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added nmea
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srinathhs
srinathhs
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Also adding raw nmea strings..

$GPGGA,191215.557,1301.8784,N,07733.4765,E,0,0,,912.5,M,-88.1,M,,*68

$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,1.00*01

$GPGSV,3,1,11,29,53,169,18,21,49,005,,18,44,334,17,15,34,037,*76

$GPGSV,3,2,11,14,31,211,,22,27,284,,09,27,107,,27,22,087,*76

$GPGSV,3,3,11,25,10,183,,06,09,318,,30,04,261,*42

$GPRMC,191215.557,V,1301.8784,N,07733.4765,E,0.009,0.00,160712,,N*68

$GPVTG,0.00,T,,M,0.009,N,0.017,K,N*3D

$GPACCURACY,27947.3*04

$GPGGA,191216.557,1301.9128,N,07733.4723,E,0,0,,911.4,M,-88.1,M,,*6A

$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,1.00*01

$GPGSV,3,1,11,29,53,169,18,21,49,005,,18,44,334,18,15,34,037,*79

$GPGSV,3,2,11,14,31,211,,22,27,284,,09,27,107,,27,22,087,*76

$GPGSV,3,3,11,25,10,183,,06,09,318,,30,04,261,*42

$GPRMC,191216.557,V,1301.9128,N,07733.4723,E,0.001,0.00,160712,,N*60

$GPVTG,0.00,T,,M,0.001,N,0.002,K,N*31

$GPACCURACY,27942.6*04

$GPGGA,191217.557,1301.8573,N,07733.5089,E,0,0,,909.4,M,-88.1,M,,*6F

$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,1.00*01

$GPGSV,3,1,11,29,53,169,18,21,49,005,,18,44,334,18,15,34,037,*79

$GPGSV,3,2,11,14,31,211,,22,27,284,,09,27,107,,27,22,087,*76

$GPGSV,3,3,11,25,10,183,,06,09,318,,30,04,261,*42

$GPRMC,191217.557,V,1301.8573,N,07733.5089,E,0.068,0.00,160712,,N*63

$GPVTG,0.00,T,,M,0.068,N,0.126,K,N*39

$GPACCURACY,19781.4*0A

Also, I am finding it very hard to visualize this data using excel, can anyone suggest better tools ( I use a MAC )

Also, I am finding it very hard to visualize this data using excel, can anyone suggest better tools ( I use a MAC )

Also adding raw nmea strings..

$GPGGA,191215.557,1301.8784,N,07733.4765,E,0,0,,912.5,M,-88.1,M,,*68

$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,1.00*01

$GPGSV,3,1,11,29,53,169,18,21,49,005,,18,44,334,17,15,34,037,*76

$GPGSV,3,2,11,14,31,211,,22,27,284,,09,27,107,,27,22,087,*76

$GPGSV,3,3,11,25,10,183,,06,09,318,,30,04,261,*42

$GPRMC,191215.557,V,1301.8784,N,07733.4765,E,0.009,0.00,160712,,N*68

$GPVTG,0.00,T,,M,0.009,N,0.017,K,N*3D

$GPACCURACY,27947.3*04

$GPGGA,191216.557,1301.9128,N,07733.4723,E,0,0,,911.4,M,-88.1,M,,*6A

$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,1.00*01

$GPGSV,3,1,11,29,53,169,18,21,49,005,,18,44,334,18,15,34,037,*79

$GPGSV,3,2,11,14,31,211,,22,27,284,,09,27,107,,27,22,087,*76

$GPGSV,3,3,11,25,10,183,,06,09,318,,30,04,261,*42

$GPRMC,191216.557,V,1301.9128,N,07733.4723,E,0.001,0.00,160712,,N*60

$GPVTG,0.00,T,,M,0.001,N,0.002,K,N*31

$GPACCURACY,27942.6*04

$GPGGA,191217.557,1301.8573,N,07733.5089,E,0,0,,909.4,M,-88.1,M,,*6F

$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,1.00*01

$GPGSV,3,1,11,29,53,169,18,21,49,005,,18,44,334,18,15,34,037,*79

$GPGSV,3,2,11,14,31,211,,22,27,284,,09,27,107,,27,22,087,*76

$GPGSV,3,3,11,25,10,183,,06,09,318,,30,04,261,*42

$GPRMC,191217.557,V,1301.8573,N,07733.5089,E,0.068,0.00,160712,,N*63

$GPVTG,0.00,T,,M,0.068,N,0.126,K,N*39

$GPACCURACY,19781.4*0A

Also, I am finding it very hard to visualize this data using excel, can anyone suggest better tools ( I use a MAC )

Added more details
Source Link
srinathhs
srinathhs
  • 153
  • 1
  • 6

Details for error 2 :

Typically, when in a traffic signal / just plainly stopped on road. The android api tells me the new lat long pair when there is a displacement of minimum 5 meters. The problem is the api informs me of even the "drifted" lat long to be 5m away and hence I increment the odometer value which keeps accumulating errors because device did not move.Hence if the device is stationary it keeps accumulating this error.

