz.
#include <MFRC522.h>     
int RST_PIN = 9;                          //RC522 modülü reset pinini tanımlıyoruz.
int SS_PIN = 10;   
MFRC522 rfid(SS_PIN, RST_PIN);            //RC522 modülü ayarlarını yapıyoruz.
byte ID[4] = {145, 90, 212, 38};          //Yetkili kart ID'sini tanımlıyoruz. 
byte ID2[4] = {243, 98, 199, 22};  
bool yetkili=0;


//------plaka
#define up A6
#define down 5
#define left 6
#define right 7
#define enter 8
bool upval=0;
bool downval=0;
bool leftval=0;
bool rightval=0;
bool enterval=0;
char Letters[34]={"ABCDEFGHIJKLMNOPRSTUVYZ 1234567890"};
char plaka[11]="";
int plaka_position=0;
int letter_position=0;

//record
#include <EEPROM.h>
int address = 0;
byte value;
//-----eeprom val
//150,160 long sum dist
//0-11 plaka
//100,101,102 ref year




//--Geçerlilik süresi----
unsigned long refyymmdd;
char urunKodu[11]="1111111111";
int urunKodu_position=0;




//*****************************************************
//****************************************************


void setup()
{  
  Serial.begin(115200);  
  ss.begin(9600);

  //sensors and taksimetre
  pinMode(sensor1pin,INPUT);
  pinMode(sensor2pin,INPUT);
  pinMode(sensor3pin,INPUT);
  pinMode(sensor4pin,INPUT);
  pinMode(taksimetrepin,INPUT);
  attachInterrupt(digitalPinToInterrupt(taksimetrepin), ISR2, FALLING);
  //---plaka
  pinMode(up,INPUT);
  pinMode(down,INPUT);
  pinMode(left,INPUT);
  pinMode(right,INPUT);
  pinMode(enter,INPUT);
  for (int i=0;i<10;i++){
    plaka[i] = EEPROM.read(i);
    }  

      

  //opening screen
  u8g.firstPage();
    do {
      draw1();
    } while (u8g.nextPage() );
    delay(2000);
    
    
//----yetkilendirme 
  SPI.begin(); 
  rfid.PCD_Init(); 
  
    
  while(1){
    u8g.firstPage();
      do {
        draw2();
      } while (u8g.nextPage() );
      delay(100);
          
    authorization();
    if(yetkili==1) break;
  }

   yetkili=0; // inorder to unauthorize

  //--plakagirilmesi
  while(1){
    plakaGir();
    if (enterval==1) break;
    
  }
  
  //---geçerlilik süresi
  int yy=EEPROM.read(100);
  int mm=EEPROM.read(101);
  int dd=EEPROM.read(102);
  refyymmdd=long(yy)*10000+long(mm)*100+dd;
  Serial.print("refyymmdd:  ");Serial.println(refyymmdd);

  //reading distances from eeprom
  EEPROM.get(150,sum_distance1);
  EEPROM.get(160,sum_distance2); 
  
  

//gps bağlanma beklemesi
int counter=0;
  while(1){
    smartdelay(1000);
    gps.f_get_position(&slat, &slon, &age);  
    Serial.print("slat: "); Serial.println(slat,6);
    Serial.print("slon: "); Serial.println(slon,6);   
    if(slat>1 && slat<100) break;

    
    u8g.firstPage();
    do {
      u8g.setFont(u8g_font_profont12);
      u8g.setPrintPos(0, 10);
      u8g.print("GPS Sinyali Araniyor");         
      u8g.setPrintPos(counter*3, 25);
      u8g.print("*");
      } while (u8g.nextPage() );
    delay(2000);
    counter++;
    if (counter>45) counter=0;
    
  }
  
}

//******************************************************
//******************************************************

void loop()
{
  Serial.println("--------------------");

  //GPS informations 
  smartdelay(1000);

  uint8_t sat =gps.satellites();
  Serial.print("sat: "); Serial.println(sat);

  float flat, flon;
  unsigned long age;
  gps.f_get_position(&flat, &flon, &age);
  Serial.print("flat: "); Serial.println(flat,6);
  Serial.print("flon: "); Serial.println(flon,6);
  Serial.print("slat: "); Serial.println(slat,6);
  Serial.print("slon: "); Serial.println(slon,6);

  float spd=gps.f_speed_kmph();
  int intspd=spd;
  Serial.print("spd "); Serial.println(spd);

  int year;
  byte month, day, hour, minute, second, hundredths;
  unsigned long age2;
  gps.crack_datetime(&year, &month, &day, &hour, &minute, &second, &hundredths, &age2);
  hour+=3;if(hour>=24)hour-=24;

//gps get date time

  unsigned long date, time;
  gps.get_datetime(&date, &time, &age);
  Serial.print("Date(ddmmyy): "); Serial.print(date); Serial.print(" Time(hhmmsscc): ");
  Serial.print(time);
  Serial.print(" Fix age: "); Serial.print(age); Serial.println("ms.");
//CheckDate
  checkDate(date);

  

  //-----------------------------------------------------------------

  // sensordeğeri okuma  
  readSensors(); 
  if( (millis()-previousMillis5) > 1200000) {  //taksimetre time interval
    taksimetrepressed=0; 
    sum_distance3=0;
  }
  if (sensor1>350 || sensor2>350 || sensor3>350 || sensor4>350 ) {
    taksimetrepressed=0;
    previousMillis6=millis(); //kısa/uzun
  }
 
  //distance measurement
  currentMillis=millis();
  if(currentMillis - previousMillis >= 2000){ //calculate disance one in every 2 sec
    distance = TinyGPS::distance_between(flat, flon, slat, slon);
    distance=300;
    
    
    if(distance>30){
      slat=flat;
      slon=flon;
      sum_distance1=sum_distance1+distance;

      if (taksimetrepressed==1) sum_distance3=sum_distance3+distance; //taksimetre pressed but passenger didnt sit
      
      if (sensor1>350 || sensor2>350 || sensor3>350 || sensor4>350 || ((millis()-previousMillis6)<6000) )  { // anlık kesilme önlemesi
        sum_distance2=sum_distance2+sum_distance3+distance;        
        taksimetrepressed=0;
        sum_distance3=0;

        //kısa mesafe uzun mesafe
        
        sum_distance4=sum_distance4+distance;
               
        }
      
     
      
      Serial.print("sum_distance1: "); Serial.println(sum_distance1);
      Serial.print("sum_distance2: "); Serial.println(sum_distance2);
      Serial.print("sum_distance3: "); Serial.println(sum_distance3);
      }
    
      Serial.print("distance "); Serial.println(distance);
    

    
    previousMillis=currentMillis;
  }

 //kısa mesafe uzun mesafe 
  if ( sensor1<350 && sensor2<350 && sensor3<350 && sensor4<350 && ( (millis()-previousMillis6)>20000) ){
    if (sum_distance4>250 && sum_distance4<2000){
      kyolcu++;
      sum_distance4=0;
    }
    
    if (sum_distance4>=2000){
      uyolcu++;
      sum_distance4=0;
    }
    
    sum_distance4=0;
  }
 

//print oled  
   u8g.firstPage();
    do {
      u8g.setFont(u8g_font_profont12);
      u8g.setPrintPos(0, 64);
      u8g.print("Uzun: ");
      u8g.print(uyolcu);
      u8g.setPrintPos(64, 64);
      u8g.print("Kisa: ");
      u8g.print(kyolcu);
      
      u8g.setPrintPos(0, 55);
      u8g.print("Son:");
      u8g.print(sum_distance4);
      
      
      u8g.setPrintPos(0, 10);
      if(hour<10) u8g.print("0"+String(hour));
      else u8g.print(hour);
      u8g.setPrintPos(10, 10);
      u8g.print(":");
      u8g.setPrintPos(16, 10);
      if(minute<10) u8g.print("0"+String(minute));
      else u8g.print(minute);

      
      u8g.setDefaultForegroundColor();
      u8g.drawBox(60, 0, 64, 11);      
      u8g.setDefaultBackgroundColor();
      u8g.setPrintPos(64, 10);
      u8g.print(plaka);
      u8g.setDefaultForegroundColor();  

   
      
      u8g.setPrintPos(0, 25);
      u8g.print("Top:"); u8g.print(sum_distance1/1000);
      u8g.setPrintPos(64, 25);
      u8g.print("Dolu:"); u8g.print(sum_distance2/1);
      if (sensor1>350 || sensor2>350 || sensor3>350 || sensor4>350){
        u8g.setPrintPos(120, 25);
        u8g.print("+");
        }

        
      //hız
      u8g.drawFrame(0,29,60,14);
     
      u8g.setPrintPos(4, 40);
      u8g.print("HIZ: ");
      u8g.print(intspd);
      
//sil sum distance
      u8g.setPrintPos(84, 40);
      u8g.print(sum_distance1);
      ;

    //sensör verisi
      u8g.setPrintPos(64, 55);
      u8g.print("Durak:");
      u8g.print(sum_distance3);
      if(taksimetrepressed==1){
        u8g.setPrintPos(120, 55);
        u8g.print("+");
      }
      else {u8g.setPrintPos(120, 55); u8g.print(" "); }
      
      
    } while (u8g.nextPage() );
    delay(10);


    //KM sıfırlama
  zeroizeDistance();

  //Save Distance  
  if ((currentMillis-previousMillis3)>900000){
    previousMillis3=currentMillis;
    saveDistance();  
  }


  //security GPS cable is Not Connected 
  if (sat>=3)previousMillis4=millis();
  if (sat<3 && millis()-previousMillis4>1200000){
    Serial.print("GPS bağlantısı kesildi: "); 
    yetkili=0;
    while(1){  
      u8g.firstPage();
      do {
        u8g.setFont(u8g_font_profont12);
        u8g.setPrintPos(0, 10);
        u8g.print("GPS Baglantisi");         
        u8g.setPrintPos(0, 25);
        u8g.print("Koptu!");      
        u8g.setPrintPos(0, 40); 
      } while (u8g.nextPage() );
        delay(1000);
      
      u8g.firstPage();
        do {
          draw2();
        } while (u8g.nextPage() );
        delay(500);
            
      authorization();
      if(yetkili==1) break;
    }
  }
  
  
}

static void smartdelay(unsigned long ms)
{
  unsigned long start = millis();
  do 
  {
    while (ss.available())
      gps.encode(ss.read());
  } while (millis() - start < ms);
}


void authorization(){
  yetkili=0;

   if ( ! rfid.PICC_IsNewCardPresent()){    //Yeni kartın okunmasını bekliyoruz.
   
     delay(200);
    return;
  }
  if ( ! rfid.PICC_ReadCardSerial())      //Kart okunmadığı zaman bekliyoruz.
    return;

  if ((rfid.uid.uidByte[0] == ID[0] &&     //Okunan kart ID'si ile ID değişkenini karşılaştırıyoruz.
    rfid.uid.uidByte[1] == ID[1] && 
    rfid.uid.uidByte[2] == ID[2] && 
    rfid.uid.uidByte[3] == ID[3] ) ||
   (rfid.uid.uidByte[0] == ID2[0] &&     //Okunan kart ID'si ile ID değişkenini karşılaştırıyoruz.
    rfid.uid.uidByte[1] == ID2[1] && 
    rfid.uid.uidByte[2] == ID2[2] && 
    rfid.uid.uidByte[3] == ID2[3] ) ){
        Serial.println("cihaz acilıyor...");
        ekranaYazdir();
        yetkili=1;

