130 lines
2.7 KiB
Go
130 lines
2.7 KiB
Go
package gps
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import (
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"fmt"
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"strconv"
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"strings"
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)
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type Status struct {
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GotResponses bool `json:"gotResponses"`
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IsValidData bool `json:"isValidData"`
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FoundSatelitesCount int `json:"foundSatelitesCount"`
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ActiveSatelitesCount int `json:"activeSatelitesCount"`
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}
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var StatusNil = Status{
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GotResponses: false,
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IsValidData: false,
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FoundSatelitesCount: 0,
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ActiveSatelitesCount: 0,
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}
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func (g *gps) GetStatus() (Status, error) {
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// Provides more information about signal and possible problems using NMEA reports
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// Collect reports
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reports, err := g.collectNmeaReports(nmeaFlagsAll) // Now minimum
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if err != nil {
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return StatusNil, fmt.Errorf("collect nmea reports: %w", err)
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}
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// Annalise
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st := Status{}
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checkLoop:
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for _, s := range reports {
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// Check for NMEA format
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if len(s) < 1 || s[0] != '$' {
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continue checkLoop
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}
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st.GotResponses = true
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g.logger.Println("NMEA check:", s)
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values := strings.Split(s, ",")
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if len(values[0]) != 6 {
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return StatusNil, fmt.Errorf("nmea invalid sentence: %s", s)
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}
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switch values[0][3:] { // Switch by content
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case "GSV":
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g.logger.Println("check GSV")
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// Check len
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if len(values) < 17 {
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g.logger.Println("GSV too small values")
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continue checkLoop
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}
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// Decode
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// 0 - msg type
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// 1 - number of msgs
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// 2 - index of this msg
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// 3 - number of visible satelites
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// 4: - other data
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// Msg index
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index, err := strconv.Atoi(values[3])
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if err != nil {
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g.logger.Println("GSV too small values")
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continue checkLoop
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}
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_ = index
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// if index != 0 {
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// g.logger.Println("discard not first GSV msg")
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// continue checkLoop
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// }
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// Count
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satCount, err := strconv.Atoi(values[4])
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if err != nil {
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g.logger.Println("GSV too small values")
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continue checkLoop
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}
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st.FoundSatelitesCount = satCount
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case "GSA":
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g.logger.Println("check GSA")
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// Check len
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if len(values) < 17 {
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g.logger.Println("GSV too small values")
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continue checkLoop
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}
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// Decode
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// 0 - msg type
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// 1 - mode of selecting format
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// 2 - mode of selected format
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// 3:15 - IDs of active satelites
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// 15: - other data
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// Counting active satelites
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count := 0
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for _, v := range values[3:15] {
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if _, err := strconv.Atoi(v); err == nil {
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count += 1
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}
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}
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st.ActiveSatelitesCount = max(st.ActiveSatelitesCount, count)
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case "RMC":
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g.logger.Println("check RMC")
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// Check len
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if len(values) < 12 {
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g.logger.Println("RMC too small values")
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continue checkLoop
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}
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// Decode
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// 0 - msg type
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// 1 - time
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// 2 - is data valid or not
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// 3: - other data
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// Msg index
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if values[2] == "A" {
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st.IsValidData = true
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}
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}
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}
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return st, nil
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}
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