## POS File ##

The POS File contains information such as GPS time, longitude, latitude, height, roll, pitch, heading, GridX and GridY. GPS time, longitude, latitude, height, roll, pitch and heading must be necessary, while longitude and latitude or GridX and GridY include at least one. If POS file doesn't include GridX and GridY, we need to set projection coordinate system when we input trajectory files. GridX and GridY can be calculated according to projection coordinate system, longitude and latitude in strip alignment module.

The trajectory information stored in its file is structured as follows:

|Data | Units |Type|
|:-------:|:-------:|:-------:|
|GPS time | seconds | double|
|longitude | degree | double|
|latitude | degree | double|
|height | meters | double |
|roll | degree | double |
|pitch | degree | double  
|heading | degree | double| 
|GridX(Optional) | meters | double| 
|GridY(Optional) | meters | double| 

The examples the POS file is shown below.
Example 1(not including GridX，GridY):

     380954.000,112.5311950876, 26.8969520123,378.543,  7.1701230000,  3.0890110000,-39.4065340000
     380954.008,112.5311938923, 26.8969533249,378.537,  7.2001860000,  3.0914780000,-39.4034150000
     380954.016,112.5311926975, 26.8969546376,378.531,  7.2368710000,  3.0936380000,-39.4011190000
     380954.024,112.5311915034, 26.8969559507,378.525,  7.2683090000,  3.1015050000,-39.3975470000
     380954.032,112.5311903098, 26.8969572641,378.518,  7.3007560000,  3.1115160000,-39.3929590000
     380954.040,112.5311891169, 26.8969585779,378.512,  7.3269790000,  3.1179720000,-39.3878260000
     380954.048,112.5311879247, 26.8969598920,378.506,  7.3525870000,  3.1180460000,-39.3804020000
     380954.056,112.5311867331, 26.8969612065,378.500,  7.3745730000,  3.1151630000,-39.3713830000


Example 2(including GridX，GridY):

	383207.336,112.5421590662,26.9034172036,313.865,3.538615,2.660518,-67.848653,653147.099716932,2976670.62354689
	383207.344,112.5421572108,26.9034177865,313.861,3.533299,2.659177,-67.840828,653146.914649722,2976670.68587654
	383207.352,112.5421553554,26.9034183697,313.857,3.522385,2.658042,-67.828619,653146.729582108,2976670.74823943
	383207.36,112.5421535001,26.9034189529,313.854,3.512757,2.659231,-67.816251,653146.544524429,2976670.81060244
	383207.368,112.5421516447,26.9034195363,313.85,3.502656,2.662677,-67.807435,653146.35945655,2976670.87298749
	383207.376,112.5421497892,26.9034201198,313.846,3.502243,2.664987,-67.803265,653146.174378605,2976670.9353835
	383207.384,112.5421479336,26.9034207035,313.843,3.500293,2.668456,-67.80232,653145.989290462,2976670.99780155
	383207.392,112.5421460783,26.9034212874,313.839,3.501546,2.671267,-67.797563,653145.804231844,2976671.06024212
	383207.4,112.5421442231,26.9034218713,313.835,3.496569,2.674773,-67.789195,653145.619183163,2976671.12268281
	383207.408,112.542142368,26.9034224554,313.832,3.483849,2.676885,-67.774991,653145.434144147,2976671.18514579
	383207.416,112.5421405129,26.9034230395,313.828,3.471533,2.676137,-67.765536,653145.24910513,2976671.24760876
	383207.424,112.5421386577,26.9034236237,313.824,3.47028,2.675779,-67.760612,653145.064056049,2976671.3100827
	383207.432,112.5421368024,26.9034242079,313.82,3.475101,2.677064,-67.761833,653144.878997039,2976671.37255652
	383207.44,112.5421349471,26.9034247923,313.817,3.476053,2.681571,-67.761664,653144.69393776,2976671.43505249