An example "error" data when device is stationary

Device  Latitude    Longitude   Accuracy    Speed   Altitude    Heading
gps 13.0311466666667    77.5577383333333    41.5    1.9193991   894.7   295.77
gps 13.0311516666667    77.557795   38.8    0.99907583  892.8   294.88
gps 13.0311616666667    77.55784    38.4    0.5883275   886.4   294.88
gps 13.031175   77.5578866666667    37.5    0.74892086  886.1   294.88
gps 13.0311816666667    77.5579383333333    32.5    0.6552414   886 294.88
gps 13.0311516666667    77.557975   27.6    0   885.9   294.88
gps 13.0312016666667    77.5579733333333    32.4    0.7175228   885.9   294.88
gps 13.0312316666667    77.5579366666667    31.8    0.5610472   885.9   294.88
gps 13.031235   77.557885   30.4    0.9028228   885.9   294.88
gps 13.031245   77.5578366666667    30.5    0.81634945  885.8   294.88
gps 13.0312416666667    77.55779    27.9    0.5559  885.8   294.88
gps 13.0312233333333    77.5578433333333    23.9    0.43236667  886 294.88
gps 13.0312066666667    77.5578883333333    23.6    0.43905807  886.2   294.88
gps 13.03119    77.5579366666667    23.6    0.49258918  886.3   294.88
gps 13.0311666666667    77.5579983333334    24.9    0.77208334  886.7   294.88
gps 13.0311316666667    77.557945   22.4    0.3958214   887.8   241.89
gps 13.03113    77.5578416666667    25.2    0.24089 890.5   269.19
gps 13.0311133333333    77.5579 20.7    0.40663055  891.2   221.69
gps 13.0311116666667    77.5578516666667    21.9    0.47302973  891.3   251.03
gps 13.03104    77.55787    26.7    0.40199804  891.3   134.23
gps 13.0311033333333    77.5579333333333    23.6    0.5193547   891.6   332.92
gps 13.0310766666667    77.557985   19  0.38346806  893 118.18
gps 13.0311333333333    77.557945   27.9    0.3381725   896.9   287.31

Full data set is available here . It has > 5000 data points corresponding to a round trip from my home to office and back. From the start about ~800 data points are error beyond that the device starts moving.

Also, I am finding it very hard to visualize this data using excel, can anyone suggest better tools ( I use a MAC )

Can some one give me ideas to reduce the errors , perhaps a better algorithm to consider even altitude?

Can some one give me ideas to reduce the errors , perhaps a better algorithm to consider even altitude?

Details for error 2 :

Typically, when in a traffic signal / just plainly stopped on road. The android api tells me the new lat long pair when there is a displacement of minimum 5 meters. The problem is the api informs me of even the "drifted" lat long to be 5m away and hence I increment the odometer value which keeps accumulating errors because device did not move.Hence if the device is stationary it keeps accumulating this error.

An example "error" data when device is stationary

Device  Latitude    Longitude   Accuracy    Speed   Altitude    Heading
gps 13.0311466666667    77.5577383333333    41.5    1.9193991   894.7   295.77
gps 13.0311516666667    77.557795   38.8    0.99907583  892.8   294.88
gps 13.0311616666667    77.55784    38.4    0.5883275   886.4   294.88
gps 13.031175   77.5578866666667    37.5    0.74892086  886.1   294.88
gps 13.0311816666667    77.5579383333333    32.5    0.6552414   886 294.88
gps 13.0311516666667    77.557975   27.6    0   885.9   294.88
gps 13.0312016666667    77.5579733333333    32.4    0.7175228   885.9   294.88
gps 13.0312316666667    77.5579366666667    31.8    0.5610472   885.9   294.88
gps 13.031235   77.557885   30.4    0.9028228   885.9   294.88
gps 13.031245   77.5578366666667    30.5    0.81634945  885.8   294.88
gps 13.0312416666667    77.55779    27.9    0.5559  885.8   294.88
gps 13.0312233333333    77.5578433333333    23.9    0.43236667  886 294.88
gps 13.0312066666667    77.5578883333333    23.6    0.43905807  886.2   294.88
gps 13.03119    77.5579366666667    23.6    0.49258918  886.3   294.88
gps 13.0311666666667    77.5579983333334    24.9    0.77208334  886.7   294.88
gps 13.0311316666667    77.557945   22.4    0.3958214   887.8   241.89
gps 13.03113    77.5578416666667    25.2    0.24089 890.5   269.19
gps 13.0311133333333    77.5579 20.7    0.40663055  891.2   221.69
gps 13.0311116666667    77.5578516666667    21.9    0.47302973  891.3   251.03
gps 13.03104    77.55787    26.7    0.40199804  891.3   134.23
gps 13.0311033333333    77.5579333333333    23.6    0.5193547   891.6   332.92
gps 13.0310766666667    77.557985   19  0.38346806  893 118.18
gps 13.0311333333333    77.557945   27.9    0.3381725   896.9   287.31

Full data set is available here . It has > 5000 data points corresponding to a round trip from my home to office and back. From the start about ~800 data points are error beyond that the device starts moving.

Also, I am finding it very hard to visualize this data using excel, can anyone suggest better tools ( I use a MAC )

Can some one give me ideas to reduce the errors , perhaps a better algorithm to consider even altitude?

Source Link
srinathhs
srinathhs
  • 153
  • 1
  • 6

Distance calculation : Integrating incremental gps data

I am trying to build a GPS based odometer based on android.

Currently , I am calculating incremental distance changes very frequently ( < 5 meter movement). The distance calculation in android is using the WGS84 ellipsoid.

Currently on test runs, The gps calculations overshoots by 3 - 5% depending on route taken and duration of travel.

There are two problems I am facing :

  1. The distance calculation is not considering altitude.
  2. When the vehicle is stationary, gps starts injecting errors due to position changes which even though the device is stationary gps does calculation errors. This is the source of most of the error.

Can some one give me ideas to reduce the errors , perhaps a better algorithm to consider even altitude?