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Sylphase SDGPS
The software-defined GPS(/GNSS) toolkit
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Sylphase SDGPS
The software-defined GPS(/GNSS) toolkit
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The solution interface describes the trajectory of a point or a rigid body. If the motion of only a point is being described, then the position and velocity of the point are provided at evenly-spaced time instants. If a rigid body is being described, then the orientation and angular velocity of the body are also included.
The following nodes consume or generate solution streams:
| Node | Node |
|---|---|
| generate-simple-trajectory | Generates a rigid-body solution stream |
| kf2 / static-kf2 | Generates a rigid-body solution stream |
| simple-pvt-solver | Generates a point solution stream |
| simulate-INTERFACE | Consumes a rigid-body solution stream |
| plot-solution | Consumes any solution stream |
| pretty-print | Consumes any solution stream |
You can run ...
... to see an example of a rigid-body solution stream. Note that the output of the pretty-print node is not itself a valid solution stream (e.g. because newlines are inserted in the middle of packets to make them more readable). Use ...
... to generate a valid solution stream file.
JSON schema representations: Config | Packet
The solution interface representation consists of one or more newline-delimited JSON Objects. Unix-style line endings (\n) are used.
The first line contains a header with the following keys:
| Key | Type | Unit | Required | Description |
|---|---|---|---|---|
| type | String | Yes | Stream type and format version. Must be solution_v3. | |
| sample_rate | Real | Hz | Yes | The rate of trajectory samples in the following stream |
| metadata | Object | No | Information about the program and command that were used to generate the file |
All subsequent lines contain packets, which are the trajectory sampled at a given time t = index / sample_rate. The sample packets have the following keys:
| Key | Type | Unit | Required | Description |
|---|---|---|---|---|
| index | Integer | Yes | Zero-based index of sample packet; must start at 0 and increment by 1 with every packet | |
| running | Boolean | Yes | true if a solution is available | |
| running_reason | String | Iff running is false | Reason that running is falseExample: "not enough SVs being tracked" | |
| time | Object | seconds | Iff running is true | GPS Time (represented as an Object with "sec" and "fs" keys, representing integer seconds + femtoseconds) Example: {"sec": 1813335305, "fs": 770000000000000} |
| position_ecef | 3-vector | meters | Iff running is true | Position of body origin in ECEF frame Example: [ 740883.0, -5497747.0, 3136908.0 ] |
| velocity_ecef | 3-vector | meters | Iff running is true | Velocity of body origin in ECEF frame |
| orientation_ecef | quaternion | Iff running is true andthis is a rigid-body stream | Quaternion that rotates body-frame vectors into ECEF frame Example: {"w": -0.850, "x": -0.477, "y": -0.157, "z": 0.159} | |
| angular_velocity_body | 3-vector | radians/second | Iff running is true andthis is a rigid-body stream | Angular velocity of body frame with respect to ECEF frame, given in body frame Example: [ 0.0, 0.0, 1.0 ] |
iff stands for if and only if.
The following was produced as the output of sdgps generate-simple-trajectory --duration 1 --rate 10 ! write-solution-file test.sol --allow-overwrite:
This is the same data, but pretty-printed for ease of reading. Note that it SDGPS will not accept it due to the newlines present within the header and packets.
1.8.17