Haversine 公式错误 - 距离不正确 - Arduino

Posted 2023-03-05

【中文标题】Haversine 公式错误 - 距离不正确 - Arduino

【英文标题】：Haversine Formula Error - Incorrect Distance - Arduino

【发布时间】：2017-02-03 15:29:21

【问题描述】：

目前参与的项目需要从 GPS 模块获取读数，然后使用这些模块计算读数与固定航路点之间的距离。 Gps 工作并给出 LAT - 54.9289 和 LON - -1.368 的值，这应该给出大约 3,200 米的距离。但是它给出了大约 6105。我也有一种感觉，6105 是公里到哈哈。我想知道它是否没有正确地取负数，或者我在代码中是否有一些变量冲突。对此有任何启示都会很棒，谢谢。

#include <TinyGPS.h>
#include <SoftwareSerial.h>
#include <rgb_lcd.h>
#include <Wire.h>

//Sets TX And RX Pins
SoftwareSerial GPS(2,3);
TinyGPS gps;
void gpsdump(TinyGPS &gps);
bool feedgps();
void CheckGPS();
void GetCoords();
 long lat, lon;
 float LAT, LON; // Latitude is gained from GPS and stored in another variable to avoid errors - Should change with changing GPS value - Which would alter distance to waypoint.
 float LAT1,LON1;
rgb_lcd lcd;


void setup()

// Sets Baud Rate
  GPS.begin(9600);
  Serial.begin(115200);

// Determines The Distance Between Current Location And Waypoint

void GetDistance() 

  // Calculating Distance Between Waypoints

  double Distance_Lat; // Distance between Lattitude values
  double Distance_Lon; // Distance between Lonitude values
  double Distance_Total = 0;// Total Distance 
  double val,val2; // Subsidary variable for holding numbers. - No actual value represented.
  double fLAT1,fLAT2;
  double LAT2 = 54.900000; // Waypoint Latitude
  double LON2 = -1.368072; // Waypoint Longitude

 // Initialising Calculation
  Distance_Lat = radians(LAT2-LAT1); // Must be done in radians
  fLAT1 = radians(LAT1);
  fLAT2 = radians(LAT2);
  Distance_Lon = radians((LON2)-(LON1));

  // Calculating Distance - Using Haversines Formulae
  Distance_Total = (sin(Distance_Lat/2.0)*sin(Distance_Lat/2.0));
  val = cos(fLAT1);
  val = val*(cos(fLAT2));
  val = val*(sin(Distance_Lon/2.0));
  val = val*(sin(Distance_Lon/2.0));
  Distance_Total = Distance_Total + val;

  Distance_Total = 2*atan2(sqrt(Distance_Total),sqrt(1.0-Distance_Total)); 
  Distance_Total = Distance_Total*6371.0000; // Converting to meters.
Serial.println("Distance: ");
Serial.println(Distance_Total);

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


// Returns Latitude And Longitude As Decimal Degrees (DD).
void GetCoords()

 long lat, lon;
  CheckGPS();
  Serial.print("Latitude : ");
  Serial.print(LAT/1000000,7);
  Serial.print(" :: Longitude : ");
  Serial.println(LON/1000000,7);



void CheckGPS()

  
  bool newdata = false;
  unsigned long start = millis();
 // Every 1 seconds, Print an update
  while (millis() - start < 1000)
    
    if (feedgps ())
    newdata = true;
    if (newdata)
    gpsdump(gps);
    
  

// Checks If The GPS Has Any Data To Transmit
  bool feedgps()
  
    while (GPS.available())
    if (gps.encode(GPS.read()))
      return true;
    else
      return false;  
  

// Transmits GPS Data And Gets Latitude And Longitude Positions.
  void gpsdump(TinyGPS &gps)

    gps.get_position(&lat, &lon);
     LAT = lat;
     LON = lon;
     //Keeps The GPS Fed To Avoid Checksum Errors.
     feedgps();



void loop()

// Function That Returns The GPS Coordinates In DD.
  GetCoords();
  GetDistance();

【参考方案1】：

我现在在 Wikipedia 上查看的半正弦公式 https://en.wikipedia.org/wiki/Haversine_formula 有 arcsin(sqrt(Distance_Total)) 你有你的 atan2。

【讨论】：

谢谢，我认为这是问题所在，因为我现在收到的值是 3052.94，它非常接近应有的值。