the interval timestamp indicates the absolute time of the nmea sentence in seconds since jan. 1, 1970. it is possible to have multiple timestamp sentences within a nmea data stream. the time indicated in the interval timestamp is a local time on the receiver. the time of the satellite at that moment is indicated by the satellite timestamp. the satellite timestamp is in the utc time format.
the receiver time is the time indicated in the receiver’s internal clock. the position of the receiver is given by the receiver time, the timestamp of the sentence, the latitude, the longitude and the altitude of the satellite. the timestamp, latitude, and longitude of the satellite are all relative to the receiver. the altitude of the satellite is relative to the receiver. for example, if the receiver was at the equator, the altitudes given by nmea sentences would be the same regardless of which satellite they were.
the receiver position is given by the latitude, the longitude, the receiver time, and the longitude of the satellite. the latitude and longitude of the satellite are in the wgs84 format. the latitude and the longitude of the satellite are relative to the receiver, not the earth’s surface.
skydel stores the attitude information for the satellite in its database. the attitude of the satellite is not the same as the one given by the nmea sentences. the attitude described in skydel is based on information from a servo system that controls the elevation and azimuth of the satellite.
the vehicle simulation trajectory type is a great way to make a fairly realistic trajectory quickly. you can import the data from use street map (openstreetmap.org), import kml (google earth or earth.google.com), or your own csv file. the csv file should contain a list of locations with speed values for each. if your csv file contains timestamps instead of speed, it is considered to be a track. 3d9ccd7d82