    }
    else{                                 //Yetkisiz girişte içerideki komutlar çalıştırılır.
      Serial.println("Yetkisiz Kart");
      ekranaYazdir();
      yetkili=0;
      
      u8g.firstPage();
      do {
        drawYetkisizKart();
      } while( u8g.nextPage() );
      delay(1500);
    }
  rfid.PICC_HaltA();
  
}

void ekranaYazdir(){
  Serial.print("ID Numarasi: ");
  for(int sayac = 0; sayac < 4; sayac++){
    Serial.print(rfid.uid.uidByte[sayac]);
    Serial.print(" ");
  }
  Serial.println("");
  
}

//-----draw section-----------------------

void draw1(void){
  
    u8g.setFont(u8g_font_profont12);
    u8g.setPrintPos(0, 10);
    u8g.print("Mesafe Olcer");         
    u8g.setPrintPos(0, 25);
    u8g.print("v5");      
    u8g.setPrintPos(0, 40); 
  
}

void draw2(void){
    u8g.setFont(u8g_font_profont12);
    u8g.setPrintPos(0, 10);
    u8g.print("Lutfen Yetki Kartini");         
    u8g.setPrintPos(0, 25);
    u8g.print("Okutunuz!");      
    u8g.setPrintPos(0, 40); 
  
}

void drawYetkisizKart(void){
    u8g.setFont(u8g_font_profont12);
    u8g.setPrintPos(0, 10);
    u8g.print("!!!Gecersiz kart!!!");         
    u8g.setPrintPos(0, 25);
    u8g.print("Lutfen Yetkili Karti");      
    u8g.setPrintPos(0, 40); 
    u8g.print("Okutun!");  
  
}



//----------------------

void plakaGir(){

   int analogupval; //sometimes analog pin lowers 800 so it result low
   analogupval=analogRead(up);
   if (analogupval>10) upval=1;
   else upval=0;
   
   downval=digitalRead(down);
   leftval=digitalRead(left);
   rightval=digitalRead(right);  
   enterval=digitalRead(enter);

/*
  Serial.println("---------");
  Serial.print("up: ");Serial.println(upval);
  Serial.print("down: ");Serial.println(downval);
  Serial.print("left: ");Serial.println(leftval);
  Serial.print("right: ");Serial.println(rightval);
  Serial.print("enter: ");Serial.println(enterval);
  Serial.print("plaka: ");Serial.println(plaka);
  Serial.print("plaka_position: ");Serial.println(plaka_position);
  Serial.print("letter_position: ");Serial.println(letter_position);
  Serial.print("letter: ");Serial.println(Letters[letter_position]);
*/
  
  if( upval==1){
    letter_position++;
    if(letter_position>33)letter_position=0;
    plaka[plaka_position]=Letters[letter_position];
    EEPROM.update(plaka_position,Letters[letter_position]);
   }
  if(downval==1){
    letter_position--;
    if(letter_position<0)letter_position=33;
    plaka[plaka_position]=Letters[letter_position];
    EEPROM.update(plaka_position,Letters[letter_position]);
   }
  
  
  if( rightval==1){
     plaka_position++;
     if(plaka_position>9)plaka_position=0;
     for (int i=0; i<35; i++) {
     if (plaka[plaka_position] == Letters[i]) {
       letter_position = i;       
       break;
     }
     }
  }
  if(leftval==1){
    plaka_position--;
    if(plaka_position<0)plaka_position=9;
    for (int i=0; i<35; i++) {
    if (plaka[plaka_position] == Letters[i]) {
     letter_position = i;       
     break;
    }
    }
  }
   //print oled
  u8g.firstPage();
  do {
      uint8_t i, h;
      u8g_uint_t w, d;
    
      u8g.setFont(u8g_font_6x13);
      u8g.setFontRefHeightText();
      u8g.setFontPosTop();
      h = u8g.getFontAscent()-u8g.getFontDescent();
      w = u8g.getWidth();
      
       
      u8g.setPrintPos(0, 10);
      u8g.print("Plakayi Giriniz");         
      u8g.setPrintPos(0, 25);
      for (  i = 0; i < 10; i++ ) {
        u8g.setDefaultForegroundColor();
        if ( i == plaka_position ) {
          u8g.drawBox(i*6, 25, 6, h);
          u8g.setDefaultBackgroundColor();
        }
        u8g.print(plaka[i]);   
      }
      u8g.setDefaultForegroundColor();  
      u8g.setPrintPos(plaka_position*6, 40); 
      u8g.print(Letters[letter_position]);
    } 
    
    while (u8g.nextPage() );
  delay(20);
   
