Using the GPS in each frame, software can easily extract photos that are 1 meter apart.Ĭompare that to shooting in time lapse mode, especially if moving quickly, where the capture interval will provide varying distances between photos (unless you’re travelling at a constant speed), and photos might have larger distance between them than the 1 meter you’re aiming for. More frames gives you (or software) the flexibility to cherry-pick the ones you want to use in your tour.įor example, you want to use frames that are (almost) exactly 1 meter apart. The real benefit of capturing 360 sequences (like walks or bike rides) using video over time lapse is the higher number of frames created when compared to photo time lapses. If you haven’t already read that post, it is well worth wrapping your head around some of the concepts discussed before you jump into this one. Last week I explained the metadata found in 360 photos, and promised a post on video metadata.
#Gps almanac file format how to#
If you are using your own almanac file, the week number in the almanac file and the week number in the configuration object must match.įurther, this example shows how to generate a GPS baseband waveform, which can be extended to generate an intermediate frequency (IF) waveform from the baseband waveform by multiplying a cosine signal on the in-phase branch and a sine signal on the quadrature-branch.Īdditionally, this example shows how to generate a GPS waveform from one satellite, which can be combined along with multiple satellite PRN codes to get an integrated signal.With the help of a 360 video shot using a GoPro Fusion, I take a look at GoPro’s GPMF video telemetry standard. Additionally, you can specify your own almanac file. You can also change the ephemeris parameters with an existing real data set and pass those parameters into the CEI data set. You can replace the property values in this configuration object and observe how the GPS data is generated. This example uses a configuration object to generate GPS data bits and the navigation signal in the baseband. To observe the adjacent band spectrum for the GPS signal, repeat the signal at the baseband. Plot the signal power spectral density at the baseband. 'Comparison of Power Spectral Density of GPS baseband I and Q Signals'. IqScope = dsp.SpectrumAnalyzer( 'SampleRate',1.023e6*repeatFactor. IBranchUpsampled = real(IBranchUpsampled(:)) IBranchUpsampled = repmat(IBranchData(:).',repeatFactor/10,1)
Repeat the in-phase branch samples ten times less % as every sample in quadrature-branch corresponds to 10 samples in in-phase branch % Repeat the generated BPSK signal of in-phase component to see the % adjacent bands spectrum. QBranchUpsampled = repmat(QBranchData(:).',repeatFactor,1) % Repeat the generated BPSK signal of C/A-code to see the adjacent bands spectrum This figure does not show an actual GPS satellite, and the figure is for illustration only. This figure shows five orbital parameters for a satellite in the Earth-centered Earth-fixed (ECEF) coordinate system. Each GPS satellite transmits its own ephemeris data on subframes 2 and 3 for LNAV data and on message types 10 and 11 for CNAV data. A set of orbital parameters that accurately defines a satellite position in this elliptical orbit is called ephemeris. GPS satellites revolve around the Earth in an elliptical orbit, with Earth at one of the focal points of the ellipse.
These errors deviate the satellite clocks from the GPS system time. In practice, deterministic satellite clock error characteristics of bias, drift, and aging as well as satellite implementation characteristics of group delay bias and mean differential group delay exist. In theory, clocks of all satellites must be synchronized, which implies that all GPS satellite clocks must show the same time at a given moment in time. The property, CEIDataSet, is a configuration object of type HelperGPSCEIConfig, which contains clock, ephemeris, and integrity (CEI) data parameters. TextInMessageType15: 'This content is part of Satellite Communications Toolbox'
TextInMessageType36: 'This content is part of Satellite Communications Toolbox' HelperGPSNavigationConfig with properties: