Description
Resolve a GPS week remainder against a nearby full-week reference, rejecting half-period ambiguity.
Geodesy distinguishes a mathematical reference ellipsoid, a realized coordinate datum and the physical gravity field. Geodetic latitude follows the ellipsoid normal; geocentric latitude follows a radius from the center. Ellipsoidal height, orthometric height and geoid undulation are separate signed quantities. Keep the declared ellipsoid, coordinate axes, angular units and time scale with a result.
Resolve a GPS week remainder against a nearby full-week reference, rejecting half-period ambiguity.
When to use this tool
Use this tool when you need to resolve a GPS week remainder against a nearby full-week reference, rejecting half-period ambiguity.
How to use the tool and how it works
- Enter broadcastWeek, referenceFullWeek, bits using the definitions below.
- Run the operation. Resolve input-format errors before interpreting an output.
- Read result.resolvedFullWeek, result.era, result.differenceFromReferenceWeeks, result.ambiguous, using the stated boundary, ordering, sign and absence conventions.
Let period=2^bits and choose the integer rollover era nearest referenceFullWeek using the broadcast remainder. Reject a negative resolved week or an exact half-period tie; otherwise return full week, era and signed difference from reference.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| broadcastWeek | Integer transmitted week remainder from zero through 2^bits−1. | Finite safe integer satisfying the stated bounds. |
| referenceFullWeek | Known nearby nonnegative full GPS week, integer at most 10⁷. | Finite safe integer satisfying the stated bounds. |
| bits | Integer broadcast week width, one through sixteen. | Finite safe integer satisfying the stated bounds. |
| Output field | Interpretation |
|---|---|
| result | Object containing the fields below. |
| result.resolvedFullWeek | Nonnegative full GPS week chosen nearest the supplied reference. |
| result.era | Integer rollover era floor(resolvedFullWeek/2^bits). |
| result.differenceFromReferenceWeeks | Resolved week minus referenceFullWeek, in weeks. |
| result.ambiguous | False after half-period ambiguity has been rejected as an input error. |
{
"input": {
"broadcastWeek": 0,
"referenceFullWeek": 2048,
"bits": 10
},
"output": {
"result": {
"resolvedFullWeek": 2048,
"era": 2,
"differenceFromReferenceWeeks": 0,
"ambiguous": false
}
}
}Limitations and assumptions
- bits is an integer 1–16, broadcastWeek in [0,2^bits), and referenceFullWeek an integer 0–10⁷. The reference must already identify the nearby era; the output ambiguous=false follows successful rejection of ambiguous cases.
- All quantities are finite and retain the units stated for this operation. Ellipsoid-parameter tools use semi-major axis 1–10⁸ m and dimensionless flattening 0–0.02; explicit-axis tools use 0.9a≤b≤a unless a tighter bound is stated. These tools do not fetch datums, geoid grids, satellite observations or Earth-orientation updates.
- Every declared outer field is required and unknown outer fields are rejected. Strings and JSON text have size limits, lists are bounded to 128 entries, and JSON nesting/node counts are bounded. Tighter operation-specific bounds stated above take precedence.
- Numeric results must be finite. Large physical magnitudes are allowed by the output evidence checks, while integer fields and source schemas retain their exactness rules. Source indexes are zero-based. Floating-point residues can remain even where an ideal formula gives an exact zero.
Alternative or Complementary methods
Use a coordinate transform for a change of representation and explicit datum parameters for a change of reference frame. Preserve model and convergence metadata, and use observation and datum information appropriate to a real survey before interpreting a computed tolerance as accuracy.
References
Similar or alternative tools
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