}

void checkDate(unsigned long date){
    
   long reverseDate= date/10000;   // dd
   reverseDate += (date/100) % 100*100;  // mm 
   reverseDate += (date % 100) *10000; // yy
   
    if (reverseDate>refyymmdd){
      uptadeDate();
      return;
    }
}

void uptadeDate(){

  
  while(1){
    upval=digitalRead(up);
    downval=digitalRead(down);
    leftval=digitalRead(left);
    rightval=digitalRead(right);  
    enterval=digitalRead(enter);


  if( upval==1){
    letter_position++;
    if(letter_position>33)letter_position=0;
    urunKodu[urunKodu_position]=Letters[letter_position];
    
   }
  if(downval==1){
    letter_position--;
    if(letter_position<0)letter_position=33;
    urunKodu[urunKodu_position]=Letters[letter_position];
   
   }
  
  
  

  if( rightval==1){
     urunKodu_position++;
     if(urunKodu_position>9)urunKodu_position=0;
     for (int i=0; i<35; i++) {
     if (urunKodu[urunKodu_position] == Letters[i]) {
       letter_position = i;       
       break;
     }
     }
  }
  if(leftval==1){
    urunKodu_position--;
    if(urunKodu_position<0)urunKodu_position=9;
    for (int i=0; i<35; i++) {
    if (urunKodu[urunKodu_position] == Letters[i]) {
     letter_position = i;       
     break;
    }
    }
  }
   //print oled
  u8g.firstPage();
  do {
      uint8_t i, h;
      u8g_uint_t w, d;
    
      u8g.setFont(u8g_font_6x13);
      u8g.setFontRefHeightText();
      u8g.setFontPosTop();
      h = u8g.getFontAscent()-u8g.getFontDescent();
      w = u8g.getWidth();
      
       
      u8g.setPrintPos(0, 10);
      u8g.print("Kullanim Suresi doldu");
      u8g.setPrintPos(0, 25);
      u8g.print("Lutfen Kodu Giriniz"); 
              
      u8g.setPrintPos(0, 40);
      for (  i = 0; i < 10; i++ ) {
        u8g.setDefaultForegroundColor();
        if ( i == urunKodu_position ) {
          u8g.drawBox(i*6, 40, 6, h);
          u8g.setDefaultBackgroundColor();
        }
        u8g.print(urunKodu[i]);   
      }
      u8g.setDefaultForegroundColor();  
      u8g.setPrintPos(urunKodu_position*6, 55); 
      u8g.print(Letters[letter_position]);
    } 
    
    while (u8g.nextPage() );
    delay(10);

    Serial.print("urunkodu");Serial.println(urunKodu);



  
    if(enterval==1){
        if(String(urunKodu)=="2111111111"){
          refyymmdd=240625;
          EEPROM.put(100,24);
          EEPROM.put(101,06);
          EEPROM.put(102,25);
          
          Serial.println("Dogru kod girildi");
          return;
        }
         if(String(urunKodu)=="311111111"){
          refyymmdd=250626;
          EEPROM.put(100,25);
          EEPROM.put(101,06);
          EEPROM.put(102,26);
          Serial.println("Dogru kod girildi");
          return;
        }
         if(String(urunKodu)=="411111111"){
           refyymmdd=260627;
           EEPROM.put(100,26);
           EEPROM.put(101,06);
           EEPROM.put(102,27);
           Serial.println("Dogru kod girildi");
           return;
        }

        
     }
 
  }
    
}


void zeroizeDistance(){
    enterval=digitalRead(enter);
    if (enterval==1){
      u8g.firstPage();
      do {
        draw2();
        } while (u8g.nextPage() );
      delay(100);

      unsigned long previousMillis2 = millis();
      while(millis()-previousMillis2<20000){ //after 10 sec exit this mode
        authorization();        
        if (yetkili==1){
          sum_distance1=0;
          sum_distance2=0; 
          EEPROM.put(150,sum_distance1);
          EEPROM.put(160,sum_distance2);
          uyolcu=0;
          kyolcu=0;
          break;
        }        
      }          
    }


  
}

void saveDistance(){
  unsigned long sum_distance1_v2;
  unsigned long sum_distance2_v2;
  EEPROM.get(150,sum_distance1_v2);
  EEPROM.get(160,sum_distance2_v2);

  //to protect eeprom lifecycle write values if only they changes.
  //EEPROM.update is not working cuz they are long.
  if (sum_distance1>sum_distance1_v2) EEPROM.put(150,sum_distance1);
  if (sum_distance2>sum_distance2_v2) EEPROM.put(160,sum_distance2);
  
}

void readSensors(){

  
  sensor1=analogRead(sensor1pin);
  sensor2=analogRead(sensor2pin);
  sensor3=analogRead(sensor3pin);
  sensor4=analogRead(sensor4pin);

  Serial.print("sensors: "); Serial.println(sensor1);Serial.println(sensor2);Serial.println(sensor3);Serial.println(sensor4);
  // sensor bağlantısı kesilme emniyeti
  if (sensor1<10 ||sensor2<10 || sensor3<10 || sensor4<10){
    Serial.print("Sensor bağlantısı kesildi sensor: "); 
    yetkili=0;
    while(1){  
      u8g.firstPage();
      do {
        u8g.setFont(u8g_font_profont12);
        u8g.setPrintPos(0, 10);
        u8g.print("Sensor Baglantisi");         
        u8g.setPrintPos(0, 25);
        u8g.print("Koptu!");      
        u8g.setPrintPos(0, 40); 
      } while (u8g.nextPage() );
        delay(1000);
      
      u8g.firstPage();
        do {
          draw2();
        } while (u8g.nextPage() );
        delay(500);
            
      authorization();
      if(yetkili==1) break;
    }
  }
}


void ISR2(){
  taksimetrepressed=1;
  Serial.println("-----ISR*******------------------------");
  previousMillis5=millis();
  taksimetrepressed=1;  
  sum_distance3=0; 
}
2

Have you tried using some form of averaging to reduce the error? One big problem you face - the measurements are inherently cumulative. You can't avoid that because the path may not be a straight line. Cumulative measurements become more and more inaccurate with the number of measurements because each new data point depends on the one before it. This multiplies the error. There is no technological solution because it's "baked into" the math.

3

Hi,

Over what total distance?

A long time ago I did a GPS project, I looked the the speed figure coming from the GPS and only update the odometer when speed was over, I think, 3kph. (But don't quote me!)

Tom... :smiley: :+1: :coffee: :australia:
PS Is your project for walking speed or vehicular speed?

4

Hello obyilmaz

Take a look to Kalmanfilter to reduce "noisy" signals.

Have a nice day and enjoy programming in C++ and learning.
MIND THE GAP

5

O didn't do it. What is averaging? İ will search it now on Google. İf you have any documentation please send.

The other thing is my Android app, which is sport tracker, calculate distance much more accurately. So i think that tachnically it is possible. There for I think that my device has some major problem.

6

İ travel with my car total of 10 km and my device calculate it as 9.5 km. Another Android app calculate it is 10 km.

7

Thanks for advice. İf you give me some specific z points i will be very appreciated

8

Hello obyilmaz

Take a view here to gain the knowledge.

Have a nice day and enjoy programming in C++ and learning.
MIND THE GAP