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1 // Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies). |
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2 // All rights reserved. |
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3 // This component and the accompanying materials are made available |
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4 // under the terms of "Eclipse Public License v1.0" |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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7 // |
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8 // Initial Contributors: |
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9 // Nokia Corporation - initial contribution. |
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10 // |
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11 // Contributors: |
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12 // |
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13 // Description: |
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14 // System |
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15 // |
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16 // |
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17 |
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18 /** |
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19 @file |
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20 @internalTechnology |
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21 |
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22 */ |
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23 |
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24 #include <e32base.h> |
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25 #include <e32math.h> |
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26 |
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27 // Component |
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28 #include "netpmutils.h" |
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29 |
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30 /** |
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31 Constants used in encoding of uncertainty data |
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32 |
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33 @see CSuplStart::Uncertainty() |
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34 @see CSuplStart::UncertaintyAltitude() |
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35 */ |
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36 const TReal KLbsLogOnePointOne = 0.095310179804324860043952123280765; |
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37 const TReal KLbsLogOnePointZeroTwoFive = 0.02469261259037150101430767543669; |
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38 const TInt KLbsMaxUncert = 127; |
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39 |
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40 /** |
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41 * TODO: update asn1 code to use this version and delete the CSuplMessageBase version? |
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42 Uncertainty() |
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43 |
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44 Converts a minumum accuracy value in meters to an uncertainty value K as |
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45 described in 3GPP 23.032 (Universal Geographical Area Description) section 6.2. |
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46 |
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47 r = C((1+x)^K - 1) |
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48 |
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49 where r = distance in meters |
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50 C = 10 |
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51 x = 0.1 |
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52 K = uncertainty value |
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53 |
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54 hence K = ln(r/C + 1) / ln(1.1) |
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55 |
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56 @param aDistance - distance measurement in meters |
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57 @return uncertainty value K |
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58 */ |
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59 EXPORT_C TInt NetPmUtils::Uncertainty(const TReal32& aDistance) |
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60 { |
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61 TReal uncert; |
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62 Math::Ln(uncert, (aDistance/10) + 1 ); |
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63 uncert /= KLbsLogOnePointOne; |
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64 if (uncert>KLbsMaxUncert) |
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65 { |
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66 uncert = KLbsMaxUncert; |
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67 } |
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68 |
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69 // round to nearest whole number |
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70 TReal uncertRounded; |
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71 Math::Round(uncertRounded, uncert, 0); |
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72 |
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73 return (TInt)uncertRounded; |
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74 } |
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75 |
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76 |
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77 /** |
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78 UncertaintyAltitude() |
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79 |
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80 Converts a minumum accuracy value in meters to an uncertainty altitude value K as |
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81 described in 3GPP 23.032 (Universal Geographical Area Description) section 6.4. |
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82 |
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83 r = C((1+x)^K - 1) |
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84 |
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85 where r = distance in meters |
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86 C = 45 |
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87 x = 0.1 |
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88 K = uncertainty value |
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89 |
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90 hence K = ln(r/C + 1) / ln(1.1) |
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91 |
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92 @param aDistance - altitude accuracy in meters |
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93 @return uncertainty altitude value K |
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94 */ |
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95 EXPORT_C TInt NetPmUtils::UncertaintyAltitude(const TReal32& aDistance) |
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96 { |
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97 |
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98 TReal uncert; |
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99 Math::Ln(uncert, (aDistance/45) + 1 ); |
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100 uncert /= KLbsLogOnePointZeroTwoFive; |
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101 if (uncert>KLbsMaxUncert) |
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102 { |
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103 uncert = KLbsMaxUncert; |
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104 } |
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105 // round to nearest whole number |
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106 TReal uncertRounded; |
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107 Math::Round(uncertRounded, uncert, 0); |
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108 |
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109 return (TInt)uncertRounded; |
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110 } |
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111 |
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112 /** |
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113 EncodeAltitude() |
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114 |
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115 Converts an value for altiutude to an 15 bit binary coded number N |
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116 |
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117 @param aAltitude - altitude in meters |
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118 @return uncertainty altitude value K |
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119 */ |
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120 EXPORT_C TInt NetPmUtils::EncodeAltitude(const TReal32& aAltitude) |
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121 { |
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122 TInt altEncoded = (TInt)aAltitude; |
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123 if (altEncoded>KLbsMaxAltitude) |
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124 { |
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125 altEncoded = KLbsMaxAltitude; |
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126 } |
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127 |
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128 return altEncoded; |
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129 } |